Arthritis News:

Rheumatoid Arthritis More Disabling for Some Women Smokers

Women who smoke are at higher risk of developing severe rheumatoid arthritis, and the disease may be even more disabling for smokers who lack the GSTM1 gene, according to a report in the journal Arthritis and Rheumatism.

GSTM1 is a gene that produces an enzyme that works to fight cancer-causing agents, like those found in cigarette smoke. But according to researchers, More than half of all Caucasian individuals do not carry the gene, and therefore cannot produce the enzyme.

For non-smokers, that's not a problem. But for current and past smokers, absence of the gene leads to more severe joint damage.

"This appears to be an example of how environmental and genetic factors can act together to influence disease outcome," said Dr. Derek Mattey of North Staffordshire Hospital, Stoke-on-Trent, United Kingdom.

Their research confirms and extends previous studies showing a link between smoking and severity of rheumatoid arthritis. The study included 164 women with rheumatoid arthritis -- 51.3 had never smoked, 29.9 were current smokers, and 58.5 percent lacked the GSTM1 gene.

Based on x-ray scores and functional ability evaluations, past and current smokers were significantly more disabled than those who had never smoked. X-rays also pointed to more severe disease in patients who smoked but did not have the GSTM1 gene than in those who smoked and had GSTM1 present.

The researchers also found higher levels of rheumatoid factor (which is found in 85 percent of rheumatoid arthritis patients, and often associated with more severe disease) in smokers who were GSTM1-null.

In fact, patients who had smoked in the past and lacked the gene were more than three times as likely to be rheumatoid factor positive than GSTM1-null patients who had never smoked. GSTM1-null current smokers were more than five times as likely to be rheumatoid factor positive than those who had never smoked.

But significant differences were not found in patients who carried the gene -- whether they smoked or not.

"This is also an important finding, and may provide clues as to how rheumatoid factor is produced," Mattey said.

"It is very likely that other genes will be important in the association between smoking and severity of (rheumatoid arthritis)," Mattey said. "This study has prompted us to investigate whether other genetic factors are involved."

Source: Arthritis Week of March 17, 2002