Washington, April 17 : Researchers at Harvard University in Boston have shown that exposure to a common environmental chemical might increase the risk of developing amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease.
The findings, which will be presented at the American Academy of Neurology 60th Anniversary Annual Meeting in Chicago, April 12-19, 2008, was based on the Cancer Prevention Study II of the American Cancer Society.
In the study, over one million people were asked to report their exposure to 12 types of chemicals.
The participants were followed for 15 years, and the number of people who died during that time of ALS was tracked.
Researchers found that a total of 617 men and 539 women died from ALS during the study.
They found no significant association between ALS and exposure to most chemicals, including pesticides and herbicides.
However, people who reported that they had regular exposure to formaldehyde were 34 percent more likely to develop ALS than those with no exposure to formaldehyde.
"Although this finding could well be a chance observation, it merits further investigation, particularly because people with longer exposure to formaldehyde had a greater risk of developing ALS than those with shorter exposures," said study author Marc Weisskopf, PhD, of Harvard University in Boston.
"People who reported 10 or more years of exposure were almost four times as likely to develop ALS as those with no exposure," he added.
He said that the results are preliminary and more study needs to be done to test the results.
"This finding was somewhat surprising, because formaldehyde has not been raised as an issue in ALS before," he said.
Formaldehyde is used in particleboard and other wood products, permanent press fabrics, glues, and other household products, such as cosmetics and shampoo.
The chemical is also used as a preservative in medical laboratories and mortuaries, and as an industrial disinfectant.
Researchers also noted that the participants were asked about their exposure to formaldehyde and other chemicals in 1982.
In 1987, formaldehyde was classified as a probable human carcinogen at high exposure levels by the U.S. Environmental Protection Agency in 1987.
"Exposure since then has generally decreased, but it certainly isn't gone," he said.