Tag Archives: health

Lots of sexual partners is apparently good for you !

5 Nov

Even by the standards of the British media this is a very strange bit of reporting. Last week a number of usually fairly conservative parts of the British press reported on a study suggesting that having more that twenty sexual partners could reduce a males chances of developing prostate cancer !


Each of these newspaper stories is reporting a paper by Spence, Rousseau and Parent called ‘Sexual partners, sexually transmitted infections, and prostate cancer risk’ published in the journal  Cancer Epidemiology.

As a teaching example, this story has two great things going for it. First, as I’ve previously written about, ‘sex’ stories are a great way of engaging undergraduate students, and second you don’t have to be a urology expert to start demolishing this story. A moments thought about what hypothesis might be being tested here is worthwhile. Initially you might imaging some sort of ‘exercise’ theory, but of course we’re not talking here about frequency of sexual intercourse, but number of sexual partners (one could have had 21 sexual partners and only had sex 21 times, or one sexual partner and sex many hundreds of times !), which leaves me to think that we might be talking about a ‘promiscuous personality’ in some way inoculates against prostate cancer. As you might imagine, what you actually find is only post-hoc theorising about causality !

When you actually delve into the paper itself two things emerge, firstly that the 19% reduction in cancer risk reported in the newspaper stories wasn’t statistically significant, and secondly that the effect reported only appeared with 20+ sexual partners, 19 partners made no difference at all.

As the wonderful NHS Choices websites speculates, you do wonder if this isn’t an example of just recycling the press release, rather than actually reading the original paper, and whether those writing these stories have and ‘science’ knowledge to back up their work. I shall try this out with my students next week, and report back on the impact !


Eating lots of cheese will save you from diabetes ?

30 Sep


The last week has seen a run of stories in the UK press suggesting that the solution to diabetes maybe a diet rich in full fat dairy products. The Daily Telegraph’s version of the story was sub headed ‘Eating eight portions of full-fat dairy products a day could cut the risk of diabetes by 25 per cent, a study has suggested’. The Daily Mail’s version of the story  even managed to include a swipe at doctors, who had clearly got things very wrong !


What I find rather interesting about this story, and what separates it from the usual run of media health is quite how specific the newspapers are about the study, for example the Telegraph story says ‘The new findings compared people who ate eight portions of full fat diary products a day with those who ate one or fewer per day and found they were 23 per cent less likely to developed type 2 diabetes.”. This same story has appeared around the world, the farthest example I’ve found is this one from New Zealand.

At face value this story seems to be reasonably strong, the newspapers reporting that it used a sample of 27,000 people and was conducted by a respected university in Sweden. However, it’s a lovely example to use to encourage students to delve a little deeper into the story.

As ever, the UK’s National Health Service provides a great resource for rational thinking about health related stories. The ‘Behind the Headlines’ section of the NHS Choices website does a great job of rapidly unpicking the media’s coverage of health news. What’s interesting here is that this seems to have stemmed from a study conducted over two years ago. This study Europe-wide  (of 340,2234 people) did find a relationship between high levels of fermented diary products in the diet and reduced diabetes, HOWEVER the results were rather more complex than that !

  • There was no relationship between total diary intake and diabetes risk
  • People in France who ate more cheese had reduced diabetes risk
  • People in the UK who ate more cheese were at increased risk of diabetes

A rather different story from the Swedish study that prompted the current round of stories. It’s also of note that the Swedish study is in fact a conference paper that has yet to be published. It could also prompt a discussion about sampling i.e. is a study of 27,00 Swedes more reliable than a study of 340,000 people from across Europe ?

All in all, if nothing else this is a great example of getting students to dig a bit beneath the headlines. It might also be worth asking students if other illnesses might be made worse by eating large quantities of cheese !




Suddenly, looking at ‘screens’ might actually be good for you.

17 Sep

A couple of weeks ago I wrote about the spate of reports that computer screens are addling the brains of teenagers. Imagine my delight to this week come across a paper saying that playing video games and watching TV might actually be good for you !

What’s interesting about this is that is seems a quite plausible study, and actually suggests that the reason that some people don’t benefit from ‘relaxing’ in front of the TV is that they negatively interpret it as procrastination. This seems quite valuable in a teaching situation. The idea that a popular idea i.e. ‘the internet is bad for children’ might get more media coverage than a less popular idea i.e. ‘watching TV might do you good’ might be a good way of getting students to thing about sources of information, and whether they might only ever hear about ideas that are ‘popular’

It also occurs to me that this is a lovely illustration of the necessity of reading around the literature, not just relying on one study !

Even more on the ‘value’ of university sport… oh the irony

22 Jul

Only yesterday I wrote about a story from the USA about how university sport ‘allegedly’ makes you cleverer, and then this morning the Sports Centre of my own institution tweeted a link to a UK story suggesting that university sport makes you more employable and results in you earning more money !!!!. This story comes from what seems an unimpeachable source, an academic study funded by BUCS.

As with the study I wrote about yesterday from the US, in the 59 pages of the BUCS report I can find no mention of the Socio-economic of the students surveyed. I am well aware that there are a some honourable exceptions to this (my own institution is based in an economically reprieved area but has a successful rowing club !), but it’s not beyond the bounds of possibility that universities that draw their students from higher SES groups make larger investments in sports, and students at those institutions have a higher disposable income and more free time (not working part-time) and thus more time to devote to sport. It’s hardly surprising that students from such institutions are more employable and earn higher salaries. I’m just not convinced that the sport is what is driving the higher salaries !!!

Now of course I’m not suggesting that university sport is a bad thing, but people really need to look at the source of stories. One wonders if BUCS would have funded a study that said ‘Students at Russell Group Universities (the UK equivalent of the Ivy League) have a higher disposable income and more free time that students at Post-92 universities (State unis in the US) and go on to earn more’. That’s rather more a point about the socio-economic climate that it is a point about university sport..

As ever the take home message of this is that just because you find a correlation it doesn’t mean that variable A causes condition B !!!!!!

Being a member of a gym makes you do better at University…. The return of the Mediteranean Diet Effect

21 Jul

One of the most used examples for teaching rational thinking is the ‘Mediterranean Diet’ story. Put simply this is the idea that Northern Europeans live longer if they stick to the diet of Southern Europeans i.e. Lots of salad and olive oil. A few moment’s thought demonstrates how silly this idea is i.e. Northern Europeans who consume lots of salad and olive oil tend to come from higher income brackets, and it’s the higher economic status that is the predictor of longevity, not the diet itself.

This can to mind when I read a story in the Daily Mail this week:


This story reports a study from the Michigan State University suggesting that students who join an on-campus gym get better grades and stay in university longer. Sadly the original paper is behind a paywall, but the available abstract makes no reference to controlling for the disposable income of the students. (Working in a university I am fortunate that I have access to the full-text of this paper. As I suspected, the study doesn’t control for disposable income, indeed the paper actually acknowledges that Socio-economic status could confound the results) It seems possible that students who can afford to join a gym might have a high disposable income, and indeed that those with a higher disposable income might spend less time in paid employment and thus have more time for sporting activities (and college work !!).

All of this leaves me wondering who is at fault here. It’s interesting that whilst the paper itself acknowledges a potentially dramatic confounding variable it still makes claims about the importance of the relationship found. At times I worry that in a drive to gain publicity for their research scientists may end up actually making matters worse by facilitating a lack of understand that correlation doesn’t necessarily equal causation.

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