Children are not only cute, they also may help their fathers stave off cardiovascular disease, and the more kids the better, researchers found.
Married men with no children had a 17% increased risk of dying from cardiovascular causes compared with married men who had children, reported Michael L. Eisenberg, MD, from Stanford University School of Medicine in Stanford, Calif., and colleagues.
Compared with fathers of five or more children, married men with no children had a 21% increased risk of cardiovascular death, according to the study published online in Human Reproduction.
Those who had one child had an 11% greater risk of dying from cardiovascular causes than did those with five kids or more.
Researchers noted previous studies that found links between cancer malignancies and male fertility. They posited that since about 35% of the male human genome is involved in reproduction, “it is conceivable that other health ailments, such as cardiovascular disease, may also be linked to defects in fertility.”
Although studies have examined links between fertility and cardiovascular health, most have been restricted to women.
“As such, the association between fatherhood and cardiovascular disease remains uncertain,” Eisenberg and colleagues wrote.
To help fill in the gaps, they examined data from 137,903 men (ages 50 to 71) without prior cardiovascular disease who were followed up for an average of 10.2 years.
The cohort, part of the NIH-AARP Diet and Health Study, had filled out questionnaires at three different time points.
The average age of the men was 62 and nearly 95% were white. About 92% of the men were fathers, with an overall mean of 2.6 children each.
Overall, 22% of the 13,702 deaths were attributed to a cardiovascular cause, “yielding an age-adjusted cardiovascular mortality rate of 2.70 per 1,000 person-years.”
When fully adjusted for age, education, race, current marital status, income, smoking history, alcohol consumption, BMI, physical activity, diabetes status, and self-reported health status, the hazard ratio among childless fathers for death from a cardiovascular cause was 1.17 (95% CI 1.03 to 1.32) when compared with those with one or more children.
When compared with fathers with five or more children, childless men had a hazard ratio of 1.21 (95% CI 1.03 to 1.41). The risk decreased, but not linearly, with an increasing number of offspring:
- One child — 1.11 (95% CI 0.95 to 1.30)
- Two children — 1.02 (95% CI 0.90 to 1.16)
- Three children — 1.02 (95% CI 0.90 to 1.16)
- Four children — 1.06 (95% CI 0.92 to 1.22)
Married men with no children had a slightly higher risk (7%) of all-cause mortality compared with fathers, as did married men with one or no children compared to those with two or more (5%).
The researchers noted that impaired androgen states could confer a “biologic plausibility” for a link between infertility and cardiovascular disease.
Eisenberg and colleagues admit that “offspring number is an imperfect surrogate measure of reproductive potential.” They also cannot discount that other confounding factors or chance was responsible for the link between cardiovascular disease and fertility.
Another limitation of the study is the relatively short study period (10.2 years beginning at age 50), which “may underestimate the true association between childlessness on cardiovascular mortality.”
Funding for the NIH-AARP study was through the Intramural Research Program of the National Institutes of Health, National Cancer Institute, Division of Cancer Epidemiology and Genetics.
The authors had no conflicts of interest to declare.
-By Chris Kaiser, Cardiology Editor, MedPage Today
Published: September 27, 2011
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner