Height gives clue to cancer

Scientists from the Cancer Research UK-funded Million Women Study1 found an increase in women's cancer risk of about 16% for every 10cm increase in height.

Previous studies have shown that height can affect risk of cancer, but this research confirms the link for a wide range of cancers2, and for women with differing lifestyles and economic backgrounds.

This is the largest study to date of height and cancer risk, including 97 000 cancers in over a million middle-aged UK women whose health was followed for 9 years.3
The study showed that taller women had an increased risk of at least 10 types of cancer, including breast, skin, bowel and ovarian - a wider range than initially thought.

And comparing this study with others, the researchers confirmed a similar link between height and cancer risk for both men and women from different populations worldwide.

A basic common mechanism

Jane Green, lead author of the study based at the Cancer Epidemiology Unit at the University of Oxford, said: "The fact that the link between height and cancer risk seems to be common to many different types of cancer in different people suggests there may be a basic common mechanism, perhaps acting early in peoples' lives, when they are growing.

"Of course people cannot change their height. And being taller has actually been linked to a lower risk of other conditions, such as heart disease."

Possible reasons for the link between height and cancer risk include hormone levels related to childhood growth, and in turn to cancer risk in later life. It was also suggested that the link could simply be down to the fact that taller people have more cells in their bodies, and so a greater chance of developing cancerous cell changes.

The height of European adults increased by about 1cm per decade during the 20th century, and the study suggests that this may explain around 10-15% of the rise in cancer cases seen over this period.4

No need for alarm

Sara Hiom, director of health information, at Cancer Research UK, said: "Tall people need not be alarmed by these results. Most people are not a lot taller (or shorter) than average, and their height will only have a small effect on their individual cancer risk.

"This study confirms the link between height and cancer paving the way for studies to help us understand why this is so.
"On average, people in the UK have a more than one in three chance of developing cancer in their lifetime. So it's important that everyone is aware of what is normal for their body and go see their doctor as quickly as possible if they notice any unusual changes.

"And while we can't control our height, there are many lifestyle choices people can make that we know have a greater impact on reducing the risk of cancer such as not smoking, moderating alcohol, keeping a healthy weight and being physically active."

Notes:

1. The Million Women Study is funded by Cancer Research UK, the NHS Cancer Screening Programme and the Medical Research Council. It is the biggest study ever undertaken to look at women and cancer risk.

2. Results showed an increased risk for 15 of the 17 specific cancers studied, with little variation in risk between cancer sites. Risk was statistically significantly increased for 10 individual sites: colon, rectal, malignant melanoma, breast, womb, ovarian, kidney, brain, non-Hodgkin lymphoma and leukaemia - and no cancer showed decreased risk.

3. Researchers looked at women with heights ranging from under 155cm to 175cm and taller.

4. Average adult height in Europe has increased by about 1cm per decade throughout the twentieth century. Because the risk associated with height appears to be independent of other risk factors which have also changed over time, such changes in population height may account for part of the increased risk of cancer seen in recent decades.

Source: Cancer Research UK