A few days ago, we were telling you about a potentially groundbreaking study which found a rather surprising correlation between height and cancer incidence. The study made quite a wave within the scientific community and was met with quite mixed opinions. Here are some of those impressions, from leading experts in the field.
Prof Mel Greaves, Director of the Centre of Evolution and Cancer, The Institute of Cancer Research, London believed that while the study has to be taken seriously, it's a bit worrying that it still hasn't went through peer review.
“It is difficult to assess the strength of this new study because there is no paper available and nothing has yet been through peer review or published. But there are reasons for taking seriously the reported findings. This observation has been made before in previous studies, and we already knew that breast and prostate cancers can be associated with height. What would be a biologically plausible reason for this association? It could be to do with growth hormone, and the suggestion for this is two-fold.
“Firstly, a previous study has reported that people who have genetic dwarfism appear to have very little cancer (even in an age-matched study, so not because of reduced life expectancy). People with genetic dwarfism have a mutation in their growth hormone receptor, and we know that growth hormone and growth hormone receptor are critical to tumour growth too.
“Secondly, we know from experiments in mice that if they are engineered to make excess or very little growth hormone then their cancer rates escalate or decrease correspondingly (along with their size). We know that in humans growth hormone not only stimulates bone growth during our growing years, but stimulates cell growth in general and blocks cell death. So the level of growth hormone someone has could affect cancer risk by pushing up cell numbers.
“Of course for cancers like breast and skin cancer there are factors that have a much greater effect on risk, like family history, reproductive patterns and obesity, so tall people shouldn’t worry that they are destined to get cancer. I’ll be interested to see the results of the present study once it has been written up in more detail and been through the peer review process, and in order to say how confident we can be in its findings we’d need to know whether these other factors that also influence cancer incidence were measured and controlled for.”
Professor David Coggon, Professor of Occupational and Environmental Medicine, University of Southampton, was even more blunt, dismissing the study as not contributing anything useful.
“It is unclear from the information provided (the abstract) whether the associations with height were adjusted for other known causes of the cancers examined, such as reproductive history (breast cancer) and sun exposure (melanoma). Even if we knew that the study was robust and had controlled for all relevant confounding factors, the finding is such a non-specific observation that I cannot see it contributing usefully towards prevention of cancer.”
So for a study that made news everywhere and that was praised by many science outlets (ourselves included), it made quite a small impression within the scientific community. Furthermore... i's not even entirely news. Eve Roman, Director of the Epidemiology and Cancer Statistics Group, Department of Health Sciences, University of York, said:
“The association between height and cancer incidence is old news and has been shown in previous studies – in this context the title of the press release, ‘Large-scale Swedish study discovers link between height and cancer’, is inaccurate in my opinion. Although it seems from the information available that the study is likely to be robust and has been done well, as far as I can see this study contributes little that is new.”
That feeling was echoed by Jack Cuzick, Director of the Wolfson Institute of Preventive Medicine and Head of Centre for Cancer Prevention, QMUL, said:
“The association between height and cancer has been known for some time; many cancers are increased in incidence in tall people. This study should add important further confirmation in a population based setting. The mechanisms for this effect are not clear and are worth further study. They may relate to the fact that the growth hormones related to height also are in some way stimulating cancer cells, but details are lacking.”
So, the take-away is as follows: we sometimes get overly excited and may tend to exaggerate some of the finds. While there most certainly is a correlation between height and cancer incidence, it's not exactly news. While this study did surprise some characteristics of this connection, we still need to see a peer reviewed paper before it's clear what the exact merits of the study are.