By Robert Preidt
WEDNESDAY, April 3 (HealthDay News) -- Men with low levels of the hormone testosterone may be at greater risk for rheumatoid arthritis, according to a new study.
Both men and women with rheumatoid arthritis have lower levels of testosterone in their blood than people without the disease. But it has not been known whether low testosterone levels are a cause or effect of rheumatoid arthritis.
Rheumatoid arthritis causes pain, swelling, stiffness and loss of joint function. Severe cases can last a lifetime.
In this study, Swedish researchers analyzed blood samples collected from 104 men who were later diagnosed with rheumatoid arthritis and 174 men of the same age who did not develop the disease. The average time between collection of the blood sample and a diagnosis of rheumatoid arthritis was just less than 13 years, but ranged from 1 to 28 years.
After taking into account known rheumatoid arthritis risk factors such as smoking and weight, the researchers found that men with lower testosterone levels were more likely to develop rheumatoid arthritis. They did not, however, prove a cause-and-effect link between the two.
These men also had significantly higher levels of follicle stimulating hormone -- a chemical involved in sexual maturity and reproduction -- before they were diagnosed with rheumatoid arthritis, according to the study, which was published online April 3 in the journal Annals of the Rheumatic Diseases.
The findings suggest that hormonal changes occur before rheumatoid arthritis develops and could influence disease severity, the researchers said in a journal news release.
Rheumatoid arthritis results from the immune system attacking the body's own tissues. Previous research suggests that testosterone may dampen the immune system, the researchers said.