Familial resemblance of adiposity-related parameters: results from a health check-up population in Taiwan

The mechanisms of obesity is still unclear, however, genetic and environmental factors are two major possible causes of obesity. The purpose of this study was to assess the degree of familial resemblance of different obesity-related parameters in a health check-up population in Taiwan. We measured body mass index (BMI), waist-to-hip ratio (WHR) and percentage of body fat (BFAT) anthropometrics in 1724 members of 431 families participating in the MJ Health Screening program. Each family contributed four members, i.e. father, mother, son, and daughter. All the participants were free from coronary heart disease, hypertension, diabetes, dyslipidemia, and generally in good health. The degree of familial aggregation was measured by heritability that was calculated based on age-adjusted familial (parent-offspring, sibling, spouse) correlations. The maximal heritability estimates were 39, 30 and 35% for BMI, WHR and BFAT, respectively. For WHR, the correlation between spouses was not significant and the heritability appears to be predominantly due to genetic causes. Furthermore, for BMI and BFAT, the spouse correlations were 0.08 and 0.11, respectively. The heritabilities for BMI and BFAT were mostly explained by genetic factors and familial environmental factors such as dietary habits or physical activity. The familial resemblance of various obesity-related parameters was moderate in a health check-up population in Taiwan. While the heritability for WHR appears to be mainly due to genetic factors, the familial resemblance for BMI and percentage of BFAT may involve both genetic and familial environmental factors.