"For a woman of any height, the risk of cancer was 16% greater than for a woman 10 cm shorter. The association was seen across the whole normal range of heights," lead author Jane Green, DPhil, University of Oxford, United Kingdom, told Medscape Medical News.
"Other people have found links between height and some common cancers," Dr. Green said in an interview. "We had a study large enough to examine this link in detail for a range of cancers, and taking into account factors such as smoking and socioeconomic factors, so we were able to extend the previous findings."
Dr. Green and her team assessed the association between height and cancer incidence in the Million Women Study, in which close to 1.3 million middle-aged women in the United Kingdom were enrolled between 1996 and 2001. Their mean age at recruitment was 56.1 years.
Taller women tended to be of higher socioeconomic status, drink more alcohol, be older at first menstruation, have fewer children, be more active, and have their first child later in life than shorter women. They were also less likely to be obese or to be current smokers.
The mean height of the study population was 160.9 cm. The mean height of the tallest women was 174 cm and of the shortest women was 153 cm, for a difference of 21 cm.
The women were followed for a total of 11.7 million person-years, or a median of 9.4 years per woman (interquartile range, 8.4 to 10.2 years). During this time, 97,376 incident cancers occurred.
The study found that the relative risk (RR) for total cancer was 1.16 (95% confidence interval [CI], 1.14 to 1.17; P < .0001) for every 10 cm increase in height.
The increased risk was statistically significant for 10 different cancers.
RR for Individual Cancers per 10 cm Increase in Height
| Cancer Type | RR | 95% CI |
| Colon | 1.25 | 1.19–1.30 |
| Rectal | 1.14 | 1.07–1.22 |
| Malignant melanoma | 1.32 | 1.24–1.40 |
| Breast | 1.17 | 1.15–1.19 |
| Endometrial | 1.19 | 1.13–1.24 |
| Ovary | 1.17 | 1.11–1.23 |
| Kidney | 1.29 | 1.19–1.41 |
| Central nervous system | 1.20 | 1.12–1.29 |
| Non-Hodgkin's lymphoma | 1.21 | 1.14–1.29 |
| Leukemia | 1.26 | 1.15–1.38 |
The researchers also conducted a meta-analysis, combining their results with those from 10 published prospective studies, and found that the height-associated risk of developing cancer was similar in Europe, North America, Australasia, and Asia.
Asked why she thinks taller people have a greater cancer risk, Dr. Green said: "Taller people have more cells in their bodies, so will have a greater chance of one of those cells developing cancerous changes."
She added that growth hormones, which have been linked both to childhood growth and to cancer, might also play a part.
So What's a Tall Person to Do?
"You can't change your height, nor would most people want to," Dr. Green said. "Being tall has health advantages, including lower risk of heart disease. The increased cancer risk is just part of the picture. Most people are not a lot taller or shorter than average, and their cancer risks will not be greatly affected by their height."
She added that the single most important risk factor for cancer is smoking, "and that is something that can be changed."
Dr. Green said her hope is that the results of this study will contribute to knowledge of how cancers develop.
In an accompanying comment, Andrew G. Renehan, PhD, from the University of Manchester, United Kingdom, writes that attained adult height is unlikely to directly modify cancer risk. He calls for future research to explore the predictive value of nutrition, psychosocial stress, and illness during childhood, rather than final adult height.
"Extended follow-up of large childhood cohorts with longitudinal repeated exposure measurements are needed," Dr. Renehan states.
"Assessing these cohorts will need new methods (e.g., latent class analyses) to tease out key factors that influence the subsequent development of height-related cancers," he concludes.
The study was funded by Cancer Research UK and the UK Medical Research Council. Dr. Green has has disclosed no relevant financial relationships. Dr. Renehan reports financial relationships with Novo Nordisk.
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