Oil exposure increases arthritis risk

WASHINGTON, Sep 21, 2005 (United Press International via COMTEX) -- Scientists said Wednesday the results of a new study indicate occupational exposure to motor oil significantly increases the chances a person will develop rheumatoid arthritis.

"According to the results of our study, mineral oils (in particular, hydraulic oil and motor oil) appear to be associated with a particular high risk of" two different forms of rheumatoid arthritis, a team of Swedish researchers led by Lars Klareskog of the Karolinska Institutet in Stockholm wrote in the Sept. 23 issue of Arthritis Research and Therapy.

Although it is uncertain how the oil may have caused the arthritis to develop, the researchers note that the findings go along with previous studies that found oil induced arthritis in rats.

Further research could help elucidate whether other agents, such as occupational chemicals, bacteria or viruses, also play a role in triggering arthritis, the researchers said.

Further studies also could help scientists "develop a better understanding of both (how the disease develops) and treatment" of rheumatoid arthritis, they wrote.

More than 2 million people are afflicted with rheumatoid arthritis in the United States. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, the cause of the disease is unknown, but it may be due to genes, environment or hormones.

In people with rheumatoid arthritis, the body's immune system malfunctions and begins to attack the joints, leading to swelling, pain and disability. The disease can be treated with medications and surgery, but it usually can't be cured.

In the study, more than 1,400 people diagnosed with rheumatoid arthritis between 1996 and 2003 filled out a questionnaire regarding occupational exposure to certain chemicals.

Significant exposure to oil was only reported by men. Those who reported exposure to hydraulic or motor oil at the workplace had a 30-percent higher risk of developing a severe form of rheumatoid arthritis called rheumatoid factor positive compared to men who had not worked around oil products. The exposed men also were 60-percent more likely to develop another form of the disease called anti-citrulline positive rheumatoid arthritis.