Heritability of Obesity-Related Variables in Tehran Families: Tehran Lipid and Glucose Study

Abstract

Patients and Methods: This cross-sectional family-based study was conducted on 769 TLGS families in Iran. All families with two biological parents, at least one offspring (nuclear family) and at least two overweight or obese members were eligible for this study. Participants, who lacked the complete family and demographic variables were excluded. Consequently, 529 two-generation nuclear families (1066 parents and 1394 offspring) remained. Obesity-related variables, including waist circumference (WC), waist to hip ratio (WHR), body mass index (BMI), resting energy expenditure (REE), and body size (BS) were determined. Variance component method was used to estimate the age and sex adjusted heritability for obesity-related variables using SOLAR software. Results: Recruited families consisted of 2460 individuals (493 fathers, 573 mothers, 720 sons, and 674 daughters). Parents and offspring were aged 45.7 ± 10.2 and 18.4 ± 9.7 years respectively. The age and sex adjusted heritability for all obesity-related variables were significant (P < 0.0001) and varied from 0.21 (hip) to 0.51 (BS). The heritability for body size considerably surpasses the heritabilities, which were estimated in this study. Conclusions: This study indicates that Tehran families are genetically predisposed to obesity; although, inappropriate lifestyle may interfere with genetic patterns.