Parameters related to 25-OH-D levels in a population-based study of women

We surveyed calcidiol levels (25-OH-D) in a geographically-defined population of 373 women, ages 20-80 yr to test for an association between occult osteomalacia and excess bone loss. Bone mass was measured by photon densitometry and an estimate of vitamin D was determined by measuring dietary and supplemental intake as well as sunlight exposure equivalent. The relationship of smoking practices, alcohol use, exogenous estrogen use, and medications to calcidiol level was assessed. Calcidiol levels were not associated with bone mass levels observed at two different forearm sites. Low levels of calcidiol, indicative of generalized vitamin D deficiency, were not observed in this population though mean estimates of vitamin D intakes from food 119 +/- 148 IU) or food and supplements (319 +/- 463 IU) were less than the Recommended Dietary Allowance (400 IU). Calcidiol was significantly associated with estimates of vitamin D intake from food (r = 0.11), supplement use (r = 0.21), and sunlight equivalent exposure (r = 0.26). Calcidiol levels were negatively related to age (p = 0.0020) and positively related to exogenous estrogen use and premenopausal state independent of age.