Fatherhood may be a kick in the old testosterone,
but it may also help keep a man alive. New research suggests that dads are a
little less likely to die of heart-related problems than childless men are.
The study — by the AARP, the government and several
universities — is the largest ever on male fertility and mortality, involving
nearly 138,000 men. Although a study like this can't prove that fatherhood and
mortality are related, there are plenty of reasons to think they might be,
several heart disease experts said.
Marriage, having lots of friends and even having a
dog can lower the chance of heart problems and cardiac-related deaths, previous
research suggests. Similarly, kids might help take care of you or give you a
reason to take better care of yourself.
Also, it takes reasonably good genes to father a
child. An inability to do so might mean a genetic weakness that can spell heart
trouble down the road.
"There is emerging evidence that male
infertility is a window into a man's later health," said Dr. Michael
Eisenberg, a Stanford University urologist and fertility specialist who led the
study. "Maybe it's telling us that something else is involved in their
inability to have kids."
The study was published online Monday by the
journal Human Reproduction.
Last week, a study by other researchers of 600 men
in the Philippines found that testosterone, the main male hormone, drops after
a man becomes a dad. Men who started out with higher levels of it were more
likely to become fathers, suggesting that low levels might reflect an
underlying health issue that prevents reproduction, Eisenberg said.
In general, higher levels of testosterone are
better, but too much or too little can cause HDL, or "good
cholesterol," to fall — a key heart disease risk factor, said Dr. Robert
Eckel, past president of the American Heart Association and professor of
medicine at the University of Colorado, Denver.
"This is a hot topic," Eckel said.
"I like this study because I have five children," he joked, but he
said many factors such as job stress affect heart risks and the decision to
have children.
Researchers admit they couldn't measure factors
like stress, but they said they did their best to account for the ones they
could. They started with more than 500,000 AARP members age 50 and over who
filled out periodic surveys starting in the 1990s for a long-running research
project sponsored by the National Cancer Institute.
For this study, researchers excluded men who had
never been married so they could focus on those most likely to have the intent
and opportunity to father a child. Men with cancer or heart disease also were
excluded to compare just men who were healthy when the study began.
Of the remaining 137,903 men, 92 percent were fathers
and half had three or more children. After an average of 10 years of follow-up,
about 10 percent had died. Researchers calculated death rates according to the
number of children, and adjusted for differences in smoking, weight, age,
household income and other factors.
They saw no difference in death rates between
childless men and fathers. However, dads were 17 percent less likely to have
died of cardiovascular causes than childless men were.
Now for all the caveats.
Researchers don't know how many men were childless
by choice and not because of a fertility problem.
They don't know what fertility problems the men's
partners may have had that could have left them childless.
They didn't have cholesterol or blood pressure
information on the men — key heart risk factors.
Less than 5 percent of participants were blacks or
other minorities, so the results may not apply to them.
All those questions aside, however, some prominent
heart experts were reassured by the study's large size and the steps researchers
took to adjust for heart disease risk factors.
"I think there's something there," and
social science supports the idea that children can lower heart risks, said Dr.
Eric Topol, a cardiologist and genetics expert at Scripps Health in La Jolla,
Calif. "Whether it's with a pet, a spouse or social interaction ... all
those things are associated with better outcomes."
Dr. Daniel Rader, director of preventive cardiology
at the University of Pennsylvania, said: "It's biologically plausible that
there's a connection," but the reduced risk attributed to having children
"is pretty modest."
Men often ask him what they can do to keep from
dying of a heart attack, he said.
"I'm not really prepared to, on the basis of
this, tell them to start having a few kids," Rader said.
Copyright 2011 The Associated Press.
(AP
Photo/The Charlotte Observer, Gary O'Brien, File)
