
==== Front
Braz Oral Res
Braz Oral Res
bor
Brazilian Oral Research
1806-8324
1807-3107
Sociedade Brasileira de Pesquisa Odontológica - SBPqO

38477801
08600
10.1590/1807-3107bor-2024.vol38.0015
Systematic Review and Meta-Analysis Pediatric Dentistry
Overweight/obesity and dental caries in Brazilian children and adolescents: a systematic review and meta-analysis
https://orcid.org/0000-0001-5286-9945
PIZZI Julia Faria (a)
https://orcid.org/0000-0002-3173-2904
CARRADA Camila Faria (b)
https://orcid.org/0000-0003-3775-7755
ZEFERINO Maria Vitória de Sá (a)
https://orcid.org/0000-0001-9429-0085
DORIGUÊTTO Paulo Victor Teixeira (c)
https://orcid.org/0000-0003-2258-8071
ABREU Lucas Guimarães (d)
https://orcid.org/0000-0002-0552-0414
SCALIONI Flávia Almeida Ribeiro (e)
https://orcid.org/0000-0001-5037-5466
DEVITO Karina Lopes (f)
https://orcid.org/0000-0001-6472-5965
RIBEIRO Rosangela Almeida (e)
(a) Universidade Federal de Juiz de Fora – UFJF, School of Dentistry, Juiz de Fora, MG, Brazil.
(b) Faculdade de Ciências Médicas e da Saúde – Suprema, School of Dentistry, Department of Paediatric Dentistry, Juiz de Fora, MG, Brazil.
(c) Centro Universitário Governador Ozanam Coelho – Unifagoc, School of Dentistry; Ubá, MG, Brazil.
(d) Universidade Federal de Minas Gerais – UFMG, Schoool of Dentistry, Department of Oral Health for Children and Adolescents, Belo Horizonte, MG, Brazil.
(e) Universidade Federal de Juiz de Fora – UFJF, School of Dentistry, Department of Social and Paediatric Dentistry; Juiz de Fora, MG, Brazil.
(f) Universidade Federal de Juiz de Fora – UFJF, School of Dentristry, Department of Dental Clinic, Juiz de Fora, MG, Brazil.
Corresponding Author: Camila Faria Carrada E-mail: camilacarrada_89@hotmail.com
Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.

11 3 2024
2024
38 e01510 4 2023
13 9 2023
25 10 2023
https://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract

This review aimed to assess the association between overweight/obesity and dental caries in Brazilian children/adolescents. Searches were performed in the Web of Science, Scopus, Cochrane, PubMed, Embase and SciELO, Lilacs and Open Grey literature databases up to June 2022. The Joanna Briggs Institute checklist for analytical cross-sectional studies, the checklist for cohort studies, and the checklist for case-control studies were used. A total of 41 publications were included, and 15 meta-analyses were performed. The authors analyzed the differences in weighted mean difference (MD) and odds ratios (OR), and their corresponding confidence intervals (CI) (95%) for dental caries among eutrophic and obese and/or overweight children/adolescents. Meta-analyses showed that there was no association between overweight and/or obesity and dental caries in Brazilian children/adolescents for most anthropometric reference curves using BMI (Body Mass Index). A greater experience of dental caries was associated with well-nourished adolescents in permanent dentition, compared with obese individuals in the same dentition, as classified by the CDC 2000 curve (OR = 2.53, 95% CI;1.49–4.29; p = 0.0006; I2 = 0%) in dichotomous outcome studies, and (MD = 0.61, 95%CI: 0.08–1.15; p = 0.02; I2 = 0%) in continuous studies. The strength of the evidence of the results was classified as very low, low or moderate. It was concluded that there is no association between overweight and/or obesity and dental caries in Brazilian children/adolescents for most anthropometric reference curves using BMI. A greater experience of dental caries was associated with well-nourished adolescents in permanent dentition, compared with obese individuals in the same dentition, as classified by the CDC 2000 curve.

Keywords

Obesity
Overweight
Dental Caries
Child
Systematic Review
==== Body
pmcIntroduction

Overweight and obesity in children and adolescents used to be considered a condition restricted to high-income countries, but is now increasing worldwide. 1 Obesity is a multifactorial disease attributed to genetic factors, such as alterations in specific, non-genetic factors, such as lack of physical activity and eating patterns with foods rich in sugars and fats, and to biopsychosocial processes that include political, economic, social and cultural factors. 2,3 The high prevalence of obesity in the population aged 2 to 18 years has been an important public health problem in both developed and developing countries, since obesity in childhood and adolescence can be perpetuated in adulthood, and may be associated with non-communicable diseases, such as type 2 diabetes, hypertension, and cardiovascular disease. 4,5

A recent systematic review and meta-analysis investigated the prevalence of overweight and obesity among young Brazilian children and adolescents aged 5 to 19 years. In children (5–9 years), the pooled prevalence rates of overweight were 16.2% in girls and 14.4% in boys. The prevalence rates of obesity were 9.2% and 9.0% for girls and boys, respectively. Regarding adolescents (10–19 years), the prevalence rates in girls were 16.4% for overweight and 6.2% for obesity; in boys, 15.3% for overweight and 7.5% for obesity. The review identified considerable and increasing trends in the prevalence rates of overweight and obesity in the last two decades, with implications for the current health of young people, and for the future health of the entire population, unless something is done to stave off their effects. 6

Diet is the primary determinant of obesity. A poor diet can have a negative impact on health through its effects on the functioning of the immune system, growth, development, aging, and also on oral health. 7 Among the oral diseases, dental caries is still one of the most highly prevalent chronic diseases among children worldwide. 8,9 In Brazil, according to data from the latest National Survey of Oral Health – SB Brazil 2010, the proportion of individuals without caries experience (dmft/DMF = 0) decreases as age increases, i.e., 46.6% of Brazilian children aged 5 years were free from dental caries in the primary dentition; at age 12, that number dropped to 43.5% for the permanent dentition. From age 15 to 19 years, the number of adolescents free from caries experience was even lower, i.e., 23.9%. It was also found that the percentage of children and adolescents with DMFT = 0 was always lower in the Midwest, North and Northeast, compared with the higher percentage in the South and Southeast. 10

Dental caries is considered a sugar-dependent polymicrobial dysbiosis, capable of leading to mineral loss of the dental hard tissues. 11 Dental caries has negative effects on the child’s quality of life, which can lead to discomfort, pain, changes in sleep habits, and poor nutrition. In addition, it can lead to difficulties in the patient’s school performance, socialization and self-esteem, and can compromise the daily life of parents or caregivers. 8,12-15

Overweight/obesity and dental caries share common risk factors apart from high sugar diet intake, such as lower socioeconomic status (SES), and social-environmental factors, which might explain the association between these two conditions. Moreover, although the scientific literature supports the coexistence of overweight/obesity and dental caries, conflicting results have been described in different populations 7,16 . Several systematic reviews have been undertaken to understand the association of overweight/obesity and dental caries; 17-20 however, existing evidence remains uncertain and inconclusive. 8

Hence the present study addresses a focused research question by looking at the evidence for the association between overweight/obesity and dental caries in Brazilian children and adolescents, since a more accurate analysis of this relationship is needed to address the continental dimensions and socioeconomic differences among the different regions of Brazil. This research could support Brazilian health managers in their health decision-making process, in addition to facilitating collaborative and multidisciplinary approaches among specialists involved in the care of children and adolescents. Therefore, the objective of this systematic review and meta-analysis was to evaluate the association between overweight and obesity and dental caries in Brazilian children and adolescents.

Methodology

Protocol and registration

A protocol for this study was registered at the International Prospective Register of Systematic Reviews (Prospero) under registration number #CRD42021056843. This systematic review and meta-analysis complies with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). 21,22

Eligibility criteria

The inclusion criteria for this systematic review and meta-analysis were observational studies (cross-sectional, case-control, and cohort studies) and clinical trials that evaluated the association between overweight/obesity and dental caries in Brazilian children and adolescents. The study sample could include children and adolescents ≤ 19 years of age of both sexes, regardless of race, socioeconomic status or region of residence in Brazil. The included studies had to use BMI (Body Mass Index) to assess overweight/obesity. Dental caries experience had to be diagnosed by standardized indices using the visual method, with clinical examinations that evaluated the teeth or surfaces, instead of using radiographic methods.

The PECO question was as follows:

P (Patients): Brazilian children and adolescents ≤ 19 years

E (Exposure): High BMI

C (Comparison): Normal BMI

O (Outcome): Dental caries

Case reports, case series, systematic reviews, abstracts of meetings, or studies whose full texts were unpublished or unavailable were excluded. No restrictions were placed on publication year or publication language.

