Age and sex trends in depressive symptoms across middle and older adulthood: Comparison of the Canadian Longitudinal Study on Aging to American and European cohorts

•Non-linear age trends and gender differences were apparent across 3 cohorts.•Depression was negatively associated with age through midlife.•Depression was positively associated with age through late life.•Females reported greater depressive symptoms than males.•Interactions between age and sex varied by cohort. The literature suggests depressive symptoms differ in a non-linear fashion across adulthood and are more commonly reported in women as compared to men. Whether these trends are observed across countries in population-based cohorts is unclear. Cross-sectional observational study of approximately 138,000 women and men between the ages of 45 and 95 from three population-based cohorts representing Canadian, European, and American populations. Age, gender, educational attainment and annual income were assessed in each cohort. Depressive symptoms were assessed by the Center for Epidemiological Studies Depression Scale in the US and Canadian cohorts, and by the EURO-D in the European cohort. Across all three cohorts, non-linear age trends and gender differences were observed in the report of depressive symptoms, independent from educational attainment and annual income effects. The non-linear age trends reflected a negative association between depressive symptoms and age during midlife and then a positive association in late life. Females reported greater depressive symptoms than males; however, an interaction between gender and age was also observed in the Canadian and European cohorts. Among Canadians, the gender differences were largest after age 70, whereas among Europeans, gender differences where largest among those approximately aged 60. Limitations include: 1) the cross-sectional nature of the study, resulting in age differences potentially reflecting cohort effects rather than a developmental process; and 2) the use of different depressive symptoms measures across cohorts. Characterization of depressive symptoms over mid and late adulthood in women and men provides insights into potential focal points for intervention and allocation of resources.