Men who don't have children may be at increased risk of dying from heart disease, a new study says.
Childless men in the study had a 17 percent higher risk of death from cardiovascular disease than fathers, the researchers said. Only married men were included in the study.
The results suggest infertility might be a risk factor for developing cardiovascular disease, said study researcher Dr. Michael Eisenberg, an assistant professor of urology at Stanford University in Palo Alto, Calif.
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Low testosterone levels, which may contribute to infertility, are a known risk factor for cardiovascular disease, and may be what's driving this link, the researchers said.
However, it's also possible that something about being a father protects against cardiovascular disease.
"Maybe having children causes men to have healthier behaviors, so fathers will live longer," Eisenberg said.
Fertility and heart disease
Eisenberg and colleagues analyzed questionnaires completed by about 135,000 members of the American Association of Retired Persons (AARP). All men were over the age of 50 at the start of the 10-year study, and did not have a history of heart disease, stroke or conditions that could interfere with reproduction. The researchers said they tried to include only men who had the intent and opportunity to reproduce by limiting their study to married or formerly married men.
Ninety-two percent of participants were fathers; the average number of children was 2.6.
Between 1995 and 2005, 10 percent of participants died.
Childless men were more likely to die of any cause than were fathers, but this increased risk of death was almost entirely due to death from cardiovascular disease, the study showed.
Men with one child also had an increased risk of death. As a group, childless men and men with one child were 13 percent more likely to die from cardiovascular disease than men with two or more children.
The results held even after the researchers took into account factors that could affect risk of dying from heart disease, including body-mass index (BMI), activity level, tobacco and alcohol use, income and education.
Other factors
"It certainly is an intriguing [finding]," said Dr. Stephen Kopecky, a professor of medicine at the Mayo Clinic in Rochester, Minn., who was not involved in the study. The results are in line with those of earlier studies that linked erectile dysfunction and cardiovascular disease.
However, the new study cannot explain why childlessness and heart disease are linked, Kopecky said.
Although infertility is suggested as a reason for the link, the number of children is not a direct marker of fertility, the researchers noted.
Kopecky said he would like to see further work this topic. Studies that use large databases instead of self- reports, or research that analyzes hormone levels might tell us more about this link, he said.
If infertility is indeed linked to cardiovascular disease, researchers may have another way to screen for the condition.
"As a man's fertility potential is often known in early life, our work suggests that the fatherhood status may provide insight into a man's risk of cardiovascular disease and death later in his life," the researchers wrote in the Sept. 26 issue of the journal Human Reproduction.
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