Sixty-Year Study of Type 1 Diabetes: Cardiovascular and Cognitive Results

type 1 diabetes
type 1 diabetes
In a decades-long study, men with type 1 diabetes were followed for 60 years to see whether there is a link between the disease, cardiovascular events, and cognitive ability.

A decade-long study found that men with type one diabetes (T1D) have historically poorer cardiovascular outcomes and higher mortality rates compared with their nondiabetic counterparts. Additionally, compared with general population, increased mortality was not inversely related with cognitive function. These findings were published in Diabetic Medicine.

Men in the study with T1D (n=120) who were born in Sweden between 1934 and 1943 and a similar demographic cohort of men (n=469), among whom ~50% had a family history of diabetes, were included in the study.  All were followed for morbidity and mortality during a 60-year follow-up period, with participants reaching a maximum age of 77 years. Cognitive ability at military conscription, presented as a g-factor (range, 1-9 points), was used as a proxy for cognitive function.

The men with T1D and control cohorts had a mean g-factor of 5.24 (standard deviation [SD], 1.97) and 4.51 (SD, 1.76) points (P <.001), 59% and 65% had 0-7 years of education, and 70% and 28% had low socio-economic status, respectively.

Most of the men in the T1D group (80%) had died before the end of follow-up period compared with 31% of the control cohort. Death before 50 years of age occurred among 32% of the men with diabetes in and 5% of the control group..

Type 1 diabetes was associated with all-cause mortality (hazard ratio [HR], 4.62; 95% CI, 3.56-5.60; P <.001), cardiovascular mortality (HR, 5.60; 95% CI, 3.27-9.57; P <.001), cardiovascular events (HR, 3.97; 95% CI, 2.79-5.64; P <.001), heart failure (HR, 4.98; 95% CI, 3.11-7.97; P <.001), acute myocardial infarction (HR, 4.17; 95% CI, 2.72-6.37; P <.001), and stroke (HR, 3.68; 95% CI, 2.22-6.09; P <.001).

In a multivariate model which incorporated g-factor, only all-cause mortality was found to have an interaction effect with g-factor (P =.023). All-cause mortality was associated with both T1D (HR, 3.79; 95% CI, 2.63-5.47; P <.001) and g-factor (HR, 0.59; 95% CI, 0.39-0.91; P =.015).

Stratified by cognitive ability, higher cognitive ability decreased risk for all-cause mortality (HR, 0.59; 95% CI, 0.39-0.90) among the control cohort. This trend was not observed among the T1D group (HR, 1.19; 95% CI, 0.76-1.86). Similar trends were observed in a propensity-matched analysis.

Researchers acknowledge the study was limited by the small sample size and the potential for missing data; however, they said this was unavoidable given the reliance on historical documentation in a study of this length. However, they also noted the study’s strengths, including the long follow-up time, the high number of men with T1D of the same age in the study, and the validity of the follow-up data.

The study’s findings, according to the researchers, revealed a number of insights helpful to both younger and older men with T1D.

“For younger age groups, these findings provide perspective on how diabetes treatment and prognosis have developed and could therefore serve as motivating evidence of the benefits of today’s treatment,” the researchers concluded. “There is a need of studies on larger and later-born cohorts of T1D to detect possible associations between early cognitive ability and prognosis later in life.”


Dybjer E, Aslan AKD, Engström G, et al. Type 1 diabetes, cognitive ability and incidence of cardiovascular disease and death over 60 years of follow-up time in men. Diabet Med. Published online February 7, 2022.  doi:10.1111/dme.14806