Intrauterine programming of adult body composition.

Epidemiological studies suggest an association between weight in infancy and the risk of osteoporosis in later life. The extent to which this reflects environmental influences on skeletal growth and metabolism before birth or during the first year of postnatal life remains uncertain. We therefore examined the association between birth weight and adult body composition (bone, lean, and fat mass) in a cohort of 143 men and women, aged 70-75 yr, who were born in Sheffield, UK, and still lived there. The subjects underwent assessment of body composition by dual energy x-ray absorptiometry. Neonatal anthropometric information included birth weight, birth length, head size, and abdominal circumference. There were significant (P < 0.01) positive associations between birth weight and adult, whole body, bone, and lean mass among men and women. These were mirrored in significant (P < 0.03) associations between birth weight and bone mineral content at the lumbar spine and femoral neck. Associations between birth weight and whole body fat were weaker and not statistically significant. The associations of birth weight with whole body bone mineral and lean mass remained statistically significant after adjustment for age, sex, and adult height. They also remained significant after adjustment for cigarette smoking, alcohol consumption, dietary calcium intake, and physical inactivity. These data are in accord with previous observations that anthropometric measures in infancy are associated with skeletal size in adulthood. The presence of these relationships at birth adds to the evidence that bone and muscle growth may be programmed by genetic and/or environmental influences during intrauterine life.