Objective: The goal of this study was to determine the behavioral and clinical characteristics of diabetes that are associated with depression after controlling for potentially confounding variables.
Research design and methods: A population-based mail survey was sent to patients with diabetes from nine primary care clinics of a health maintenance organization. The Patient Health Questionnaire was used to diagnose depression, and automated diagnostic, pharmacy, and laboratory data were used to measure diabetes treatment intensity, HbA(1c) levels, and diabetes complications.
Results: Independent factors that were associated with a significantly higher likelihood of meeting criteria for major depression included younger age, female sex, less education, being unmarried, BMI > or = >30 kg/m(2), smoking, higher nondiabetic medical comorbidity, higher numbers of diabetes complications in men, treatment with insulin, and higher HbA(1c) levels in patients <65 years of age. Independent factors associated with a significantly higher likelihood of meeting criteria for minor depression included younger age, less education, non-Caucasian status, BMI > or = 30 kg/m(2), smoking, longer duration of diabetes, and a higher number of complications in older (> or = 65 years) patients.
Conclusions: Smoking and obesity were associated with a higher likelihood of meeting criteria for major and minor depression. Diabetes complications and elevated HbA(1c) were associated with major depression among demographic subgroups: complications among men and HbA(1c) among individuals <65 years of age. Older patients with a higher number of complications had an increased likelihood of minor depression.