The absence of the appetite hormone leptin, even in obese individuals, reduces the risk of arthritis, a new study finds.
The study was conducted on a group of mice. Previous studies have linked leptin to arthritis, but this is the first study that suggests the absence of this hormone may totally eliminate the risk of the disorder.
"We were completely surprised to find that mice that became extremely obese had no arthritis if their bodies didn't have leptin," said Farshid Guilak, PhD, director of orthopaedic research in the Duke Department of Surgery in a press statement. "Although there was some earlier evidence that leptin might be involved in the arthritis disease process, we didn't think that there would be no arthritis at all."
Leptin is known to affect many factors that are associated with arthritis. These include body weight, inflammation, sex hormone levels, and bone metabolism.
"We knew from other studies that obese people got arthritis in their hands, too, which don't bear weight. This indicated that something besides just body-weight level affected their joints," the study authors said.
For the study, researchers compared mice that were part of the research with normal mice to document knee osteoarthritis. Researchers did notice some knee bone changes in mice that were leptin-free but none of these changes were associated with arthritis.
Researchers confirmed that this study doesn't debunk previous studies that suggest obese people are at a higher risk of arthritis. In fact, researchers said that such people can benefit a lot from shedding some of those extra pounds.
"If you are obese, there are benefits to losing weight in terms of arthritis. For example, if you are obese and lose just 10 pounds, pain decreases significantly. Pain modulation is another clue it might be a chemical or systemic metabolic effect, rather than just a mechanical effect of less weight on the joints," the researchers said.
According to data released by the Centers of Disease Control and Prevention, 52.5 million U.S. adults suffer from arthritis - about 23 percent. The most common symptom of arthritis involves the joints. Joint pain and stiffness, mostly in the morning, are typical signs, along with swelling of the joints. You may also experience a decrease in range of motion of your joints or redness of the skin around the joint.
The treatment of arthritis is very dependent on the precise type of arthritis present. An accurate diagnosis increases the chances of successful treatment, according to a Mayo Clinic report. Treatments available include physical therapy, splinting, cold-pack application, paraffin wax dips, anti-inflammatory medications, pain medications (ranging from acetaminophen [Tylenol] to narcotics), immune-altering medications, and surgical operations. For treatments of particular forms of arthritis, see the corresponding articles for the form of arthritis of interest.
The study was published online in the journal Arthritis & Rheumatism. It was sponsored by the National Institute for Arthritis, Musculoskeletal and Skin Diseases and the Arthritis Foundation.