Information source and search strategy

Searches were carried out in Cochrane Library, LILACS (Latin American and Caribbean Health Sciences), PubMed, Embase, Scopus, and Web of Science. The searches were conducted as of the date of inception of the database up to July 2023. Keywords and MeSH terms were selected, and electronic search strategies were developed for each database. An additional search in the gray literature (Open Grey) and Google Scholar, and a hand search of the references of the included studies were also performed. The searches in Open Grey and Google Scholar were restricted to the first 300 hits by order of relevance (Table 1). 21 Endnote software (EndNote X7®, Clarivate Analytics, Toronto, Canada) was used to collect references and remove duplicates.

Table 1 Search strategies for all the databases.

Pubmed	((Obesity [Mesh] OR overweight [Mesh] OR BMI OR body mass index [Mesh] OR body weight [Mesh]) AND (dental caries [Mesh] OR oral health [Mesh] OR DMF Index [Mesh] OR teeth decay) AND (child [Mesh] OR adolescent [Mesh] OR preschool, child [Mesh]))	
Embase	(obesity OR obese OR overweight OR BMI OR “body mass index” OR “body weight”) AND (caries OR “dental caries” OR “DMF Index” OR DMF OR “teeth decay” OR “tooth demineralization”) AND (child OR adolescent OR “child, preschool” OR pediatric)	
Web of Science	(obesity OR obese OR overweight OR BMI OR body mass index OR body weight) AND (caries OR dental caries OR DMF Index OR DMF OR teeth decay OR tooth demineralization) AND (child OR adolescent OR child, preschool OR pediatric)	
Cochrane	(obesity OR obese OR overweight OR BMI OR body mass index OR body weight) AND (caries OR dental caries OR DMF Index OR DMF OR teeth decay OR tooth demineralization) AND (child OR adolescent OR child, preschool OR pediatric)	
Scopus	(obesity OR obese OR overweight OR BMI OR body mass index OR body weight) AND (caries OR dental caries OR DMF Index OR DMF OR teeth decay OR tooth demineralization) AND (child OR adolescent OR child, preschool OR pediatric)	
Lilacs	(obesity OR obese OR overweight OR BMI OR body mass index OR body weight) AND (caries OR dental caries OR DMF Index OR DMF OR teeth decay OR tooth demineralization) AND (child OR adolescent OR child, preschool OR pediatric)	
SciELO	(obesity OR obese OR overweight OR BMI OR body mass index OR body weight) AND (caries OR dental caries OR DMF Index OR DMF OR teeth decay OR tooth demineralization) AND (child OR adolescent OR child, preschool OR pediatric)	
Gray literature	(obesity OR obese OR overweight OR BMI OR body mass index OR body weight) AND (caries OR dental caries OR DMF Index OR DMF OR teeth decay OR tooth demineralization) AND (child OR adolescent OR child, preschool OR pediatric)	

Study selection

The selection of studies was performed by two reviewers (JFP and MVSZ), independently, in two stages. In Stage 1, titles and abstracts were selected according to eligibility criteria using online software (Rayyan, Qatar Computing Research Institute). 23 Those that appeared to satisfy the eligibility criteria were assessed in Stage 2. The full texts of studies selected in Stage 1 were screened in Stage 2, applying the same criteria. The studies whose full texts fulfilled the eligibility criteria were included. Any discrepancies between the review authors were resolved in both stages with discussion, and a third review author (PVTD) was consulted if discrepancies persisted.

Data collection process

Data collection was conducted by two independent reviewers (JFP and MVSZ). The following data were extracted: author/year of publication, study design, sample size, participants’ age, aim of the study, the measurements evaluated and the indices used to assess overweight/obesity and dental caries, statistical analyses, results of the association between dental caries and obesity in Brazilian children, and main conclusion of the study. The authors of the included studies were contacted if the required data were incomplete. In cases of incomplete data, the study authors were contacted via the corresponding author’s email address or Research Gate (http://www.researchgate.net/).

Risk of bias within studies

Risk of bias was assessed with the Joanna Briggs Institute Critical Appraisal Checklist according to the design of the included studies. The Joanna Briggs Institute checklist for analytical cross-sectional studies, the checklist for cohort studies, and the checklist for case-control studies were used.

Two reviewers (JFP and MVSZ) performed the risk of bias evaluation separately, and categorized each article included as a ‘high risk’ study when the study bias rating of ‘low risk of bias’ score was between 0% and 49% of all the items of the tool, a ‘moderate risk’ study when the study bias rating of ‘low risk of bias’ score was between 50% and 69% of all the items of the tool, and a ‘low risk’ study when the study bias rating of ‘low risk of bias’ score was above 70% of all the items of the tool. 24 In cases of discordance between the two reviewers in rating the bias, a third reviewer (PVTD) was consulted to resolve the disagreement.

Summary measures

The main outcome assessed was the association between overweight and dental caries, between obesity and dental caries, and between overweight/obesity and dental caries. The summary measure considered the odds ratios (OR) in dichotomous variables, with 95% confidence intervals (CI). Regarding continuous variables, the MD and median range (MR) were considered, as well as 95%CI.

Synthesis of results

Fifteen meta-analyses were conducted with the Review Manager 5.4 (Review Manager 5.4, The Cochrane Collaboration) software. Statistical heterogeneity was quantified using the I2 test, and a value > 50% was considered as an indicator of substantial heterogeneity among studies. 24,25,26 The fixed effect model was used when I2 was lower than 50%. The random effect model was used when I2 was higher than 50%. 25 The rationale for aggregating studies in different meta-analyses was homogeneity between/among studies according to the dentition (deciduous or permanent) of children/adolescents, the reference curves used to define overweight and obesity in children and adolescents, the classification of the anthropometric variable related to dental caries, and whether the outcome assessed was continuous or dichotomous.

Strength of the evidence assessment

The strength of evidence of the selected studies for the meta-analyses was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Summary of Findings (SoF) tables were produced with GRADE online software (GRADEpro GTD, Copenhagen, Denmark). 27

Results

Study selection

A total of 1,405 references were retrieved within all the searches. After the removal of duplicate hits, 1,362 remained for screening of title and abstract in Stage 1. After screening, 81 references were selected for Stage 2. After applying the eligibility criteria to the full text, 40 articles were excluded. Thus, 41 articles were finally included in this systematic review (Figure 1).

Figure 1 Flow diagram of literature search and selection criteria.

Study characteristics

Thirty-seven cross-sectional studies, three cohorts, and one case-control study were included. The Brazilian cities and regions where the studies had been performed were: Camboriú, 28 Londrina, 29,30 Porto Alegre, 31-33 Pato Branco, 34 Pelotas, 35,36 Santa Cruz do Sul, 37 Florianópolis, 38 Califórnia 39 and Curitiba 13 in the South; Diadema, 40 Juiz de For a, 41 Piracicaba, 42-44 Araraquara, 45 São Paulo, 46,47 Bauru, 48,49 Dois Córregos, 50 Araçatuba, 51 Nova Friburgo, 52 Ribeirão Preto, 53 Diamantina, 54 and Alfenas 55 in the Southeast; Goiânia 56 in the Mid-west; Acrelândia, 57 Manaus, 58-60 and Barcelos 61 in the North; Carauru, 62 Cabo de Santo Agostinho, 63 Campina Grande, 64,65 Teresina, 66 and São Luis 15 in the Northeast.

The studies were published between 2008 and 2021. The number of participants in the study with the largest sample was 1,528 individuals, 31 and the number of participants in the study with the smallest sample was 54 38 . The age of the participants ranged from 12 months 33 to 19 years old. 29,40,66 Summary information for all the articles can be made available by the authors upon request.

