Association of maternal vitamin D status during pregnancy with bone-mineral content in off spring: A prospective cohort study

Background Maternal vitamin D status in pregnancy is a suggested determinant of bone-mineral content (BMC) in off spring, but has been assessed in small studies. We investigated this association in a large prospective study. Methods Eligible participants were mother-and-singleton-off spring pairs who had participated in the Avon Longitudinal Study of Parents and Children, and in which the mother had recorded measurements of 25(OH)D concentration in pregnancy and the off spring had undergone dual-energy x-ray absorptiometry at age 9-10 years. 25(OH)D concentrations in pregnancy were assessed per 100 nmol/L and classifi ed as suffi cient (more than 5000 nmol/L), insuffi cient (4999-2750 nmol/L), or defi cient (lower than 2750 nmol/L). Associations between maternal serum 25(OH)D concentrations and off spring total body less head (TBLH) and spinal BMC were assessed by trimester. Results 3960 mother-and-off spring pairs, mainly of white European origin, were assessed (TBLH BMC n=3960, spinal BMC n=3196). Mean off spring age was 99 years. 2644 (67%) mothers had suffi cient, 1096 (28%) insuffi cient, and 220 (6%) defi cient 25(OH)D concentrations in pregnancy, but TBLH and spinal BMC did not diff er between off spring of mothers in the lower two groups versus suffi cient 25(OH)D concentration. No associations with off spring BMC were found for any trimester, including the third trimester, which is thought to be most relevant (TBLH BMC confounder-adjusted mean diff erence -003 g per 100 nmol/L, 95% CI -171 to 165; spinal BMC 004 g per 100 nmol/L, 95% CI -012 to 021).