Dietary Calcium and Serum 25-Hydroxyvitamin D Status in Relation to BMD Among U.S. Adults

Abstract

A higher calcium intake is still the primary recommendation for the prevention of osteoporosis, whereas vitamin D deficiency is often not addressed. To study the relative importance of dietary calcium intake and serum 25‐hydroxyvitamin D [25(OH)D] status in regard to hip BMD, 4958 community‐dwelling women and 5003 men ≥20 yr of age from the U.S. NHANES III population‐based survey were studied. Calcium supplement users and individuals with a prior radius or hip fracture were excluded. We calculated standardized means for BMD by quartiles of sex‐specific calcium intake for three 25(OH)D categories (p value for trend: p = 0.005) only for women with 25(OH)D status 566 mg/d) was not significantly associated with BMD at 25(OH)D concentrations >50 nM. Among men, there was no significant association between a higher calcium intake beyond the upper end of the lowest quartile (626 mg/d) and BMD within all 25(OH)D categories. Among both sexes, BMD increased stepwise and significantly with higher 25(OH)D concentrations (p value for trend: women < 0.0001; men = 0.0001). Among men and women, 25(OH)D status seems to be the dominant predictor of BMD relative to calcium intake. Only women with 25(OH)D concentrations <50 nM seem to benefit from a higher calcium intake.