Could height be a cancer risk?
24 October 2018
Taller people are at more risk of getting cancer, a new study looking at over a million people claims. Past reports have reached the same conclusion, but should lofty people be alarmed, or is this just a tall story? Experts stress the results only point to a very small increase in risk compared with factors like smoking. Plus it is unclear what might be the driver behind the link. The leading theory is tall people have more cells that can turn cancerous. But hormone levels, other illnesses and how affluent or deprived people are when young, might have an impact on height and cancer risk too. Report author Dr Leonard Nunney told the BBC a person's risk factor depended on their exact height. "If 50/500 average height women got cancer then 60/500 tall (178cm) women would be expected to get cancer. If you consider a very tall woman, say 6'2" (188cm), then you'd expect 67/500." He added: "The effect of smoking is massive. Even a light smoker (about three per day) has a huge six times increase in lung cancer risk ie: 50/500 becomes 300/500." The report, published by the Royal Society, says that for every 4in (10cm) increase in human height above the average used in the study of 5ft 7in for men and 5ft 3in for women, there is a 10% greater risk of that person getting cancer. The data was compiled from four large-scale studies, including the Million Women Study, on 23 cancer types in the UK, US, South Korea, Austria, Norway and Sweden. Each study chosen had to include 10,000 cancer cases for each sex. Of 18 cancer types analysed in both men and women, four - pancreas, oesophagus, stomach and mouth/pharynx - showed no apparent increase with height. And in the sex-specific cancers, only one - cervix - was unaffected. Height is only one of many factors that determine a person's cancer risk and it's definitely not a big one. Plus it can't be modified, unlike lifestyle risk factors, such as body weight. Experts say that the key to increasing chances of avoiding illness is living a healthy lifestyle. Georgina Hill, from Cancer Research UK, told the BBC: "The increased risk is small and there's plenty you can do to reduce the risk of developing cancer such as not smoking and keeping a healthy weight." Dr John O'Neill, research group leader, MRC Laboratory of Molecular Biology (LMB), said: "If you have more cells, you have a greater risk of cancer. Tall people have a greater surface area, and therefore more melanocytes, and so of course they're more likely to get melanoma." Prof Andrew Sharrocks, professor of molecular biology, University of Manchester, said: "Extrapolating from a height correlation to increased cell number being the reason for higher cancer incidence is a big leap and is only one possible explanation. "Similarly, saying that the higher incidence is due to a higher proliferation rate is also dubious, given the fact that most cancers arise much later in life, long after the increased proliferation associated with enhanced growth during childhood and adolescence has ceased." This report follows on from a 2011 one from the University of Oxford and a similar study in Sweden in 2015. Prof Tim Cole, a professor of medical statistics at University College London, said tall people should not be too worried about any of the findings. "Being tall has quite a lot of benefits, so having one minus factor is not too disastrous," he told the BBC. "There are actually lots of status benefits for tall people. People who earn more money tend to be taller and world leaders tend to be taller, so things stack up in their favour." Stuart Logan, a director of the UK's Tall Persons Club, feels that researchers tackle their studies in the wrong way. His club, which was founded in 1991, has around 250 members in the UK and Ireland, as well as some in other European countries. "We've noticed that a lot of men are averaging around 6ft 3in or 6ft 4in and women around 5ft 10in or 5ft 11in," Mr Logan told the BBC. "So it would be more useful if researchers contacted different associations like ourselves and used our members to produce their reports. "Reports like this are unhelpful - they may produce better headlines but those are not backed up by the data included. "What slightly annoys me is that on the positive side, the taller you are the less chance you have of diabetes, stroke or heart disease - but then you are told you have more risk of getting cancer."
The report, published by the Royal Society, says that for every 4in (10cm) increase in human height above the average used in the study of 5ft 7in for men and 5ft 3in for women, there is a 10% greater risk of that person getting cancer. The data was compiled from four large-scale studies, including the Million Women Study, on 23 cancer types in the UK, US, South Korea, Austria, Norway and Sweden. Each study chosen had to include 10,000 cancer cases for each sex. Of 18 cancer types analysed in both men and women, four - pancreas, oesophagus, stomach and mouth/pharynx - showed no apparent increase with height. And in the sex-specific cancers, only one - cervix - was unaffected.
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What did the study say?
Height is only one of many factors that determine a person's cancer risk and it's definitely not a big one. Plus it can't be modified, unlike lifestyle risk factors, such as body weight. Experts say that the key to increasing chances of avoiding illness is living a healthy lifestyle. Georgina Hill, from Cancer Research UK, told the BBC: "The increased risk is small and there's plenty you can do to reduce the risk of developing cancer such as not smoking and keeping a healthy weight." Dr John O'Neill, research group leader, MRC Laboratory of Molecular Biology (LMB), said: "If you have more cells, you have a greater risk of cancer. Tall people have a greater surface area, and therefore more melanocytes, and so of course they're more likely to get melanoma." Prof Andrew Sharrocks, professor of molecular biology, University of Manchester, said: "Extrapolating from a height correlation to increased cell number being the reason for higher cancer incidence is a big leap and is only one possible explanation. "Similarly, saying that the higher incidence is due to a higher proliferation rate is also dubious, given the fact that most cancers arise much later in life, long after the increased proliferation associated with enhanced growth during childhood and adolescence has ceased."
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What do experts think?
Stuart Logan, a director of the UK's Tall Persons Club, feels that researchers tackle their studies in the wrong way. His club, which was founded in 1991, has around 250 members in the UK and Ireland, as well as some in other European countries. "We've noticed that a lot of men are averaging around 6ft 3in or 6ft 4in and women around 5ft 10in or 5ft 11in," Mr Logan told the BBC. "So it would be more useful if researchers contacted different associations like ourselves and used our members to produce their reports. "Reports like this are unhelpful - they may produce better headlines but those are not backed up by the data included. "What slightly annoys me is that on the positive side, the taller you are the less chance you have of diabetes, stroke or heart disease - but then you are told you have more risk of getting cancer."
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What do tall people think of the findings?