Vitamin D deficiency among older women with and without disability

Background: Vitamin D deficiency is associated with bone loss and bone frac tures, and the identification of vulnerable populations is important to cli nical practice and public health. Objective: The objectives of this study were to determine the prevalence of vitamin D deficiency and to examine associated risk factors for vitamin D deficiency in older women. Design: We measured serum concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], intact parathyroid hormone (PTH), o steocalcin, and ionized calcium in women aged greater than or equal to 65 y who were participating in the Women's Health and Aging Study I, an observa tional study of women representing the approximately one-third most disable d women living in the community, and women aged 70-80 y who were participat ing in the Women's Health and Aging Study I, an observational study of wome n among the two-thirds Least disabled women living in the community in Balt imore. Results: The women were classified into 3 domains of physical disability. A mong 371 women with 0 or 1 domain of disability and 682 women with greater than or equal to 2 domains of disability, 6.2% and 12.6%, respectively, had vitamin D deficiency [serum concentrations of 25(OH)D < 25 nmol/L]. In uni variate analyses, risk factors for vitamin D deficiency included increasing age, black race, low educational level, high body mass index, high triceps skinfold thickness, increasing level of disability, winter season, and ele vated creatinine concentration. In multivariate models, black race had a st rong association with vitamin D deficiency when other risk factors were adj usted for. Conclusions: Vitamin D deficiency, a preventable disorder, is a common and important public health problem for older disabled women living in the comm unity; black women are at higher risk than are white women.