Much more investigation is necessary before the role of vitamin D in fibromyalgia, if there is one, is established. Fibromyalgia is a chronic condition associated with pain in the muscles and bones, as well as any of the following signs and symptoms:
Fatigue
Joint stiffness
Lack of abnormal diagnostic tests
Lack of abnormalities on physical examination
Sleep disturbance
The lack of abnormalities results in confusion over whether this is a disease or a psychiatric condition. Many theories abound, but no cause has been found. Patients are often depressed because of the inability to live a normal life and the failure of treatment. Some of the features of the condition are consistent with the response to chronic stress.
Treating fibromyalgia is difficult and focuses on the symptoms that are occurring. If pain is prominent, pain medication is offered. If the patient is depressed, antidepressants are given. Psychotherapy also may help.
When vitamin D levels are measured in patients with fibromyalgia, as many as 60 percent have low levels of 25-hydroxyvitamin D. Whether this means low vitamin D causes fibromyalgia is unclear; it may instead be the result of fibromyalgia patients not getting outdoors or consuming a healthy diet due to pain, stiffness, and depressed mood.
If patients are treated with vitamin D, many, but not all, gradually get better over a prolonged period of time. Sometimes it takes several months for the patient to feel better.
Also promising are the results from a recent study of 100 older people with serum 25-hydroxyvitamin D levels below 25 ng/ml (62.5 nmol/L) that showed people with lower levels were more likely to have fibromyalgia, and that those who got 50,000 IU vitamin D per week for eight weeks reported lower scores on clinical tests designed to identify the signs and symptoms of fibromyalgia.