Maternal vitamin D status during pregnancy and childhood bone mass at age 9 years: a longitudinal study

In a longitudinal study, the authors studied 198 children born in 1991â€“92 in a hospital in Southampton, UK; the body build, nutrition, and vitamin D status of their mothers had been characterised during pregnancy. The children were followed up at age 9 years to relate these maternal characteristics to their body size and bone mass. 49 (31%) mothers had insufficient and 28 (18%) had deficient circulating concentrations of 25(OH)-vitamin D during late pregnancy. Reduced concentration of 25(OH)-vitamin D in mothers during late pregnancy was associated with reduced whole-body (r=0Â·21, p=0Â·0088) and lumbar-spine (r=0Â·17, p=0Â·03) bone-mineral content in children at age 9 years. Both the estimated exposure to ultraviolet B radiation during late pregnancy and the maternal use of vitamin D supplements predicted maternal 25(OH)-vitamin D concentration (p<0Â·0001 and p=0Â·0110, respectively) and childhood bone mass (p=0Â·0267). Reduced concentration of umbilical-venous calcium also predicted reduced childhood bone mass (p=0Â·0286).