Nutritional status was classified based on BMI in all the studies, and the following reference curves were used to define obesity in children: National Center for Health Statistics, 5,46,62 Centers for Disease Control and Prevention (NCHS/CDC), 28,29,34,42,53,63 International Obesity Task Force (IOTF), 41 WHO/2006, 12,15,30,36,40,46,48,51,54,55,59 WHO/2007, 31,34,35,38,43,44,47,49,51,53,55-57, 60,61,64,66 Hammer et al., criteria, 52 Conde and Monteiro 37 and Cole et al. 33

Six studies 28,29,34,42,62,64 assessed child and adolescent overweight and obesity using the BMI for age and gender percentiles from the Centers for Disease Control and Prevention 2000 (CDC 2000) growth charts for children and adolescents from 2 to 20 years old (overweight: ≥ 85th percentile < 95th percentile, and obesity: ≥ 95th percentile), while one paper 52 used similar parameters based on Hammer et al. Ten studies used BMI for age and gender according to WHO for children younger than five years old, expressed by percentiles (overweight: ≥ 85thpercentile < 97th percentile, and obesity: ≥ 97th percentile) 30,48,51,54,55 or by Z-score (overweight: Z-score > 1, and obesity: Z-score > 2). 14-16,40,59 One study used BMI for age and gender according to WHO, but did not report the classification used (percentile or Z-score). 51 Seventeen studies used BMI for age and gender according to WHO (2007) for children and adolescents between 5 and 19 years, expressed by percentiles (overweight: ≥ 85thpercentile < 97th percentile, and obesity: ≥ 97th percentile) 38,47,49,50,53 or by Z-score (overweight: Z-score > 1, and obesity: Z-score > 2). 31,32,35,56-58,60,61,64,66 Two studies used BMI for age and gender according to WHO (2007), but did not report the classification used (percentile or Z-score). 43,44 In four studies, overweight and obesity were identified from the curves equivalent to BMI 25.0 kg/m2 and 30.0 kg/m2, respectively, as recommended by Cole et al. (2000) 33,41,45 and by Conde and Monteiro. 37 One study 65 assessed child and adolescent overweight using standards for adult overweight (BMI > 24.9 kg/m2) recommended by the WHO. In one study, the reference curve that had been used to assess childhood overweight and obesity based on BMI was not reported. 39

Twenty-nine studies assessed dental caries using the DMFT/dmft indices; 36,12,,28-31,33,35,37-39,41-43,45,48-53,57,58,61,62,64 four studies used the decayed component of the DMFT/dmft; 50,57,60,63 one study used the dft (decayed and filled primary teeth), 46 and one study used the disaggregated components of the dmft index. 58 Two studies evaluated decayed, missing, or filled surfaces in primary teeth (dmfs). 32,40 One study assessed early childhood caries (ECC) (including cavitated and active non-cavitated lesions, as well as missing teeth and filled cavities) in the primary teeth of children younger than 71 months of age. 67 Two studies took into consideration the severity of dental caries in their analyses using dmft ≥ 6 (S-ECC) 52 and dmfs ≥ 6 (S-ECC). 40 Three studies assessed caries severity with the Significant Caries Index (SiC index). 41,50,56 Five studies assessed dental caries using the ICDAS index. 47,54,55,64,67 White spot lesions (WSL) were also evaluated in one study. 52

Results of individual studies

Overweight vs. dental caries

Twenty-three studies tested the association between overweight and dental caries. 12,36,29,30,32,34,35,37,39,43,44,47,48,52,53,55-61,66 Of these, 21 found no association between the two variables investigated in children/adolescents. 12,36,29,30,32,34,37,39,43-45,48,51-53,56-60,66 Three studies concluded that overweight children/adolescents were less likely to exhibit dental caries than their normal weight peers. 47,55,61

Obesity vs. dental caries

Twenty-three studies tested the association between obesity and dental caries. 36,29,30,32,34,37,39,40,43-46,48,51-53,55,57-60,63,65 Of these, 18 found no association between these two variables investigated in children/adolescents. 36,29,30,34,37,39,40,43-45,48,51-53,57,58,60,61 Three studies demonstrated that obesity was associated with greater dental caries experiences in children/adolescents. 46,59,63 In one of these three studies, the measurement of the association was limited to bivariate analysis. 63 Two studies showed that obesity was associated with fewer dental caries experiences in children/adolescents. 32,55

Overweight/obesity vs. dental caries

Fourteen studies tested the association between overweight/obesity and dental caries. 28,31,35,33,41,42,49,50,54,55,62,64,65,67 Of these, 10 found no association between these two variables investigated in children/adolescents. 28,31,35,41,42,49,55,62,64,65 Four studies demonstrated that overweight/obesity was associated with fewer dental caries experiences in children/adolescents. 15,33,50,54 In one of these four studies, the measurement of the association was limited to bivariate analysis. 50

Risk of bias within the studies

In the cross-sectional studies, 30 studies exhibited low risk of bias, 12,15,36,28,29,31,34,33,37,38,40-43,45,47-50,52-58,60,61,53,54 while five studies exhibited moderate risk of bias 30,39,43,46,59 . In addition, two studies showed a high risk of bias. 51,65 Eleven studies increased the risk of bias when evaluating the reliability of the exposure measure. 30,35,37,39,43,44,47,51,54,55,65 Of these, one 30 did not report the anthropometric curve used for BMI index, and 10 30,35,37,43,44,47,51,54,55,65 showed errors in the description of parameters to assess obesity and overweight using the BMI index. In general, the question that most commonly contributed to increasing the risk of bias was “Were the strategies to deal with confounding factors stated?” Only 22 studies declared strategies to deal with confounders. 12,31,33,37,38,40,43,45,49,50,53,57,60,61,63,64,66 The same occurred with the case-control 62 study, which was considered as having a low risk of bias, and which received a negative score only for the question about strategies to deal with stated confounding factors. In the cohort studies, all the studies exhibited low risk of bias, 15,32,35 and the confounding factors were controlled in all of them. Further information about the criteria for scoring the questions as ‘low risk of bias’ or ‘high risk of bias’ can be found in Table 2, Table 3 and Table 4.

Table 2 Risk of bias for cross-sectional studies.

Author, year	Were the criteria for inclusion in the sample clearly defined?	Were the study subjects and the setting described in detail?	Was the exposure measured in a valid and reliable way?	Were objective, standard criteria used to measure the condition?	Were the confounding factors identified?	Were the strategies to deal with confounding factors stated?	Were the outcomes measured in a valid and reliable way?	Was appropriate statistical analysis used?	
Oliveira; Sheiham; Bönecker, 2008 40	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Carvalho et al., 2009 41	Yes	Yes	Yes	Yes	No	No	Yes	Yes	
Crispim et al., 2010 28	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Tambelini et al., 2010 29	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Tureli, Barbosa; Gavião, 2010 42	Yes	Yes	Yes	Yes	No	No	Yes	Yes	
Silva et al., 2013 16	Unclear	Yes	Unclear	Unclear	Yes	Yes	Yes	Yes	
Campos et al., 2011 45	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Alves et al., 2013 31	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Costa; Daher; Queiroz, 2013 56	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Xavier et al., 2013 48	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Santos Junior et al., 2014 63	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Frazão et al., 2014 57	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Freitas et al., 2014 50	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Lima et al., 2014 34	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Martins et al., 2014 51	Yes	Yes	Yes	Yes	Unclear	No	Yes	Yes	
Aznar, 2015 49	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Antunes et al., 2016 52	Yes	Yes	No	No	Yes	No	Yes	Yes	
Aragão et al., 2016 65	Yes	No	Yes	Yes	No	No	Yes	Yes	
Assi et al., 2016 58	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Silva et al., 2016 53	No	No	Yes	Yes	Yes	Yes	Yes	Yes	
Borges et al., 2016 37	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	
Gonçalves et al., 2016 38	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Pinto-Sarmento et al., 2016 64	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Porcelli et al., 2016 39	Yes	Yes	Unclear	Yes	Yes	No	Yes	Yes	
Araújo et al., 2017 43	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Fernández et al., 2017 33	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Soares et al., 2017 54	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Fraiz et al., 2019 12	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Guaré et al., 2019 47	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Lima, 2017 66	Yes	Yes	Yes	Yes	Unclear	Unclear	Yes	Yes	
Porcelli et al., 2019 30	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Vasconcelos et al., 2019 59	No	Yes	Yes	Yes	No	No	Yes	Yes	
Aranha et al., 2020 61	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Araujo et al., 2020 44	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	
Rego et al., 2020 50	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Barbosa et al., 2021 55	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	
Shqair et al., 2021 36	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	

Table 3 Risk of bias for case-control studies.

Author, year	Were the groups comparable other than presence of disease in cases or absence of disease in controls?	Were cases and controls matched appropriately?	Were the same criteria used for identification of cases and controls?	Was exposure measured in a standard, valid and reliable way?	Was exposure measured in the same way for cases and controls?	Were the confounding factors identified?	Were the strategies to deal with confounding factors stated?	Were outcomes assessed in a standard, valid and reliable way for cases and controls?	Was the exposure period of interest long enough to be meaningful?	Was appropriate statistical analysis used?	
Jamelli; Rodrigues; Lira, 2010 62	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	

Table 4 Risk of bias for cohort studies.

Author, year	Were the two groups similar and recruited from the same population?	Were the exposures measured similarly to assign people to both exposed and unexposed groups?	Was the exposure measured in a valid and reliable way?	Were the confounding factors identified?	Were the strategies to deal with confounding factors stated?	Were the groups/participants free of the outcome at the start of the study (or at the moment of exposure)?	Were the outcomes measured in a valid and reliable way?	Was the follow-up time reported and long enough for the outcomes to occur?	Was follow-up complete, and if not, were the reasons to loss to follow-up described and explored?	Were the strategies to address incomplete follow-up used?	Was appropriate statistical analysis used?	
Silva, 2014 35	Not applicable	Not applicable	Yes	Yes	Yes	No	Yes	Yes	Yes	No	Yes	
Ribeiro et al., 2017 15	Not applicable	Not applicable	Yes	Yes	Yes	No	Yes	Yes	Yes	Not applicable	Yes	
Lock et al., 2019 32	Not applicable	Not applicable	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	

Synthesis of results

Meta-analyses were performed according to the reference curves that had been used to define overweight and obesity in children and adolescents.

