ALS study looks for links to exposure from toxic waste sites: August 27.

A 2-year study by the Agency for Toxic Substances and Disease Registry (ATDSR) is designed to determine the prevalence of amyotrophic lateral sclerosis (ALS) in areas around waste sites in Illinois, Massachusetts, Missouri, Texas, and Washington State.

The study's goal is to determine the number of ALS patients in the communities around the hazardous-waste areas, then look for "different commonalities" among the individuals to determine if there was some common environmental exposure, according to a New Fork Times article. The agency is working with public-health agencies, health care groups, and physicians to develop data to estimate the prevalence of ALS in the study areas.

Other studies over the years have indicated possible links between ALS and heavy metals, phosphates, and agricultural chemicals. While researchers have identified trends, they have found nothing conclusive about environmental Factors.

"There is some sort of genetic susceptibility, but that doesn't explain why people get the disease, so it's hypothesized that there is some environmental trigger, but we are not sure what that environmental trigger is," says Dhelia Williamson, an epidemiologist and coordinator for the study at ATSDR, a subagency of the US Department of Health and Human Services.