Birth-weight and resting metabolic rate in adulthood - sex-specific differences

Introduction. Low birth-weight is associated with an increased risk of cardiovascular disease, hypertension, and the metabolic syndrome (MetS) in adulthood. Resting metabolic rate (RMR) has been suggested to be associated with the development of obesity as well as MetS and might be an indirect indicator of sympathetic activity. This study's aim was to examine the association between birth-weight and adult RMR. Methods. A total of 896 men and women from the Helsinki Birth Cohort Study born 1934-44, for whom a detailed set of birth records were available, underwent measurement of body composition and RMR in adulthood. Results. Among women, birth-weight adjusted for age and fat-free mass (FFM) was inversely associated with RMR (r = -0.12; P < 0.01). For men, a u-shaped relationship was observed, both independently and after adjustment for age, fat mass, and FFM (P = 0.05 for final model). Discussion. The sex-specific differences for the association between birth-weight and adult RMR might partly be explained by differences in the developmental programming of the sympathetic nervous system between men and women. The higher adjusted RMR among those with the lowest birth-weights is consistent with previous evidence of higher sympathetic drive among these individuals.