Background: This cohort study used nationally representative data from PolSenior2 Study of 5,987 adults aged over 60 years carried out in 2018-2019 in Poland to examine the relationship between religiosity and mortality, with particular attention to mediating roles of depression and dementia.
Methods: Survival status was ascertained through national registry data up to December 2023. Religiosity was assessed using the Duke University Religion Index, capturing organizational (ORA), non-organizational (NORA), and intrinsic religiosity (IR1-3). Depressive symptoms were measured with the 15-item Geriatric Depression Scale, and cognitive status with the Mini-Mental State Examination. Associations between religiosity and survival was evaluated using Cox proportional hazard model adjusted for age, sex, education, economic status, loneliness, depression, dementia and functional status. Additionally, mediation analyses were conducted to assess the effect of depression and dementia in the relationship between survival and religiosity.
Results: The median follow-up for the total sample was 3.5 years. ORA showed the strongest association with survival (Hazard Ratio [HR] = 0.86, 95% Confidence Interval [CI] 0.83–0.90). NORA was also associated with reduced mortality (HR = 0.95, 95% CI 0.92–0.99). IR items demonstrated similar protective associations (IR2: HR = 0.91, 95% CI 0.86–0.96). Across all religiosity measures, associations with mortality were driven by controlled direct effects, while neither depression nor dementia acted as mediators. Dementia modified the effect of ORA (p=0.004 for interaction) showing smaller survival benefit in dementia. Conclusions: Religiosity was a significant predictor of mortality within this cohort and this relationship was not explained by mediation through depression or dementia.