Psychological Distress and Incidence of Type 2 Diabetes in High-Risk and Low-Risk Populations: The Whitehall II Cohort Study

OBJECTIVE We examined whether psychological distress predicts incident type 2 diabetes and if the association differs between populations at higher or lower risk of type 2 diabetes. RESEARCH DESIGN AND METHODS This was a prospective cohort of 5,932 diabetes-free adults (4,189 men and 1,743 women, mean age 54.6 years) with three 5-year data cycles (1991-2009): a total of 13,207 person-observations. Participants were classified into four groups according to their prediabetes status and Framingham Offspring Type 2 Diabetes Risk Score: normoglycemia with a risk score of 0-9, normoglycemia with a risk score of 10-19, prediabetes with a risk score of 10-19, and prediabetes with a risk score of >19. Psychological distress was assessed by the General Health Questionnaire. Incident type 2 diabetes was ascertained by 2-h oral glucose tolerance test, doctor diagnosis, or use of antihyperglycemic medication at the 5-year follow-up for each data cycle. Adjustments were made for age, sex, ethnicity, socioeconomic status, antidepressant use, smoking, and physical activity. RESULTS Among participants with normoglycemia and among those with prediabetes combined with a low risk score, psychological distress did not predict type 2 diabetes. Diabetes incidence in these groups varied between 1.6 and 15.6%. Among participants with prediabetes and a high risk score, 40.9% of those with psychological distress compared with 28.5% of those without distress developed diabetes during the follow-up. The corresponding adjusted odds ratio for psychological distress was 2.07 (95% CI 1.19-3.62). CONCLUSIONS These data suggest that psychological distress is associated with an accelerated progression to manifest diabetes in a subpopulation with advanced prediabetes.