Environmental pollutants could affect the chances a person develops amyotrophic lateral sclerosis, or ALS, says a new study from the University of Michigan in Ann Arbor.
"From the first ALS patient I saw over 25 years ago to the ALS patient I diagnosed this week, I am always asked the same question, 'Why me? What is different about my life that I got this disease?'" says Dr. Eva Feldman, co-author of the study, and director of the A. Alfred Taubman Medical Research Institute at U-M and the program for neurology research. "I want to answer that question for my patients."
Feldman and her research team studied both people with ALS and without, asking them to describe their exposure to pollutants at work and home. The researchers also measured toxic persistent environmental pollutants in their blood.
"We found these toxic chemicals in individuals both with and without ALS," says Dr. Stephen Goutman, co-author of the study and director of the U-M Comprehensive ALS Clinic. "We are likely all exposed without our own knowledge, from the air, water, and our diet, as these chemicals can last decades in the environment. However, persons with ALS, overall, had higher concentrations of these chemicals, especially in regards to pesticides."
ALS, also known as Lou Gehrig's disease, is a degenerative motor neuron disease that causes those afflicted to eventually lose their strength and ability to move their arms, legs, and body. There is no cure for ALS.
Goutman says blood tests showed increased odds of ALS for those with exposure to several different types of chemicals, many of which are no longer widely used because of environmental concerns, like DDT. However, he says some of the classes of chemicals studied, such as polybrominated diphenyl ethers (used as flame retardants), have only experienced recent scrutiny as potential health hazards.
"The challenge is that persons are likely exposed to multiple chemicals and therefore it is too soon for us to know whether individual chemicals, or mixtures of chemicals, lead to motor neuron damage," Goutman says. "Next, we will really dive into particular chemicals that could be risk factors for the disease."
As part of a larger study on environmental risk factors for ALS, the work is published in JAMA Neurology.