The Association Between Religiosity and Lifelong Cancer Incidence in an Israeli Male Cohort: A Competing Risk Survival Analysis

Background: While religious involvement has been linked to better health outcomes, its specific association with cancer incidence remains uncertain. The potential for confounding by lifestyle factors, such as physical activity, body weight, and smoking, complicates the interpretation of this relationship, necessitating further research in large, well-defined cohorts. This study aims to investigate the association between religiosity and cancer incidence in a large Israeli cohort while controlling for a comprehensive set of confounders and the competing risk of mortality. Methods: We conducted a retrospective analysis of 8746 male city-hall employees from the Israeli Ischemic Heart Disease (IIHD) cohort, enrolled in 1963. Cancer and mortality follow-up lasted through 2019. Religiosity was self-reported at baseline and categorized as secular, traditional, or religious. We employed a cause-specific Cox proportional hazards model with age as the time scale to analyze the risk of cancer incidence, treating death as a competing risk. The model was adjusted for a comprehensive set of baseline confounders, including socioeconomic status, smoking, physical activity, body mass index, systolic blood pressure, cholesterol, and diabetes. Results: During the follow-up period, cancer was diagnosed in 2692 participants. We observed a significant inverse association between religiosity and cancer incidence. Compared to secular participants, the religious group had a significantly lower risk of cancer (multivariable-adjusted hazard ratio HR = 0.80, 95% CI: 0.73–0.87; p < 0.001); the traditional group had a nonsignificantly lower risk (HR = 0.91, 95% CI: 0.82–1.02; p = 0.10). This association was specific to cancer incidence, as religiosity was not significantly associated with the competing risk of mortality. Conclusions: In this cohort study, a higher level of religiosity was associated with a significantly lower risk of lifelong cancer incidence, independent of a wide range of lifestyle, social, and clinical factors. These findings suggest that psychosocial and biobehavioral pathways associated with a religious lifestyle may play a protective role in cancer etiology.