Earlier this week, we wrote about recent research which suggests that marriage puts women at a higher risk for weight gain, while divorce makes men more likely to put on pounds. Married and divorced individuals appear more likely than their never-married peers to experience weight gain.

Studies like this, coupled with the already high rates of divorce, make some people ask: why should I get married? Are there any advantages? However, according to another recent study, marriage could add years to your life.

Research published in the American Journal of Epidemiology examined data from 90 previous studies about mortality rates among single vs. married individuals. In all, the 90 studies contained data on over 500 million people.

Over a lifetime, single men have a risk of death 32 percent higher than men who marry and stay married. This translates to a life expectancy that is 8 to 17 years shorter for single men.

Single women have a lifetime mortality risk that is 23 percent higher than their married counterparts. This means a 7-to-15-year reduction in life expectancy.

The study's lead author explains: "If you're a couple, a spouse may be after you to eat better and go to the doctor. Sometimes it's just easier to be healthier and less of a risk taker when you're married."

However, some are critical of the study's results. One social psychologist familiar with the study says that this type of research is often biased toward marriage. She says the numbers are skewed because they don't include mortality statistics on those who are divorced or widowed.

She adds: "You can't say that single people would live longer if they got married, based on this research, because the researcher is only counting the people who got married and are still currently married. Divorced and widowed people got married at one time, too."

So do married people, on average, live longer than singles? The answer appears to be yes, but only for those who stay married for life. Perhaps that was the original reasoning behind the vow "till death do us part."

Source: MSNBC, "Single people may die younger, new study finds," Joan Raymond, Aug. 18, 2011