Married men who have no children have a 17% higher risk of dying from cardiovascular disease after the age of 50 than men with two or more children. But whether that's because of a physical cause, a sociological effect or self-selection (sick people may choose not to have kids) isn't known.
To determine if the number of kids predicts cardiovascular death, researchers used data from the NIH-AARP Diet and Health Study of nearly 135,000 men ages 50 to 71 without prior cardiovascular disease who were followed-up for an average of 10 years. That study mailed 3.5 million questionnaires from 1995 through 1996 to AARP members living in California, Florida, Pennsylvania, New Jersey, North Carolina, and Louisiana or in Atlanta or Detroit. Nearly 586,000 people returned the questionnaire, which underwent follow-up surveys in 1996-1997 and 2004-2006. Results appeared online Sept. 26 in the journal Human reproduction.
Almost all (92%) men had at least one child and 50% had three or more. Nearly 3,100 men died of cardiovascular causes during follow-up for an age-adjusted incidence rate of 2.70 per 1,000 person-years. After adjusting for sociodemographic and lifestyle factors, childless men had a higher risk of death from cardiovascular disease compared to fathers (hazard ratio [HR], 1.17; 95% confidence interval [CI], 1.03 to 1.32). When pooled with men who had one child, there was still a risk (HR, 1.13; 95% CI, 1.03 to 1.23)
And, in comparison with fathers of five or more children, adjusted relative hazards for cardiovascular mortality were 1.06 (95% CI, 0.92 to 1.22) for four children; 1.02 (0.90 to 1.16) for three children; 1.02 (0.90 to 1.16) for two children; 1.11 (0.95 to 1.30) for one child; and 1.21 (1.03 to 1.41) for no children.
What isn't known is why. Biology and socioeconomic factors intermingle. There's caveats, too. Researchers couldn't account for men who were childless by choice or who had partners with fertility problems.
Still, Eric Topol, MD, FACP, a cardiologist and genetics expert at Scripps Health in La Jolla, Calif., told the Associated Press that, "I think there's something there," and "Whether it's with a pet, a spouse or social interaction ... all those things are associated with better outcomes."
But one confounder the study didn't account for is that kids induce stress, and stress is bad for the heart. As ACP Member Ves Dimov, MD, pointed out via Twitter, stress free parenting isn't possible.