Prevalence of vitamin D depletion among subjects seeking advice on osteoporosis: a five-year cross-sectional study with public health implications

We assessed vitamin D nutritional status in unselected consecutive patients seeking advice on osteoporosis. The prevalence of vitamin D depletion ranged from 15-72% depending upon the cut-off levels used for serum 25-hydroxyvitamin D, and the prevalence did not change over the 5 years of the study. Introduction Vitamin D depletion is a significant public health problem and has been studied in different populations using different cut-off levels, but the optimal level is yet to be established. Methods In a cross-sectional study of 2924 patients seen for osteoporosis advice we determined the prevalence of vitamin D depletion, as assessed by 25-hydroxyvitamin D (25-OHD), using three different cut-off levels stratified by gender, race and the year of the study over 5 years. Results Mean age was 68.3 +/- 10.0 years; 90% women and 88% white. Mean 25-OHD level was 24.6 +/- 10 ng/ml and mean PTH was 48.4 +/- 32 pg/ml. The prevalence of vitamin D depletion was 15% with a cut-off level of < 15 ng/ml, and rose to 32% and 72% with cut-off levels < 20 ng/ml and < 30 ng/ml, respectively. The prevalence was higher in men and blacks and remained constant over 5 years, regardless of the cut-off level. The expected inverse relationship between 25-OHD and PTH was observed irrespective of gender or ethnicity. Conclusions The prevalence of vitamin D depletion in patients seeking advice for osteoporosis is high and did not change over the 5 years of the study.