McCormack VA et al. (2005) Birth characteristics and adult cancer incidence: Swedish cohort of over 11,000 men and women. Int J Cancer 115: 611–617

Smaller birth size, as an indicator of the fetal environment, has been linked to an increased risk of ischemic heart disease and type 2 diabetes. Conversely, a larger size at birth has been associated with increased rates of adult cancer, although few robust data are available to support this hypothesis. McCormack et al. have recently examined this question in a large cohort study.

The analysis, based on the Uppsala Birth Cohort Study, included 11,166 Swedish men and women born between 1915 and 1929. Details of maternal age, birth order, birth weight and placental weight were recorded for all participants. Follow-up extended from 1960 to 2001 and 2,685 first primary cancers were recorded during this period.

In both sexes, higher birth weight was associated with moderately increased rates of digestive and lymphatic cancers. In women, higher birth weight was also related to an increase in the rate of breast cancer before the age of 50 years, and an inverse relationship was seen between birth weight and endometrial cancer risk. No associations were found between birth weight and cancers at other sites.

Noting that these associations were modest and only related to a few cancer sites, the authors suggest that more studies are needed to investigate pre-natal influences on cancer risk.