There's an interesting paper (or, actually, it's not a paper, it's a description of an ongoing study; Lee et al., Cohort Profile: The biopsychosocial religion and health study (BRHS)) in the December International Journal of Epidemiology, (2009 38(6):1470-1478) but it probably interests us for all the wrong reasons. It's a teaser of a piece, a profile of a sample that's been chosen for a study of the effects of religion on mortality, and a call for collaborators.
The piece describes the aims of the study, and the characteristics of the cohort being studied, thousands of Seventh Day Adventists living in Loma Linda, CA, both black and white. The idea is that Seventh Day Adventists live longer than non-Adventists, even when their healthy lifestyle is controlled for (the relevant lifestyle factors mentioned in the piece are vegetarian diet, not smoking, social support and eating nuts -- the Adventists' position statement on diet doesn't emphasize nuts, we notice, but maybe in Loma Linda, CA, nuts are a big part of the diet?). The investigators are collecting piles of data on religious observance, social and economic variables, as well as health indicators, to try to figure out what it is about religion that contributes to longer life.
This is curious, really, and not a little tantalizing. Because the Loma Linda study is still underway, there are no results yet to report, so we turned to the literature to see what's already been written on the correlation of religion and mortality. It turns out there's quite a lot, including, for example, this meta-analysis of 42 different studies of this question, which concludes that "[r]eligious involvement was significantly associated with lower mortality (odds ratio = 1.29; 95% confidence interval: 1.20-1.39), indicating that people high in religious involvement were more likely to be alive at follow-up than people lower in religious involvement." Indeed, the IJE paper notes that "In fact, Hall concluded religious attendance was more cost-effective in increasing longevity than statin-type medications." Powerful stuff.
Obviously, the question is Why? What is it about religion that protects people from death? (This is a little paradoxical, since religion is ultimately supposed to protect people after death, or maybe even increase their desire to hasten death so as to get to Heaven quicker -- but, ok, we'll stick with the premise.) Do religious people live healthier lives? Is it healthier people who answer 20 page questionnaires on their religious views? Could it be simply the fact of belonging to a group (which, admittedly isn't really so 'simple', since what is it about group membership that would be protective, and how would you figure it out?)? In which case, do people in book groups or Elks Clubs or stamp collecting clubs live longer, too? That is, is religion a proxy variable for group cohesion? If so, why all these studies considering religion as though there were something specific and unique about its practice that explains longer lifespans?
Which there is. It's prayer. But the possibility that the power of prayer is the explanation doesn't seem to get mentioned in this field, where instead it's all talk of social and psychological variables. (The way to test the power of prayer, of course, is to look at whether Unitarians live longer, too. ) We're not suggesting that it is prayer, just pointing out that it's odd that epidemiologists are looking at the association of religion with health when religion has everything in common with any other group behavior, except this one thing, which isn't being considered. Why privilege religion, then? It just throws confounding variables into the mix, already a potential problem in even the best of studies.
Though, at least one recent study did look at the power of prayer to heal the sick. What the investigators found was that if you knew people were praying for you, it improved your recovery. But if you didn't know that, you didn't recover more quickly. So this suggests that it's the power of knowledge of prayer rather than divine intervention because of prayer. That's consistent with the psychological effects of believing you have something going for you -- the placebo effect, if you will.
And, anyway, if the vast majority of the American people consider themselves to be religious, as shown in poll after poll, who are all these religious people living longer than? Why is our life expectancy embarrassingly lower than that of much more secular societies such as in Japan or Europe? Would it be enough for us to move to Europe, take advantage of their civilized national health care systems (where society really is trying to make you better), and forget Mass?