Serum vitamin D status and bone mineral density in fibromyalgia.

Objectives: To compare serum vitamin D levels and bone mineral density (BMD) values in patients with fibromyalgia and healthy controls.

Background: The so far available reports of low levels of vitamin D and low BMD values in patients with fibromyalgia are inconsistent.

Methods: Serum 25-hydroxyvitamin D (25-OHD) levels and BMD values were measured in thirty women with fibromyalgia and compared with thirty age-matched healthy women. Serum calcium, phosphorus, alkaline phosphatase and parathyroid hormone (PTH) levels were also measured. All participants completed the Fibromyalgia Impact Questionnaire (FIQ) and Hospital Anxiety and Depression Score (HADS). Pain severity was assessed with visual analog scale (VAS).

Results: Mean serum 25-OHD levels did not differ between the groups (fibromyalgia 10.57 +/- 10.46, controls 10.87 +/- 5.52 ng/l; p=0.89); nor did the frequency of vitamin D deficiency (25-OHD < or = 20 ng/l) in each group (fibromyalgia 86.7%, controls 96.7%; p=0.353). Although, mean serum PTH level was found significantly higher in fibromyalgic patients than in controls (p=0.014), only one patient and two of controls had barely elevated PTH levels. There was no relationship between vitamin D level and FIQ score (p=0.707) or HADS (p=0.824) or pain VAS (p=0.414). BMD values in the patients with fibromyalgia were comparable to those in controls at both, the lumbar spine (p=0.866) and femur neck (p=0.61).

Conclusion: Neither vitamin D levels nor BMD values are different between women with and without fibromyalgia. In this cross-sectional study, mean serum PTH level was found higher in the fibromyalgic patients than in controls. Nevertheless, in order to confirm the findings of this preliminary study it is still necessary to perform a controlled longitudinal study (Tab. 2, Fig. 2, Ref. 35). Full Text in free PDF www.bmj.sk.