Breast cancer risk linked to birth weight

30/09/2008

A female infant's weight at birth affects their risk of developing breast cancer when they grow up, research out today claims.

A study in the Public Library of Science journal by medical scientists at the London School of Hygiene and Tropical Medicine shows the risk of developing cancer increases by seven per cent for every 0.5kg in birth weight.

Birth length is a stronger indicator while head circumference was also positively associated.

"Our study indicates that birth size is a marker of susceptibility to breast cancer in adulthood, at least in developed countries," professor of epidemiology Isabel dos Santos Silva commented.

Data from 32 studies was examined in the research, which assessed 22,058 cases of breast cancer among a total of more than 600,000 women.

It is not yet clear what causes the association, which appears largely independent of know risk factors. The researchers recommend further study to "unravel the biological mechanisms" underlying the birth size-breast cancer link.