Birth size, or more specifically birth length, correlates with the risk of breast cancer in later life, according to a new meta-study published in PLoS Medicine by researchers at the London School of Hygiene and Tropical Medicine. In the new study, led by Isabel dos Santos Silva, the researchers re-analyzed data from published and unpublished studies to obtain more precise estimates of the extent to which birth size affects the risk of breast cancer later in life. They examined 32 studies and found that birth weight was positively associated with breast cancer risk, with a 0.5 kg increment in birth weight being associated with an estimated 7 percent increase in the risk of breast cancer.
Birth length and head circumference were also positively associated with breast cancer risk, and birth length appeared to be the strongest independent predictor of risk. "Our study indicates that birth size is a marker of susceptibility to breast cancer in adulthood, at least in developed countries. The birth size - breast cancer association appeared to be largely independent of known risk factors. Little is known on how the pre-natal environment may affect breast cancer risk later in life. Further research is needed to unravel the biological mechanisms underlying the birth size - breast cancer association," noted Silva.
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Source: Public Library of Science
