Impact of Childhood Growth Parameters on Subsequent Development of Breast Cancer
Are there factors detemined during childhood and adolescence that impact the development of breast cancer in later life? A study (New England Journal of Medicine, v 351, p 1619, 2004) looks at a cohort of women who had undergone regular health examinations in school. 2005 women who developed breast cancer and who had good health records, were compared to 5500 women randomly chosen, with a similar age distribution. The study considered birth weight, age at peak growth, age at menarche, and height and BMI at age 14.
The study finds that for every additional 5 cm (2 inches) height increase between ages 8 and 14, there is an increase in the risk for breast cancer by 17% (risk ratio of 1.17). At the 95% confidence level the range is between 9 and 25%. In addition, birth weight and BMI at age 14 may be factors, although the statistical significance of these factors is more ambivalent. A higher BMI at age 14 leads to a lower risk (5% risk reduction per one unit of BMI), whereas a higher birth weight, leads to a higher risk (10% risk increase per Kg - 2.2 lb).
Of course, there is is not necessarily a cause and effect here. It is entirely possible that growth, BMI and subsequent breast cancer are all caused by growth factors, hormones, or other yet undetermined factors.