Nestor, who lives in the western part of the Ukraine, has been single throughout his entire life.  At 115, he's the world's oldest man.

Although he lives life one day at a time, Nestor told Reuters news service that he hopes to celebrate his next birthday on March 15.

Singles should also take note that Julie Bertrand, who had been the world's oldest woman at 115, until she died two months ago, was also single throughout her life.  Bertrand lived in Canada.

The fact that the world's oldest man is a life-long singleton prompted me to do some research into the correlation between health, longevity, and marital status.  What I found was a bundle of complexities.

True, many studies conducted over the past 140 years have shown that married persons tend to live longer than their unmarried counterparts.  But is that because married people are healthier or because healthier people tend to marry more frequently than those is poor health?

Is it marriage that accounts for a higher degree of longevity for those who tie the knot, or is it the lifestyle of married people that produces a longer life?

Recent research at the Rand Center for the Study of Aging has attempted to answer these questions and to discover the connection, if any, between marital status and the aging of men.

Rand's researchers used a nationally representative dataset to track more than 4,000 men over a 22-year time frame. The study analyzed changes in the men's health status alongside the course of their major marital transitions--their history of marriage, divorce, death of a spouse, and remarriage.

The Rand study found that "married men in their 50s, 60s, and 70s have lower mortality rates than those who are unmarried (never married, divorced, or widowed)."

For divorced men, the higher risk of death was explained primarily by their poorer health. But among never-married men and widowers, "excess mortality rates are less related to self-reported health status--a finding that raises questions about the factors that lead to earlier death."

Previous research has suggested that part of the marriage advantage stems from co-residence with a partner or with other adults, not marital status per se. Since men who are lifelong singles may prefer to live alone, they may tend to die younger than their married counterparts more because of their lack of a social network than the fact that they are single.

According to the Rand study, "the relationship between marriage and longevity is more complex than had been generally believed."  Although evidence indicates that marital status has an effect on mortality, "the determining factors underlying this effect are not always clear."

Professor Bella DePaulo further complicates the issue by suggesting the possibility of a stigma theory, wondering whether the fact that married and single people are differentially valued in society may partially explain differences in health, longevity, and marital status.  DePaulo is the author of "Singled Out: How Singles are Stereotyped, Stigmatized, and Ignored, and Still Live Happily Ever After." (St. Martin's Press)

But for Hryhory Nestor, the matter is not complex at all.  Personal freedom played a major part in his long life.

"I always stayed in the fresh air and went barefoot everywhere. I slept out of doors in the summer. And I would drink milk and eat cheese and potatoes."

I'll lift my glass and make a toast to Hryhory Nestor and wish all single people a healthy and long life.

(Ed. Note:  A Reuters news story on March 16 reported that Hryhory celebrated his 116th birthday on March 15 with a glass of champagne with a house full of well wishers.)