Featured Research

from universities, journals, and other organizations

Childless men more at risk of death from cardiovascular disease

Date:
September 27, 2011
Source:
Stanford University Medical Center
Summary:
The risk of dying from cardiovascular disease is higher for childless men than for fathers, according to a large study.

The risk of dying from cardiovascular disease is higher for childless men than for fathers, according to a large study led by a researcher at the Stanford University School of Medicine.

The new study, which will be published online Sept. 26 in Human Reproduction, tracked some 135,000 male members of the American Association of Retired Persons over a 10-year period, in order to determine whether the number of offspring a man has offers any clues about that man's long-term health. The findings show an association between parental status and cardiovascular risk and should not be interpreted as proof of a cause and effect.

"This was the largest-ever study in the United States to examine the relationship between fatherhood and cardiovascular disease," said Michael Eisenberg, MD, assistant professor of urology at Stanford. Moreover, the study was carefully controlled to minimize confounding variables that might otherwise cloud investigators' capacity to generate meaningful results.

Eisenberg initiated the study while doing his urologic residency training at the University of California-San Francisco, and carried it through his joining the faculty at Stanford. (The paper's senior author is Mark Pletcher, MD, MPH, associate professor of epidemiology & biostatistics at UCSF.) He had wondered whether infertile men's long-term health outcomes might differ from those of fertile men, and he reasoned that the number of offspring a man fathered could be a rough proxy for ability to reproduce.

"So we asked: Is not having children a predictor of death from cardiovascular disease?" he said.

To find out, Eisenberg and his associates pored over data compiled from a series of questionnaires that hundreds of thousands of AARP members had completed over a period of about 10 years. The scientists narrowed their health-outcome analysis to some 135,000 married or formerly married men (about 95 percent of them white) who were all over age 50 when the study began. Their median age at the start of the study was 62.7 years old.

To ensure, as much as possible, that the men they were looking at had both the intent and the opportunity to reproduce, Eisenberg and his colleagues restricted their sample population to those who were married or had once been married. To further level the playing field, they also excluded men with any previous history of various health conditions including heart disease, stroke or a related condition, which could have impeded successful reproduction. The resulting subject group was thus in a state of relatively good initial health.

Over the study's duration, the investigators tallied mortality from between 60 and 70 different causes. Deaths were assessed via various methods including through Social Security Administration and other national databases as well as surviving relatives' responses to mailed questionnaires.

Next, all participants living or dead were grouped according to the number of children they had fathered, and mortality rates within each group were calculated. In their statistical analysis, Eisenberg and his colleagues corrected for body-mass index, self-reported activity levels and health status, tobacco and alcohol use, race, age, median household income, and education.

Over the course of the study, about 10 percent of the men died. About one in every five of those deaths was attributable to cardiovascular disease. That represented a 17 percent increase in the likelihood of a childless man's dying of a condition related to cardiovascular disease, compared with fathers.

The genders of the children a man had fathered made no difference in the likelihood of his succumbing to cardiovascular disease.

There was a somewhat higher overall risk of mortality from all causes among childless men. But this increase was almost entirely attributable to cardiovascular disease, without which no statistically significant uptick would have been seen, Eisenberg said.

Eisenberg, who specializes in male infertility and sexual dysfunction, noted that it was impossible, in this study, to directly assess a man's "reproductive intent." But eliminating unmarried men from his team's analysis brought childlessness a step closer to being a proxy for infertility. The connections between infertility, as observed via that proxy, and predisposition to death from cardiovascular disease raise an important question, Eisenberg said. "Is there a real biological cause behind both? Maybe we should look closer at the childless group." Since fertility issues can surface well before any obvious outward symptoms of cardiovascular disease, such a link could help flag cardiovascular risk sooner, leading to earlier and more effective intervention, he said.

The Eisenberg team's results are being published amid widespread reporting of a smaller recent study of some 600 Philippino fathers. The study showed that men with the highest levels of testosterone, the major male steroid hormone, at the study's start were more likely to find mates and become fathers than those with lower initial levels. The study also showed that levels of testosterone fell with parenthood.

Eisenberg suggested that if initially low testosterone levels do indeed predispose to fewer offspring, this may reflect broader underlying problems that could lead to a higher risk of cardiovascular disease in later life. At the same time, many scientists believe the capacity to nurture a child may benefit from a reduction in a man's testosterone levels. But such a parenthood-induced reduction in testosterone levels would no longer imply physiological defects of the sort that may be responsible for relatively low testosterone found in those who go childless. (Eisenberg stressed that his study did not assess testosterone levels in its subjects or consider whether fathers lived with their children.)

It's possible that many other factors besides testosterone account for fathers' lower cardiovascular risk. "Maybe having children causes men to have healthier behaviors, so fathers will live longer," said Eisenberg. Other studies have shown that men live longer if they don't live alone.

The National Cancer Institute funded the study, and two NCI researchers are among its co-authors. Other co-authors came from AARP and Baylor University.


Story Source:

The above story is based on materials provided by Stanford University Medical Center. The original article was written by Bruce Goldman. Note: Materials may be edited for content and length.


Journal Reference:

  1. Michael L. Eisenberg, Yikyung Park, Albert R. Hollenbeck, Larry I. Lipshultz, Arthur Schatzkin, and Mark J. Pletcher. Fatherhood and the risk of cardiovascular mortality in the NIH-AARP Diet and Health Study. Human Reproduction, September 26, 2011 DOI: 10.1093/humrep/der305

Cite This Page:

Stanford University Medical Center. "Childless men more at risk of death from cardiovascular disease." ScienceDaily. ScienceDaily, 27 September 2011. <www.sciencedaily.com/releases/2011/09/110926173119.htm>.
Stanford University Medical Center. (2011, September 27). Childless men more at risk of death from cardiovascular disease. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2011/09/110926173119.htm
Stanford University Medical Center. "Childless men more at risk of death from cardiovascular disease." ScienceDaily. www.sciencedaily.com/releases/2011/09/110926173119.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins