Child's birthweight tied to parents' heart risks

A new study has found that the parents of children born at a lower weight may have an increased risk of dying from Heart disease or Stroke - suggesting that common genetic factors may underlie both birthweight and cardiovascular disease.

A number of studies have found evidence that people born at a low weight have a higher risk of Diabetes and cardiovascular disease as adults. One hypothesis is that factors that affect fetal development - such as a mother's nutrition - may help "program" future disease risk.

But another possibility is that certain genes passed down from parents contribute to both poorer fetal growth and later disease risk. If fathers, in particular, show a higher cardiovascular disease risk if their children are born at a low weight, then that would be some evidence of a common genetic influence.

The new study, published in the journal Epidemiology, found such evidence.

Looking at data on more than 780,000 children born in Sweden between 1973 and 1980, researchers found that as birthweight climbed, the risk of a parent dying from cardiovascular disease declined.

The pattern was the same for mothers and fathers, and factors such as smoking did not fully account for the connection between birthweight and parents' disease risk. In addition, the relationship between birthweight and cardiovascular disease was strongest among parents who died at a young age; early cardiovascular disease tends to have a strong genetic influence.

It seems likely that genes help explain research findings that have linked a person's own birthweight to the risk of adulthood cardiovascular disease, study co-author Dr. Finn Rasmussen of the Karolinska Institute in Stockholm told.

However, he added, environmental factors during fetal development are also important. Nutrition in the womb and growth during infancy have been implicated in cardiovascular illness and other diseases, the researcher noted.

It's unclear exactly which genes could underlie both birthweight and cardiovascular disease. But, Rasmussen and his colleagues write, their findings "support the search for such genes."

In addition, they note, the study highlights the fact that a child's birth characteristics can serve as an indicator of not only a mother's health, but also a father's.

SOURCE: Epidemiology, July 2005.