Vitamin D Supplementation Seems to Improve Fibromyalgia Symptoms: Preliminary Results Abstract Background: Vitamin D deficiency and insufficiency have been reported in fibromyalgia. However, to the best of our knowledge, only one study has evaluated the role of 25- hydroxyvitamin D [25(OH)D] supplementation on fibromyalgia symptoms. Objectives: To analyze the effects of 3 months of 25(OH)D supplementation on symptoms of fibromyalgia. Methods:...