Birth size linked to some adult cancers

Bigger babies seem to have a greater risk of developing certain cancers as adults, a new study finds.

Dr. Valeria A. McCormack from London School of Hygiene & Tropical Medicine in London, UK, and colleagues used Sweden's Uppsala Birth Cohort Study to investigate the relationship of birth characteristics with overall cancer rates and rates for cancers of specific sites in the body.

Higher birth weight was associated with a 13 percent increase in the rate of cancers of the digestive tract, and a 17 percent increase in the rate of blood cancers, the authors report in the International Journal of Cancer.

Larger birth size was also associated with an increased rate of all cancers combined, excluding those involving the reproductive system.

Higher birth weight was associated with increased rates of breast cancer in women under age 50, but on the other hand, women with higher birth weight had only about half the rate of endometrial cancer compared to women with lower birth weight.

"We have found some evidence supporting the hypothesis that larger birth size is associated with increased risk of certain adult cancers," the researchers conclude. "However, our findings suggest that positive associations were not uniform across all cancer sites, but were particular to just a few sites."

McCormack's team adds, "Birth size for gestational age is unlikely to be a risk factor for adult disease in itself, but may be a marker for some aspects of the fetal environment that are related to risk."

SOURCE: International Journal of Cancer, online February 7, 2005.