The research team led by Eliezer Schnall, Ph.D., clinical assistant professor of psychology at Yeshiva College of Yeshiva University analysed the religious practices of 92,395 women aged 50 to 79, participating in the Women Health Initiative.
After examining the prospective association of religious affiliation, religious service attendance, and strength and comfort derived from religion with subsequent cardiovascular events and overall rates of mortality, the researchers found that those attending religious services showed a 20 pct decrease in death risk.
"Interestingly, the protection against mortality provided by religion cannot be entirely explained by expected factors that include enhanced social support of friends or family, lifestyle choices and reduced smoking and alcohol consumption," said Dr. Schnall, who was lead author of the study.
"There is something here that we don't quite understand. It is always possible that some unknown or unmeasured factors confounded these results," he added.
The participants answered questions about baseline health conditions and religiosity and were followed by WHI researchers for an average of 7.7 years, with potential study outcomes of cardiovascular events and mortality adjudicated by trained physicians.
The investigators concluded that although religious behaviour is associated with a reduction in death rates, the physical relationships leading to that effect are not yet understood and require further investigation.
"The next step is to figure out how the effect of religiosity is translated into biological mechanisms that affect rates of survival," said Smoller.
"However, we do not infer causation even from a prospective study, as that can only be done through a clinical trial," he added.
The findings are published in Psychology and Health.