Type II diabetes mellitus and the incidence of amyotrophic lateral sclerosis

Objective: The aim of this study was to investigate the relationship between type II diabetes mellitus (T2DM) and ALS incidence using the National Health Insurance Research Database and Serious Disabling Disease database of Taiwan. Methods: This was a population-based cohort study. The index date was the date of the first T2DM diagnosis + 365 days. We included T2DM patients diagnosis between 2000 and 2013 (n = 2,135,427). These patients were matched by sex, age, urbanization, and insurance premium at a ratio of 1:1 to include patients without diabetes mellitus. Competing risk-adjusted Cox regression analysis was performed to investigate the association between T2DM and the incidence of ALS. Results: In the patients not stratified by age, T2DM was not associated with the incidence of ALS after controlling for confounding factors. The interaction test of age subgroup (< 55 and ≥ 55 years) and T2DM on ALS risk was significance (p < 0.001). Subgroup analysis showed that T2DM was negatively associated with ALS in patients whose age at the first T2DM diagnosis was ≥ 55 years. Among T2DM patients, T2DM combined with hypertension was negatively associated with ALS among patients whose age at the first T2DM diagnosis was ≥ 55 years. Among T2DM patients, T2DM combined with hyperlipidemia was positively associated with ALS among patients whose age at the first T2DM diagnosis was < 55 years. Conclusions: The late-onset of T2DM may exert negative association with ALS, especially when combined with hypertension. The early-onset of T2DM may exert positive association with ALS, especially when combined with hyperlipidemia.