Among couples undergoing in vitro fertilization (IVF) treatment, those that remained childless appeared to have a greater risk of death in the near term, researchers found.

Through at least 3 years of follow-up, the rate of death was significantly lower for parents who had a biological child compared with those who remained childless (rate ratio 0.25 for women and 0.51 for men), according to Esben Agerbo, PhD, of Aarhus University in Denmark, and colleagues.

Childless women experienced a four-fold higher rate of death (95% CI 2.56 to 6.31), they added.

Having an adopted child was associated with a lower death rate for men (RR 0.55, 95% CI 0.32 to 0.96) but not for women (RR 0.67, 95% CI 0.32 to 1.38), the researchers reported online in the Journal of Epidemiology & Community Health.

“Mindful that association is not causation, our results suggest that the mortality rates are higher in the childless,” they wrote.

Agerbo and colleagues explored the relationships between childlessness, parental mortality, and psychiatric illness using national registries in Denmark. The analysis included 21,276 childless couples who were included in an IVF registry from 1994 to 2005. Follow-up lasted through 2008.

During follow-up, 96 women and 220 men died, for rates of 51 and 117 per 100,000 person-years, respectively.

Also during the study period, 15,210 children were born and 1,564 were adopted by the couples.

The relationship between having a biological child and a lower rate of death among both men and women remained significant even after accounting for various potential confounders, including age, calendar year, income, and parental comorbidities.

After accounting for those factors, however, the association between adopting a child and a lower death rate in men disappeared.

When looking at psychiatric illness, having an adopted child, but not a biological child, was associated with a lower risk for both men (RR 0.60, 95% CI 0.38 to 0.95) and women (RR 0.63, 95% CI 0.42 to 0.95). That trend was seen across diagnoses, including substance use disorders, affective disorders, neurotic disorders, and other psychiatric illnesses.

The authors argued that the findings lend “support to the conjecture that previous reports of higher [psychiatric] risks in the childless may actually reflect reverse causality, as individuals with an undiagnosed or insidious psychiatric illness are more likely to be childless and, subsequently, diagnosed with a psychiatric illness.”

The lower risk of psychiatric illness associated with adopting a child likely reflects that effect, they said.

The researchers acknowledged that the findings of the study may not apply to other childless couples who are not seeking IVF treatment and may be limited by residual confounding and by the relatively low numbers of deaths and psychiatric diagnoses.

###

Primary source: Journal of Epidemiology & Community Health
Source reference: Agerbo E, et al “Childlessness, parental mortality, and psychiatric illness: a natural experiment based on in vitro fertility treatment and adoption” J Epidemiol Community Health 2012; DOI: 10.1136/jech-2012-201387.