High mortality rates as well as cardiovascular outcomes for men with type 1 diabetes were revealed in this historical cohort study with 60 years of follow-up time and a less effective treatment of diabetes than today. Among males with type 1 diabetes, no difference in morbidity or mortality was found between those that had low to normal or high cognitive ability.

• A Swedish cohort of 120 men with type 1 diabetes and 469 without type 1 diabetes was used to assess links between type 1 diabetes, diagnosed before age 18, and long-term morbidity and mortality, and to determine if cognitive ability has a role in long-term morbidity and mortality risk.

• Dramatically higher mortality (HR 4.62), cardiovascular mortality (HR 5.60), and cardiovascular events (HR 3.97) was experienced by men with type 1 diabetes vs men without diabetes.

• Higher cognitive ability at military conscription was found to be related to lower mortality in men without diabetes, but was not linked with any outcome in men suffering from diabetes.