Prevalence of hypovitaminosis D in elderly women in Italy: clinical consequences and risk factors

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Abstract
In order to evaluate the prevalence, risk factors, and clinical consequences of hypovitaminosis D in elderly Italian women a multicenter study of 43 osteoporosis centers from all regions of Italy was carried out. Study population included 700 women aged 60–80 years in whom blood was taken for 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) measurements. All subjects were also questioned to assess the prevalence of several risk factors for hypovitaminosis D, osteoporotic fractures and activities of daily living (ADL). Values of 25OHD lower than 5 ng/ml were found in 27% of the women and lower than 12 ng/ml in 76%. 25OHD and PTH levels were negatively correlated (r=−0.38, after logarithmic transformation of both variables). 25OHD levels significantly declined with advancing age and number of pregnancies and were positively correlated with educational level (years spent at school), dairy calcium intake, and days spent on holiday by the sea. In a multivariate model including all these variables, the only one that remained significant was the level of education. The lowest age-adjusted 25OH D levels were found in smokers or in women living in central Italy as compared with those living in northern or southern Italy. The mean (±SD) age-adjusted 25OH D values were significantly lower in women who sustained a hip fracture (7.1±2.2 versus 11.0±9.9). Women with low 25OHD levels (<12 ng/ml) had worse scores for ADL and mobility ADL (move outdoors, use stairs, walk at least 400 m, carry a heavy object). Vitamin D deficiency is extremely common among elderly Italian women. Women with lower educational level, living in central Italy, smokers or with lower intake of dairy products are at greater risk. Hypovitaminosis D is associated with worsening of the ability to perform activities of daily living and higher hip fracture prevalence. This finding should lead to an urgent population-based strategy to remedy this condition.