| Study raises red flag
over home insecticides, autoimmune diseases
New research suggests a link between women's
exposure to household insecticides — including roach and mosquito
killers — and the autoimmune disorders rheumatoid arthritis and lupus.
The scientist did not find a direct cause-and-effect relationship
between insecticide exposure and the illnesses, and it's possible that
the women have something else in common that accounts for their higher
risk. But epidemiologist Christine Parks, lead investigator of the
study, said the findings do raise a red flag.
"It's hard to envision what other factors might explain this
association," said Parks, an epidemiologist with the National Institute
of Environmental Health Sciences who was to present the study over the
weekend at the American College of Rheumatology annual meeting in
Philadelphia.
Previous research has linked agricultural pesticides to higher risk of
rheumatoid arthritis and lupus, two diseases in which the immune system
goes haywire and begins to attack the body. Farmers, among others,
appear to be vulnerable.
Parks and her colleagues wanted to find out whether smaller doses of
insecticides, such as those people might encounter at home from either
personal or commercial residential use, might have a similar effect.
The researchers examined data from a previous study of almost 77,000
postmenopausal women aged 50 to 79. Their findings were to be released
Monday at the American College of Rheumatology's annual scientific
meeting in Philadelphia.
Women who reported applying insecticides or mixing them — about half —
had a higher risk of developing the two autoimmune disorders than women
who reported no insecticide use. This was the case whether or not they
had lived on a farm. Those who used or mixed the insecticides the most —
judged by frequency or duration — had double the risk.
Even so, the risk of developing the diseases remained very low. Overall,
Parks said, about 2% of older adults develop the conditions.
Parks said the insecticides that the women used included insect killers,
such as those designed to eradicate ants, wasps, termites, mosquitoes
and roaches. They didn't include insect repellents.
There are some caveats to the research. For one, it's not clear exactly
what products the women used or when. "Over time, there have been major
changes in what products were available for home use," Parks said.
And while researchers tried to take into account the influence of
factors like age that may boost a woman's risk of getting autoimmune
diseases, it's possible they missed something that boosted the risk of
illness.
Could gardening, which often entails insecticide use, be a contributing
factor? That's possible. But Parks said a lot of insecticide use takes
place inside the home, not outside in the garden.
For now, she said, the findings indicate the need for "more research on
environmental risk factors and better understanding of what factors
might explain these findings, what chemicals might be associated with
these risks."
She declined to speculate on how insecticides might cause problems in
the body.
"I would recommend that people read the labels and take precautions to
minimize their personal exposure" to insecticides, she said. "This is
the case regardless of whether these results are implicating a chemical
that's on the market now or was before."
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