Type 2 diabetes may reduce risk for ALS
Type 2 diabetes, but not type 1 diabetes, may be associated with a reduced risk for developing amyotrophic lateral sclerosis, according to research in JAMA Neurology.
Researchers also found that both the age of diabetes diagnosis and the age of diagnosis of amyotrophic lateral sclerosis, the neurodegenerative brain disease commonly known as ALS, affect the level of risk.
“Our observed association between diabetes and ALS provides some additional information to our understanding about ALS,” Marianthi-Anna Kioumourtzoglou, ScD, of the Harvard T.H. Chan School of Public Health, told Endocrine Today. “Of course, our results should be replicated - as is always the case with epidemiologic studies - but we believe our paper could be the start of a discussion and focus further attention on the role of energy metabolism in ALS pathogenesis.”
In a population-based, nested case-control study of adults living in Denmark, Kioumourtzoglou and colleagues at other institutions analyzed data from 3,650 Danish residents diagnosed with ALS between 1982 and 2009 (46.5% women; mean age at diagnosis, 65.4 years), using data from the Danish National Patient Register to examine the association between hospital admission for diabetes and ALS diagnosis. Researchers also analyzed data from 365,000 healthy controls (100 for each ALS case) matched by age and sex. Researchers conducted analysis in 2014.
Researchers identified 9,294 patients with diabetes at least 3 years before the index date (date of ALS diagnosis or same date for matched controls), 55 of whom were subsequently diagnosed with ALS. The mean age of diabetes diagnosis was 59.7 years. There was a mean of 9.8 years between diabetes diagnosis and ALS diagnosis among patients who were diagnosed with both.
Researchers found that diabetes - but not obesity - was linked to a reduced risk for ALS.
When considering diabetes and obesity together, the estimated OR for ALS was 0.61 (95% CI, 0.46-0.8) for diabetes and 0.81 (95% CI, 0.57-1.16) for obesity. Researchers also found that the protective association was stronger with increasing age at ALS diagnosis (P = .01). Although the OR for first mention of diabetes was 1.66 (95% CI, 0.85-3.21) before age 40 years, it was 0.52 (95% CI, 0.39-0.7) for adults older than 40 years.
“Our findings provide some additional support on the idea that energy metabolism plays an important role in ALS pathogenesis,” Kioumourtzoglou said. “The specific underlying mechanisms for our observed association between diabetes and ALS are currently unknown. Therefore, the immediate clinical implications are not necessarily clear.”
The link between diabetes and ALS must be explored further in other epidemiologic and toxicologic studies in different settings, she said.
“The next steps would include identification of what related to diabetes is responsible for the protective association,” Kioumourtzoglou said. “For instance, our findings suggest that it is likely type 2 diabetes is protective, while type 1 might even be a risk factor. Once the underlying mechanism is understood, then hopefully that can lead to prevention and, maybe even at some point in the future, treatment (if diabetes is found to also impact survival).” - by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.