
==== Front
Public Health Pract (Oxf)
Public Health Pract (Oxf)
Public Health in Practice
2666-5352
Elsevier

S2666-5352(24)00073-9
10.1016/j.puhip.2024.100536
100536
Short Communication
Temporal changes and educational disparities in the frequent consumption of sugar-sweetened beverages among Estonian adults during 2006–2022
Reile Rainer rainer.reile@tai.ee
a⁎
Oja Renata b
a Department of Epidemiology and Biostatistics, National Institute for Health Development, Tallinn, Estonia
b Institute of Psychology, University of Tartu, Tartu, Estonia
⁎ Corresponding author. rainer.reile@tai.ee
22 8 2024
12 2024
22 8 2024
8 10053618 6 2024
23 7 2024
6 8 2024
© 2024 The Authors. Published by Elsevier Ltd on behalf of The Royal Society for Public Health.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Objectives

Excessive consumption of sugar-sweetened beverages (SSBs) contributes to adverse health outcomes but is differentiated by socio-economic indicators. The study analyses the educational disparities in adults frequent consumption of sugar-sweetened beverages (SSBs) in Estonia and its temporal changes between 2006 and 2022.

Study design

Repeated cross-sectional survey.

Methods

Nationally representative data from 9 biennial cross-sectional surveys on 25–64-year-old Estonian residents (n = 20396) was used for the study. Changes in frequent (on 6–7 days per week) consumption of SSBs by study year, sex, age, and education is analysed using descriptive statistics and binomial logistic regression. Prevalence and odds ratios (OR) with 95 % confidence intervals (CIs) are presented focusing on temporal and educational patterns in frequent SSB consumption.

Results

The prevalence of frequent SSB consumption among Estonian adults declined consistently from 2006 (14.0 %) to 2018 (5.2 %), followed by statistically non-significant increases in 2020 (6.8 %) and 2022 (7.1 %). Prevalence of frequent SSB consumption was significantly (p < 0.01) higher among adults with primary or lower education (12.4 %) compared to tertiary education group (4.8 %). The educational differences in SSB consumption (12.4 % in primary or lower vs. 4.8 % in tertiary education) were nearly three-fold after adjusting for sex, age, and period effects (OR 2.84, 95 % CI 1.71–4.74) and have been consistent since 2010.

Conclusions

Although frequent consumption of SSBs has been generally decreasing among Estonian adults, the findings illustrate the persisting educational gradients in exposure that expectedly translates into socio-economic inequalities in adverse health outcomes resulting from excessive SSB consumption.

Keywords

Sugar-sweetened beverages
Health inequalities
Education
Estonia
Trends
==== Body
pmc1 Introduction

Sugar-sweetened beverages (SSB) are carbonated or non-carbonated soft drinks and other beverages that contain free sugars [1]. Due to their high calorie content, low nutritional value, and consumption patterns, the SSBs are associated with increased risk for several non-communicable diseases and higher all-cause mortality [2]. SSBs contribute also to weight gain in both children and adults [3], and have detrimental effect for oral health [4]. In the context of a recent study [5] reporting 16 % increase in intake of SSBs between 1990 and 2018 globally, the SSBs constitute a significant challenge for public health.

Social inequalities in aforementioned health outcomes are well known [6] and they extend also to underlying risk factors with those in low socioeconomic status (SES) being generally at higher risk of poorer diets [7]. Although mixed patterns for education–SSB consumption association have been observed globally [5], several earlier studies [8,9] have demonstrated that higher educational level in adulthood and higher educational intentions in adolescence are associated with less frequent consumption of SSBs. Our study focuses on the Eastern-European region where temporal trends and inequalities in SSB consumption have, to the best of our knowledge, been studied mostly in the context of adolescent population. For example, Chatelan et al. [10] demonstrated a declining trend for SSB consumption during 2002–2018 in the region with largest relative decreases found for adolescents from well-off families.

Acknowledging the potential SES variations in adult SSB consumption and its contribution to health inequalities in Eastern Europe, the study aims to analyse the temporal variations in frequent SSB consumption and its educational disparities among the adult population of Estonia.

2 Data and methods

Data from the Health Behaviour Survey among Estonian Adult Population [11], a series of nationally representative cross-sectional surveys conducted biennially since 1990 were used for this study. This study covers data from 9 consecutive surveys from 2006 to 2022 with each survey being based on an individual random sample of 5000 Estonian residents aged 16–64 years obtained from population registry. Survey response rates varied between 57.3 % in 2006 to 46.5 % in 2020. To capture educational variance based on the highest level of completed education, data was restricted to 25–64-year-olds resulting in analytic sample consisting of 9989 men and 10407 women in total.

