Depression subtypes and 5-years risk of mortality in aged 70 years: a population-based cohort study

To estimate the mortality risk related to different mood disorders in a geriatric sample of subjects aged 70 years and over without dementia.

All non-demented subjects at baseline who participate on a second phase of a population-based cohort study were included. Adjusted Cox proportional hazards models were used to determine the association between depression and 5-year survival of 451 elderly people without dementia originally recruited for a representative community dementia cohort study. Baseline evaluation included the Cambridge Mental Disorders of the Elderly Examination Schedule. Depressive disorders (major and minor episode) were assessed according DSM-IV criteria and classified according the age of onset (late vs. early). The late-onset depression was classified according to the presence or absence of depression-executive dysfunction syndrome (DEDS).

The initial cohort size was 451 subjects, among which 10.9% (n = 49) suffered a major depressive episode and 10.4% (n = 47) a minor depressive disorder. Among the total affective disorders, 77.9% (n = 74) were late-onset depressions and 29.5% (n = 28) had executive dysfunction. After 5 years, the vital status of 94% (n = 424) of the participants was known and the mortality was 18.9% (n = 80). Late-onset major depressive episode with executive dysfunction was related to mortality after adjustment by age, gender, marital status, level of education, comorbidity (or health global status) and cognitive impairment (HR = 3.70; 95% CI = 1.55-8.83). The executive dysfunction was found to be an independent mortality risk factor (HR = 2.05; 95% CI = 1.15-3.64).

There is a statistically significant association between mortality and late-onset major depression with executive dysfunction.