They may feel like they are going to be the death of you, but having kids may not take years off your life. In fact, a study published Thursday shows that people who tried but failed to have children are two to four times more likely to die young than parents.
The startling findings support other research that shows childless couples don’t live as long as parents. They also add another piece to the puzzle: This one looks at people who either adopted children, or had them through fertility treatments.
It’s a way to filter out people who choose not to have children, says Esben Agerbo of Aarhus University in Denmark, who led the study.
“Several previous studies have found strong associations between childlessness and psychiatric illness,” Agerbo told NBC News by email. “I think that our study is superior, because it is only based on people who want to have children, whereas previous research included everybody,” Agerbo said.
Agerbo was able to make use of Denmark’s detailed and complete system of medical records. They looked at data on 21,276 childless couples who registered for in vitro fertilization (IVF) treatment between 1994 and 2005. The first three cycles of IVF were free until 2010 in Denmark’s national health system.
During this time, 15,210 children were born and 1,564 were adopted, Agerbo reports in the Journal of Epidemiology and Community Health. And over the same time, 96 of the women and 200 of the men died. Four times as many women who did not have children died as women who had or adopted a child, Agerbo’s team found. Death rates were twice as high among the men who did not have children.
“Mindful that association is not causation, our results suggest that the mortality rates are higher in the childless,” the researchers wrote.
What could the reason be?
“Parents are less likely to die from accidents, circulatory diseases, cancer, and external causes -- thus I suggest a behavioral difference,” Agerbo says. “Our study was not large enough to say whether suicide was less common among parents, but the rate of accidents is higher among non-parents -- perhaps I am more prone to buy a big motorcycle or a fast car than family-friendly slow van.”
Alice Domar, a psychologist at Beth Israel Deaconess Medical Center in Boston and director of mind-body services at Boston IVF, agrees. “When you have kids, it completely changes the way you live your life. I suspect that is what going on,” she said.
And while the study didn’t show any difference in psychiatric illness between people who had children using IVF and those who did not, the parents who ended up adopting children were half as likely to be diagnosed with mental illness.
“Our analyses show that childlessness has little impact on the rate of psychiatric illness,” they wrote.
But that doesn’t rule out stress as a possible cause, says Agerbo. “Studies indicate that stress is linked to disease, and perhaps non-parents are more stressed.”
This makes sense to Domar.
“I think this one of these studies that people are going to stop and think about what did this mean,” said Domar, who was not involved in the research. “It’s making me think.”
Domar led a study published last year in the journal Fertility and Sterility that showed women undergoing IVF who also had stress reduction therapy were more likely to get pregnant.
“It is also possible that people who have children have a lot of social support,” Domar added in a telephone interview. “Your friends are your kids’ friends’ parents. I think it is also possible that people who don’t have children do live in a different way -- they probably travel more, they probably eat out more, they probably drink more alcohol.”
But both Domar and Agerbo stress that the study wasn’t designed to show why parenthood might help prevent premature death.
“You basically give up sleeping for a few years and perhaps that in the long run makes your body stronger,” Domar said, only half-joking.
Stress could be a factor in the high death rates of relatively young men and women who have failed IVF treatment, Domar said. “Going through unsuccessful fertility treatment is profoundly stressful,” said Domar. “We know that stress suppresses the immune system.” That could lead to higher death rates.
“The harder you have to work at something, the more you appreciate it when you get it,” Domar added. “This study is in people who put themselves through hell and back to have a child. The people who have children through IVF think they hit the lottery, so perhaps people who didn’t have IVF feel all the more disappointed."