Vitamin D deficiency as adverse drug reaction? A cross-sectional study in Dutch geriatric outpatients

Abstract

Purpose: Adverse drug reactions as well as Vitamin D deficiency are issues of public health concern in older people. However, relatively little is known about the impact of drug use on Vitamin D status. Our primary aim is to explore associations between drug use and Vitamin D status in older people. Furthermore, prevalences of drug use and Vitamin D deficiency are estimated. Methods: In a population of 873 community-dwelling Dutch geriatric outpatients, we explored the cross-sectional relationships of polypharmacy (≥5 medications concomitantly used), severe polypharmacy (≥10 medications), and use of twenty-one specific drug groups, with serum 25-hydroxyVitamin D (25(OH)D) by analysis of covariance. Results: Overall prevalence of polypharmacy was 65 %, of severe polypharmacy 22 %. Depending on the cut-off value, prevalence of Vitamin D deficiency was 49 % (<50 nmol/l) or 77 % (<75 nmol/l). Of the patients using a Vitamin D supplement, 17 % (<50 nmol/l) or 49 % (<75 nmol/l) were still deficient. In non-users of supplemental Vitamin D, after adjustment for age and gender, negative associations were found for severe polypharmacy, metformin, sulphonamides and urea derivatives (SUDs), vitamin K antagonists, cardiac glycosides, loop diuretics, potassium-sparing diuretics, ACE inhibitors, and serotonin reuptake inhibitors; for non-selective monoamine reuptake inhibitors (NSMRIs) the association was positive. The most extreme impacts of drug use on adjusted mean 25(OH)D were -19 nmol/l for SUDs and +18 nmol/l for NSMRIs. Conclusion: Drug use should be considered a risk factor for Vitamin D deficiency amongst geriatric outpatients.