Background Evidence for an association between mental health and religiosity largely supports a positive effect of religiosity on mental health. However, there remains a lack of research into the underlying mechanisms of these associations involving other social and health factors, particularly in older women. We aimed to investigate causal pathways between religious attendance and depressive symptoms, and test whether this relationship is mediated by loneliness.

Methods We analysed three waves of The Irish Longitudinal Study on Ageing (TILDA) (2000011, 2012, 2014–2015), a stratified probability cohort of men and women aged over 50 resident in Ireland. A total of 3400 women were included in this analysis. A theoretical longitudinal model of religious attendance and depressive symptoms was tested using Structural Equation Modelling (SEM), adjusted for age, marital status, self-rated health, education and recent adverse life events. Log likelihood tests were used to compare model fit. Depressive symptoms were measured using the 8-item Centre for Epidemiologic Studies Depression Scale (CES-D) and loneliness with the UCLA Loneliness Scale. Religious practice and beliefs were also collected. Changes in religious attendance between waves were calculated. All analyses were conducted using Stata 14.

Results A majority of women attended religious services (86%) and 60% attended at least once a week at baseline, with a decrease in attendance at subsequent time points (85% and 57% at Wave 2; 84% and 55% at Wave 3). Mean (SD) depressive symptoms were 3.38 (4.07) at Wave 1; 3.19 (3.99) at Wave 2; and 3.62 (4.03) at Wave 3. Regular attendance at Wave 1 and Wave 2 predicted fewer depressive symptoms at Wave 2 (Incident Rate Ratio (IRR):0.81 95% CI:0.73–0.89) and Wave 3 (IRR:0.92 95% CI:0.86–1.00) respectively. When loneliness was included in the model, the effect of regular attendance remained unchanged between Wave 1 and Wave 2. The effect was attenuated, but not mediated, between Wave 2 and Wave 3 (IRR: 0.94 95% CI: 0.87–1.02). Depressive symptoms consistently predicted changes in attendance, with higher depressive symptoms predicting subsequent increased and decreased attendance.

Conclusion Longitudinal analyses of religious attendance and depressive symptoms suggest this is a complex relationship which is at least in part bidirectional. Evidence did not support loneliness as a mediator of this relationship. Analyses using other measures of religiosity may help further elucidate these associations.