Taller women have an even greater risk for colon cancer — 25 percent for every 10 centimeters. There is a 14 percent increased risk for rectal cancer.
There is about a 37 percent increase in the chance of getting any cancer between the shortest women (less than 5 feet, 1 inch) and the tallest (over 5 feet, 9 inches) according to a very large study in the United Kingdom.
Between 1996 and 2001, nearly 1,300,000 women were part of the Million Women Study. Height at recruitment was part of the information collected. During the study a little over 97,000 women got cancer.
After figuring in a number of known cancer risk factors, height remained a significant influence on whether a woman developed cancer during an average about ten years of follow-up.
The size of the height-associated increase in cancer risk was similar for women with different years of birth and from different socioeconomic groups. The impact of height was also important when alcohol intake, body-mass index, amount of physical activity, age at first menstrual period, number of children, age when the first child was born, menopausal status, and use of oral contraceptives or hormone replacement therapy were considered.
For smoking-related cancers height differences had a smaller impact on women who were current smokers, but changes in height conveyed similar risks for smokers and nonsmokers for other cancers, including colorectal cancer.
Since adult height reaches its maximum between 20 and 30 years of age, the authors speculated that genetic and environmental factors during childhood affect cancer development. Among possibilities might be
- childhood nutrition and infections.
- hormones, particularly insulin-like growth factors (IGFs), which impact growth of the skeleton.
- the increased number of cells in taller women which increase the risk of mutation during cell division.
Dr. Jane Green and the Million Women Study Collaborators concluded,
Cancer incidence increases with increasing adult height for most cancer sites. The relation between height and total cancer relative risk is similar in different populations.