Overweight vs. dental caries

Four meta-analyses were performed for the studies that evaluated overweight children and adolescents using BMI for age and sex percentiles from the CDC 2000 growth charts. Two meta-analyses were performed for the continuous outcome studies using the mean difference (MD) and inverse analysis of variance, and two meta-analyses, for dichotomous data using the OR. Regarding continuous outcomes, a meta-analysis with two studies 34,53 that included children in primary dentition showed that there was no difference between overweight and normal weight children in relation to dental caries (MD = 0.31 95%CI: -0.10 to 0.73; p = 0.14; I2= 0%) (Figure 2). Another meta-analysis, which included two studies 29,52 with children/adolescents in permanent dentition, also showed that there was no difference between overweight and normal weight children/adolescents in relation to dental caries (MD = -0.06 95%CI: -1.03 to 0.91; p = 0.90; I2= 59%) (Figure 3). Regarding dichotomous outcomes, a meta-analysis with two studies 41,52 that included children in primary dentition showed that there was no difference between overweight and normal weight children in relation to dental caries (OR = 1.02 95%CI: 0.69–1.53; p = 0.91; I2= 0%) (Figure 4). Another meta-analysis, which included two studies 29,34 with children/adolescents in permanent dentition, also showed that there was no difference between overweight and normal weight children/adolescents in relation to dental caries (OR = 1.01 95%CI: 0.43–2.35;p = 0.99; I2= 71%) (Figure 5).

Figure 2 Forest plot of meta-analysis for continuous outcome studies evaluating dental caries in children with primary dentition with normal and overweight using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 3 Forest plot of meta-analysis for continuous outcome studies evaluating dental caries in children/adolescents in permanent dentition with normal and overweight using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 4 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries children in primary dentition with normal and overweight using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 5 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries children/adolescents in permanent dentition with normal and overweight using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Of the studies that evaluated overweight using the WHO BMI for age and sex (2007) for children/adolescents between 5 and 19 years old, expressed by the Z-score, a meta-analysis was performed with two studies 58,59 that evaluated the d component measured as untreated dental caries. No difference between overweight and normal weight children/adolescents was found in relation to untreated dental caries (MD = 0.03 95%CI: -0.24 to 0.30; p = 0.82; I2= 0%) (Figure 6).

Figure 6 Forest plot of meta-analysis for continuous outcome studies evaluating untreated dental caries in children/adolescents with normal and overweight using BMI for age and sex percentiles from the WHO BMI 2007 expressed by the Z-score.

Obesity vs. dental caries

Four meta-analyses were performed with studies that evaluated obese children and adolescents using BMI for age and sex percentiles from the CDC 2000 growth charts, two meta-analyses for continuous outcomes studies using the MD and inverse analysis of variance method, and two meta-analyses for dichotomous data using the OR. Regarding continuous outcomes, a meta-analysis with two studies 34,52 with children in primary dentition showed that there was no difference between obese and normal weight children in relation to dental caries (MD = -0.34 95%CI: -0.96 to 0.27; p = 0.27; I2= 0%) (Figure 7). Another meta-analysis comprising two studies 29,34 with children/adolescents in permanent dentition, showed a higher mean of dental caries in children/adolescents with normal weight (MD = 0.61 95%CI: 0.08–1.15; p = 0.02; I2= 0%) (Figure 8). Regarding dichotomous data, a meta-analysis made up of two studies 34,52 with children in primary dentition showed that there was no difference between obese and normal weight children in relation to dental caries (OR = 0.44 95%CI: 0.08–2.61; p = 0.37; I2= 91%) (Figure 9). Another meta-analysis comprising two studies 29,34 with children/adolescents in permanent dentition, showed a higher odds of dental caries in children/adolescents with normal weight (OR = 2.53 95% CI 1.49-4.29;p = 0.0006; I2 = 0%) (Figure 10).

Figure 7 Forest plot of meta-analysis for continuous outcomes studies evaluating dental caries children in primary dentition with normal and obesity using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 8 Forest plot of meta-analysis for continuous outcomes studies evaluating dental caries in children/adolescents in permanent dentition with normal and obesity using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 9 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries children in primary dentition with normal and obesity using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 10 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries children/adolescents in permanent dentition with normal and obesity using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Of the studies that evaluated obesity using the WHO BMI for age and sex (2007) for children/adolescents, and expressed by the Z-score, a meta-analysis was performed with two studies 58,59 that evaluated the d component measured as untreated dental caries. No difference was found between overweight and normal weight children/adolescents in relation to untreated dental caries (MD = 0.20 95%CI: -0.03 to 0.59; p = 0.08; I2= 0%) (Figure 11).

Figure 11 Forest plot of meta-analysis for continuous outcome studies evaluating untreated dental caries in children/adolescents with normal and obesity using BMI for age and sex percentiles from the WHO BMI 2007 expressed by the Z-score.

Overweight/obesity vs. dental caries

Of the studies that evaluated overweight/obese children and adolescents using BMI for age and sex percentiles from the CDC 2000 growth charts, two meta-analyses were performed to determine continuous outcome. One meta-analysis with two studies 34,52 included children in primary dentition. It showed that there was no difference between overweight/obese and normal weight children in relation to dental caries (OR = 0.83 95%CI: 0.45–1.54; p = 0.55; I2= 73%) (Figure 12). Another meta-analysis included three studies 29,34,62 with children/adolescents in permanent dentition, and showed no difference between overweight/obese and normal weight children in relation to dental caries (OR = 1.18 95%CI: 0.71-1.95; p = 0.53; I2= 65%) (Figure 13).

Figure 12 Forest plot of meta-analysis for dicothomous outcomes studies evaluating dental caries children in primary dentition with normal and overweight/obesity using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Figure 13 Forest plot of meta-analysis for dichotomous outcomes studies evaluating dental caries children/adolescents in permanent dentition with normal and overweight/obesity using BMI for age and sex percentiles from the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

A meta-analysis with two studies was performed for the studies that evaluated overweight/obesity using the WHO BMI for age and sex (2007) for children/adolescents, expressed by the Z-score. 31,34 No difference was found between overweight/obese and normal weight children/adolescents in relation to dental caries (OR = 0.93 95%CI: 0.78–1.12; p = 0.45; I2= 0%) (Figure 14).

Figure 14 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries in children/adolescents with normal and overweight/obesity using BMI for age and sex percentiles from the WHO BMI 2007 expressed by the Z-score.

A meta-analysis with two studies was performed for the studies that evaluated overweight/obesity using the WHO BMI for age and sex (2007) for children/adolescents, expressed by the percentiles. 49,50 No difference was found between overweight/obese and normal weight children/adolescents in relation to dental caries (OR = 0.83 95%CI: 0.35–1.94; p = 0.67; I2= 74%) (Figure 15).

Figure 15 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries in children/adolescents with normal and overweight/obesity using BMI for age and sex percentiles from the WHO BMI 2007 expressed by the percentiles.

A meta-analysis with three studies was performed for the studies that evaluated overweight/obesity using the BMI for age and gender classified by WHO for children younger than five years, expressed by the Z-score. 12,15,36 No difference was found between overweight/obese and normal weight children/adolescents in relation to dental caries (OR = 0.86 95%CI: 0.60–1.22; p = 0.40; I2= 74%) (Figure 16).

Figure 16 Forest plot of meta-analysis for dichotomous outcome studies evaluating dental caries in children with normal and overweight/obesity using BMI for age and sex percentiles from the WHO BMI 2006 expressed.

Strength of the evidence assessment

Based on the GRADE assessment, the strength of evidence was rated as very low for the results of the meta-analyses that used the anthropometric reference curves: CDC 2000 for obesity in children with primary teeth, CDC 2000 for overweight and obesity in children/adolescents with permanent and deciduous teeth, and CDC 2000 for overweight children and adolescents with permanent and deciduous teeth; and those that used the WHO 2007 percentile for overweight and obese children and adolescents with permanent teeth, and the WHO 2006 Z-Score for overweight and obese children with primary and permanent teeth. The strength of evidence was rated as low for the results of the meta-analyses that used the anthropometric reference curve WHO 2007 Z-Score to assess obesity in children with untreated dental caries, the WHO 2007 Z-Score to assess overweight in children with untreated dental caries, and the WHO 2007 Z-Score to assess obese and overweight children and teenagers with permanent teeth. The strength of evidence was rated as moderate for the meta-analysis outcome that used the CDC 2000 anthropometric reference curve for obesity in children/adolescents in permanent dentition. Additional information on the strength of evidence assessment is available in Tables 5, 6, 7 and 8.

