Study Finds Link Between Type 2 Diabetes And Amyotrophic Lateral Sclerosis

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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In a recent study entitled “Diabetes Mellitus, Obesity, and Diagnosis of Amyotrophic Lateral Sclerosis – A Population-Based Study” researchers investiagated the link between diabetes and amyotrophic lateral sclerosis, confirming that type 2 diabetes, but not type 1, has a protective role against amyotrophic lateral sclerosis evidenced specially in older patients. The study was published in the journal JAMA Neurology.

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurodegenerative disease characterized by the degeneration and ultimately death of motor neurons in the brain and the spinal cord. When motor neurons die the brain is unable to initiate and control muscle movement, leaving patients incapable of speaking, eating, moving and breathing which leads to patients’ death. The disease is usually diagnosed in people between the ages of 40 and 70 years old and has a prevalence of 3.9 cases per 100,000 persons in the United States general population, according to the National ALS Registry.

The team investigated the association between diabetes and obesity with the onset of ALS, a link suggested in previous studies. To this end, they performed a population-based control study with Danish patients diagnosed with ALS between 1982 and 2009. As controls, the authors used healthy subjects in a total of 365 000 (with 100 for each ALS case) matched by sex and age to their ALS patient cohort. The team determined the odds of ALS associating with diabetes or obesity before an ALS diagnostic.

The authors found a significant protective association between ALS and type 2 diabetes (but not with type 1 diabetes) which became stronger with increased age at the time of ALS diagnosis – while patients before age 40 years exhibited an odds ration of 1.66 with diabetes, for older ages this number decreased for 0.52.

The authors summarize that their results are in agreement with previous studies and highlight the importance of taking into account ALS patients’ age and diabetes status. Notably, they confirmed that indeed diabetes, type 2 but not type 1, has a protective role in ALS and further studies are necessary to understand what are the molecular mechanisms behind this effect.