
==== Front
BMC Public Health
BMC Public Health
BMC Public Health
1471-2458
BioMed Central London

20080
10.1186/s12889-024-20080-0
Study Protocol
Camp-style lifestyle modification program (CAMP) for diabetes prevention among rural women with prior GDM: study protocol for a three-arm cluster hybrid type 2 randomized controlled trial
Chen Yao 1
Zhong Qinyi 2
Lv Wencong 3
Long Qing 1
Wang Man Ping 4
Chen Jyu-Lin 5
Willey James Allen 6
Whittemore Robin 7
Guo Jia guojia621@163.com

1
1 https://ror.org/00f1zfq44 grid.216417.7 0000 0001 0379 7164 Xiangya School of Nursing, Central South University, 172 Tongzipo Road, Changsha, Hunan 410013 China
2 https://ror.org/027m9bs27 grid.5379.8 0000 0001 2166 2407 Manchester Centre for Health Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PL UK
3 https://ror.org/056swr059 grid.412633.1 The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
4 https://ror.org/02zhqgq86 grid.194645.b 0000 0001 2174 2757 School of Nursing, University of Hong Kong, Hong Kong, 100872 China
5 grid.266102.1 0000 0001 2297 6811 Department of Family and Community Medicine, University of California, San Francisco, San Francisco, CA 94118 USA
6 grid.266102.1 0000 0001 2297 6811 Philip R. Lee Institute for Health Policy Research, University of California, San Francisco, San Francisco, CA 94118 USA
7 https://ror.org/03v76x132 grid.47100.32 0000 0004 1936 8710 School of Nursing, Yale University, New Haven, CT 06520 USA
20 9 2024
20 9 2024
2024
24 257011 9 2024
13 9 2024
© The Author(s) 2024
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Background

Intensive lifestyle interventions were effective to reduce the risk of type 2 diabetes mellitus (T2DM) for women with gestational diabetes mellitus (GDM) history. However, reaching these mothers and maintaining participation in lifestyle interventions is suboptimal in real-world settings. Effective, feasible and sustainable new lifestyle interventions are needed. The objectives of this three-arm trial are to (1) compare diabetes risk outcomes of an evidence-based intensive lifestyle modification (ILSM) intervention, a camp-style lifestyle modification program (CAMP) intervention, and usual care among women with GDM history; and (2) evaluate the comparative efficacy of the CAMP versus ILSM intervention on implementation outcomes.

Methods

A three-arm cluster randomized clinical trial (RCT) using a hybrid type 2 implementation design will be conducted in two counties in Hunan province in China. Six towns from each county will be randomly selected and assigned to CAMP, ILSM, and the usual care group (25 women from each of 12 towns, 100 women in each arm). The ILSM includes six biweekly in-person sessions and 3-month telephone health consultations, while the CAMP consists of a 2-day camp-based session and 3-month health consultations via a popular social media platform. Both interventions share the same session content, including six lifestyle skills. Efficacy (T2DM risk score and behavioral, anthropometric, psychosocial, and glycemic variables) and implementation outcomes (recruitment, acceptability, feasibility, fidelity, and cost-effectiveness) will be collected at baseline, 6-month, and 12-month. Pre-planned ANOVA F-test and generalized estimating equations will be included to test time-by-arm interactions.

Discussion

The CAMP intervention is expected to have better reach, better attendance, and comparable effectiveness in reducing the risk of T2DM, thus improving postpartum care for GDM in China. The delivery of a concentrated format supplemented with technology-based support may provide an efficient and effective delivery model for implementing maternal health promotion programs in primary care settings.

Trial registration

Registered in the Chinese Clinical Trial Registry (ChiCTR2200058150) on 31st March 2022.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-024-20080-0.

Keywords

Woman
Gestational diabetes Mellitus
Prevention
Type 2 diabetes Mellitus
Implementation
Hybrid type 2 Randomized Control Design
issue-copyright-statement© BioMed Central Ltd., part of Springer Nature 2024
==== Body
pmcBackground

Gestational diabetes mellitus (GDM) is one of the most common complications in pregnancy, with a global prevalence of 10.6% [1, 2]. GDM affects 17.6% of pregnant women in mainland China, with a 3.5-fold increase over the past decade [3]. Women with GDM history had higher risks of developing type 2 diabetes mellitus (T2DM) later in life is 7-fold higher than those who had normal glycemia during pregnancy [4–6]. Lifestyle interventions are recommended as the first-line approach to prevent T2DM globally given the lower cost and scalability without side effects [7]. However, the effectiveness is tempered by variability in the design of the clinical trials and real-world conditions, which may limit wide-spread implementation to a broader audience [8, 9].

We have developed and confirmed the effectiveness of a group-based lifestyle intervention called Intensive LifeStyle Modification (ILSM), including six in-person sessions held every 2 weeks for 12 weeks and five monthly telephone-based sessions (provided by local nurses) [10]. Significant improvement in reducing T2DM risk among mothers (aged 31.9 ± 4.9 years) with GDM history in rural China was demonstrated [11–13]. However, the implementation outcomes (recruitment rate 54.1%, attendance 65.0%) [13] fell below benchmark rates of 80% [14]. Such outcomes were comparable to the recent implementation studies of lifestyle interventions targeting women with GDM history, which showed 10–64% of young mothers (33.8 ± 5.2 yrs) attended and completed all sessions, and 43% did not attend a single session [8, 15]. Reach and attendance among young mothers in health promotion interventions is a worldwide challenge [15].

