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

To assess racial variation in depression risk factors and symptom trajectories among older women.

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.

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.

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.