One of the widely held truths about religious belief is that it helps keep people healthy. Of course, there are dissenters (like Richard Sloan at Columbia University) - much of the evidence is pretty shaky. Nevertheless, it's fair to say that most researcher think that there is some kind of connection, although the hows and wherefores are much debated.
Recent research in larger samples with tighter controls is beginning to shed some light on this fairly murky subject. It seems that, as with much else about religion, it's going to religious services, and not belief per se, that may be responsible for any effect. Late last year, for example, a study showed that women who went to church once a week, regardless of their beliefs, were about 10% less likely to die over an 8 year period (see Sick women don't go to church). They controlled for all the factors they could think of, bit still saw this residual, unexplained effect.
So a recent new study that shows no effect at all comes as a bit of a surprise.
The researchers looked at data from 450-odd men living in an inner city region who have been followed since 1950 (when they were teenagers). They found that there was no link between church attendance and death. But there was a small, but statistically significant, correlation between church attendance and health (as measured by lumping together a number of factors like how active they were, and their doctor's opinion).
Then they started to strip out the other factors that could be clouding the analysis. For example, church goers were wealthier, better educated, and smoked and drank less. All of these factors contribute to better health. Taking these factors into account demolished the effect of church attendance. In other words, it wasn't church attendance per se, but a bunch of other factors that may or may not be causally related to church attendance.
So how come there was such a difference with the earlier study? There are a couple of important differences.
First, the earlier study was in women, not men. Previous research seems to show that the effect of religion on health is greater for women than it is for men. Men just are less likely to see the benefit.
Second, this new study controlled for one fact that the first did not. Happiness. Religious people tend to be happier than non-religious, and happier people tend to be more healthy (Veenhoven 2007). That's exactly what this new study found. Those who were regular church goers were more happy, and mood had a major effect on health (almost as big as smoking).
I think this study gives a key insight into why religiosity and health are correlated. We humans are social animals. And being sociable makes us happy and healthy. Religion provides one means to achieve that end.
Laura B. Koenig, George E. Vaillant (2009). A prospective study of church attendance and health over the lifespan. Health Psychology, 28 (1), 117-124 DOI: 10.1037/a0012984
R. Veenhoven (2007). Healthy happiness: effects of happiness on physical health and the consequences for preventive health care Journal of Happiness Studies, 9 (3), 449-469 DOI: 10.1007/s10902-006-9042-1
8 hours ago in The Phytophactor