Young mothers in our study reported barriers to attend the intervention sessions because of time constraints and difficulties in keeping appointments at frequent group-based sessions although in-person interpersonal interaction was attractive to them. In addition, the local nurse also proposed that frequent and decentralized sessions increased the workload of the organization and management. Taken together, stakeholders from providers and users positively endorsed a concentrated intervention held over weekends or long holidays combined with technology-assisted support to reduce the providers’ workload and improve participation. These findings echo those in the literature, stating that frequent schedule adjustment and transportation are the main barriers women face in health promotion programs [16]. A concentrated format supplemented with technology-based support may be an effective delivery format of intervention alternatives in primary maternal healthcare settings, especially in rural areas when resources are limited.

Camp-based programs offer a novel implementation strategy, that may improve participation by providing a concentrated intervention for those who face transportation barriers or schedule conflicts [17]. This format has been used in health education for patients with chronic health conditions (e.g., diabetes, cancer) [17], but little is known about the benefits of preventing chronic illness among high-risk groups who are not aware of the disease burden [18, 19]. However, more than a single camp session is needed to change and maintain lifestyle behaviors to prevent T2DM [18]. Maintenance sessions are needed after camp sessions to provide assessment, education, and ongoing behavioral support [18, 20]. Other implementation strategies for intervention providers such as external facilitation, peer comparison, and feedback during the camp and ongoing consultation sessions, could increase their passion and capability to engage in implementation; and these performances were also found to influence participants’ engagement in interventions [21]. Thus, an adapted ILSM intervention via cooperating with these implementation strategies for intervention providers may reach a wider audience, facilitate participation, and maintain efficacy among women with prior GDM.

This study aims to: (1) compare the efficacy outcomes (T2DM risk score, behavioral, anthropometric, psychosocial, and glycemic variables) among an evidence-based intensive lifestyle modification (ILSM) intervention, a camp-style lifestyle modification program (CAMP) intervention, and usual care among women with prior GDM; (2) evaluate the comparative efficacy of CAMP versus ILSM intervention on implementation outcomes (recruitment rate, acceptability, feasibility, fidelity, cost-effectiveness).

Methods

In this study, we will use a three-arm, clustered RCT with a hybrid type 2 implementation design [22] to compare efficacy and implementation outcomes among the CAMP program, ILSM program, and usual care. The trial was registered in the Chinese Clinical Trial Registry (ChiCTR2200058150) and will be conducted in accordance with the rules of Good Clinical Practice outlined in the Declaration of Helsinki. Ethics approval has been obtained from the Ethics Review Committee (E2021162). The study flowchart is displayed in Fig. 1.

Fig. 1 Flowchart of the project

Setting and randomization

This study will be conducted in Hunan province, which is representative of Central South China in geography (mixed plains and mountainous areas), climate (humid subtropical), demographics (Han and multi-minorities), developing economy, and health policy. To enhance generalizability, Yongding County which comprises 17 towns with a large ethnic minority population in Western Hunan, and You County, which comprises 14 towns with a large ethnically Han population in Eastern Hunan, were selected. These two counties represent different cultures, lifestyles, and ethnic groups in Hunan province, but have similar population sizes and birth rates. Six towns from each county (a total of 12 towns) will be randomly selected as clusters and assigned at random to three different arms using a randomization protocol available on the internet (http://stattrek.com/statistics/random-number generator.aspx). No specific eligibility criteria are identified for towns.

Study participants

The target population includes women from the selected towns with a history of GDM. Inclusion criteria are a history of GDM, ≥ 18 years of age, at least 6 weeks but within 3 years postpartum, intending to live in the research county for at least 2 years, having smartphones access, and being able to speak Chinese. Exclusion criteria: plan to be pregnant in the next 2 years, currently pregnant, have been diagnosed with T2DM, take medications that influence glucose metabolism, physical or cognitive disability, current history of substance abuse, history of severe psychiatric disorder, or previous participation in a lifestyle intervention.

The power calculations for sample size estimates are conducted based on the primary hypothesis of the superiority of CAMP and ILSM than control group for T2DM risk scores and insulin resistance. For women with a history of GDM who have relatively normoglycemic status, T2DM risk scores with a comprehensive assessment of potential risk factors are a more sensitive and stabling indicator. The risk score has also been widely used in tracking the effectiveness of intervention to prevent diabetes over time, such as in Finland, Germany and India [23–25]. At the same time, 75-g oral glucose tolerance test (OGTT-2 h) are also selected as co-primary outcomes because of its ability to identify isolated post-challenge hyperglycaemia. In this study, we assumed a decrease in the T2DM risk score and OGTT-2 h by 2 points and 0.87 mmol/L, respectively of ILSM (based on previous results) and CAMP groups and an interclass correlation coefficient of 0.2 for cluster randomization. Recruitment of at least 20 participants per town will provide over 80% power at alpha = 0.05. Allowing for attrition within 12 months, we will recruit a total of 300 participants, with 25 per town.

