Low calcium intake and inadequate vitamin D status in postmenopausal osteoporotic women

Abstract

An observational cross-sectional study was conducted to assess calcium intake and vitamin D status by measurement of 25-hydroxyvitamin D (25(OH)D), in postmenopausal osteoporotic women (PMOW) treated and untreated for osteoporosis. To assess the influence of sunlight exposure on vitamin D status, the study group was categorized on the basis of sunlight exposure (above or below 2500 sunlight h/year). A group of 336 PMOW older than 65 years was identified (190 [56.5%] treated and 146 [43.5%] untreated for osteoporosis). The demographic and clinical data of the PMO women included history of prior fractures, pharmacological treatments and dietary calcium intake. BMD was measured by DEXA and 25(OH)D was determined by an HPLC method.

Results: vitamin D serum levels were lower in the untreated group as compared with the treated group (58±27 vs. 67±27nmol/l; p=0.006). Prevalence of vitamin D deficiency (cut-off point set at <50nmol/l) was higher in the non-treated group (43.8% vs. 29.5%; p=0.009). Nearly all PMOW, whether treated or not for osteoporosis had a total calcium intake of less than 1200mg. Sunlight exposure did not influence the vitamin D status.

Conclusions: vitamin D deficiency and an insufficient calcium intake are highly prevalent in both treated and untreated Spanish PMOW older than 65 years. This can be related to low therapeutic adherence and/or insufficient prescription. Therefore physician's and patient's knowledge regarding the optimization of vitamin D status and calcium intake should be improved and implemented. This article is part of a Special Issue entitled 'Vitamin D workshop'.