Genetic and Environmental Influences on Obesity-Related Phenotypes in Chinese Twins Reared Apart and Together.

The relative importance of genetic and environmental influences on obesity-related phenotypes remains unclear, and few studies have targeted the Chinese population. Here, we used Chinese twins reared apart and together to explore genetic and environmental influences on body mass index (BMI), waist circumference (WC) and waist-height ratio (WHtR), further to differentiate phenotype heritability between different age groups and genders separately and to differentiate influences of rearing environment and correlated environment. Phenotype heritability was calculated using the structural equation model in 11,401 twin pairs aged 25-85 years. BMI (0.70, 95 % confidence interval (CI) 0.66-0.74) of the total population was highly heritable, while WC (0.53, 95 %CI 0.50-0.57) and WHtR (0.48, 95 %CI 0.45-0.51) were moderately heritable. Age and gender stratified analyses found higher heritability in the younger group and males than the older group and females. The correlated environment had a greater influence on the phenotypes than the rearing environment, especially on WC and WHtR, indicating that more correlated environment actions should be taken to prevent the rising trend of abdominal obesity.