Table 5 Assessment of certainty of evidence of studies that used the WHO 2007 Z score as an anthropometric curve of the BMI

Certainty assessment	No. of patients	Effect	Certainty	Importance	
No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Obesity/ Overweight and Obesity/ Overweight	Normal Weight	Relative (95% CI)	Absolute (95% CI)	
WHO 2007 Z Score_Obesity_D_Mean	
2	observational studies	seriousa	not serious	not serious	not serious	all plausible residual confounding would reduce the demonstrated effect	40	416	-	MD 0.28 higher	⨁⨁◯◯	IMPORTANT	
(0.03 lower to 0.59 higher)	Low	
WHO 2007 Z Score_Overweight_D_Mean	
2	observational studies	seriousb	not serious	not serious	not serious	all plausible residual confounding would reduce the demonstrated effect	99	416	-	MD 0.03 higher	⨁⨁◯◯	IMPORTANT	
(0.24 lower to 0.3 higher)	Low	
WHO 2007 Z Score_Overweight and Obesity_DMFT_Dichotomous	
2	observational studies	not serious	not serious	not serious	not serious	none	 	 	not estimable	not estimable	⨁⨁◯◯	IMPORTANT	
-	0.0%	 	Low	
CI: confidence interval; MD: mean difference.

a. One of the included studies did not mention the strategies used to deal with confounders; b. One of the included studies did not mention the strategies used to deal with confounders.

Table 6 Assessment of the certainty of the evidence of studies that used WHO 2007 percentile as an anthropometric curve of BMI

Certainty assessment	No. of patients	Effect	Certainty	Importance	
No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Overweight and Obesity	Normal weight	Relative	Absolute	
	
(95% CI)	(95% CI)	
WHO 2007 Percentile_Overweight and Obesity_DMFT_Dichotomous	
2	observational studies	not serious	seriousa	not serious	seriousb	none	91/166 (54.8%)	111/189 (58.7%)	OR 0.83	46 fewer per 1,000	⨁◯◯◯	IMPORTANT	
(0.35 to 1.94)	(from 255 fewer to 147 more)	Very low	
CI: confidence interval; OR: odds ratio.

a. i2 = 74. There is no effect estimate similarity to overlapping confidence intervals; b. Although the CI is small (0.35–1.94), the number of events is fewer than 300.

Table 7 Assessment of certainty of evidence of studies that used the WHO 2006 z score as an anthropometric curve of the BMI.

Certainty assessment	No. of patients	Effect	Certainty	Importance	
No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Obesity/ Overweight and Obesity/ Overweight	Normal Weight	Relative (95% CI)	Absolute (95% CI)	
WHO 2006 Z Score_Overweight and Obesity_dmft_Dichotomous	
3	observational studies	seriousa	seriousb	seriousc	not serious	none	 	 	not estimable	 	⨁◯◯◯	IMPORTANT	
Very low	
WHO 2006 Z Score_Overweight and Obesity_DMFT_DIchotomous	
2	observational studies	not serious	seriousd	not serious	not serious	none	 	 	not estimable	 	⨁◯◯◯	IMPORTANT	
Very low	
CI: confidence interval.

a. Some included studies did not mention the strategies used to deal with confounders. One study did not report whether groups/participants were outcome-free at baseline (or at the time of exposure); b. i2 = 74%. There is no similarity of effect estimates to overlapping confidence intervals; c. Although the results refer only to the primary dentition, the children included in the studies ranged from 2–8 years old; d. i2 = 85%. There is no similarity of effect estimates to overlapping confidence intervals.

Table 8 Assessment of the certainty of the evidence of studies that used the CDC 2000 score as an anthropometric curve of the BMI.

Certainty assessment	No. of patients	Effect	Certainty	Importance	
No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Obesity/ Overweight and Obesity/ Overweight	Normal Weight	Relative (95%CI)	Absolute (95%CI)	
CDC 2000_Obesity_DMFT_Dichotomous	
2	observational studies	seriousa	not serious	seriousb	not serious	very strong association	28/70 (40.0%)	361/589 (61.3%)	OR 2.53	187 more per 1.000	⨁⨁⨁◯	IMPORTANTE	
all plausible residual confounding would reduce the demonstrated effect	(1.49 to 4.29)	(from 89 more to 259 more)	Moderate	
CDC 2000_Obesity_dmft_Dichotomous	
2	observational studies	seriousc	seriousd	seriouse	seriousf	all plausible residual confounding would reduce the demonstrated effect	53/93 (57.0%)	272/616 (44.2%)	OR 0.44	183 fewer per 1.000	⨁◯◯◯	IMPORTANTE	
(0.08 to 2.61)	(from 382 fewer to 232 more)	Very low	
CDC 2000_Obesity_DMFT_Mean	
2	observational studies	seriousg	not serious	serioush	not serious	all plausible residual confounding would reduce the demonstrated effect	70	589	-	MD 0 0.61	⨁◯◯◯	IMPORTANTE	
(0.08 higher to 1.15 higher)	Very low	
CDC 2000_Obesity_dmft_Mean	
2	observational studies	seriousi	not serious	seriousj	not serious	all plausible residual confounding would reduce the demonstrated effect	93	617	-	MD 0 -0.34	⨁◯◯◯	IMPORTANTE	
(0.96 lower to 0.27 higher)	Very low	
CDC 2000_Overweight and Obesity_DMFT_Dichotomous	
3	observational studies	seriousk	seriousl	seriousm	not serious	strong association	160/268 (59.7%)	729/1109 (65.7%)	OR 1.18	36 more per 1.000	⨁◯◯◯	IMPORTANTE	
all plausible residual confounding would reduce the demonstrated effect	(0.71 to 1.95)	(from 81 fewer to 132 more)	Very low	
CDC 2000_Overweight and Obesity_dmft_Dichotomous	
2	observational studies	seriousn	seriouso	seriousp	seriousq	all plausible residual confounding would reduce the demonstrated effect	101/210 (48.1%)	272/616 (44.2%)	OR 0.83	45 fewer per 1.000	⨁◯◯◯	IMPORTANTE	
(0.45 to 1.54)	(from 179 fewer to 108 more)	Very low	
CDC 2000_Overweight_DMFT_Dichotomous	
2	observational studies	seriousr	seriouss	serioust	seriousu	strong association	70/117 (59.8%)	361/589 (61.3%)	OR 1.01	2 more per 1.000	⨁◯◯◯	IMPORTANTE	
all plausible residual confounding would reduce the demonstrated effect	(0.43 to 2.35)	(from 208 fewer to 175 more)	Very low	
CDC 2000_Overweight_dmft_Dichotomous	
2	observational studies	seriousv	not serious	seriousw	seriousx	strong association	51/117 (43.6%)	272/617 (44.1%)	OR 1.02	5 more per 1.000	⨁◯◯◯	IMPORTANTE	
all plausible residual confounding would reduce the demonstrated effect	(0.69 to 1.53)	(from 89 fewer to 106 more)	Very low	
CDC 2000_Overweight_DMFT_Mean	
2	observational studies	seriousy	seriousz	seriousaa	seriousab	all plausible residual confounding would reduce the demonstrated effect	117	329	-	MD 0.06 lower	⨁◯◯◯	IMPORTANTE	
(1.03 lower to 0.91 higher)	Very low	
CDC 2000_Overweight_dmft_Mean	
2	observational studies	seriousac	not serious	seriousad	seriousae	all plausible residual confounding would reduce the demonstrated effect	117	617	-	MD 0.31 higher	⨁◯◯◯	IMPORTANTE	
(0.1 lower to 0.73 higher)	Very low	
CI: confidence interval; MD: mean difference; OR: odds ratio.

a. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; b. Although the results refer only to permanent dentition, the children and adolescents of the included studies ranged from 6–19 years old; c. The included studies did not mena.tion the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; d. i2 = 91%; e. Although the results refer only to the primary dentition, the children included in the studies ranged from 2 –15 years old; f. The number of effects was less than 300. The CI ranged from 0.08–2.61. The prism passes through the null line; g. Although the results refer only to permanent dentition, the children and adolescents of the included studies ranged from 6–19 years old; h. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; i. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; j. Although the results refer only to the primary dentition, the children included in the studies ranged from 2–15 years old; k. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations. Two of the studies included in the meta-analysis are cross-sectional and one is a case-control study; l. i2 = 65% and there is no similarity of effect estimates on overlapping confidence intervals; m. Although the results refer only to permanent dentition, the children and adolescents of the included studies ranged from 6–19 years old; n. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; o. i2 = 73% and there is no similarity of effect estimates on overlapping confidence intervals; p. Although the results refer only to the primary dentition, the children included in the studies ranged from 2–15 years old; q. Although the CI is small (0.45–1.54), the number of events is less than 300; r. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; s. i2 = 71% and there is no similarity of effect estimates on overlapping confidence intervals; t. Although the results refer only to permanent dentition, the children and adolescents of the included studies ranged from 6–19 years old; u. The number of effects was less than 300. The CI ranged from 0.43–2.35. The prism passes through the null line; v. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitation; w. Although the results refer only to the primary dentition, the children included in the studies ranged from 2 to 15 years old; x. Although the CI is small (0.69–1.53), the number of events is less than 300; y. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; z. i2 = 5 9% and there is no similarity of effect estimates on overlapping confidence intervals; aa. Although the results refer only to permanent dentition, the children and adolescents of the included studies ranged from 6–19 years old; ab. Although the sample was greater than 400, the CI was (-1.03 to 0.91). The prism passes through the null line; ac. The included studies did not mention the strategies used to deal with confounders. Thus, we believe that the studies have serious methodological limitations; ad. Although the results refer only to the primary dentition, the children included in the studies ranged from 2–15 years old; ae. Although the sample was greater than 400, the CI was (-0.10 to 0.73). The prism passes through the null line.

