Men benefit more from marriage than women do. Have you heard statements like that before? I’m sure I have. It’s partly based on evidence that, compared to their unmarried counterparts, both women and men tend to live longer if they are married, but that men’s lifespan is increased even more, on average, if they are married. Some of this may be down to the fact that wives push their husbands to the see the doctor when they get sick.

But most marriage and health studies are based on self-reports of health -- which can be unreliable -- or general records of mortality, which tell researchers very little about why marriage, health and death may be linked.

So Princeton sociologist Michael McFarland and colleagues decided to look at biological risk factors in a sample of older men and women (ages 57 to 75) -- factors such as blood pressure, resting heart rate, waist circumference, and metabolic factors that put people at risk of Type II diabetes. They also measured a protein that is found in the blood and indicates inflammation.

Lo and behold, women came out best over-all on these measures. The longer their marriage, the fewer their cardiovascular risk factors: a 13 percent decrease for every 10 years of continuous marriage.

But when marriage is disrupted, it can be hard on the health. Women who were continuously married had a 40 percent lower count of metabolic risk factors than women who experienced two episodes or divorce or widowhood, the researchers found.

Unexpectedly, the researchers found no protective effect of marriage in men. This could be because, in the older cohort being studied, the least healthy men had already died. Also, the results may be skewed by men who married very young -- in their late teens, very early 20s -- and who were more likely to have warning signs of chronic inflammation later in life. (Inflammation is crucial to healing but chronic inflammation can be harmful.) However, even a five-year increase in age at marriage reduced this risk by 30 percent among men.

The increased risk among men who married very young may be linked to lower educational attainment, which is associated with higher biological risk, the researchers said.

So the picture is more complex than we thought, but in general the study confirms the health benefits of marriage. However, with people getting married later, and women staying in the workforce longer -- and with the trend towards marriage as an upper-middle-class phenomenon (between men and women with matching socioeconomic and educational backgrounds) -- the differences between the sexes may begin to even out.