Birth weight and body composition in young adult men - a prospective twin study

OBJECTIVES: To evaluate the association between birth weight and adult body composition in twins, controlling for maternal and genetic influences. DESIGN: Twins were randomly selected from the East Flanders Prospective Twi n Survey, a population-based historic twin cohort. SUBJECTS: Male members of 229 twin pairs between 18 and 34y of age who part icipated in the Prenatal Programming Twin Study. MEASUREMENTS: Adult body mass, height, BMI, lean body mass, sum of skinfold s and waist-to-hip-ratio. Lean body mass, sum of skinfolds and waist-to-hip -ratio were also adjusted for body mass. Intra-pair difference in adult ant hropometric measures between the heaviest and the lightest twin at birth. RESULTS: Per kg increase in birth weight, body mass (4.2 kg), height (3.3 c m), lean body mass (3.1 kg) and to a lesser extent BMI (0.49 kg /m(2)) incr eased, whereas waist-to-hip-ratio (-1.4%) and sum of skinfolds (-0.11 s.d.) decreased, when adjusted for body mass. In a pair-wise analysis, the heavi er twin at birth was taller and heavier as an adult, but, when adjusted for body mass, he had a lower waist-to-hip-ratio, less subcutaneous fat, and m ore lean body mass, compared to his lighter sib. Intra-pair difference in b ody composition was associated with intra-pair birth weight difference in m onozygotic and dizygotic twins. CONCLUSIONS: An adverse intra-uterine environment, as measured by birth wei ght, is associated with more subcutaneous and abdominal fat and less lean b ody mass in adulthood. This association is independent of maternal and gene tic influences. However, we cannot exclude the existence of genes that act on both birth weight and adult body composition.