There are a number of studies that have evaluated the relationship between fibromyalgia (FM) and vitamin D deficiency with conflicting results. The aim of this study was to assess vitamin D deficiency in patients with FM and to evaluate the relationship with the common symptoms of FM and levels of serum vitamin D. Forty premenopausal female fibromyalgia patients and 40 age- and sex-matched control subjects were included in the study. The demographic characteristics of all subjects, including age, sex, and body mass index, were recorded. The number of tender points was recorded, and the intensity of the widespread pain of the subjects was measured by the visual analog scale. The activities of daily living component of the Fibromyalgia Impact Questionnaire (FIQ-ADL), was used to assess physical functional capacity. Serum vitamin D was measured in both groups, and vitamin D levels <37.5 nmol/L were accepted as vitamin D deficiency. The vitamin D levels and clinical and laboratory characteristics of the patient and control groups were comparatively analyzed. The relationship between vitamin D levels and clinical findings of the FM patients were also determined. The mean age was 41.23 ± 4.8 and 39.48 ± 4.08 years for the patient and control groups, respectively. The pain intensity, number of tender points, and FIQ-ADL scores were higher in FM patients than in control subjects. The mean levels of vitamin D in the patient and control groups were determined to be 31.97 ± 15.50 and 28.97 ± 13.31 nmol/L, respectively (p > .05). The incidence of vitamin D deficiency was similar between the patient and control groups (67.5% vs. 70%). Vitamin D levels significantly correlated with pain intensity (r = -0.653; p = .001) and FIQ-ADL scores in the FM group (r = -0.344; p = .030). In conclusion, the results of this study indicate that deficiency of vitamin D is not more common in premenopausal female patients with FM than in control subjects without FM. However, the association between pain and vitamin D levels in FM patients emphasizes that hypovitaminosis of vitamin D in the FM syndrome may have an augmenting impact on pain intensity and functional status. Future studies are needed to show the effect of vitamin D supplementation in the reduction of pain intensity and disability in patients suffering from this chronic condition.
Copyright © 2013 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.