Research Paper Title

A cross-national study of depression in preclinical dementia: A COSMIC collaboration study.

Background

Depression commonly accompanies Alzheimer’s disease, but the nature of this association remains uncertain.

Methods

Longitudinal data from the COSMIC consortium were harmonized for eight population-based cohorts from four continents.

Incident dementia was diagnosed in 646 participants, with a median follow-up time of 5.6 years to diagnosis.

The association between years to dementia diagnosis and successive depressive states was assessed using a mixed effect logistic regression model.

A generic inverse variance method was used to group study results, construct forest plots, and generate heterogeneity statistics.

Results

A common trajectory was observed showing an increase in the incidence of depression as the time to dementia diagnosis decreased despite cross-national variability in depression rates.

Conclusions

The results support the hypothesis that depression occurring in the preclinical phases of dementia is more likely to be attributable to dementia-related brain changes than environment or reverse causality.

Reference

Carles, S., Carriere, I., Reppermund, S., Davin, A., Guaita, A. et al. (2020) A cross-national study of depression in preclinical dementia: A COSMIC collaboration study. Alzheimer’s & Dementia. doi: 10.1002/alz.12149. Online ahead of print.