Discussion

The current systematic review and meta-analysis provides information on the association between overweight and obesity (as determined by BMI) and dental caries in Brazilian children and adolescents. The results indicated that the evidence of an association between overweight and obesity and dental caries in Brazilian children and adolescents is contrasting and not consistent, as evaluated in other systematic reviews in which studies from several countries in the world were included. 7,16,67-69 The data of the meta-analyses showed no association between obesity, overweight, overweight/obesity and dental caries for most anthropometric reference curves used to assess BMI, and had very low or low strength of evidence. Moderate strength of evidence was found for the meta-analysis showing a greater experience of dental caries in the permanent dentition of normal weight adolescents, compared with obese individuals, as classified by the CDC 2000 curve.

Few studies included in this systematic review and meta-analysis showed an association between obesity, overweight, overweight/obesity and greater experience of dental caries in Brazilian children/ adolescents. 46,69 The primary studies that included this association reported an increased prevalence and/or severity of caries in overweight/obese individuals who consumed particularly high levels of carbohydrates. 46,62 This interpretation cognizes sugar as an etiological factor in caries development. 59,69 Aside from these explanations, a systematic review 69 evaluating the association between dental caries and obesity in studies developed worldwide highlighted that Swedish researchers found a reduced salivary flow in obese adolescents, compared with their normal weight peers. 70 The authors suggested that reduced salivary flow intensifies the development of dental caries, thereby placing obese adolescents at an increased risk of caries. 70

Nonetheless, the explanation for the non-association between high BMI and dental caries, shown by the primary studies that found this result, is backed by the hypothesis that parents/caregivers of overweight/obese children may restrict the supply of high energy content foods in an attempt to control their children’s weight, and consequently also influence the dental caries experience. 12 In a Brazilian study, children with excess body weight were submitted to greater snack consumption control. 12 In this study, 12 excess body weight was a protective factor against dental caries, when analyzed separately. However, when it was controlled to reflect the level of parental restriction of snack consumption, the association between excess body weight and dental caries lost its statistical significance. 12 Obesity and dental caries in children have multifactor etiology, and their development involves important social-behavioral components. Nevertheless, the volume, frequency and quality of the foods ingested are the most important factors in obesity, 71 while the frequency and quality of eating practices have a seemingly greater impact on dental caries than the systemic effect of nutrient intake. 72

In the literature, there have been other attempts to explain the lower prevalence of dental caries in obese individuals. One such endeavor has suggested that the observed association between lower prevalence of dental caries and high BMI may be due to the increased consumption of high-fat and non-high-sugar diets, which are positively associated with obesity rather than dental caries. There are also reports in the literature of a possible protective effect of fatty foods on the frequency of dental caries. 73 Furthermore, the lower prevalence of dental caries in obese children has been justified by the fact that overweight/obese children have high levels of immunoglobulin A antibody (IgA-s) in their saliva. 20,74 This is an important factor that influences the microbial adhesion on tooth surfaces, and may hence interfere in the process of caries development and prevention. 32,47,51

Many studies have also suggested that both caries and obesity are strongly influenced by socioeconomic factors. 28,31,39,49,54,55,57,62,64 Families with better social conditions have greater access to dental treatments, leading to lower dental caries rates. Additionally, these families also have more access to foods that contribute to obesity. According to a national survey exploring data that evaluate nutrient consumption, the caloric participation of lipids in the diet of the population of the Brazilian Southeast is higher than that of other Brazilian regions and the national average. 75 However, social inequality in Brazil makes it difficult to extrapolate the interpretation of these results to all Brazilians. There are 16 million people who live below the poverty line in Brazil, and who cannot meet their basic food needs, and many regions are affected by food insecurity. 76 Inappropriate eating habits may interfere with oral health conditions when combined with a lack of inadequate hygiene or difficulties in accessing preventive care. In this regard, inequalities in the oral health of the Brazilian population well portray the very unequal distribution of wealth across the country.78 These factors are considered to be potential effect modifiers that can lead to a weak association between obesity and dental caries.

Studies that have evaluated the association between dental caries and obesity indicate that a variety of issues should be discussed before this relationship can be fully understood. The first issue refers to the methods for diagnosing both outcomes. 70 In an attempt to reduce the heterogeneity between/among studies, the present systematic review and meta-analysis included only studies that evaluated dental caries using the visual method in clinical exams assessing teeth or surfaces, and excluded those that used radiographic methods. There are also aspects that can interfere in the measurement of overweight and obesity. All studies included in this systematic review and meta-analysis evaluated overweight and obesity by means of BMI measurement. There was no study that measured obesity using other diagnostic methods, such as skinfolds, waist circumference, waist-to-hip ratio, or radiographic densitometry (DXA). However, there was great variation between/among the studies in relation to the anthropometric reference curve applied to classify the participant as an overweight or obese individual. These factors may also account for the heterogeneity of the results among the primary studies included herein.

These findings reinforce the evidence that the association between BMI and caries is complex. Differences in methodology, such as experimental design, population and sample size, as well as access to health services, fluoride use, oral health habits, socioeconomic status, diet, dental caries index and BMI classification, should be considered when seeking to explain the conflicting data. 15

Based on the current published literature, there is no association between obesity and/or overweight and dental caries in Brazilian children/adolescents for most anthropometric reference curves using BMI. A greater experience of dental caries was associated with well-nourished adolescents in permanent dentition compared with obese adolescents, classified by the CDC 2000. Caution should be exercised due to the very low, low, and moderate strength of evidence of the results supporting this association. Assessments with stronger methods and more standardized prospective studies, using a universal measurement system for both overweight/obesity and dental caries, and possible effect-modifying factors are needed to increase the quality of evidence to confirm or negate this possible association, and to help clarify the direction of the association between these two important health conditions.

Conclusions

It was concluded that there is no association between overweight and/or obesity and dental caries in Brazilian children/adolescents for most anthropometric reference curves using BMI. A greater experience of dental caries was associated with well-nourished adolescents in permanent dentition compared with obese individuals in the same dentition, classified by the CDC 2000 curve for studies. The strength of the evidence of the meta-analysis results was considered very low, low and moderate.
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References

