ALS risk linked to wide range of lifestyle and health factors in study

A wide range of potentially modifiable factors related to lifestyle, the environment, mental and physical health, and socioeconomic circumstances may be linked to the risk of developing amyotrophic lateral sclerosis (ALS), a study in China suggests.

The researchers identified 45 factors significantly associated with ALS in an analysis of more than 326,000 UK Biobank participants, including 744 who developed the disease during follow-up. Statistical modeling suggested that changing these factors to more favorable levels might reduce the number of new ALS cases.

However, because the study was observational, it cannot prove that the identified factors cause ALS or that changing them would prevent the disease. Still, the researchers said they “may serve as targets for future studies.”

The study, “Identifying Modifiable Factors and Their Joint Effect on Amyotrophic Lateral Sclerosis: A Prospective Cohort Study in the UK Biobank,” was published in Brain and Behavior.

Recommended Reading

Oct. 16, 2026 News by Marisa Horak, MS

Wearable robotic leg device can improve walking ability in ALS

Researchers examine 184 potential factors linked to ALS risk

ALS is a progressive disease in which motor neurons, the nerve cells that control voluntary movement, gradually die. While genetic factors are known to influence the risk of developing ALS, researchers have also studied whether lifestyle habits, environmental exposures, and other potentially modifiable factors play a role.

Most studies, however, have examined risk factors one at a time or in small groups, making it difficult to understand how they may contribute to ALS risk together.

Researchers in China therefore took a broader approach. They conducted an exposome-wide association study (EWAS), analyzing data from 326,050 adults, ages 40 to 69, who enrolled in the UK Biobank between 2006 and 2010. This type of study examines many factors at once to identify possible links with a health outcome.

At the start of the study, researchers examined 184 potentially modifiable factors across seven areas: lifestyle behaviors, local environment, medical history, psychological factors, physical measures, socioeconomic status, and early life factors.

Researchers excluded people who developed ALS within the first six years of follow-up. This was intended to reduce the chance that early, undiagnosed disease had already affected factors such as physical activity or muscle strength. Follow-up continued until an ALS diagnosis, loss to follow-up, or October 2025.

During follow-up, 744 people developed ALS. Of the 184 factors examined, 45 were significantly associated with ALS risk — 27 linked to a lower risk, suggesting possible protective effects, and 18 linked to a higher risk. However, only 12 factors remained significantly associated with ALS after a stricter statistical test that accounted for the large number of comparisons.

Among the 10 factors most strongly associated with ALS, seven were linked to a lower risk. These included higher household income, better lung function, greater handgrip strength, later age at first sexual encounter, higher egg intake, and a history of chickenpox, or varicella. The other three were linked to a higher risk: lower education, unemployment, and more time spent watching television, which the researchers viewed as a sign of physical inactivity.

Study estimates potential impact of multiple ALS risk factors

The researchers then examined the combined associations of these factors with ALS risk across six of the seven areas assessed. Early life factors were excluded because none was significantly associated with ALS in the overall analysis. Higher scores reflecting less favorable factors in each of the six remaining areas were independently linked to greater ALS risk.

The team next used statistical modeling to estimate how many ALS cases might theoretically be avoided if those factors were changed. They calculated population attributable fractions (PAFs), which estimate the percentage of cases that might be prevented if risk factors were changed to more favorable levels, assuming the factors actually contribute to causing the disease.

Under a conservative scenario, in which unfavorable factors were shifted to intermediate levels, the model produced a combined PAF of 25.9%. This suggested that about one-quarter of ALS cases might theoretically be avoided under those conditions. Socioeconomic and local environmental factors accounted for the largest portions of that estimate, at 6.8% and 6.6%, respectively.

Under a theoretical ideal scenario, in which both unfavorable and intermediate factors were shifted to favorable levels, the estimate rose to 87.4%, with lifestyle factors accounting for the largest portion (41.3%).

That does not mean nearly nine in 10 ALS cases could actually be prevented. The 87.4% estimate assumes that the associations are causal and that all factors could be shifted to favorable levels.

Still, the researchers wrote, “ALS may have greater preventive potential than we previously thought.” They also concluded, “Interventions targeting modifiable risk factors, particularly those related to lifestyle and socioeconomic status, may help reduce the incidence of ALS.”