The Relationship Between Vitamin-D Level and Fibromyalgia

Role of Vitamin-D deficiency in musculoskeletal pain had been recognized previously. However, there is still controversy about the relationship of fibromyalgia, as a prototype of musculoskeletal pain disorders, with Vitamin-D deficiency.
This study was designed to assess serum vitamin D status (25-OHVit.D) in the fibromyalgia (FM) patients and to compare it with a healthy control group. It also aimed to investigate the correlation of serum vitamin D level with FM symptom severity and invalidation experiences.
This cross sectional study was done in patients in Razi hospital, Rasht, Iran. A total of 74 consecutive patients with FM and 68 healthy control participants were enrolled. The eligible FM patients completed the Illness Invalidation Inventory (3*I), the Revised Fibromyalgia Impact Questionnaire (FIQR) and a short-form health survey (SF-12). Venous blood samples were collected from all participants to evaluate serum 25-OHVit.D levels. Mann-Whitney tests and multiple logistic regression analyses were performed and Spearman’s correlations were calculated.
88.4% of FM patients had low levels of serum 25-OHVit.D (below than 20ng/ml). FM patients had a significantly higher level of serum 25-OHVit.D than that in the control group (17.24±13.50 and 9.91±6.47ng/ml, respectively, p=0.0001). There were no significant correlations between serum 25-OHVit.D levels and the clinical measures of disease impact, invalidation dimensions, and health status. Multiple logistic regression analyses revealed that an increased discounting of the disease by the patient’s spouse was associated with a 4-fold increased risk for vitamin D deficiency (OR=4.36; 95% CI, 0.95−19.87, p=0.05).
This study showed that although high rates of vitamin D insufficiency or deficiency were seen among FM patients and healthy non-FM participants, but it seems there was no intrinsic association between FM and vitamin D deficiency. Addressing of invalidation experience especially by the patient’s spouse is important in the management of FM. (Korean J Pain 2016; 29: 172-8) Chronic pain syndrome; Fibromyalgia; Invalidation; Iran; Surveys and Questionnaires; Vitamin D.