New research adds a level of knowledge to the link between vitamin D and the poorly understood disease, fibromyalgia. Turkish researchers found that people with fibromyalgia and low levels of vitamin D have significantly more pain and balance problems.

About 5 million Americans suffer from fibromyalgia, according to the Department of Health and Human Services. Most of the people who have the disease are women and most develop symptoms in middle age. Symptoms include chronic pain and fatigue along with sleep disorders, morning stiffness, poor concentration and occasionally mild-to-severe mental symptoms like anxiety and depression. There is no cure.

Subjects in the new study included men and women, ages 35 to 65, with fibromyalgia and a control group matched by age and gender. Researchers used the fibromyalgia impact scale (FIQ), Berg Balance Scale (BBS), the Nottingham Health Profile (NHP) and visual analog scale (VAS) to measure their findings. The participants were divided into two groups by vitamin D level being above or below 30 ng/ml.

“The results indicated that there was a statistically significant difference between FMS patients with low and those with normal levels by pain and balance tested with BBS,” the authors wrote in Modern Reumatology. “A positive significant correlation was established between balance and [vitamin D]."

A meta-analysis of recent studies exploring vitamin D and fibromyalgia published earlier this year suggests that the vitamin may hold a key to understanding the disease.