Recruitment

We will recruit the participants through recruitment flyers and telephone invitations. The two county-level hospitals which have the largest birth number in the respective counties were selected as the research sites. Recruitment flyers containing inclusion criteria and contact information will be posted there and the town level hospitals. Telephone invitations will also be conducted by trained local registered nurse from the two county-level hospitals. First, they will review the medical records of the women who delivered babies in either the maternal health care providers of each county will allow us to identify potential participants. These women who meet inclusion criteria will receive a phone call from nurses to explain the purpose of the study and determine interest in participation. Once potential participants express their interest, nurses will confirm their eligibility and invite them to participate. Signed informed consent will be obtained in-person. The recruitment rate and reasons why women decline to participate will also be documented.

Intervention

Intervention content

All participants will receive usual care based on current clinical guidelines and recommendations for T2DM prevention, including general information about their diabetes risk, the importance of lifestyle behavior, and a recommendation for diabetes screening every 3 years. As part of usual care, a brochure on diabetes prevention of the six lifestyle skills (i.e., orientation and goal setting, healthy eating patterns, physical activity, stress management, family support on healthy lifestyle patterns, and relapse prevention) will be provided to each participant. The CAMP and ILSM interventions are guided by Social Cognitive Theory [26]. Both interventions share the same session content with the aforementioned six lifestyle skills with different delivery format, as described below.

Participants in the ILSM group will receive the intervention following the ILSM protocol [11]. The program comprises six biweekly, in-person group-based sessions and five biweekly telephone health consultations for three months. Each in-person session will last 90 min, and each telephone health consultation will last about 20 min (100 min in total). Telephone sessions will be conducted one week after each in-person session, to review of progress toward dietary, physical activity and goals, identify challenges faced in achieving goals, assist with setting new action plans, and encourage achievement of goals [11].

Participants in the CAMP group will receive the intervention following the CAMP protocol which was finalized based on a pilot study (n = 25). The intervention includes a 2-day camp-based session and 3-month maintenance sessions via WeChat which is the most commonly used social media platform in China. Six lifestyle skills in six sessions with the same length and content as the ILSM program will be presented over 2 days. Maintenance health consultations will be provided once a day for 3 months via a WeChat mini-program (Software copyright owned by our team, No.2021SR1055662), which has been tested for usability and acceptability with the target population. Participants will be asked to watch a 1-minute video on the six lifestyle skills promotion which was developed and evaluated by the experts panel. And then, they need to answer five multi-choice questions based on the specific video content. The short video-based tool kit includes 90 videos. In addition, participants will be encouraged to comment or ask questions in a chat community or chat privately with the trained local nurses about their goal achievement and challenges with feedback provided within 24 h during working days. Privacy settings of the WeChat mini program will be used to safeguard personal information.

Intervention delivery

Twelve local registered nurses (6 per county/hospital) will be trained to work as the local project field officers and each nurse will be responsible for organizing a group of 25 participants from each town. The research team will go to counties to train each nurse for one intervention arm they are responsible for (i.e., CAMP, ILSM, or usual care). The CAMP or ILSM training will include self-study, class sessions, and live practice, which is anticipated to take two days, with homework and practice required between training. Training will cover orientation of the project’s goals; protection of human subjects; protocol and documentation; motivational interviewing techniques for behavioral change; team roles, responsibilities, and supervision. These nurses will be responsible for making site arrangements, conducting the interventions, and scheduling onsite data collection with the participants for each group. Details of an intervention’s content will be provided using a specified protocol and manual for each group. A research assistant will serve as a resource person at each research site and attend sessions to prompt the nurses if they overlooked any content or activity via a fidelity checklist.

Implementation strategies

Appropriate implementation strategies will be adopted to improve the participation of targeted women and intervention providers. The 2-day concentrated sessions of CAMP group will be held on weekends accompanied by themed meals or visiting activities (e.g., Hospital History Museum, Health Education Gallery) to increase the feasibility and attractiveness of interventions. Child care, air conditioning, transportation and/or accommodation allowance, healthful snacks, and drinks will also be provided at the CAMP and ILSM in-person sessions. The follow-up maintenance sessions will be delivered via WeChat to facilitate participation and outreach only for CAMP group.

A private social media group will be set up for nurses to share success and challenges in intervention implementation. The principal investigator and research assistants are available to answer questions or provide advice regarding the implementation and send daily verbal encouragement and compliments to each nurse. Peer learning activities will also be held through regular webinars (once a week for a total of 12 sessions) to discuss successes and challenges and share experiences for implementing the recruitment and intervention. They will receive stepped incentives/allowances (money and honors) according to their performance.

Blinding

Due to the nature of the interventions, it is not possible to mask participants or nurses in the group assignments. All data assessors will be blinded to group assignments, and allocation will be concealed from the study statistician in charge of developing and conducting the statistical analysis program. To avoid contamination, the nurses and participants will be asked to sign a non-disclosure agreement not to share the training materials or protocol with others before the completion of the study.

Data collection and measurement

To guide evaluation of the implementation outcomes of interventions, we will use the RE-AIM model which assesses an intervention’s potential for sustainable implementation in real-world settings [27]. We will evaluate reach, efficacy, and implementation due to time constraints. The trained data assessors (i.e., research assistants who do not know the group assignment) will collect data at the research sites. Self-report questionnaire data will be collected by paper and pencil; anthropometric data will be measured at baseline (T-0), 6-month (T-1), and 12-month (T-2); and glycemic outcomes will only be measured at T-0 and T-2. The trained local nurses will call all participants to remind them of upcoming data collection sessions. All implementation outcomes during the study period will be documented by trained research assistants. On completing each data collection, participants will receive 50 RMB for their time and transportation.

Demographic and clinical characteristics

Sociodemographic factors (age, marital status, education, occupation, annual household income, and ethnicity), health characteristics (smoking status, alcohol consumption, pre-pregnancy BMI, gestational weight gain, parental history of diabetes, GDM), and clinical characteristics (diagnosis of GDM, number of pregnancies, pregnancy complications, birth weight of children, gestation week at delivery, treatment for GDM) will be collected by a self-report survey at baseline.

Efficacy outcomes (efficacy domain)

The primary outcomes

The primary outcomes include a comprehensive T2DM risk score and the biomarkers of insulin resistance. T2DM risk score will be measured by the Chinese Diabetes Risk Scale (CHINARISK) [28], adapted from the Canadian Diabetes Risk Questionnaire and widely validated in the Chinese population. The questionnaire’s sensitivity is 73%, with a positive predictive value of 57% and a negative predictive value of 78%. The biomarkers of insulin resistance will include glucose values on the oral 75 g glucose 2 h post-load glucose tolerance test (OGTT-2 h). Blood samples will be collected after 12 h of fasting, followed by blood samples taken 2 h after consuming 75 g of glucose.

The secondary outcomes

The secondary outcomes include anthropometric (BMI, and waist circumference), behavioral (dietary intake, intention to eat Low Glycemic Index Foods, physical activity, daily steps), and psychological (self-efficacy and social support for diet and physical activity) outcomes.

Anthropometric outcomes

BMI will be calculated by dividing each participant’s body weight in kilograms by their height in meters squared (kg/m2). Waist circumference will be measured on a horizontal plane, midway between the inferior margin of the ribs and the superior border of the iliac crest.

Behavioral outcomes

Dietary intake will be assessed by the validated food frequency questionnaire [29] to collect information on staple foods, legumes, vegetables, fruits, and dairy consumed in the past 3 months. The Intention to Eat Low Glycemic Index Foods will be assessed with a 24-item questionnaire that uses a 7-point Likert scale, on which higher scores indicate a greater intention to eat low glycemic-index foods. The Cronbach’s α ranged from 0.78 to 0.93 in previous studies. Physical activity will be assessed by the validated Chinese version of the International Physical Activity Questionnaire (Short Form) [30] to recall the intensity and duration of physical activities during the past 7 days. Daily steps will be measured on 7 consecutive days using the StepWatch Activity Monitor on their smartphone.

Psychological outcomes

Self-efficacy and social support for diet and physical activity will be assessed by an 8-item Diet and Physical Activity Self-efficacy Scale - the Chinese version [31] and the validated Social Support for Diet and Physical Activity Scale of the Chinese version [32], respectively. These four scales are scored on a 4-point scale, with higher scores indicating higher levels of individual self-efficacy and social support for eating and exercise. The Cronbach’s α for the Dietary Self-Efficacy Scale and the Physical Activity Self-Efficacy Scale ranged from 0.93 to 0.95 and 0.87–0.97, respectively, and ranged from 0.86 to 0.89 and 0.78–0.87 Dietary Social Support Scale and the Physical Activity Social Support Scale.

Implementation outcomes

Reach domain

Recruitment rate, eligibility exclusions, and enrollment will be calculated. Reasons for declining participation or not completing the study will be documented.

Implementation domain

Individual level: Acceptability of the ILSM and CAMP programs will be collected by a self-report 4-item satisfaction questionnaire which was finalized according to our intervention content; feasibility will be evaluated by attendance, attrition, and engagement of each intervention. Organizational level: Fidelity will be recorded by a trained research assistant using a fidelity checklist, which aligns with the content and sequence for each session. Cost will be measured by the costs accruing to the health and social care system and to individuals and families for the intervention and for health care, including inpatient and ambulatory care, medicines, personnel costs to deliver the ILSM, and other procedures and treatments. We will also assess the costs falling on individuals and families for non-medical costs (travel, child-minding, and time / lost income).

Data analysis

Data confidentiality will be ensured, both during the implementation phase of the study and in any resulting presentations or publications. All statistical analyses will be conducted using SPSS (version 26). Descriptive statistics such as frequency, percentage, and mean will be used to summaries all outcomes and variables. Intention-to-treat (ITT) analysis will be used in which participants who lose contact or drop out in the follow-ups will be treated as a failure to achieve any efficacy outcome. Multiple imputations will be used to compute missing data for efficacy outcome variables. Baseline group comparisons will be conducted by chi-square test, Fisher’s exact test, or Kruskal-Wallis test depending on variable types and distribution. Bonferroni corrections were used for multiple comparisons, with p < 0.05/n (n is the number of subgroups) considered statistically significant.

For Aim 1, we expect both the CAMP and ILSM programs to be superior to usual care for all efficacy outcomes. If both intervention arms are shown to be effective, a secondary exploratory analysis will be planned to evaluate if CAMP is more effective than ILSM. Estimates and significance testing will be done using repeated measures analysis of variance. We will test the normality of residuals using standard tests and supplement the ANOVA F-test for interactions with robust GEE (generalized estimating equation) estimates of the group by time interactions using a Wald Chi-Square Test. We expect the time path of efficacy-related outcomes for the CAMP and ILSM programs to be similar enough to accept the null hypothesis (CAMP and ILSM) by time interactions. If we observe meaningful and significant differences between the CAMP and ILSM programs, we will characterize them with respect to time (baseline, 6 months, 12 months) and the nature of the outcome. The cluster, potential baseline covariates, such as age, months after delivery, ethnicity, education, marriage, occupation, and family income will be controlled to adjust estimates for cluster differences and control variance inflation.