Self-reported consumption of SSBs (soft drinks, energy drinks, flavoured water) during the past 7 days was the dependent variable, with the consumption on 6–7 days being coded as 1, and consumption on 4–5 days or less frequently as 0. Study year, sex, age, and the education of the respondent were independent variables. For education, self-reported highest level obtained education was categorised as (i) primary education or less, (ii) secondary or vocational and (iii) tertiary, the university-level higher education.

Variation in SSB consumption by independent variables was analysed using descriptive statistics and pairwise z-test with Bonferroni correction. Binomial logistic regression analysis was used to assess the effects of independent variables on SSB consumption. Several different models predicting frequent SSB consumption by independent variables were fitted with Table 1 presenting odds ratios (OR) and 95 % confidence intervals (CI) for mutually adjusted model 1 and stratified model 2. All analyses were based on weighted data using post-stratification weights provided with the data.Tabel 1 Prevalence of frequent SSB consumption and its association with independent variables in mutually adjusted (model 1) and stratified (model 2) regression analysis.

Tabel 1Variable	Total, N (%)	Prevalencea of frequent SSB consumption, % (95 % CI)	Model 1b OR (95 % CI) for frequent SSB consumption	Model 2c OR (95 % CI) for frequent SSB consumption	
primary vs tertiary education	secondary vs tertiary education	
Study year	
 2006	2290 (11.2)	14.0 (12.6–15.5)a	2.09 (1.38–3.15)	1.62 (1.05–2.52)	1.56 (1.14–2.15)	
 2008	2406 (11.2)	13.1 (11.7–14.5)a	1.67 (1.10–2.53)	1.76 (1.11–2.80)	1.83 (1.32–2.55)	
 2010	2453 (12.0)	9.4 (8.3–10.6)b	1.23 (0.79–1.91)	1.21 (0.69–2.12)	1.78 (1.24–2.55)	
 2012	2449 (12.0)	9.0 (7.9–10.2)b,c	0.69 (0.42–1.14)	3.44 (1.96–6.02)	3.09 (1.99–4.81)	
 2014	2167 (10.6)	6.5 (5.5–7.6)c,d	0.73 (0.44–1.19)	3.29 (1.77–6.13)	2.01 (1.27–3.18)	
 2016	2352 (11.5)	5.8 (4.9–6.9)d	0.55 (0.33–0.92)	3.64 (2.06–6.42)	2.26 (1.40–3.66)	
 2018	2178 (10.7)	5.2 (4.3–6.2)d,e	0.58 (0.35–0.94)	2.85 (1.57–5.20)	1.97 (1.24–3.15)	
 2020	2009 (9.8)	6.8 (5.8–8.1)b,c,d	0.71 (0.44–1.15)	3.04 (1.73–5.36)	2.41 (1.53–3.80)	
 2022	2091 (10.3)	7.1 (6.0–8.3)b,c,d	1	3.26 (1.94–5.48)	1.53 (1.01–2.31)	
Sex	
 Male	9989 (49.0)	12.0 (11.3–12.6)a	2.20 (1.97–2.45)	2.23 (1.80–2.77)	2.05 (1.73–2.43)	
 Female	10407 (51.0)	5.5 (5.1–6.0)b	1	2.60 (1.91–3.53)	1.84 (1.49–2.27)	
Age	
 25–34	5315 (26.1)	10.0 (9.2–10.8)a	1.43 (1.23–1.66)	2.05 (1.53–2.76)	1.91 (1.54–2.38)	
 35–44	5215 (25.6)	8.6 (7.8–9.4)a,b	1.15 (0.98–1.34)	3.49 (2.39–5.09)	2.74 (2.05–3.67)	
 45–54	5141 (25.2)	8.6 (7.8–9.4)a,b	1.15 (0.98–1.35)	1.96 (1.34–2.88)	1.36 (1.05–1.76)	
 55–64	4724 (23.2)	7.2 (6.4–8.0)b	1	2.56 (1.70–3.84)	2.25 (1.61–3.15)	
Education level	
 Primary or lower	2327 (11.4)	12.4 (11.1–13.9)a	2.84 (1.71–4.74)	n/a	n/a	
 Secondary/vocational	11190 (55.0)	10.2 (9.7–10.8)b	1.41 (0.94–2.12)	n/a	n/a	
 Tertiary	6816 (33.5)	4.8 (4.3–5.4)c	1	n/a	n/a	
n/a - Not available for stratified model.

a Values in categories not sharing the same subscript are significantly different (p < 0.05) from each other based on pairwise z-test with Bonferroni correction.

b Adjusted to sex, age, education, study year and study year*education interaction term.

c Adjusted and stratified to sex, age, education, study year (the stratifying variable is omitted from factors included in the model).

