Bigger Female Babies Have Higher Risk of Breast Cancer
Women who were born as big or long babies have an increased risk of developing breast cancer, report researchers from the London School of Hygiene and Tropical Medicine. There are few hypotheses that may account for the association between birth size and breast cancer risk, and more research is needed to probe this link.
They reviewed 32 studies covering 22,058 cases of breast cancer among more than 600,000 women living mostly in the developed world.
Pooling data from studies that drew birth size information from official birth records rather than participant self reports (notoiously less reliable as sources of historical data), the researchers found birth weight was positively associated with breast cancer risk to the extent that a 0.5 kg (1.1 lbs) increment in birth weight was linked to an estimated 7 per cent increase in risk of breast cancer.
Further analysis of data from official records also showed a positive link between breast cancer risk in adulthood with body length and head circumference at birth, with body length being the strongest predictor. The figures did not change much when the researchers took into account established breast cancer risk factors.