Identification of factors associated with depression chronicity: An analysis of the Canadian Study on Aging (CLSA).

Objective: Identification of risk factors for depressive chronicity may reduce disease burden by informing prevention and treatment strategies. We aimed to estimate the prevalence of depression chronicity and explore factors linked to chronic depression in a longitudinal cohort.

Methods: Participants from the Canadian Longitudinal Study on Aging Comprehensive cohort who were depressed at baseline, based on a score of 10 or more on the Center for Epidemiologic Studies Depression-10 item scale (CESD-10), were included (n = 3473). Participants were considered to have chronic depression if they maintained a CESD-10 score of 10 or greater at the follow-up. Latent profile analyses (LPA) were used to determine baseline depression subtypes, baseline allostatic load biomarker (AL) profiles, and adverse childhood experience (ACE) profiles. Logistic regression was used to explore factors associated with chronic depression RESULTS: Depression was chronic for 46.6 % of the sample. Significant baseline predictors included depression subtype, with atypical and melancholic subtypes having 1.35 (95 %CI: 1.05-1.73) and 1.87 (95 %CI: 1.53-2.3) times greater odds, respectively, compared with the positive affect subtype. Greater odds of chronic depression were associated with moderate (OR 1.44, 95 %CI: 1.21-1.72) and physical ACE profiles (OR 1.47, 95 %CI: 1.16, 1.84), and with high-cardiovascular AL profile (OR 1.07, 95 %CI: 1.07-1.69), compared with low ACE and average AL profiles. Other significant baseline risk factors included lower annual household income, increased chronic conditions, lower perceived social status, and smoking.

Conclusions: Depression subtypes and stressor profiles were differentially associated with depression chronicity. The research may shed light on intervention and prevention in clinical practice.