"'Til death do us part" may come too soon for men in "unsuccessful" marriages.
Having a husband or wife has long been linked to a healthier life, with spouses thought to encourage – or perhaps nag – their other half to lead a healthy lifestyle.
Scientists from Tel Aviv University have now found, however, that men who perceived their marriages to be unsuccessful were 21% more likely to die prematurely than their contented counterparts.
The damaging effects of an unhappy union were even found to be on a par with smoking and an inactive lifestyle.
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Although it is unclear how a discontented marriage could affect a person's health, living in a contentious household may prompt people to smoke, eat badly or drink excessively.
Poor relationships have also been linked to depression, which could trigger damaging inflammation.
"Our study shows the quality of marriage and family life has health implications for life expectancy," said author Dr Shahar Lev-Ari.
"Men who reported they perceived their marriage as failure died younger than those who experienced their marriages as very successful.
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"In other words, the level of satisfaction with marriage has emerged as a predictive factor for life expectancy at a rate comparable with smoking and physical activity".
In the 1960s, the Tel Aviv scientists started collecting health information on more than 8,900 men, all Israeli state employees.
Early in the research, when most of the men were in their 40s, the participants ranked their marriage satisfaction from one – very successful – to four – unsuccessful.
Over the next 32 years, just under two thirds (64%) of the participants died.
"Dissatisfaction with married life" was found to nearly double the risk of stroke, raising the odds of the life-threatening event by 94%.
The risk of dying from any cause was 21% higher among the unsatisfied men, show the results, published in the Journal of Clinical Medicine.
Similarly, the inactive participants were 21% more likely to die over the follow-up period, while "a history of smoking" raised the risk by over a third (37%).
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Perhaps surprisingly, an unsatisfactory marriage was found to be more dangerous among the "relatively young men", aged under 50.
"At a higher age, the gap is smaller, perhaps due to processes of adjustment that life partners go through over time," said Dr Lev-Ari.
The scientists believe martial satisfaction should be assessed "as part of health promotion strategies for the general population".
The health benefits of "marital education programmes for couples" should also be investigated, they added.
"These findings were consistent with other studies that have shown the effectiveness of educational programs fostering good life partnerships as part of a national strategy to promote health and wellness for the public at large," said Dr Lev-Ari.
It is unclear if the same results apply to women.
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