Comparison of implementation outcomes in Aim 2 will focus on (a) measuring and testing differentials in rates of recruitment and retention and (b) data collected from participants on the acceptability and feasibility. We will also calculate the operation cost for each intervention; this consisted of expenses on manpower and materials needed for training, recruitment and intervention delivery.

Discussion

This is one of the first studies to examine the effectiveness and implementation of two delivery formats of interventions (standard in-person sessions versus hybrid camp-style sessions) aimed at reducing the risk for diabetes among women with a GDM history. The camp sessions include the same intervention content as the ILSM standard sessions but via a more concentrated delivery format, the follow-up sessions on a social media platform versus telephone sessions for the ISLM group, which may allow for more support and motivation via communication with other participants. In the proposed study, it is hypothesized that the camp-style intervention will be as effective as the ISLM in-person format in reducing T2DM risk but the camp-style format will reach a wider audience and improve participation. If successful, the camp-style format may be applied to other lifestyle interventions and become a model for implementing diabetes prevention interventions in primary care settings.

We will incorporate principles of pragmatic trials and implementation science by using a type 2 hybrid effectiveness-implementation design instead of the traditional sequential scientific approach (moving from clinical efficacy to effectiveness and then implementation) which requires significant time and resources [22]. The hybrid design allows for the simultaneous evaluation of efficacy and implementation outcomes, thus addressing gaps in clinical efficacy and actual use of interventions in real-world practice. The evaluation of hybrid designs involves careful attention to assessing outcomes related to both clinical effectiveness and implementation success, and we will evaluate the implementation outcomes based on the RE-AIM framework. The framework has been used extensively to improve the development and evaluation of complex interventions that have a greater likelihood of wide-spread implementation and sustainability in clinical practice.

This study has four notable strengths: (1) we propose a novel implementation strategy: camp-style intervention delivery format with a social media-based maintenance tool kit in maternal health promotion, which may reach a wider audience of women with GDM history in a cost-effective way; (2) the intervention will be delivered by local registered nurses who will receive unified training, which may facilitate reach and sustainability under limited labor and material resources conditions; (3) optimized implementation strategies, such as standardized training material and video-facilitating technology to ensure intervention fidelity, peer learning/champion-experience sharing activities and stepped incentive/allowance to increase motivation and capability, will be adopted; (4) a robust RCT design methodology including cluster randomization, masking of data collection and analysis, and intervention fidelity evaluation, will be used. In addition, we also developed some refined strategies with local health workers to ensure successful implementation of the study. For example, recruitment will start in March as it is the end of the Chinese New Year Festival of a long holiday when people tend to create personal goals, including health-related goals, and our lifestyle programs address both physical and psychological needs [33].

The researchers acknowledge several weaknesses: (1) we are unable to assess change in the incidence of T2DM, which will be infrequent at 12 months; (2) the self-report measurements for physical activity may have recall bias, although the daily step will also be evaluated by the StepWatch Activity Monitor on a smartphone; (3) clustered nature is prone to variance inflation, but we will minimize this risk by adjusting for clusters as a confounder; (4) we considered randomizing multiple local nurses from the same site to different conditions to ensure homogeneity, this would have presented a potential risk of contamination due to close contacts exist among these nurses, but confidentiality measures, such as signing non-disclosure agreement will be adopted.

This hybrid implementation-effectiveness study has the potential to illuminate the processes and complexities associated with supporting the adoption of an evidence-based program in resource-limited settings. If successful, a camp-style lifestyle program may contribute to widespread reach, better attendance, and intervention effectiveness in reducing the risk of T2DM, thus offering a novel, promising approach in implementing a maternal health promotion program in rural areas. This study will provide RCT-level evidence on camp-style lifestyle programs to the evidence-based clinical practice guidelines and is likely to provide valuable insight into T2DM prevention in low-resource areas.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary Material 1

Acknowledgements

The authors thank the China Medical Board to support this study.

Author contributions

YC was responsible for conceptualizing and designing study, writing and revising manuscript, and preparing for publication. QZ contributed to literature review of related research and was a major contributor in writing the Introduction part of manuscript. WL and QL focused on methodology and were major contributors in designing and implementation of intervention. JC, RW and MP Wang participated in conceptualization, and revising and editing manuscript. JW focused on writing the part of sample size calculation, randomization and data analysis. JG was responsible for study design and conceptualization, methodology, project administration, resources and review. All authors read and approved the final manuscript.

