Depression Symptoms Declining Among Older Adults: Birth Cohort Analyses From the Rust Belt

Objectives: To investigate potential birth cohort effects in depression symptoms in older adults. Design: Population-based prospective cohort. Setting: Small-town communities in Pennsylvania. Participants: Three thousand two hundred and twenty seven older adults (average baseline age = 71.6) born between 1902 and 1941. Measurements: Four decade-long birth cohorts were the primary predictors in this study: 1902–1911, 1912–1921, 1922–1931, and 1932–1941. The outcome was symptoms of depression assessed at baseline and follow-up study visits using a modified Center for Epidemiologic Studies Depression Scale (mCES-D). The depression outcome was operationalized as: 1). A binary outcome of having greater than equal to 5 depression symptoms on the total mCES-D at any study visit, and 2). A continuous outcome of four factor-analyzed component scores of the mCES-D including depressed mood, anergia/hopelessness, withdrawal, and poor self-esteem. All analyses were jointly modeled with attrition and adjusted for age, sex, education, Mini Mental State Examination score, antidepressant medications, and total prescription medications. Results: Participants from more recently born cohorts were significantly less likely to have a study visit in which they reported greater than or equal to 5 depression symptoms, controlling for attrition. Specifically, in comparison to the 1902–1911 referent cohort, the 1912–1921 birth cohort was 43% less likely (odds ratio [OR] = 0.566, 95% confidence interval [CI]: 0.341–0.939), the 1922–1931 birth cohort was 63% less likely (OR = 0.0369, 95% CI: 0.215–0.632), and the 1932–1941 cohort was 79% less likely (OR = 0.205, 95% CI: 0.106–0.399). The cohort effect was most evident in the depressed mood and anergia/hopelessness symptom composites. Conclusion: Reduced rates of depression symptoms observed in successive birth cohorts of older adults may reflect compression of morbidity or other secular trends.