Association of Religious Service Attendance With Mortality Among Women (2016) - https://jamanetwork.com/journals/jamainternalmedicine/fullar....
> Women who went to any kind of religious service more than once a week had a 33% lower chance than their secular peers of dying during the 16-year study-follow-up period.
Not does it account for organized religions ability to forcibly displace other social support (community gathering) organizations. (Social support was the largest factor in improved health among religious people in the study).
Study also excluded, by design, any effects religious services may have on causing cardiovascular problems or cancer, on confounders due to already sick people finding religion.
I would hazard a guess the removed bit is actually very important, because having a social network has been shown to improve lives: https://duckduckgo.com/?q=social+network+and+old+age&ia=web (hopefully that's enough citation), and regularly showing up to congregation is probably a huge step in having a social network.
[citation needed]