Maternal vitamin D and offspring trabecular bone score.

Abstract

Trabecular bone score (TBS), a novel tool derived from dual-energy X-ray absorptiometry (DXA), reflects the microarchitecture of the vertebrae. It has been shown to predict fracture independent of standard DXA parameters in adult populations. Previously, we demonstrated that maternal serum 25-hydroxyvitamin D (25(OH)D) during pregnancy is associated with offspring bone mineral content at age 11years. However, associations with TBS have not been explored, thus we aimed to determine associations between maternal 25(OH)D and offspring TBS. Data were collected from the Vitamin D in Pregnancy (VIP) study. Venous blood samples were taken at recruitment and at 28-32weeks' gestation. Maternal 25(OH)D was measured by radioimmunoassay. Offspring (n=195, n=181 with complete measures) underwent spine DXA (GE Lunar), at age 11years (median=10.9 (IQR 10.9-11.4)). TBS was calculated using TBS iNsight software. Offspring of mothers with sufficient 25(OH)D levels (≥50nmol/L) at recruitment had a higher TBS (1.363 vs. 1.340, p=0.04). In multivariable linear regression models, after adjustment for child relative lean mass, sex and pubertal stage, a 10nmol/L increase in maternal 25(OH)D was associated with a 0.005 (95% CI 0.000, 0.010, p=0.04) increase in TBS. However when stratified by sex (p for interaction=0.16), the association was significant in boys, but not girls. There were no associations with TBS and maternal 25(OH)D at 28-32weeks. We speculate that maternal 25(OH)D in early pregnancy may be associated with TBS in offspring at age 11 in boys. These hypothesis-generating findings warrant confirmation with larger interventional and long-term follow-up studies.