You'd think it would be the opposite, since Bible-thumpers would be eager to get to their Heavenly reward the sooner, whereas Atheists would be trying to avoid the final curtain for as long as possible.
Actually, I could imagine that this COULD be true, in much the same way that all studies show that, for a population on AVERAGE, married people live longer than singles. It's a matter of social support structure, greater community involvement as a couple, and overall reduced stress for the married. There's a thread running here right now that addresses similar findings for socially-isolated older gay men, even those who are partnered but living without many social contacts and support structures.http://www.realjock.com/gayforums/1468238
Being a member of an organized religion can provide social support. It can also provide emotional comfort, reducing stress, even if it requires buying into a false belief system. Even our own local Metropolitan Community Church (MCC), which is part of the largest gay denomination in the US, operates extensive senior citizen services for gays & lesbians. Belong to that church and your life expectancy might well increase.
In fact, I sometimes attend there, and have even been a Lector. Not because I'm religious, but it's a lovely social experience, with very nice gay men & women. And like most MCCs, the services are like musical stage productions, entertaining to attend just for the performances. Well, whadda yah expect when gays are running the show?