Funding

China Medical Board (Grant Number: 21–424) and Innovation Project of Graduate Students of Central South University in 2023 (Number: 2023zzts994).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The study has been approved by the Ethical Review Board of Xiangya School of Nursing Central South University (NO. E2021162) and registered in Chinese Clinical Trial Registry (ChiCTR2200058150) on 31st March 2022. The trial will be conducted in accordance with the rules of Good Clinical Practice outlined in the Declaration of Helsinki. Potential participants will be all informed about the study in writing and orally. The information will describe the purpose and process of the study, the method used and publication plans. The information will also include confidentiality assurance, the principles for voluntary participation and included contact information to the researcher and organization behind the study. The written information will also include a form for obtaining a written informed consent. All the participants need sign and return the written informed consent prior to participation.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Abbreviations

T2DM Type 2 diabetes mellitus

GDM Gestational diabetes mellitus

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
==== Refs
References

1. Metzger BE, Coustan DR. Summary and recommendations of the Fourth International Workshop-Conference on Gestational Diabetes Mellitus. The Organizing Committee. Diabetes Care. 1998;21 Suppl 2:B161-7.
2. Behboudi-Gandevani S Amiri M Bidhendi Yarandi R Ramezani Tehrani F The impact of diagnostic criteria for gestational diabetes on its prevalence: a systematic review and meta-analysis Diabetol Metab Syndr 2019 11 11 10.1186/s13098-019-0406-1 30733833
Behboudi-Gandevani S, Amiri M, Bidhendi Yarandi R, Ramezani Tehrani F. The impact of diagnostic criteria for gestational diabetes on its prevalence: a systematic review and meta-analysis. Diabetol Metab Syndr. 2019;11:11.30733833
3. Yan B Yu Y Lin M Li Z Wang L Huang P High, but stable, trend in the prevalence of gestational diabetes mellitus: a population-based study in Xiamen, China J Diabetes Investig 2019 10 5 1358 64 10.1111/jdi.13039 30869198
Yan B, Yu Y, Lin M, Li Z, Wang L, Huang P, et al. High, but stable, trend in the prevalence of gestational diabetes mellitus: a population-based study in Xiamen, China. J Diabetes Investig. 2019;10(5):1358–64.30869198
4. Bellamy L Casas JP Hingorani AD Williams D Type 2 diabetes mellitus after gestational diabetes: a systematic review and meta-analysis Lancet 2009 373 9677 1773 9 10.1016/S0140-6736(09)60731-5 19465232
Bellamy L, Casas JP, Hingorani AD, Williams D. Type 2 diabetes mellitus after gestational diabetes: a systematic review and meta-analysis. Lancet. 2009;373(9677):1773–9.19465232
5. Heida KY Franx A van Rijn BB Eijkemans MJ Boer JM Verschuren MW Earlier age of onset of chronic hypertension and type 2 diabetes Mellitus after a hypertensive disorder of pregnancy or gestational diabetes Mellitus Hypertension 2015 66 6 1116 22 10.1161/HYPERTENSIONAHA.115.06005 26459420
Heida KY, Franx A, van Rijn BB, Eijkemans MJ, Boer JM, Verschuren MW, et al. Earlier age of onset of chronic hypertension and type 2 diabetes Mellitus after a hypertensive disorder of pregnancy or gestational diabetes Mellitus. Hypertension. 2015;66(6):1116–22.26459420
6. Bower JK Butler BN Bose-Brill S Kue J Wassel CL Racial/Ethnic differences in diabetes screening and hyperglycemia among US women after gestational diabetes Prev Chronic Dis 2019 16 E145 10.5888/pcd16.190144 31651379
Bower JK, Butler BN, Bose-Brill S, Kue J, Wassel CL. Racial/Ethnic differences in diabetes screening and hyperglycemia among US women after gestational diabetes. Prev Chronic Dis. 2019;16:E145.31651379
7. Albright AL Gregg EW Preventing type 2 diabetes in communities across the U.S.: the National Diabetes Prevention Program Am J Prev Med 2013 44 4 Suppl 4 S346 51 10.1016/j.amepre.2012.12.009 23498297
Albright AL, Gregg EW. Preventing type 2 diabetes in communities across the U.S.: the National Diabetes Prevention Program. Am J Prev Med. 2013;44(4 Suppl 4):S346–51.23498297
8. Haw JS Galaviz KI Straus AN Kowalski AJ Magee MJ Weber MB Long-term sustainability of diabetes Prevention approaches: a systematic review and Meta-analysis of Randomized clinical trials JAMA Intern Med 2017 177 12 1808 17 10.1001/jamainternmed.2017.6040 29114778
Haw JS, Galaviz KI, Straus AN, Kowalski AJ, Magee MJ, Weber MB, et al. Long-term sustainability of diabetes Prevention approaches: a systematic review and Meta-analysis of Randomized clinical trials. JAMA Intern Med. 2017;177(12):1808–17.29114778
9. Awoonor-Williams JK Appiah-Denkyira E Bridging the intervention-implementation gap in primary health care delivery: the critical role of integrated implementation research BMC Health Serv Res 2017 17 Suppl 3 772 10.1186/s12913-017-2663-8 29297396
