Religious affiliation can add four years to an average American's life according to a study done at Ohio State University.

"Religious affiliation had nearly as strong an effect on longevity as gender does, which is a matter of years of life," Lara Wallace the lead author of the study said.

Scientists at Ohio State University studied over 1,000 obituaries in the U.S. and considered various factors such as marital status, sex, and religion to determine how long a person can live.

After assessing over 500 obituaries in Iowa from between January and February of 2012 and documenting age, sex, marital status, social activities, volunteer activities, and religious affiliation of each deceased person, it was shown that people with a religious affiliation lived 6.48 years longer than those with none.
A succeeding study widened its pool from only 500 obituaries from Iowa to more than 1,000 obituaries from 42 major U.S. cities in the year following August of 2010 and it was revealed that people with religious affiliations lived an additional average of 3.82 years than those with no religious beliefs.

In a published Journal called "Social Psychological and Personality Science," researchers say that abstaining from drinking alcohol or taking drugs and volunteering and social activities that are vital in religious groups may explain the longevity.

The journal also recognizes the fact that religion can act as a social identity and that it can affect people differently depending on the environment in a statement, "In highly religious cities, people who were not religiously affiliated had shorter life spans than those who were religiously affiliated. However, in less religious cities, non-religiously affiliated people lived just as long as the religiously affiliated. This pattern of effects is consistent with the theory that religion is a valued social identity, which can influence mental and physical health."

The journal also acknowledged that their findings may not generalize younger generations "where the nature and degree of involvement with religious institutions are changing."