Having a child appears to reduce the risk of an early death, particularly among women, according to a new study.

While previous research has indicated a link between not having children and higher than expected death rates, this was usually put down to unhealthy lifestyles and poor physical and mental health.

However, very few studies have looked at the difference between people who choose not to have children and people who cannot have them.

Danish scientists analysed data on births, deaths, IVF procedures, hospital admissions and contacts with psychiatric services in Denmark between 1994 and 2008. During this period, over 21,000 couples without children registered for IVF treatment, over 15,000 children were born and more than 1,500 were adopted.

The study found that those who had children had a reduced risk of an early death. This was particularly true of women.

In fact, the early death rate from accidents, cancer and heart disease among women with no children was four times higher compared to those who had children. It was also two times higher than women who had adopted.

In men, the rate of early death was around twice as high in those without children compared to those with children. The results stood irrespective of whether the children were adopted or biologically the man's.

The study also noted that parents who adopted children had a lower risk of suffering from mental health problems compared to biological parents.

"Mindful that association is not the same thing as causation, our results suggest that the mortality rates are higher in the childless. Rates of psychiatric illness do not appear to vary with childlessness, but the rate of psychiatric illness in parents who adopt is decreased," the team from Aarhus University concluded.

Details of these findings are published in the Journal of Epidemiology and Community Health.