Racial Variation in Depression Risk Factors and Symptom Trajectories among Older Women.

OBJECTIVE: To assess racial variation in depression risk factors and symptom trajectories among older women.
METHODS: Using Nurses' Health Study data, participants (29,483 non-Hispanic white and 288 black women) aged 60 years or older, free of depression in 2000, were followed until 2012. Data on race and risk factors, selected a priori, were obtained from biennial questionnaires. Incident depression was defined as depression diagnosis, antidepressant use, or presence of severe depressive symptoms. Group-based trajectories of depressive symptoms were determined using latent variable modeling approaches.
RESULTS: Black participants had lower risk (hazard ratio: 0.76; 95% confidence interval: 0.57-0.99) of incident late-life depression compared with whites. Although blacks had higher prevalence than whites of some risk factors at study baseline, distributions of major contributors to late-life depression risk (low exercise, sleep difficulty, physical/functional limitation, pain) were comparable. There was evidence of effect modification by race for relations of region of birth (Southern birthplace), smoking, and medical comorbidity to depression risk; however, wide confidence intervals occurred among blacks because of smaller sample size. Four trajectories were identified: minimal symptoms-stable (58.3%), mild symptoms-worsening (31.4%), subthreshold symptoms-worsening (4.8%), and subthreshold symptoms-improving (5.5%). Probabilities of trajectory types were similar for blacks and whites.
CONCLUSION: Although overall trajectories of late-life depressive symptoms were comparable by race, there was racial variation in depression risk estimates associated with less-studied factors, such as U.S. region of birth. Future work may address unmeasured health and resilience determinants that may underlie observed findings and that could inform clinical assessment of late-life depression risk factors.