Today the BBC is running a story claiming that tall people are more likely to develop cancer. Apparently, ‘[f]or every four inches (10cm) above five feet a person was, the researchers said they had a 16% increased cancer risk.’
The article is no more or less detailed than most BBC news stories on medicine – they include a run-down of the story and a few expert opinions and quotes. No big deal.
On Tuesday, the top Health headline was Obesity ‘leading driver’ of breast cancer, with a similar story structure.
Let’s compare:
Story A (on height): The study of more than one million women, published in The Lancet Oncology, suggested chemicals that control growth might also affect tumours.
Story B (on weight): One in eight women in the UK develop breast cancer in their lifetime, data shows, and the majority of these tumours are “hormone sensitive” meaning their growth is fuelled by hormones.
Heidi thinks: Okay, no problem. Tumors appear to be linked with hormones in some way.
Story A: The study followed 1.3 million middle-aged women in the UK between 1996 and 2001.
It linked 10 cancers to height – colon, rectal, malignant melanoma, breast, endometrial (uterus), ovarian, kidney, lymphoma, non-Hodgkin lymphoma and leukaemia.
Story B: The Oxford University team, funded by Cancer Research UK, studied the health records of nearly 6,300 post-menopausal women, looking for factors that might explain why some developed hormone sensitive breast cancer when others did not.
Heidi thinks: Based solely on the way that this story is reported by the BBC, both were statistically significant groups of people. Story A, mind you, used 1.3 million women and Story B only 6,300, but both are dramatically more than, say, the 60 women you might see in a “study” done by a cosmetics company on whether their mascara is more waterproof.
Story A: Those in the tallest group, over 5ft 9in, were 37% more likely to have developed a tumour than those in the shortest group, under 5ft.
Story B: No specific figures given in this story on how many of those 6,300 women developed cancer or the statistical increase in cancer among fat women vs. thin women.
Heidi thinks: Ah…
Story A: Dr Jane Green, lead researcher and from the University of Oxford, told the BBC: “Obviously height itself cannot affect cancer, but it may be a marker for something else.”
Story B: Experts have known for some time that factors that influence hormone levels – like pregnancy, the oral contraceptive pill and the menopause – can change a woman’s breast cancer risk.
This latest work, published in the British Journal of Cancer, suggests obesity should go at the top of this list, not least because it is a lifestyle factor that women can have some control over. (emphasis mine)
Heidi thinks: The hell, you say?
Story A: “Higher levels of growth factors could do two things. They could result in more cells – taller people are made of more stuff so there are more cells which could mutate and become tumours. Alternatively, they could increase the rate of cell division and turnover, increasing the risk of cancer…
The researchers suggested that height could also have contributed to increasing cancer incidence. In Europe, average height is thought to have increased by around 1cm every decade during the 20th Century.
They argued that the height increase in that time could have resulted in a 10-15% more cancers than if heights had remained the same.”
Story B: “Dr Julie Sharp, of Cancer Research UK, said: ‘This is an important study as it helps to show how alcohol and weight can influence hormone levels. Understanding their role in breast cancer is vital and this analysis sheds light on how they could affect breast cancer risk.
‘We know that the risk of the disease can be affected by family history and getting older, but there are also things women can do help reduce the risk of the disease. Maintaining a healthy body weight and reducing alcohol consumption are key to reducing breast cancer risk.’”
So, in conclusion, what we can take from this is that the sample size of women involved in the study on breast cancer was substantially smaller than the study of tall women. We know that tumors are probably linked to hormones and, when it comes to tall people being more at risk, researchers are willing to conclude that if growth hormones affect height, they might also make tumors grow more too. However, tall people shouldn’t worry (even though women over 5′9″ are supposed to be 37% more likely to develop tumors!!!) because it’s not under their control and it’s medicine’s job to figure out how to fix the problem.
Fat women, on the other hand, can totally control their weight (how, we don’t quite know, since science hasn’t given us a foolproof method that escapes the 97%-weight-regained stat anyway, but science says it, so it must be true). Therefore, even though we have absolutely no evidence on how much more likely we are supposed to be to get breast cancer, we need to get to losing weight NOW.
Now, it’s fairly evident that weight is based on genetics and that people with metabolic disorders can be more likely to be fat. If hormones are linked to fatness, which they probably are in at least some people, and hormones are linked to height also, why is it that the tall people get a pass because hormones are out of their control, but fat people don’t?
I’m not a scientist and I know that media reporting of obesity-related stories is biased anyway but can any of you tell me if the flaws I’m seeing in these two stories, set out side by side, actually ARE serious flaws or if I’m just hallucinating? Does this piss off anyone else?!