Research suggests diabetes may lower risk of developing ALS, especially with insulin treatment

A new study presented at the ALS Nexus conference reveals that individuals with long-standing diabetes, particularly those treated with insulin, may have a significantly reduced risk of developing amyotrophic lateral sclerosis, shedding light on potential metabolic influences on the disease.

A poster presented at the ALS Nexus conference in Orlando suggests that diabetes may be linked to a lower chance of developing amyotrophic lateral sclerosis, or ALS, adding to a body of research that has hinted at the same pattern. The study also found that longer-standing diabetes and treatment with insulin were each associated with a further reduction in ALS risk.

ALS is a progressive neurological disease in which the nerve cells that control movement gradually break down. The causes are still not fully understood, although researchers have long been examining whether metabolic conditions such as diabetes might play a role. Earlier evidence has pointed in the same direction: a 2020 systematic review and meta-analysis published in Clinical Neurology and Neurosurgery reported a significantly lower risk of ALS among people with diabetes.

In the new analysis, researchers drew on data from six large population health studies and followed more than 1.1 million adults who did not have ALS at the start. After adjusting for demographic and lifestyle factors, the team found that 14 in every 10,000 people without diabetes developed ALS over 15 years, compared with 9.8 per 10,000 among those with diabetes, a difference the researchers said corresponded to a 30% lower risk. They also reported that the result held up when they accounted for death before diagnosis, which can distort population studies of long-term disease risk.

The association was strongest among people whose diabetes had been diagnosed more than six years earlier, who had a 38% lower risk of ALS, and among those treated with insulin, whose risk was 44% lower. The researchers said the findings suggest the link is unlikely to be explained entirely by measured lifestyle factors. Still, they cautioned that the study could not track changes in diabetes status or habits over time, and that other unmeasured influences may also have affected the results. For now, the work adds another piece to an unsettled question: whether the metabolic changes involved in diabetes may somehow alter susceptibility to ALS. The ALS Association has previously noted that the relationship remains complex and that some studies have produced conflicting results.