Overweight and risk of type 2 diabetes: A prospective Chinese twin study.

OBJECTIVES: This study aimed to estimate the association between overweight and type 2 diabetes mellitus (T2DM) in twins, and further to explore whether genetic and early-life environmental factors account for this association. METHODS: This study included 31,197 twin individuals from the Chinese National Twin Registry (CNTR). Generalized estimating equation (GEE) models were applied for unmatched case-control analysis. Conditional logistic regressions were used in co-twin matched case-control analysis. Logistic regressions were fitted to examine the differences in odds ratios (ORs) from the GEE models and conditional logistic regressions. Bivariate genetic model was used to explore the genetic and environmental correlation between body mass index (BMI) and T2DM. RESULTS: In the GEE model, overweight was associated with a higher T2DM risk (OR=2.71, 95% confidence interval (CI): 1.96∼3.73), compared with participants with normal BMI. In the multi-adjusted conditional logistic regression, the association was still significant (OR=2.60, 95% CI: 1.15∼5.87). The ORs from the unmatched and matched analyses were different (P = 0.042). Particularly, overweight could increase T2DM risk in monozygotic (MZ) twins, and the difference in ORs between the unmatched and matched designs was significant (P = 0.014). After controlling for age and sex, the positive BMI-T2DM association was partly due to a significant genetic correlation (rA= 0.31, 95% CI: 0.20∼0.41). CONCLUSIONS: Our findings suggest that genetics and early-life environments might account for the observed overweight-T2DM association. Genetic correlation between BMI and T2DM further provides evidence for the influence of overlap genes on their association.

School-based Hygiene Intervention to Prevent HelicObacter Pylori infection among childrEn (SHIP HOPE): protocol for a cluster-randomised controlled trial.

INTRODUCTION: Helicobacter pylori infection rates are high in China and worldwide, and maintaining good hygiene is effective in preventing H. pylori infection. Childhood is a critical stage for developing good hygiene practices. Therefore, in this study, we aimed to explore whether a comprehensive hygiene intervention can prevent H. pylori infection in primary schools in China. METHODS AND ANALYSIS: The School-based Hygiene Intervention to Prevent HelicObacter Pylori infection among childrEn study is a cluster-randomised controlled trial, which will include approximately 2400 children in grades 2-4 from 60 classes in 10 primary schools of Linqu County, Shandong Province. Schools will be randomly assigned (1:1) via a computer-generated list, to receive either comprehensive hygiene intervention (intervention) or the usual health education lessons (control), with stratification by area (urban or rural). The interventions will include the following: (1) Children's education: lessons and cartoon books designed to provide basic knowledge about hygiene, H. pylori, hand hygiene, diet and oral hygiene will be provided to children; (2) Caregiver's education: children will be empowered to share hygiene-related knowledge with their caregivers as homework; caregivers will be also invited to the school for hygiene lessons; (3) School hygiene promotion: suggestions will be provided for improving the hygienic environment. Children in control schools will receive usual health education lessons according to the arrangements of each school. The primary outcome is the prevalence and incidence of H. pylori infection among children at 1-year follow-up. The secondary outcomes are H. pylori and hygiene knowledge, family eating customs and hygiene practices among children and their caregivers, as well as school absences owing to diarrhoea. Additionally, growth in children is set as an exploratory outcome. General linear mixed models will be used to analyse differences between the intervention and control schools. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the Institution Review Board of Tsinghua University (No: 20220020). Written informed consent will be obtained from each child and one of their caregivers. The findings of this study will be actively disseminated through scientific publications and conference presentations. TRIAL REGISTRATION NUMBER: ChiCTR2200056191.

The Roles of Genetic and Early-Life Environmental Factors in the Association Between Overweight or Obesity and Hypertension: A Population-Based Twin Study.

Aims/Hypothesis: We aimed to explore whether and to what extent overweight or obesity could increase the risk of hypertension, and further to estimate the roles of genetic and early-life familial environmental factors in their association. Methods: This prospective twin study was based on the Chinese National Twin Registry (CNTR), which collected information from self-report questionnaires. We conducted unmatched case-control analysis to examine the association between overweight or obesity and hypertension. And further to explore whether genetics and familiar environments shared within a twin pair, accounted for their association via co-twin matched case-control design. Generalized estimating equation (GEE) models and conditional logistic regressions were used in the unmatched and matched analyses, respectively. Then, we used logistic regressions to test the difference in odds ratios (ORs) between the unmatched and matched analyses. Finally, through bivariate twin model, the roles of genetic and environmental factors in the body mass index (BMI)- hypertension association were estimated. Results: Overall, we included a total of 30,617 twin individuals, of which 7533 (24.6%) twin participants were overweight or obesity and 757 (2.5%) developed hypertension during a median follow-up time of 4.4 years. In the GEE model, overweight or obesity was associated with a 94% increased risk of hypertension (OR=1.94, 95% confidence interval (CI): 1.64~2.30). In the conditional logistic regression, the multi-adjusted OR was 1.80 (95% CI: 1.18~2.74). The difference in OR between unmatched and matched analyses was significant (P=0.016). Specifically, overweight or obesity was not associated with hypertension risk in the co-twin design when we full controlled genetic and familiar environmental factors (OR=0.89, 95 CI: 0.46~1.72). After controlling for age and sex, we found the positive BMI-hypertension association was mainly explained by a genetic correlation between them (rA= 0.59, 95% CI: 0.44~1.00). Conclusions/Interpretation: Genetics and early-life environments shared by participants within a twin pair appear to account for the association between overweight or obesity and hypertension risk.