MONDAY, Sept. 26 (HealthDay News) -- Men who do not have children appear to face a higher risk of dying from heart disease than those who become fathers, a new study suggests.

The findings also showed a slightly increased risk of cardiovascular trouble among men who had only one child. The researchers noted that the results may indicate a link between infertility and heart disease risk rather than a link between choosing not to have children and heart disease.

In the study, researchers analyzed more than a decade's worth of survey responses completed by roughly 135,000 male AARP members. The men were either married or had been married, and none had a prior history of heart disease or stroke.

Researchers tracked deaths and cause of deaths, and correlated that to the number of children the men had.

About 10 percent of the men died during the study period, including about 20 percent from heart disease.

After accounting for a wide range of factors such as race, cigarette and alcohol use, education and income status, age, exercise habits and body-mass index, researchers found that men who had no children had a 17 percent higher risk of dying from heart disease.

While the study found an association between childlessness and heart disease, it did not prove a cause and effect.

Researchers used married men as a "rough proxy" for men who had the opportunity to have children and wanted to have children, while the number of children men had was an indicator, albeit not a perfect one, for a man's fertility.

"This opens up a window into men's health," suggested study author Dr. Michael L. Eisenberg, an assistant professor in the department of urology at Stanford University in Palo Alto, Calif. "It shows that fertility may protect against later health problems. And if so it could mean that when men seek medical attention for infertility, which is often the first time they seek medical attention for anything, we could have a unique opportunity to intervene and help with their overall health."

And yet, researchers acknowledged neither marital status nor number of children was a precise measure of infertility. None of the men were actually screened for infertility status or other physiological markers for infertility, such as fluctuating testosterone levels.

So, while shared biological factors such as hormone deficiencies could be driving both childlessness and heart disease death risk, it's also possible that other environmental/behavioral issues might also contribute, researchers said.

For example, the authors noted that men who have children may end up embracing healthier lifestyles, thereby lowering their risk for heart disease.

"And it is certainly the case that things that are good for fertility are also going to be good for your heart," said Eisenberg, a urology resident at the University of California, San Francisco, when he did the study. "Good exercise habits, a good diet, maintaining a healthy weight, not smoking. All these things can impact both."

Researchers also stressed that their findings show an "association" between being childless and having heart disease, rather than cause-and-effect.

The study is published in the Sept. 26 online edition of Human Reproduction.

The authors pointed out that more than one-third of the human genome is involved in the process of reproduction. That fact led the team to theorize that fertility status might be significantly correlated with a man's long-term health and disease status.

Dr. Robert Myerburg, a cardiology professor at the University of Miami Miller School of Medicine, called the findings "compelling," but said childless men shouldn't worry.

"Given the large population they looked at, I think they have identified an association that is worth exploring," he noted. "And there may certainly be clues about what's going on here that are interesting and should be examined. But this is going to take a lot of studying for a very long time."

And, he noted, "population risk is not always the same as individual risk -- an 18 percent higher mortality risk among a group of childless men does not actually mean that any one childless man will face a noticeably higher risk. There might, in fact, be no consequences, especially if an individual's risk is very low to begin with. So while this research continues, childless men should not view these findings with alarm."

More information

For more on infertility, visit the U.S. Centers for Disease Control and Prevention.

WEDNESDAY, Sept. 14 (HealthDay News) -- Men who suffer from erectile dysfunction are at increased risk for cardiovascular disease, stroke and death, Chinese researchers suggest.

Although it is well accepted that cardiovascular disease is a risk factor for erectile dysfunction, it has not been clear whether erectile dysfunction is an independent risk factor for cardiovascular disease, the researchers noted.

"Erectile dysfunction significantly increased the risk of cardiovascular disease, and the increase was probably independent of conventional risk factors," said lead researcher Dr. Li-Qiang Qin, from the department of nutrition and food hygiene in the School of Public Health at Soochow University in Suzhou.

As such, "erectile dysfunction may not only contribute to cardiovascular risk prediction, but also serve as a potential target for cardiovascular disease prevention," Qin said.

The report was published in the Sept. 13 online edition of the Journal of the American College of Cardiology.

For the study, Qin's team culled data on the relationship between erectile dysfunction and cardiovascular disease from 12 studies published between 2005 and 2011 that included a total of 36,744 people and an average follow-up of 4 to 16.2 years. This process, called a meta-analysis, tries to pool data from several sources to tease out a pattern that might not be obvious in a single study.

The researchers found a significant association between erectile dysfunction and the increased risk of cardiovascular disease, heart disease, stroke and death.

In fact, men with erectile dysfunction had a 48 percent increased risk for cardiovascular disease, a 46 percent increased risk for heart disease, a 35 percent increased risk for stroke and a 19 percent increased risk of dying of any cause, compared to men without the condition.

Even after taking risk factors such as age, weight , blood pressure, diabetes, cholesterol and smoking into account, there was still a 54 percent increased risk for cardiovascular disease associated with erectile dysfunction alone. The reasons for this association are unclear, the researchers noted.

However, based on these findings, Qin's group now thinks erectile dysfunction is an independent risk factor for cardiovascular disease and not just an early marker of the condition.

Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, noted that "erectile dysfunction impacts some million 18 million men in the United States."

Cardiovascular disease and erectile dysfunction share many common risk factors, including diabetes, obesity, smoking, hypertension and high cholesterol, he said.

"A number of prior individual studies have shown that men with erectile dysfunction are at increased risk for fatal and nonfatal cardiovascular events," Fonarow said. "Men with erectile dysfunction should be aware of this significant increase in cardiovascular risk and take proactive steps to adopt a healthy lifestyle and better control their cardiovascular risk factors."

More information

For more information on erectile dysfunction, visit the U.S. National Library of Medicine.