On the radio driving to work today the topic was an article that linked the regular practicing of religion in the US to better overall health. Note the article doesn't cite the studies, just says that there is a correlation. I don't really want to dive into the nuts and bolts of the surveys to see if they are done properly, rather just give my take on the topic.
The theory says that if you believe in a higher power that you have less stress and feel better about the world around you and are therefore healthier. I immediately thought of an angle that the folks on the radio didn't touch that I feel is very important in trying to connect the dots between practicing religion and better health.
First, you have to understand that if people are going to church in the US it is more than likely a Christian church - that is, Catholic, Lutheran, Baptist, Methodist and the like. All end up doing basically the same thing, just in a different way. Things like love your neighbor, help the poor, don't kill, don't steal and more all apply to any Christian type of religion.
Once you understand this, it is easy to see where I am going with my theory. If you go to one of these churches every Sunday, it is far more unlikely that you will be doing drugs, smoking, becoming an alcoholic, robbing stores, fighting or abusing yourself in any other way (unless you are of the opinion that Christianity is mind poison). Simply accepting the lifestyle of a traditional Christian rules out many of the hazardous or unhealthy things ("the body is a temple") that you can do to yourself in this world.