Awoonor-Williams JK, Appiah-Denkyira E. Bridging the intervention-implementation gap in primary health care delivery: the critical role of integrated implementation research. BMC Health Serv Res. 2017;17(Suppl 3):772.29297396
10. Zhong Q Chen Y Luo M Lin Q Tan J Xiao S The 18-month efficacy of an intensive LifeStyle modification program (ILSM) to reduce type 2 diabetes risk among rural women: a cluster randomized controlled trial Global Health 2023 19 1 6 10.1186/s12992-023-00910-3 36703168
Zhong Q, Chen Y, Luo M, Lin Q, Tan J, Xiao S, et al. The 18-month efficacy of an intensive LifeStyle modification program (ILSM) to reduce type 2 diabetes risk among rural women: a cluster randomized controlled trial. Global Health. 2023;19(1):6.36703168
11. Guo J Tang Y Wiley J Whittemore R Chen JL Effectiveness of a diabetes prevention program for rural women with prior gestational diabetes mellitus: study protocol of a multi-site randomized clinical trial BMC Public Health 2018 18 1 809 10.1186/s12889-018-5725-x 29954367
Guo J, Tang Y, Wiley J, Whittemore R, Chen JL. Effectiveness of a diabetes prevention program for rural women with prior gestational diabetes mellitus: study protocol of a multi-site randomized clinical trial. BMC Public Health. 2018;18(1):809.29954367
12. Li M, Lin Q, Shi J, Xi Y, Xiang C, Yong C et al. The impact of Lifestyle intervention on Dietary Quality among Rural women with previous gestational diabetes Mellitus-A Randomized Controlled Study. Nutrients. 2021;13(8).
13. Guo J, Long Q, Yang J, Lin Q, Wiley J, Chen JL. The efficacy of an intensive lifestyle modification program on psychosocial outcomes among rural women with prior gestational diabetes Mellitus: six months Follow-Up of a Randomized Controlled Trial. Int J Environ Res Public Health. 2021;18(4).
14. Treweek S Pitkethly M Cook J Fraser C Mitchell E Sullivan F Strategies to improve recruitment to randomised trials Cochrane Database Syst Rev 2018 2 2 Mr000013 29468635
Treweek S, Pitkethly M, Cook J, Fraser C, Mitchell E, Sullivan F, et al. Strategies to improve recruitment to randomised trials. Cochrane Database Syst Rev. 2018;2(2):Mr000013.29468635
15. Baucom KJW Pershing ML Dwenger KM Karasawa M Cohan JN Ozanne EM Barriers and facilitators to Enrollment and Retention in the National Diabetes Prevention Program: perspectives of women and clinicians within a Health System Womens Health Rep (New Rochelle) 2021 2 1 133 41 34036296
Baucom KJW, Pershing ML, Dwenger KM, Karasawa M, Cohan JN, Ozanne EM. Barriers and facilitators to Enrollment and Retention in the National Diabetes Prevention Program: perspectives of women and clinicians within a Health System. Womens Health Rep (New Rochelle). 2021;2(1):133–41.34036296
16. Aziz Z Mathews E Absetz P Sathish T Oldroyd J Balachandran S A group-based lifestyle intervention for diabetes prevention in low- and middle-income country: implementation evaluation of the Kerala Diabetes Prevention Program Implement Sci 2018 13 1 97 10.1186/s13012-018-0791-0 30021592
Aziz Z, Mathews E, Absetz P, Sathish T, Oldroyd J, Balachandran S, et al. A group-based lifestyle intervention for diabetes prevention in low- and middle-income country: implementation evaluation of the Kerala Diabetes Prevention Program. Implement Sci. 2018;13(1):97.30021592
17. Holbein CE Murray CB Psihogios AM Wasserman RM Essner BS O’Hara LK A camp-based psychosocialiIntervention to promote independence and social function in individuals with spina bifida: moderators of treatment effectiveness J Pediatr Psychol 2013 38 4 412 24 10.1093/jpepsy/jst003 23435204
Holbein CE, Murray CB, Psihogios AM, Wasserman RM, Essner BS, O’Hara LK, et al. A camp-based psychosocialiIntervention to promote independence and social function in individuals with spina bifida: moderators of treatment effectiveness. J Pediatr Psychol. 2013;38(4):412–24.23435204
18. Park SY Kim SY Lee HM Hur KY Kim JH Lee MK Diabetes Camp as Continuing Education for Diabetes Self-Management in Middle-aged and Elderly people with type 2 diabetes Mellitus Diabetes Metab J 2017 41 2 99 112 10.4093/dmj.2017.41.2.99 28447438
Park SY, Kim SY, Lee HM, Hur KY, Kim JH, Lee MK, et al. Diabetes Camp as Continuing Education for Diabetes Self-Management in Middle-aged and Elderly people with type 2 diabetes Mellitus. Diabetes Metab J. 2017;41(2):99–112.28447438
19. Driscoll CFB Murray CB Holbein CE Stiles-Shields C Cuevas G Holmbeck GN Camp-based psychosocial intervention dosage and changes in independence in young people with spina bifida Dev Med Child Neurol 2019 61 12 1392 9 10.1111/dmcn.14250 30980543
Driscoll CFB, Murray CB, Holbein CE, Stiles-Shields C, Cuevas G, Holmbeck GN. Camp-based psychosocial intervention dosage and changes in independence in young people with spina bifida. Dev Med Child Neurol. 2019;61(12):1392–9.30980543
20. Santiprabhob J Likitmaskul S Kiattisakthavee P Weerakulwattana P Chaichanwattanakul K Nakavachara P Glycemic control and the psychosocial benefits gained by patients with type 1 diabetes mellitus attending the diabetes camp Patient Educ Couns 2008 73 1 60 6 10.1016/j.pec.2008.05.023 18606522
