Researchers at Yeshiva University and its medical school, Albert Einstein College of Medicine evaluated the religious practices of 92,395 post-menopausal women participating in the Women's Health Initiative, a national, long-term study aimed at addressing women's health issues.

Eliezer Schnall and Sylvia Wassertheil-Smoller of Yeshiva College of Yeshiva University said study participants, ages 50 to 79 nationwide answered questions about baseline health conditions and religiosity. They were tracked for an average of 7.7 years.

The researchers adjusted for participation within communal organizations and group activities that promote social life and enjoyable routines -- behaviors known to lead to overall wellness. However, even after controlling for such behavior and other health-related factors, the improvements in morbidity and mortality rates in those attending religious services exceeded expectations.

The study, published in the journal Psychology and Health, found those attending religious services at least once per week showed a 20 percent mortality risk reduction compared with those not attending services at all.

"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," Schnall said in a statement. "There is something here that we don't quite understand."