Association of psychological distress late in life and dementia-related mortality.

Objective: It is not fully understood how subjective feelings of psychological distress prognosticate dementia. Our aim was to investigate the association between self-reported psychological distress and risk of dementia-related mortality.

Method: We included 31,043 eligible individuals between the ages of 60 and 80 years, at time of examination, from the CONOR (Cohort of Norway) database. They were followed for a period of 17.4 years (mean 11.5 years). The CONOR Mental Health Index, a seven-item self-report scale was used. A cut-off score equal to or above 2.15 on the scale denoted psychological distress. Cox regression was used to assess the association between psychological distress and risk of dementia-related mortality.

Results: Total number of registered deaths was 11,762 and 1118 (9.5%) were classified as cases of dementia-related mortality. We found that 2501 individuals (8.1%) had psychological distress, of these, 119 (10.6%) had concomitant dementia-related mortality. Individuals with psychological distress had an increased risk of dementia-related mortality HR = 1.52 (95% confidence interval (CI) 1.25-1.85) after adjusting for age, gender and education. The association remained significant although attenuated when implemented in a full adjusted model, including general health status, smoking, obesity, hypertension, diabetes and history of cardiovascular disease; hazard ratio, HR = 1.30 (95% CI 1.06-1.59).

Conclusion: Our results indicate that psychological distress in elderly individuals is associated with increased risk of dementia-related mortality. Individuals at increased risk of dementia may benefit from treatments or interventions that lessen psychological distress, but this needs to be confirmed in future clinical studies.