Making a little more time for church may add a little more time onto our lifespans, suggests a new study published Monday in JAMA Internal Medicine.

The Harvard University researchers analyzed data from the Nurses’ Health Study, a long-running population study of women. Specifically, they looked at 74,534 healthy participants who had answered a question about their attendance at religious services in 1992 and then kept track of them for up to 20 years afterwards. By 2012, 13,537 of the women had died. And after adjusting for other risk factors, the researchers found that those who said they attended a religious service more than once a week were 33 percent less likely to die of any cause than those who never attended a religious service at all. A similar, if smaller, trend was seen when it came to deaths from cancer and cardiovascular disease.

Overall, they calculated that attendance of one or more religious services a week was associated with about five months longer survival throughout the 16 years of study.

“Our study suggests those who attend services are at considerably lower risk for mortality over a fixed follow-up period,” study author Dr. Tyler VanderWeele, a professor of epidemiology at Harvard’s T. H. Chan School of Public Health, told Medical Daily. “There is evidence that it provides social support, discourages smoking, decreases depression, and promotes optimism or hope. These things affect health and appear to improve longevity.”

The Church Effect

The study is only the latest to examine the question of religious belief and health, with some but not all earlier research finding a similar positive effect. But for this go-around, VanderWeele and his colleagues sought to address a common criticism of previous efforts. Simply put, people who can regularly go to church are likely already in good stable health, and a one-time comparison between these individuals and the general population might overestimate the importance of religious belief alone. By looking at healthy people over a long period of time and repeatedly checking how often they attend services (participants were asked the question every four years), the team was able to avoid that problem.

Any study has limitations though, and this one isn’t any different. For one, it only looked at women, and the relationship between health and religion is somewhat muted for men, according to VanderWeele. “Prior studies have also found, for men, an association between religious service attendance and lower mortality, but the best evidence to date seems to suggest that the association, while present, may not be as strong for men as it is for women,” he said.

Secondly, these women were mostly white and primarily practiced Christianity, through the effect was stronger in African-American women. While VanderWeele notes that long-term studies of Jewish believers have turned up similar results, he doesn’t believe there is any identical research on those who identify as Muslim or Hindu. That doesn’t mean there isn’t an effect for these groups, it just means we shouldn’t generalize the current findings to people of every religion and creed until we know more.

Lastly, the study only looked at one aspect of religious belief. In an accompanying editorial, Duke university psychiatrist Dr. Dan German Blazer writes: “[W]e have no assurance that attendance at religious services is a marker of the strength of one’s religion or spirituality and no description of the extent of private practices of spirituality, such as prayer, or perceptions of spiritual well-being among the participants.”

And because we’ll never be able to randomly assign people to either attend church or not, it’s impossible to be fully sure how much of a cause-and-effect relationship there really is between religious service attendance and health.

Still, it’s likely that the act of attending church more often strengthens any potential effect. The vast majority of Americans report having some degree of spirituality, but only some attend services (around 45 percent did so at least once a week in the current study). “Decisions about religious practice and formation of religious beliefs are of course not made on grounds of health, but rather reflect values, relationships, experiences, evidence, thought, upbringing and so on,” said VanderWeele. “However, for those who already hold religious beliefs, but do not attend services, the study does question whether they are perhaps missing something of the communal religious experience that is powerful, at least for health.”

“In an era in which people increasingly self-identify as spiritual but not religious, the study raises the question as to whether there might be something more powerful in religious life than simply solitary spirituality,“ he added.

And though the study wisely steers clear of making any judgments about the validity of religion, VanderWeele does believe that his team’s findings indicate the need for medical professionals to be comfortable addressing that topic with their patients if and when it’s appropriate.

“The majority of patients say that they think that physicians should consider patients' spiritual needs,” he said. “This will of course be easier if the clinician and the patient share the same, or a similar, faith, but these matters can be discussed in general terms as well. If issues of religion and spirituality do come up in conversation, clinicians could inquire about service attendance as a potentially meaningful form of social participation.“

Source: Li S, Stampfer M, Williams D, et al. Association of Religious Service Attendance With Mortality Among Women. JAMA Internal Medicine. 2016.