(Newsroom America) -- Parenthood is associated with a longer life than childlessness, particularly in older age, when health and capacity may start to decline, finds new research.
By the age of 60, the difference in life expectancy, which does not seem to be influenced by the sex of the child(ren), may be as much as two years, the findings suggest.
Previous research suggests that being a parent may add years to a person's life, but it's not clear when this apparent advantage may be conferred or whether it could be influenced by the sex of the child(ren).
To find out if parenthood might help stave off death in older age, the researchers tracked the lifespan from the age of 60 onwards of all men (704,481) and women (725,290) with a birth date between 1911 and 1925 and living in Sweden, using national registry data.
The study, which ran until the end of 2014, also gathered registry data on marital status and the number and sex of any children they had.
Age specific risks of death were calculated and compared for each calendar year for people who had had at least one child and for those who were childless.
Not unexpectedly, the risk of death rose with increasing age, irrespective of whether the individuals were parents or not.
But after taking account of influential factors, such as educational attainment, the risks of death were lower among those who had had at least one child than they were among those who were childless--and more so among men than among women.
The one year risk of death for an 80 year old man with a child was 7.4%, for example, compared with 8.3% for a childless man of the same age.
The gap in absolute death risks between the two groups rose with increasing age, and was somewhat larger for men than it was for women.
At age 60 the difference in the one year risk of death was 0.06% among men and 0.16% among women. By the age of 90 these differences had risen to 1.47% among men and to 1.10% among women.
The associations found were evident among those who were married and unmarried, but seemed to be stronger among those who weren't married--at least among the men: the difference in death risk was 1.2% among unmarried men and 0.6% among those who were married.
Unmarried men might be relying more heavily on their children in the absence of a partner, suggest the researchers, by way of a possible explanation. They are also likely to be less well educated, whereas the opposite tends to be true of women, they add.
The associations were not affected by the sex of the child(ren), as has been suggested by previous research.
This could be because previous research has focused on the social benefits of having a daughter, whereas some other aspect of support, such as advocacy or navigating the health system, may matter more for staving off death, and sons could just as easily provide this, speculate the researchers.
This is an observational study, so no firm conclusions about cause and effect can be drawn. Nevertheless, the researchers write: "Our finding that the association grew stronger when parents became older is further in agreement with research suggesting that childless people face support deficits only towards the end of life."