1 Dias PC Henriques P Anjos LA Burlandy L Obesity and public policies: the Brazilian government’s definitions and strategies Cad Saude Publica 2017 07 33 7 e00006016 10.1590/0102-311x00006016 28767957
2 Güngör NK Overweight and obesity in children and adolescents J Clin Res Pediatr Endocrinol 2014 09 6 3 129 143 10.4274/jcrpe.1471 25241606
3 World Health Organization Obesity and overweight Geneva World Health Organization 2021 cited 2022 June 3 https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
4 Lee EY Yoon KH Epidemic obesity in children and adolescents: risk factors and prevention Front Med 2018 12 12 6 658 666 10.1007/s11684-018-0640-1 30280308
5 NCD Risk Factor Collaboration (NCD-RisC) Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants Lancet 2016 04 387 10026 1377 1396 10.1016/S0140-6736(16)30054-X 27115820
6 Guedes DP Mello ER Prevalence of overweight and obesity among Brazilian children and adolescents: systematic review and meta-analysis ABCS Health Sci 2021 46 e021301 10.7322/abcshs.2019133.1398
7 Hayden C Bowler JO Chambers S Freeman R Humphris G Richards D et al Obesity and dental caries in children: a systematic review and meta-analysis Community Dent Oral Epidemiol 2013 08 41 4 289 308 10.1111/cdoe.12014 23157709
8 Manohar N Hayen A Fahey P Arora A Obesity and dental caries in early childhood: A systematic review and meta-analyses Obes Rev 2020 03 21 3 e12960 10.1111/obr.12960 31721413
9 Pitts NB Baez RJ Diaz-Guillory C Donly KJ Alberto Feldens C McGrath C et al Early childhood caries: IAPD Bangkok declaration J Dent Child (Chic) 2019 05 86 2 72 10.1111/ipd.12490 31395110
10 Ministério da Saúde (BR) Secretaria de Vigilância em Saúde. SB Brasil 2010. Pesquisa Nacional de Saúde Bucal: resultados principais Brasília, DF Secretaria de Vigilância em Saúde 2012
11 Sheiham A James WP Diet and dental caries: the pivotal role of free sugars reemphasized J Dent Res 2015 10 94 10 1341 1347 10.1177/0022034515590377 26261186
12 Fraiz GM Crispim SP Montes GR Gil GS Morikava FS Bonotto DV et al Excess body weight, snack limits and dental caries in Brazilian preschoolers: a population-based study Pesqui Bras Odontopediatria Clin Integr 2019 19 1 1 9 10.4034/PBOCI.2019.191.27
13 Çolak H Dülgergil CT Dalli M Hamidi MM Early childhood caries update: a review of causes, diagnoses, and treatments J Nat Sci Biol Med 2013 01 4 1 29 38 10.4103/0976-9668.107257 23633832
14 Martins-Júnior PA Vieira-Andrade RG Corrêa-Faria P Oliveira-Ferreira F Marques LS Ramos-Jorge ML Impact of early childhood caries on the oral health-related quality of life of preschool children and their parents Caries Res 2013 47 3 211 218 10.1159/000345534 23257929
15 Ribeiro CC Silva MC Nunes AM Thomaz EB Carmo CD Ribeiro MR et al Overweight, obese, underweight, and frequency of sugar consumption as risk indicators for early childhood caries in Brazilian preschool children Int J Paediatr Dent 2017 11 27 6 532 539 10.1111/ipd.12292 28222484
16 Silva AE Menezes AM Demarco FF Vargas-Ferreira F Peres MA Obesity and dental caries: systematic review Rev Saude Publica 2013 08 47 4 799 812 10.1590/S0034-8910.2013047004608 24346668
17 Hooley M Skouteris H Boganin C Satur J Kilpatrick N Body mass index and dental caries in children and adolescents: a systematic review of literature published 2004 to 2011 Syst Rev 2012 1 57 10.1186/2046-4053-1-57
18 Chen D Zhi Q Zhou Y Tao Y Wu L Lin H Association between dental caries and BMI in children: a systematic review and meta-analysis Caries Res 2018 52 3 230 245 10.1159/000484988 29353283
19 Li LW Wong HM Peng SM McGrath CP Anthropometric measurements and dental caries in children: a systematic review of longitudinal studies Adv Nutr 2015 01 6 1 52 63 10.3945/an.114.006395 25593143
20 Paisi M Kay E Bennett C Kaimi I Witton R Nelder R et al Body mass index and dental caries in young people: a systematic review BMC Pediatr 2019 04 19 1 122 10.1186/s12887-019-1511-x
21 Simons M Busch K Avolio A Kiat H Davidson A Improving the quality of the evidence: the necessity to lead by example J Clin Neurosci 2017 12 46 165 166 10.1016/j.jocn.2017.09.004 28974392
22 Page MJ McKenzie JE Bossuyt PM Boutron I Hoffmann TC Mulrow CD et al The PRISMA 2020 statement: an updated guideline for reporting systematic reviews Syst Rev 2021 03 10 1 89 10.1186/s13643-021-01626-4
23 Pauletto P Réus JC Bolan M Massignan C Flores-Mir C Maia I et al Association between obstructive sleep apnea and health-related quality of life in untreated adults: a systematic review Sleep Breath 2021 12 25 4 1773 1789 10.1007/s11325-021-02323-1 33709191
24 Polmann H Réus JC Massignan C Serra-Negra JM Dick BD Flores-Mir C et al Association between sleep bruxism and stress symptoms in adults: a systematic review and meta-analysis J Oral Rehabil 2021 05 48 5 621 631 10.1111/joor.13142 33377534
25 Guyatt GH Oxman AD Vist GE Kunz R Falck-Ytter Y Alonso-Coello P et al GRADE: an emerging consensus on rating quality of evidence and strength of recommendations BMJ 2008 04 336 7650 924 926 10.1136/bmj.39489.470347.AD 18436948
26 Higgins J Altman D Sterne J Cochrane handbook for systematic reviews of interventions version 5.1.0 The Cochrane Collaboration 2011 Chapter 8: Assessing risk of bias in included studies
27 Haddaway NR Collins AM Coughlin D Kirk S The role of Google Scholar in evidence reviews and its applicability to grey literature searching PLoS One 2015 09 10 9 e0138237 10.1371/journal.pone.0138237 26379270
28 Crispim MGA Grillo LP Próspero ENS Mariath AB Saúde bucal e sua associação com o estado nutricional e a condição socioeconômica em adolescentes RGO 2010 Jan/Mar 58 1 41 46
29 Tambelini C Ramos D Poli-Frederico RC Tomasetti CSC Barata TJE Maciel SM Dental caries in adolescents and its association with excess weight and sociodemographic factors in Londrina, Paraná, Brazil Rev Odonto Scien 2010 25 3 245 249 10.1590/S1980-65232010000300005
30 Porcelli IC S Corsi NM Barata TJ Fracasso ML Poli-Frederico RC Seixas GF et al Sweetness taste preference levels and their relationship to the nutritional and dental caries patterns among Brazilian preschool children Pesqui Bras Odontopediatria Clin Integr 2019 19 1 1 13 10.4034/PBOCI.2019.191.20
31 Alves LS Susin C Damé-Teixeira N Maltz M Overweight and obesity are not associated with dental caries among 12-year-old South Brazilian schoolchildren Community Dent Oral Epidemiol 2013 06 41 3 224 231 10.1111/cdoe.12010 23072345
32 Lock NC Susin C Brusius CD Maltz M Alves LS Obesity and dental caries among South Brazilian schoolchildren: a 2.5-year longitudinal study Braz Oral Res 2019 07 33 e056 10.1590/1807-3107bor-2019.vol33.0056 31271568
33 Fernández MR Goettems ML Demarco FF Corrêa MB Is obesity associated to dental caries in Brazilian schoolchildren? Braz Oral Res 2017 11 31 0 e83 e83 10.1590/1807-3107bor-2017.vol31.0083 29116296
34 Lima CA Peruchi CT Poli-Frederico RC Tomasetti CS Fracasso ML Maciel SM Exploring the association between dental caries, obesity and sensory characteristics in students living in southern Brazil Pesqui Bras Odontopediatria Clin Integr 2014 14 4 283 292 10.4034/PBOCI.2014.144.03
35 Silva AER Obesidade e cárie dentária: coorte de nascimentos de 1993, Pelotas-RS Pelotas thesis Pelotas Faculdade de Medicina da Universidade Federal de Pelotas 2014
36 Shqair AQ Motta JVS Silva RA Amaral PL Goettems ML Children’s eating behaviour traits and dental caries J Public Health Dent 2022 03 82 2 186 193 10.1111/jphd.12449 33719035
37 Borges TS Renter CP Schwanke NL Neto LK Grazziotin GB Burgos MS Relação entre obesidade e presença de cárie dentária em adolescentes no município Santa Cruz do Sul - RS, Brasil Adolesc Saude 2016 13 4 25 32
38 Gonçalves JA Moreira EA Rauen MS Rossi A Borgatto AF Associations between caries experience, nutritional status, oral hygiene, and diet in a multigenerational cohort Pediatr Dent 2016 38 3 203 211 27306244
39 Porcelli IC S Braga MP Corsi NM Poli-Frederico RC Maciel SM Prevalência da cárie dentária e sua relação com as condições nutricionais entre escolares de um município do sul do Brasil Clipe Odonto 2016 8 1 2 9
40 Oliveira LB Sheiham A Bönecker M Exploring the association of dental caries with social factors and nutritional status in Brazilian preschool children Eur J Oral Sci 2008 02 116 1 37 43 10.1111/j.1600-0722.2007.00507.x 18186730
