Detection of serum 25(OH)-vitamin D level in the serum of women with fibromyalgia syndrome and its relation to pain severity

The aim of our study is to determine serum 25(OH)-vitamin D level in patients with fibromyalgia syndrome and its relation to pain. Fifty-three women with fibromyalgia syndrome diagnosed according to the American College of Rheumatology 1990 fibromyalgia diagnostic criteria and 50 age-matched healthy women as a control group were included in this study. Serum 25(OH)-vitamin D levels were determined in both the patient and the control groups. Fibromyalgia Impact Questionnaire scores and pain intensity measured by the visual analogue scale were evaluated. We found a statistically significant decrease in serum vitamin D level in the patient group in comparison with the control group. There was a significant negative correlation (P = 0.000) between vitamin D level and Fibromyalgia Impact Questionnaire. The same results are found between vitamin D level and visual analogue scale. There was no significant correlation between vitamin D level and erythrocyte sedimentation rate or C-reactive protein. We found a significant association between fibromyalgia and low 25(OH)-vitamin D levels as suggested previously in other studies. Also, there was a correlation between the level of vitamin D in serum and severity of pain. We recommend vitamin D screening in every patient with chronic nonspecific musculoskeletal pain, especially fibromyalgia, and extended research in this area with large numbers of patients.