3 Results

In 2006, 14.0 % of Estonian adults aged 25–64 consumed SSBs on 6–7 days per week (Table 1). During 2006–2018, the prevalence of frequent SSB consumption declined consistently reaching 5.2 % in 2018. Data from 2020 to 2022 indicates that respective prevalence has recently increased (7.1 % in 2022), yet the difference compared to 2018 does not reach statistical significance. However, statistically significant differences in SSB consumption were observed for age, sex, and education. The latter is of key interest and demonstrates gradual association with SSB consumption – the prevalence of frequent SSB consumption among respondents with primary education (12.4 %) is significantly higher compared to both secondary/vocational (10.2 %) and tertiary education (4.8 %) groups.

In univariate regression analysis (data not shown), all independent variables were statistically significant (p < 0.05) predictors of frequent SSB consumption with younger respondents, males, and those with less than tertiary education having higher odds for being frequent consumers of SSBs. In mutually adjusted (incl. interaction term between study year and education; other tested combinations did not reach statistical significance at p < 0.05) Model 1, the effects were slightly attenuated, but retained their significance with substantial variance in SSB consumption by study year, sex, age, and education. Statistically significant temporal effects were found for 2006 and 2008 (OR respectively 2.09 and 1.67 compared to 2022) and for 2016 and 2018 (OR respectively 0.58 and 0.55 compared to 2022). Respondents with primary or lower education had nearly threefold odds for being frequent SSB consumers compared to tertiary education (OR 2.84, 95 % CI 1.71–4.74). To analyse the educational gradient in SSB consumption, stratified analyses were performed (Model 2). In this, the categories of both primary and lower and secondary or vocational education were associated with increased odds for frequent SSB consumption compared to tertiary education in dose-response manner (except for 2010 when the difference between primary and tertiary education was non-significant).

4 Discussion

By studying educational disparities in SSB consumption, we found that the overall prevalence of frequent SSB consumption has decreased during the study period among adult population in Estonia. We also demonstrated that lower education was associated with higher odds for frequent SSB consumption, and the educational gradient has persisted during the past decade.

We found a nearly three-fold difference between primary and tertiary education in frequent SSB consumption. These findings on the socio-economic variation in SSB consumption patterns are in accordance with several earlier studies [8,10,12,13]. For example, Elfassy et al. [13] found that in addition to the poverty level of residential areas and individual deprivation, adults with lower education had higher SSB consumption. Moreover, similarly to studies from Norway [12] and Brazil [8], our findings suggest that frequent SSB consumption among adults is declining. Within the national context, public health initiatives under the framework of National Health plan 2009–2020 [14] could be seen as one potential explanation. While the prevalence of frequent SSB consumption declined consistently from 2006 to 2018, the prevalence ratio (albeit statistically non-significantly) has increased again in 2020 and 2022. Based on data provided in recent national health report [15], the possible reasons for this could be related to intertwined effects of health behaviour and mental health resulting from the COVID-19 pandemic, the conflict in Ukraine and economic recession. Another temporal aspect worth considering is the non-significant difference in SSB consumption (OR 1.21, p = n.s.) between primary and tertiary education groups in 2010 data. This time point refers to the economic recession following the 2008 global financial crisis and it is plausible that resulting income shock affected disproportionately more individuals in lower economic status, forcing them to change their dietary patterns including SSB consumption. However, the causes underlying changing SSB consumption do not fall into the scope of this study and warrant further research.

Some data-related aspects need to be considered when interpreting these findings. First, the repeated cross-sectional data does not allow causal inferences between education (and other demographic factors) and SSB consumption to be made. Secondly, only frequency estimates (covering 7-day period) for SSBs were available in survey data. Although this measure does not necessarily correspond to the sugar intake (and thus the direct health risks) from SSB consumption, the high threshold used in this study for defining frequent SSB consumption (on 6–7 days per week) could be interpreted as a behavioural risk indicator. Despite these considerations, the use of nationally representative and methodologically comparable long-term data can be seen as the strengths of this study.

Our findings on the declining trend yet persisting educational disparities in SSB consumption among adults in Estonia provide insights on the social patterning of SSB as a dietary risk factor in Eastern Europe. The temporally stable educational gradients in exposure translate expectedly into socio-economic differentials in adverse health outcomes resulting from excessive SSB consumption. Given the potentially income-related reduction of educational differences in 2010 data, the results illustrate the price-elasticity of SSBs and thus provide indirect support for public health policy measures that target the affordability of SSBs.

Ethics

Study uses anonymized secondary data from population health surveys, thus Ethical Approval for this study was not needed nor sought. All waves of initial survey have been previously approved by Tallinn Medical Research Ethic Commitee.

Funding

No funding was sought for this study.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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