Fibromyalgia is one of the most common chronic pain conditions. The disorder affects an estimated 10 million people in the U.S. and an estimated 3-6% of the world population. While it is most prevalent in women — 75-90 percent of the people who have FM are women — it also occurs in men and children of all ethnic groups. The disorder is often seen in families, among siblings or mothers and their children. The diagnosis is usually made between the ages of 20 to 50 years, but the incidence rises with age so that by age 80, approximately 8% of adults meet the American College of Rheumatology classification of fibromyalgia.