Researchers assessed obituaries to calculate whether religious affiliations boost longevity.
The Ohio State psychology researchers behind the study insist there is merit to the connection: people with religious affiliations often volunteer and engage in social activities throughout their lives - something routinely tied to longer lifespan.
The researchers have looked at more than a thousand obituaries in country's 42 major cities only to come to a conclusion that people with religious affiliations or simply religious people live four years longer than those who follow no religion, CBS reported.
A further analysis of 500 obituaries from the Des Moines Register, a newspaper in Iowa, found that religion was associated with an extra 6.48 years of life.
"We found that volunteerism and involvement in social organizations only accounted for a little less than one year of the longevity boost that religious affiliation provided", said Laura Wallace, a doctoral student in psychology at Ohio State and lead author of the study.
The study was published online June 13 in the journal Social Psychological and Personality Science.
"Religious affiliation had almost as strong an effect on longevity as gender does, which is a matter of years of life", said Laura Wallace, the study's lead author and a Ohio State University doctoral student of psychology.
Overall, the study provided additional support to the growing number of studies showing that religion does have a positive effect on health, Wallace said. Previous studies showed people who volunteer or participate in groups tend to have more longevity.
Results showed that this was only part of the reason why religious people lived longer.
"There's still a lot of the benefit of religious affiliation that this can't explain", she said.
It may be related to the rules and norms of many religions that restrict unhealthy practices such as alcohol and drug use and having sex with many partners, Way said.
The researchers acknowledged their study was limited by the fact it could not control race and lifestyle choices, which are important factors for longevity.
Those visiting church at least once a week were found to have 33% lower risk of death than those who never went.