Whether or not you like the idea of marriage, demographers would probably encourage you to get hitched. Since the middle of the 19th century, they have understood that people who marry enjoy longer and happier lives than those who remain single. In the early 70s, longevity researches added a footnote: a younger wife adds a few years to a man’s life.

But these statements seem tired today. In many countries, women are more likely than ever to be older than their husband, romantic cohabitation is commonplace and same-sex unions are winning more legal recognition. So does marriage still mean a longer lifespan?



The answer, in short, depends on age gaps, money and brains.

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Let’s focus on age gaps. A few years ago, that 70s footnote was reexamined by German demographer Sven Drefahl, who dug deep into Denmark’s population data. In doing so, he put together a highly cited and influential paper on marital age gaps and longevity.

Drefahl chose Denmark because, since 1968, the country has done as much as technology has permitted to keep a computerized register of everyone in the country. (This began, back in the day, with records on magnetic tape.)

As was reported when his study first came out in 2010, Drefahl found that women with younger husbands – so-called “cougars” – die young, as do men with older wives and women with older husbands. (I use “cougar” for brevity: as I will explain later, it’s a horrible term.) The only lifespan winners in the Danish data were the men with younger wives.



The finding that cougars die young is odd – and Drefahl didn’t claim in his paper to be able to explain it. It’s odd because, in theory, the benefits of being married to someone younger than you should apply to both sexes. In the autumn or winter of your years, having a younger spouse is likely to mean having a higher standard of health and fitness to keep up with, and when it comes to it, a younger spouse is probably a more energetic caregiver than someone your own age.

To appreciate the disparity between the lifespans of men and women with younger spouses, let’s look at some numbers. Between 1990 and 2005, a Danish woman of 50 or above, married to a man about 16 years younger than her, was 40% more likely to die by the end of 2005 than a woman of her age in a same-age union. The same set of comparisons for a man of 50-plus gives the result that he was 4% less likely to die than a man of his age married to a woman of his age.

There is also a flicker of black humor in Drefahl’s study: in the case of very wealthy older men, the husband is not 4% more likely to survive but 5% more likely to die. So, according to Denmark’s national dataset – not just tabloid headlines – super-sugar daddies should watch out.

That anomaly aside, according to Drefahl’s models, the optimum strategy for a man wanting a long lifespan is to marry a much younger wife. Meanwhile the female optimum is to seek a man born within 12 months of her date of birth. According to United Nations data from 2013, only in the Caribbean islands of Bermuda and St Kitts and Nevis does the average spousal age gap fall within the female optimum; it benefits male lifespans most in West Africa.

Since Drefahl’s research was originally published, he’s made some progress at figuring out why cougars snuff it early. He’s been looking at causes of death. The answer is that these women are far more likely to die of “external causes” than other married women – that is, they are more likely to die of accidents that are not suicides. (Consistent with the stereotype that older men stay fit and healthy because they are inspired by a younger partner, men with younger wives have low odds of dying from heart attacks, strokes and cancer.)

The elevated risk of accidents could be due to a mix of things. Like some cringeworthy stereotype of a risk-loving Mrs Robinson in a red convertible, it could be that women who generally do dangerous things are the ones who marry younger men. Or the high accident rate might reflect situations that develop as a result of the dynamic of these marriages: their young husbands might encourage activities like high-altitude mountaineering holidays, or perhaps even treat them unkindly.

It could also have something to do with the way that society treats women who go against the traditional norm. There is little evidence either way on this, but it seems reasonable that differential treatment might somehow be prompting these women to take bigger physical risks. Consider, for example, how the term “cougar” unfairly implies predatory behavior, and “toyboy” connotes insubstantiality. On the other hand, “sugar daddy”, for all its blunt instrumentalism, sounds, well, a bit sweeter.

What’s true for Denmark can probably be applied to the US. Today, the average Danish married man is three years older than his wife, which is close to the US average of two years and four months. And over the whole of the 20th century, the two countries have displayed the same trends in the spousal age-gap: on average men were older than their wives by the greatest amount in the 1950s, and older than their wives, but by a lesser amount, in the decades before and after. This implies that similar social factors are driving changes in both countries.

But Denmark is different in a few ways. Danes are extraordinarily happy people. This month they yet again came top in an international survey of national happiness levels. Danes are also very liberal. For example, back in 1989, Denmark became the first country in the world to give same-sex partners similar legal rights and duties to married heterosexuals.

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Denmark’s statistics office also keeps excellent data on cohabitation, making it possible to answer the broader question of whether marriage still does a better job of fending off death than less formal, stable unions, in an uber-liberal society. Drefahl has also studied the benefits of marriage in Denmark and found that, for heterosexual relationships, it comes down to class. People with little income and education live longer if they’re married than if they cohabit. For Danes with middling socioeconomic status, there’s not much difference. Yet cohabiters with high levels of income and education live longer than married people of their class.

This last bit goes against the results of some US studies. Conservative institutions that publish on this matter in the US consistently claim that marriage is better than cohabitation in a broad-brush kind of way. But relatively little is known about the extent to which their findings are true for politically and socially different communities.

What is true for some towns and cities in the US might not be true for others: depending on where you are, it seems, marriage has a different social meaning. Liberal San Franciscans and New Yorkers, for example, might in fact be quite Danish in their relationship habits.



