[Heritability of body mass index on Chinese adult twins from nine provinces/cities in China].

Objective: To explore the heritability of body mass index (BMI) in twins across different regions and genders in China.
Methods: A total of 11 122 adult twin pairs from the Chinese National Twin Registry were interviewed. A structural equation model was used to estimate the heritability of BMI.
Results: This study included 6 226 monozygotic twin pairs and 4 896 dizygotic twin pairs, with the age range as 25-85 (39.0 ± 10.8) years. Under stratified analysis by region, results showed that the highest and lowest rates on heritability of BMI in men were seen in Tianjin and Zhejiang, as 67.8% (95% CI: 50.1%-85.8%) and 42.1% (95% CI: 27.2%-60.9%), while in women were seen in Sichuan and Heilongjiang as 56.2% (95% CI: 47.5%-70.0%) and 11.2% (95% CI: 0.0%-31.7%), respectively. Results from the stratified analysis showed that, by gender, the heritability of BMI in men was higher than that in women from the same region. The biggest differences of heritability of BMI between men and women were seen in Heilongjiang as 55.3% (95% CI: 35.5%-80.0%) and 11.2% (95% CI: 0-31.7%), while the smallest differences were seen in Sichuan as 61.5% (95% CI: 40.7%-86.4%) and 56.2% (95% CI: 47.5%-70.0%), respectively.
Conclusion: The heritability of BMI across different regions and genders showed certain differences in the Chinese twins.