April 29, 2010 -- Overweight and obese women -- especially those who do not exercise at all or exercise for less than an hour a week -- are at higher risk for developing the widespread pain disorder fibromyalgia, according to new research in the May issue of Arthritis Care & Research.
"Being overweight or obese was associated with an increased risk of fibromyalgia, especially among women who also reported low levels of leisure time physical exercise," the researchers conclude. "Community-based measures aimed at reducing the incident of fibromyalgia should emphasize the importance of regular physical exercise and maintenance of normal body weight."
Fibromyalgia affects an estimated 10 million people in the U.S. and is marked by widespread pain and tender points along the body, extreme fatigue, sleep problems, depression, and problems with cognition, according to the National Fibromyalgia Association. Other suspected risk factors for fibromyalgia include stressful or traumatic events such as an automobile accident, family history, or the presence of rheumatic diseases such as lupus.
In the new study, Paul Mork, DPhil, and colleagues culled data from the Nord-Trondelag Health (HUNT) Study. HUNT1, the first part of the study, was conducted in 1984-1986, while HUNT 2 was conducted from 1995 to 1997. There were 380 new cases of fibromyalgia diagnosed among 15,990 women during the 11 years between the two surveys.
Women with a body mass index (BMI) greater than or equal to 25 had a 60% to 70% greater risk of developing fibromyalgia, when compared with their thinner counterparts. A BMI takes height and weight into account to measure body fat. If your BMI is greater than 25, you are considered overweight. If it is over 30, you are considered obese; a BMI over 40 is considered severely obese.
Exercise tended to offset the fibromyalgia risks posed by obesity, the study showed. The more that women exercised, the lower their risk of developing fibromyalgia. The protective effects of exercise on fibromyalgia risk even held among overweight or obese women.
Exactly how being overweight or obese could increase risk of developing fibromyalgia is not fully understood, but some research suggests that increased levels of certain inflammatory proteins may play a role in both fibromyalgia and obesity.