Santiprabhob J, Likitmaskul S, Kiattisakthavee P, Weerakulwattana P, Chaichanwattanakul K, Nakavachara P, et al. Glycemic control and the psychosocial benefits gained by patients with type 1 diabetes mellitus attending the diabetes camp. Patient Educ Couns. 2008;73(1):60–6.18606522
21. Ford JH 2nd, Vranas L, Coughlin D, Selle KM, Nordman-Oliveira S, Ryther B, et al. Effect of a standard vs enhanced implementation strategy to improve antibiotic prescribing in nursing homes: a Trial Protocol of the improving management of urinary tract infections in nursing institutions through facilitated implementation (IMUNIFI) study. JAMA Netw Open. 2019;2(9):e199526.
22. Curran GM Bauer M Mittman B Pyne JM Stetler C Effectiveness-implementation hybrid designs: combining elements of clinical effectiveness and implementation research to enhance public health impact Med Care 2012 50 3 217 26 10.1097/MLR.0b013e3182408812 22310560
Curran GM, Bauer M, Mittman B, Pyne JM, Stetler C. Effectiveness-implementation hybrid designs: combining elements of clinical effectiveness and implementation research to enhance public health impact. Med Care. 2012;50(3):217–26.22310560
23. Heller S Lingvay I Marso SP Philis-Tsimikas A Pieber TR Poulter NR Development of a hypoglycaemia risk score to identify high-risk individuals with advanced type 2 diabetes in DEVOTE Diabetes Obes Metab 2020 22 12 2248 56 10.1111/dom.14208 32996693
Heller S, Lingvay I, Marso SP, Philis-Tsimikas A, Pieber TR, Poulter NR, et al. Development of a hypoglycaemia risk score to identify high-risk individuals with advanced type 2 diabetes in DEVOTE. Diabetes Obes Metab. 2020;22(12):2248–56.32996693
24. Schmiedel K Mayr A Fießler C Schlager H Friedland K Effects of the lifestyle intervention program GLICEMIA in people at risk for type 2 diabetes: a cluster-randomized controlled trial Diabetes Care 2015 38 5 937 9 10.2337/dc14-2206 25784662
Schmiedel K, Mayr A, Fießler C, Schlager H, Friedland K. Effects of the lifestyle intervention program GLICEMIA in people at risk for type 2 diabetes: a cluster-randomized controlled trial. Diabetes Care. 2015;38(5):937–9.25784662
25. Alssema M Vistisen D Heymans MW Nijpels G Glümer C Zimmet PZ The evaluation of screening and early detection strategies for type 2 diabetes and impaired glucose tolerance (DETECT-2) update of the Finnish diabetes risk score for prediction of incident type 2 diabetes Diabetologia 2011 54 5 1004 12 10.1007/s00125-010-1990-7 21153531
Alssema M, Vistisen D, Heymans MW, Nijpels G, Glümer C, Zimmet PZ, et al. The evaluation of screening and early detection strategies for type 2 diabetes and impaired glucose tolerance (DETECT-2) update of the Finnish diabetes risk score for prediction of incident type 2 diabetes. Diabetologia. 2011;54(5):1004–12.21153531
26. Bandura A Social cognitive theory: an agentic perspective Annu Rev Psychol 2001 52 1 26 10.1146/annurev.psych.52.1.1 11148297
Bandura A. Social cognitive theory: an agentic perspective. Annu Rev Psychol. 2001;52:1–26.11148297
27. Glasgow RE Vogt TM Boles SM Evaluating the public health impact of health promotion interventions: the RE-AIM framework Am J Public Health 1999 89 9 1322 7 10.2105/AJPH.89.9.1322 10474547
Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE-AIM framework. Am J Public Health. 1999;89(9):1322–7.10474547
28. Guo J Shi Z Chen JL Dixon JK Wiley J Parry M Translation and validation of the Canadian diabetes risk assessment questionnaire in China Public Health Nurs 2018 35 1 18 28 10.1111/phn.12380 29285800
Guo J, Shi Z, Chen JL, Dixon JK, Wiley J, Parry M. Translation and validation of the Canadian diabetes risk assessment questionnaire in China. Public Health Nurs. 2018;35(1):18–28.29285800
29. Li YPHY, Zhai FY, Yang XG, Hu XQ, Zhao WH et al. Comparison of assessment of food intakes by using 3 dietary survey methods. Zhonghua Yu Fang Yi Xue Za Zhi [Chinese journal of preventive medicine]. 2006;40(4):273–80.
30. Qu NNLK. Study on the reliability and validity of international physical activity questionnaire (Chinese Vision, IPAQ). Zhonghua Liu Xing Bing Xue Za Zhi = Zhonghua liuxingbingxue zazhi. 2004;25(3):265–8.
31. Sallis JFPR, Grossman RM, Patterson TL, Nader PRJHER. The development of self-efficacy scales for healthrelated diet and exercise behaviors1988.
32. Sallis JF Grossman RM Pinski RB Patterson TL Nader PR The development of scales to measure social support for diet and exercise behaviors Prev Med 1987 16 6 825 36 10.1016/0091-7435(87)90022-3 3432232
Sallis JF, Grossman RM, Pinski RB, Patterson TL, Nader PR. The development of scales to measure social support for diet and exercise behaviors. Prev Med. 1987;16(6):825–36.3432232
33. Rössner SM Hansen JV Rössner S New Year’s resolutions to lose weight–dreams and reality Obes Facts 2011 4 1 3 5 10.1159/000324861 21372604
Rössner SM, Hansen JV, Rössner S. New Year’s resolutions to lose weight–dreams and reality. Obes Facts. 2011;4(1):3–5.21372604
