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.
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.
that's not a problem. But for current and past smokers, absence
of the gene leads to more severe joint damage.
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,
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.
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.
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.
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.
differences were not found in patients who carried the gene
-- whether they smoked or not.
is also an important finding, and may provide clues as to
how rheumatoid factor is produced," Mattey said.
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."
of March 17, 2002