41 Carvalho MF Carvalho RF Cruz FL Rodrigues PA Leite FP Chaves MG Correlação entre a merenda escolar, obesidade e cariogenicidade em escolares Odonto 2009 17 34 56 63 10.15603/2176-1000/odonto.v17n34p56-63
42 Tureli MCM Barbosa TS Gavião MB Associations of masticatory performance with body and dental variables in children Pediatr Dent 2010 32 4 283 288 20836946
43 Araujo DS Marquezin M Barbosa TS Fonseca F Fegadolli C Castelo PM Assessment of quality of life, anxiety, socio-economic factors and caries experience in Brazilian children with overweight and obesity Int J Dent Hyg 2017 11 15 4 e156 e162 10.1111/idh.12248 27699998
44 Araujo DS Klein MI Scudine KG Leite LS Parisotto TM Ferreira CM et al Salivary microbiological and gingival health status evaluation of adolescents with overweight and obesity: a Cluster analysis Front Pediatr 2020 07 8 429 10.3389/fped.2020.00429
45 Campos JA Melanda EA Antunes JS Foschini AL Dental caries and the nutritional status of preschool children: a spatial analysis Cien Saude Colet 2011 10 16 10 4161 4168 10.1590/S1413-81232011001100021 22031145
46 Silva E Rando-Meirelles M Sousa M Sigulem D Exploring oral health and childhood obesity in children from the shantytowns of São Paulo Rev Odontol Bras 2012 21 59 564 568
47 Guaré RO Perez MM Novaes TF Ciamponi AL Gorjão R Diniz MB Overweight/obese children are associated with lower caries experience than normal-weight children/adolescents Int J Paediatr Dent 2019 11 29 6 756 764 10.1111/ipd.12565 31336007
48 Xavier A Bastos RD Arakawa AM Caldana MD Bastos JR Correlation between dental caries and nutritional status: preschool children in a Brazilian municipality Rev Odontol UNESP 2013 42 5 378 383 10.1590/S1807-25772013000500010
49 Aznar FDC Análise da relação entre as condições de saúde bucal e a qualidade de vida em adolescentes com sobrepeso/obesidade e eutróficos em Bauru - SP thesis Bauru Faculdade de Odontologia de Bauru da Universidade de São Paulo 2015
50 Freitas AR Aznar FD Tinós AM Yamashita JM Sales-Peres A Sales-Peres SH Association between dental caries activity, quality of life and obesity in Brazilian adolescents Int Dent J 2014 12 64 6 318 323 10.1111/idj.12121 25123152
51 Martins RJ Moimaz SA Silva MR Saliba O Garbin CA Body mass index, dental caries and sugar intake in 2-5 year-old preschoolers Braz J Oral Sci 2014 13 3 209 212 10.1590/1677-3225v13n3a09
52 Antunes LA Machado CM Couto AC Lopes LB Sena FC Abreu FV et al A polymorphism in the MTRR gene is associated with early childhood caries and underweight Caries Res 2017 51 2 102 108 10.1159/000451037 28118645
53 Silva RA Barreiros D Oliveira S Silva LA Nelson-Filho P Küchler EC Association between body mass index and caries experience in Brazilian children and adolescents J Dent Child (Chic) 2016 09 83 3 146 151 28327265
54 Soares ME Ramos-Jorge ML Alencar BM Oliveira SG Pereira LJ Ramos-Jorge J Influence of masticatory function, dental caries and socioeconomic status on the body mass index of preschool children Arch Oral Biol 2017 09 81 69 73 10.1016/j.archoralbio.2017.04.032 28482240
55 Barbosa MCF Reis CLB Lopes CMCF Madalena IR Küchler EC Baratto-Filho F et al Assessing the association between nutritional status, caries, and gingivitis in schoolchildren: a cross-sectional study Glob Pediatr Health 2021 8 2333794X211001237 10.1177/2333794X211001237
56 Costa LR Daher A Queiroz MG Early childhood caries and body mass index in young children from low income families Int J Environ Res Public Health 2013 03 10 3 867 878 10.3390/ijerph10030867 23462435
57 Frazão P Benicio MH Narvai PC Cardoso MA Food insecurity and dental caries in schoolchildren: a cross-sectional survey in the western Brazilian Amazon Eur J Oral Sci 2014 06 122 3 210 215 10.1111/eos.12124 24754799
58 Assi SP Pires JR Pontes AE Barroso EM Zuza EP Oral conditions and body weight in children from a public school in Manaus, AM, Brazil Rev Odontol UNESP 2016 45 6 362 367 10.1590/1807-2577.09816
59 Vasconcelos K Evangelista S Silva RA Oliveira S Dutra A Santos A et al Assessing the association between dental caries and nutritional status in children from the Brazilian State of Amazonas Int J Clin Pediatr Dent 2019 12 4 293 296 10.5005/jp-journals-10005-1638 31866713
60 Rego IN Cohen-Carneiro F Vettore MV Herkrath FJ Herkrath AP Rebelo MA The association between nutritional status and dental caries in low-income children: a multilevel analysis Int J Paediatr Dent 2020 09 30 5 607 618 10.1111/ipd.12637 32115793
61 Aranha LAR Lima RV Gualberto WO Associação entre excesso de peso corporal e experiência de cárie dentária em estudantes do município de Barcelos, Amazonas, Brasil : um estudo transversal Arq Odontol 2020 56 1 9 10.7308/aodontol/2020.56.e11
62 Jamelli SR Rodrigues CS Lira PIC Nutritional status and prevalence of dental caries Oral Health Prev Dent 2010 8 1 77 84 20480058
63 Santos VE Junior Sousa RM Oliveira MC Caldas AF Junior Rosenblatt A Early childhood caries and its relationship with perinatal, socioeconomic and nutritional risks: a cross-sectional study BMC Oral Health 2014 05 14 1 47 10.1186/1472-6831-14-47
64 Pinto-Sarmento TC Abreu MH Gomes MC Costa EM Martins CC Granville-Garcia AF et al Determinant factors of untreated dental caries and lesion activity in preschool children using ICDAS PLoS One 2016 02 11 2 e0150116 10.1371/journal.pone.0150116 26900846
65 Aragão AS Fernandes LH Brandt LM Auad SM Cavalcanti AL Association between nutritional status and dental caries in Brazilian teenagers with and without risk for eating disorders Pesqui Bras Odontopediatria Clin Integr 2016 16 1 479 489 10.4034/PBOCI.2016.161.50
66 Lima AN Cárie dentária, condição periodontal e obesidade em adolescentes Piauí dissertation Teresina Faculdade de Odontologia da Universidade Federal do Piauí 2016
67 Sharma B Indushekar KR Saraf BG Sardana D Sheoran N Mavi S Are dental caries and overweight/obesity interrelated? A cross-sectional study in rural and urban preschool children J Indian Soc Pedod Prev Dent 2019 37 3 224 231 10.4103/JISPPD.JISPPD_140_18 31584020
68 Battaglia G Lages VA Sousa ML Oliveira AJ Junior Meneghim MC DE Cheicchi MHR Cárie dentária e obesidade em crianças e adolescentes em diferentes continentes Rev FAIPE 2021 10 2 25 37
69 Silva JV Machado FC Ferreira MA Social inequalities and the oral health in Brazilian capitals Cien Saude Colet 2015 08 20 8 2539 2548 10.1590/1413-81232015208.12052014 26221819
70 Modéer T Blomberg CC Wondimu B Julihn A Marcus C Association between obesity, flow rate of whole saliva, and dental caries in adolescents Obesity (Silver Spring) 2010 12 18 12 2367 2373 10.1038/oby.2010.63 20339364
71 Feldens CA Kramer PF Cascaes LC Borges TS Antoniazzi RP Vítolo MR No impact of lower intake of micronutrients on severe early childhood caries: findings from a prospective cohort study Pesqui Bras Odontopediatria Clin Integr 2015 15 1 131 142 10.4034/PBOCI.2015.151.15
72 Giacaman RA Muñoz-Sandoval C Cariogenicity of different commercially available bovine milk types in a biofilm caries model Pediatr Dent 2014 36 1 1E 6E
73 Instituto Brasileiro de Geografia e Estatística Pesquisa de orçamentos familiares 2008-2009: análise do consumo pessoal de alimentos no Brasil Rio de Janeiro Instituto Brasileiro de Geografia e Estatística 2011
74 Perez MM Pessoa JS Ciamponi AL Diniz MB Santos MT Alves HH et al Correlation of salivary immunoglobulin A with Body Mass Index and fat percentage in overweight/obese children J Appl Oral Sci 2018 11 27 0 e20180088 10.1590/1678-7757-2018-0088 30427474
75 Santin GC Pintarelli TP Fraiz FC Oliveira AC Paiva SM Ferreira FM Association between untreated dental caries and household food insecurity in schoolchildren Cien Saude Colet 2016 02 21 2 573 584 10.1590/1413-81232015212.00022015 26910164
76 Pandey S Goel M Nagpal R Kar A Rapsang E Matani P Evaluation of total salivary secretory immunoglobulin A and Mi/fans-specific SIgA among children having dissimilar caries status J Contemp Dent Pract 2018 06 19 6 651 655 10.5005/jp-journals-10024-2314 29959291
77 Passos JS Araújo TM Gomes IS Filho Cruz SS Condições de vida e saúde bucal: uma abordagem teórico conceitual das desigualdades sociais Rev Baiana Saúde Pública 2011 35 1 138 150 10.22278/2318-2660.2011.v35.n0.a152
