Type A behavior and risk of all-cause mortality, CAD, and CAD-related mortality in a type 1 diabetic population: 22 years of follow-up in the Pittsburgh Epidemiology of Diabetes Complications Study.

OBJECTIVE

To determine whether type A behavior predicts all-cause mortality and incident coronary artery disease (CAD) in a type 1 diabetic population.

RESEARCH DESIGN AND METHODS

Follow-up data (22 years) from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study of childhood-onset type 1 diabetes were analyzed for the 506 participants who completed the Bortner Rating Scale (measuring type A behavior) and Beck Depression Inventory (BDI) at baseline (1986-1988). CAD comprised myocardial infarction as determined by hospital records/Q waves on electrocardiogram (ECG), CAD death (determined by a mortality classification committee), angiographic stenosis, ischemic ECG, and angina.

RESULTS

There were 128 deaths (25.3%) during follow-up. Univariate analysis showed an inverse relationship between Bortner scores and all-cause mortality (P=0.01), which remained significant after allowing for age, sex, duration, HbA1c, education, smoking, BMI, and physical activity (P=0.03). However, the addition of BDI scores attenuated the relationship (P=0.11) with a significant interaction (P=0.03) such that any protective effect against mortality was limited among individuals with lower BDI scores (bottom three quintiles) (P=0.07), whereas no effect was seen in those with higher BDI scores (P=0.97). Bortner scores showed only a borderline association with incident CAD (P=0.09).

CONCLUSIONS

Those with higher type A behavior have lower all-cause mortality in our type 1 diabetic population, an effect that interacts with depressive symptomatology such that it is only operative in those with low BDI scores. Further research should focus on understanding this interaction.