Vitamin D status of older women in a residential care facility in Auckland

A sample of 39 older women (aged 73-98 years) in residential care in Auckland was studied midsummer and midwinter to determine serum levels of 25-hydroxy vitamin D (25-OHD) and to estimate sun exposure using an outdoor activity questionnaire. The use of dietary supplements, sunscreens, protective clothing when outdoors, mobility and length of stay in care were also recorded. Mean 25-OHD levels for midwinter and midsummer were 10.44 mu g/L and 15.61 mu g/L, respectively. Levels indicative of frank hypovitaminosis D were found in 49% of women in winter and 33% in summer. Increased sun exposure was a predictor of increased 25-OHD levels (p = 0.004) when mobility, age, weight, clothing cover, length of stay in care and vitamin D supplements were also included in the statistical model.