Becoming a prisoner in your own body may sound like a nightmare, but for those suffering from amyotrophic lateral sclerosis (ALS), it’s a daily reality that may be caused by pesticide exposure, according to a new study. More commonly known as Lou Gehrig’s Disease, ALS is a progressive and ultimately fatal disease that destroys the line of communication between the brain, spinal cord, and muscles. Its victims eventually lose their capacity to initiate and control muscle movement, leading to their inability to speak, eat, move, and breathe typically within three to five years.

Current treatments fail to halt or reverse any damage a person may incur, leaving them with few options to maintain their quality of life. A team of researchers from the University of Michigan investigated the potential environmental factors surrounding the risk for ALS. Their findings, published in the JAMA Neurology, reveal how repeated exposure to common pesticides may influence a person’s chances of developing the debilitating disease.

For the study, between 2011 and 2014 researchers recruited 156 patients with ALS and another 128 patients without ALS to serve as the control group. Each participant, all of whom lived in Michigan, provided blood samples and completed a survey detailing their rates of exposure to pesticides. When researchers tested their blood, they found those who had reported higher pesticide exposure had a “significant” increased risk of ALS compared to those who did not.    

The at-risk participants had blood concentrations with elevated levels of environmental pollutants, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and brominated flame retardants (BRFs).The traces of pesticides found in blood samples are chemicals used to protect crops and livestock from farming pests, such as pathogens and insects that threaten to damage or destroy them.

However OCPs, which are broken down into five different chemical groups, one being the commonly known DDT (dichloro-diphenyl-trichloroethane), were banned from use by the Environmental Protection Agency in the 1970s after their link to numerous health risks affecting both humans and animals was discovered. But that’s not the only chemical concern from the study’s findings.

According to the Center for Environmental Research & Children’s Health, PCBs, which are also linked to an increased risk of cancer, last for a very long time in the human body, accumulating in fat and oftentimes found in breast milk. A 2003 study published in Environmental International warns that BRFs, which are a mixture of man-made industrial chemicals used to make products less flammable, are potential carcinogens that also alter reproductive organs, liver, and thyroid hormones.

Researchers aren’t sure how the chemicals trigger ALS, if that’s indeed the case. But with more than 20,000 Americans living with ALS at any given time and an additional 6,400 diagnosed each year, further investigation is in desperate demand.

The study results lead to more questions than answers, as researchers plan to look further into the risk factors of exposure to pesticides, including different chemicals and how they affect ALS patients on a cellular level. The authors of the study conclude: "Finally, as environmental factors that affect the susceptibility, triggering and progression of ALS remain largely unknown, future studies are needed to evaluate trends in exposure measurements, assess newer chemicals, consider mechanisms, and assess variations."

Source: Feldman EL, SU FC, and Goutman SA, et al. Association of Environmental Toxins With Amyotrophic Lateral Sclerosis. JAMA Neurology. 2016.