Sex-specific associations of birth weight with measures of adiposity in mid-to-late adulthood: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Background/Objectives: To investigate sex-specific associations of birth weight with body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) in mid-to-late adulthood.Subjects/Methods: ELSA-Brasil is a multicenter cohort study of adults aged 35-74 years affiliated with universities or research institutions of six capital cities in Brazil. After exclusions, we investigated 11 636 participants. Socio-demographic factors and birth weight were obtained by interview. All anthropometry was directly measured at baseline. We categorized birth weight as low (≤2.5 kg); normal (2.5-4 kg) and high (≥4 kg). We performed analysis of covariance (ANCOVA) for continuous outcomes and ordinal logistic regression for categorical adiposity outcomes. We examined interaction on the multiplicative scale by sex and by race. Results: High birth weight uniformly predicted greater overall and central obesity in men and women. However, low (vs normal) birth weight, in ANCOVA models adjusted for participant age, family income, race, education, maternal education, and maternal and paternal history of diabetes, was associated with lower BMI, WC and WHR means for men, but not for women (P interaction =0.01, <0.0001 and <0.0001, respectively). In similarly adjusted ordinal logistic regression models, odds of obesity (odds ratio (OR)=0.65, 0.46-0.90) and of being in the high (vs low) tertile of WC (OR=0.66, 0.50-0.87) and of WHR (OR=0.79, 0.60-1.03) were lower for low (vs normal) birth weight men, but trended higher (BMI: OR=1.18, 0.92-1.51; WC: OR=1.21, 0.97-1.53; WHR: OR=1.44, 1.15-1.82) for low (vs normal) birth weight women. Conclusions: In this Brazilian sample of middle-aged and elderly adults who have lived through a rapid nutritional transition, low birth weight was associated with adult adiposity in a sex-specific manner. In men, low birth weight was associated with lower overall and central adult adiposity, while in women low birth weight was generally associated with greater central adiposity.