Wednesday, December 15, 2004

Headache from Living in Sin?

That's how the most recent study about the relationship between health and marital status could be interpreted. Many studies have shown a positive correlation between good health and being married, though at least some of the early studies found this only for men. The popularization of this finding is to say that marriage is good for your health. In fact, these studies can't prove causality, and if causality exists, it could run in either direction: either marriage makes people healthier or healthy people are more likely to get and stay married. The most recent of these health-marriage studies is commendably careful about this:

Married people are healthier than other adults, other than a tendency for husbands to pack on some extra pounds, says the National Center for Health Statistics.
The center's report on Wednesday, based on a survey of more than 125,000 people, didn't specify reasons. But health statistician Charlotte Schoenborn said in an interview that there are two major theories.
One is that marriage may be protective of health. For example married couples may have advantages in terms of economic resources, social and psychological support and encouragement of healthful lifestyles.
A second possibility is marital selection, "the theory that healthy people get married and stay married, whereas less healthy people either do not marry or are more likely to become separated, divorced or widowed."

There are yet other possibilities. This study, for example, is based on answers from the individuals themselves, not on actual medical data. Maybe married people report their health differently from others? More importantly, age and marital status are linked and the very old tend not to married anymore. This could bias the findings if age has not been controlled for in the findings, as increasing age is the best single predictor of poor health. Some support for this idea comes from the fact that this most recent study found that the widowed had the worst self-assesment of health, and this group is likely to have a high average age.

Most of these health-marriage studies don't ask the respondents about domestic violence. This makes it hard to judge what the overall correlation between marriage and health might be, but it seems likely that marriage has a positive effect on at least the individuals' social health. It is well known that people with good social support networks have better health outcomes than those who are social loners. It would have been interesting to see how the results differ between people who have good marriages and those who do not.

The study didn't ask about how good the marriages were. Instead, they compared the married people's health to the health of those who were cohabiting, and here's the hidden moral message: cohabiting is bad for your health:

For most negative health indicators, adults living with a partner had higher rates than married adults: they were more likely to be in fair or poor health, to have some type of limitation of activity for health reasons and to have experienced low back pain and headaches ... and serious psychological distress," Schoenborn reported.

This is a little odd. Those cohabiting are likely to be younger, on average, than the married sample. I would dearly love to see the actual data here (on age, income and education at least) as well as some real medical data on the two groups. In fact, this finding is so odd that it makes me suspicious of the motives of the researchers. Is this another arrow in the war organized by the descendants of the moral majority movement?

Cohabiting should provide the same social support as marriage does, and this is what makes the finding so odd. If cohabiting actually is correlated with lower health in the United States this might be due to the way marital status is bundled together with goodies such as health insurance for the spouse. Those who live together without being married may have less access to medical care, which could result in long-term untreated health problems. In some areas of the country, "living in sin" could also cause societal disapproval and this could cause psychological problems in those exposed to it.

Whatever the truth about this, it's important to stress that these studies are not telling us to add marriage to our health promotion activities.