According to an American study published in Jama Neurology, exposure to pesticides and other chemical substances increases the risk of ALS, amyotrophic lateral sclerosis, a fatal degenerative disease.
Amyotrophic lateral sclerosis, also known as Lou Gehrig's disease because it struck the legendary baseball player of the same name, is a rare progressive neurodegenerative disease that attacks the nerve cells responsible for controlling voluntary muscle movement. The first symptoms of ALS manifest as loss of muscle strength, difficulty walking and speaking, and cramps. Over time, it leads to complete paralysis and respiratory failure. In Italy, there are approximately 6,000 people living with ALS, and an estimated 1,000 new cases are diagnosed each year. Some 5–10 per cent of cases can be attributed to hereditary causes, but for more than 90 per cent of patients the origins of the disease remain unknown.
A study by researchers at the University of Michigan, coordinated by Eva Feldman, director of the A. Alfred Taubman Medical Research Institute, has now found that a link exists between exposure to pesticides and environmental pollutants and the development of ALS.
The researchers analysed 156 people affected by the disease and 128 people without it. Participants were asked to describe any occupational or proximity exposure to environmental toxins, after which the concentration of these substances in their blood was measured. The results detected their presence in all samples tested, but in those of ALS patients the levels were significantly higher, particularly for pesticides.
A total of 122 chemical substances were examined in the study. Three, in particular, were linked to the risk of ALS by the experts. Prolonged exposure to the pesticide cis-chlordane was shown to increase the risk sixfold; exposure to pentachlorobenzene, used in the manufacture of fungicides, would double the likelihood of ALS; and polybrominated diphenyl ether, used as a flame retardant in furniture and fabrics, would increase the possibility by approximately 2.7 times.
"We found toxic chemicals in individuals both with and without ALS. We are probably all exposed without being aware of it, as they are present in the air, in water and in what we eat, and can persist in the environment for decades. However, people with ALS had higher concentrations, particularly with regard to pesticides," said Stephen Gutman, co-author of the research.