Bone mineral density at age 7 years does not associate with adherence to vitamin D supplementation guidelines in infancy or vitamin D status in pregnancy and childhood: an Odense Child Cohort study

Vitamin D supplementation in infancy is recommended to prevent rickets. At the population level, its effects on bone mineralisation are largely unknown. We aimed to explore whether adherence to national vitamin D supplementation guidelines (10 mu g/d up to the age of 2 years), supplementation at the ages of 5 and 7 years, and serum 25-hydroxyvitamin D (s-25(OH)D) at various time points associated with bone mineral density (BMD) at the age of 7 years in the Odense Child Cohort, Denmark (n 1194). High adherence was defined as supplementation with 10 mu g of vitamin D 6-7 times per week during >= 80 % of the observation time. s-25(OH)D was analysed using LC-MS/MS. Total-body-less-head (TBLH) BMD was measured by dual-energy X-ray absorptiometry. At the median age of 18 center dot 1 months, 53 center dot 9 % (n 475/881) reported high adherence. The median s-25(OH)D was 64 center dot 7, 78 center dot 8, 46 center dot 0 and 71 center dot 8 nmol/l in early pregnancy, late pregnancy, cord blood and at 5 years, respectively. The mean TBLH BMD at the median age of 7 center dot 1 years was 0 center dot 613 (SD 0 center dot 049) g/cm(2) (z-score +0 center dot 363 (SD 0 center dot 824)). In adjusted analyses, vitamin D supplementation up to 18 months, and at 5 and 7 years, was not associated with TBLH BMD. Similarly, no robust associations were found between TBLH BMD and s-25(OH)D at any time point. No associations were found for TBLH bone mineral concentration or bone area. In this population with relatively high s-25(OH)D concentrations, no consistent associations were found between adherence to vitamin D supplementation recommendations or vitamin D status in pregnancy or childhood, and bone mineralisation at the age of 7 years.

Automated summary

The study found no consistent association between adherence to vitamin D supplementation guidelines, as well as vitamin D status during pregnancy and childhood, in populations with relatively high s-25(OH)D concentrations, and bone mineralisation at the age of 7 years.