A concerning rise in amyotrophic lateral sclerosis (ALS) diagnoses, particularly among active and seemingly healthy individuals, is prompting experts to examine lifestyle factors and environmental exposures as potential contributors to the devastating neurological condition.
While an aging population accounts for some of the increase in ALS cases, it does not fully explain the growing number of diagnoses in athletes and military veterans with no known genetic predisposition. Around 33,000 Americans were living with ALS, also known as Lou Gehrig's disease, in 2022, a figure projected to exceed 36,000 by 2030.
Recent research is focusing on whether elements of modern lifestyles, from physical trauma to chemical exposures, could be driving this trend. Neurologists point to several factors that have been linked to a higher risk of developing ALS.
Occupational and Environmental Exposures
Certain professions have long been associated with an elevated risk of ALS. Jobs involving prolonged exposure to workplace toxins such as metals, welding fumes, solvents, pesticides, and industrial chemicals are under scrutiny. A 2022 study found that individuals in manufacturing and chemical industries, as well as construction and trade jobs, reported greater exposure to hazards like particulate matter, diesel exhaust, and metals. Exposure to metals, in particular, showed a 48 percent increased risk.
Even common leisure activities are being investigated. A 2024 study from the University of Michigan suggested a link between golfing and a threefold increase in ALS risk, while gardening and yard work were associated with a 71 percent rise, possibly due to exposure to pesticides and lawn care chemicals. Woodworking has also been flagged due to potential exposure to chemicals like formaldehyde.
Experts suggest that repeated exposure to these toxic substances may gradually damage the motor neurons that control movement, either by triggering inflammation or causing toxic protein buildup in the body.
Head Trauma and Intense Physical Activity
Professional athletes, especially those in contact sports like football, appear to face a significantly higher risk of ALS. A 2021 analysis of more than 19,000 former NFL players found they were nearly four times more likely to develop and die from ALS compared to the general population. The average age of diagnosis for these players was in their mid-30s. Earlier research has also indicated that individuals with multiple head injuries have a substantially higher risk of developing the disease.
The role of intense exercise, particularly anaerobic activity, in ALS risk remains a subject of investigation. Some studies suggest that frequent, strenuous physical activity may be linked to a higher risk, potentially by increasing oxidative stress and placing strain on motor neurons. However, experts emphasize that for the majority of people, regular exercise remains safe and beneficial, and that intense exercise may act as a trigger in genetically predisposed individuals rather than a direct cause.
Other Lifestyle Factors
Smoking is a more established lifestyle risk factor for ALS. Scientific analyses have indicated that smokers have a higher risk of developing the disease, with some studies showing a 40 percent increased risk compared to non-smokers. The exact mechanism is not fully understood, but smoking is believed to directly damage motor neurons or accelerate cellular stress.
Diet and metabolism are also being considered, though the evidence is less certain. Researchers believe that factors influencing oxidative stress and inflammation, such as diet, may play a role. While healthy eating is generally advised, its direct impact on preventing ALS is still unclear, although nutrients with antioxidant properties may be protective.
Notable public figures diagnosed with ALS include physicist Stephen Hawking, actor Eric Dane, and rugby players Rob Burrow and Lewis Moody. Former NFL star Chris Johnson recently revealed his diagnosis at age 40, highlighting the ongoing concern surrounding the disease's prevalence.