Vitamin D, SSRIs and the Musculoskeletal System

In recent years it has become evident that some types of antidepressants are associated both with an increased risk of falling and decreased bone mineral density. These factors predispose patients for serious fractures such as hip fractures with substantial morbidity and mortality. The specific mechanisms involved in this negative impact on bone and postural control have not been fully elucidated. It is well known that Vitamin D plays an important role for bone health as well as muscle function and thus indirectly postural control. Furthermore, vitamin D deficiency has been observed among depressed patients. To our knowledge no study has investigated the involvement of Vitamin D in relation to the increased risk of fractures associated with antidepressants. Therefore, this project will investigate the underlying mechanisms leading to skeletal impairment and musculoskeletal symptoms in patients receiving different types of antidepressants. Moreover, the effect of vitamin D supplementation will be investigated among patients taking these antidepressants. 150 subjects will participate in this study: 50 of which is diagnosed with depression and receive Citalopram (SSRIs); 50 depressed subjects receiving Mirtazapine(NaSRI); and 50 controls. Through randomisation half of the subjects in each group will receive daily Vitamin D supplementation for a period of one year. Through this period all 150 subjects will be followed through different measurements including bone density, muscle function and balance, nociception, quality of life and depression severity. It is expected that results from this study will provide increasing awareness and knowledge of the side effect profile of antidepressants on bone metabolism. This may prompt clinicians to screen patients at high risk of drug-induced osteopenia or osteoporosis and accordingly provide treatment, which may reduce the incidence of potentially avoidable fractures. Moreover, some types of antidepressants may show to produce