Researchers funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases have determined that excess body weight and older age increase a woman's chances of needing a total hip replacement to treat osteoarthritis.
Matthew Liang, M.D., M.P.H., Elizabeth Karlson, M.D., and Lisa Mandl, M.D., M.P.H., and their colleagues at Harvard Medical School studied 568 participants from the ongoing Nurses Health Study who received a hip replacement to treat hip osteoarthritis. The researchers examined risk factors--including body mass index, use of hormones after menopause, age, alcohol consumption, physical inactivity and cigarette smoking--for hip replacement. Of these potential risk factors, only body mass index and age were associated with needing a hip replacement. Body mass index is a standard measure of weight in relation to height and is used to estimate body fat. Participants with a high body mass index showed double the risk of having a hip replacement compared with low body mass index participants. The risk from obesity appeared to be established early in life. Participants who had a high body mass index at age 18 showed five times the risk of receiving a hip replacement to treat hip osteoarthritis later in life. Women age 70 and older were nine times more likely to have a hip replacement compared with those under age 55.
According to the authors, this is one of the first long-term prospective studies to show an association between a modifiable risk factor and osteoarthritis. Results suggest that reducing weight may improve quality of life and decrease health care costs related to osteoarthritis.
The Nurses Health Study, from which data were drawn, is one of the largest studies of risk factors for chronic diseases in women. Over 116,000 women are enrolled.
Osteoarthritis is a degenerative joint disease in which cartilage, the slippery tissue that covers the ends of bones in a joint, wears away. This allows bones under the cartilage to rub together, causing pain, swelling, and loss of motion of the joint. Osteoarthritis is one of the most frequent causes of physical disability among adults. It mostly occurs in older people but can also affect younger men and women.
Support for this study was also provided by the National Cancer Institute and the Arthritis Foundation. NIAMS and the National Cancer Institute are part of the National Institutes of Health (NIH), the Federal Government's primary agency for biomedical and behavioral research. NIH is a component of the U.S. Department of Health and Human Services.
Karlson E, Mandl L, Aweh G, Sangha O, Liang M, Grodstein F. Total hip replacement due to osteoarthritis: The importance of age, obesity, and other modifiable risk factors. Am J Med 2003;114:93-98.