Prevalence of depressive disorders among the very old in the 21st century

Background: The aim of this study is to explore the prevalence of depressive disorders in very old adults over time, in rural/urban environments, between men/women, as well as to explore other factors associated with depressive disorders. Methods: This study was conducted utilizing the GERDA-database data, which consists of four cohorts of 85, 90 and 95+ year olds living in Northern Sweden. Participants could reside independently or in residential care. Data collections took place between 2000 and 2017. Descriptive data and logistic regression models were utilized to explore data. Results: The prevalence of depressive disorders increased between 2000/02 and 2015/17 in all age groups, with the highest percentages observed in the 95+ age group, reaching 53.6 % in 2015/17. The prevalence varied from 20.3 % in those without dementia to 65.1 % in those with dementia. Sex or living in an urban/rural environment was not associated with an increased risk of depression in the fully adjusted models. Dementia and reduced capacity in activities of daily living were associated with depressive disorders among 85 and 90-year-olds, while living alone was associated with depressive disorders in the 95+ age group. Limitations: Potentially limited generalizability, as this study took place in northern Sweden. Conclusions: The prevalence of depressive disorders among very old adults increases with age and the prevalence also increases throughout cohorts and time. These alarming rates of depressive disorders among the very old require immediate measures and further investigation. Future studies are needed to explore and monitor trends and to plan and design tailored interventions.