Objective: To assess the role of premorbid type 2 diabetes in patients with amyotrophic lateral sclerosis (ALS) in China.Methods: We compared data from ALS patients with premorbid type 2 diabetes (T2D) and ALS patients without T2D with regard to the age of onset of ALS. In addition, survival was compared between these two groups of patients using propensity score matching (PSM). Results: Among 1331 consecutive sporadic ALS patients, 100 (7.5%) were labeled as ALS-T2D and 1231 were labeled as ALS-control according to the presence or absence of premorbid T2D. The mean age of onset in patients in the ALS-T2D group was 57.0 years, with a 4.4-year delay compared to that in the ALS-control group [57.0 (SD, 9.6) years vs 52.6 (SD, 10.3) years, respectively; p = 0.000]. This 4.4-year delay was significant after adjusting for sex and the site of onset in a multiple linear regression model. Additionally, after comparison with matched pairs, a nonsignificant increase in survival was observed among the ALS patients with premorbid T2D. Conclusions: The results support the protective role of diabetes in ALS. It is possible to infer that these beneficial effects occur mainly in the preclinical and early stages of the disease course.
Keywords: Amyotrophic lateral sclerosis; onset; premorbid type 2 diabetes; survival.