I cannot look into the future, at least not too far ahead, and to be honest that is a major inconvenience. I guess however, that is how everyone else feels about this issue as well. I can make the reasonable assumption though that, if I don’t get ill or die of anything else earlier, I’ll probably get some form of cancer and may well die of that.
With over 12 million new cases in 2008 worldwide, of which over 3 million in Europe alone, (link) the probability of me getting it, or someone I know, is quite high. So knowing more about cancer (here is a good read (link)) and whether there are ways that may reduce the change of getting it is important. Luckily much research is being dedicated across the world; some of it a bit more accessible than other. And regularly there is someone who dedicates some of her or his time to summarize it all for us. Yesterday, the results of a large review funded by Cancer Research UK (landmark, by their own words so that’s big stuff) were published on CRUK’s own website (link) and, arguably more important, in 16 peer-reviewed publications in a dedicated issue of their British Journal of Cancer. All papers are Open Access, which is awesome, so go and have a look here. The review estimate fractions of cancer that could be attributed to (for simplicity let’s say “were caused by”) lifestyle and environmental factors in the UK last year.
There is quite a lot of technical, geeky stuff to say about population attributable fractions, how they are calculated, why they never add up to 100%, and other disadvantages and advantages. Some of it can be found within the 16 publications, and if you are into equations have look over here or check the people’s encyclopaedia here. Nonetheless, it is quite cool and with some “huffs, puffs, yes buts, and uhms” it gives us an idea of how much of cancers is caused by a specific lifestyle or exposure. A nice graphical overview by Cancer Research UK can be found here.
So this particular landmark(!) review looked at the impact of 
tobacco smoking (obviously), alcohol consumption, eating fruit and veggies, meat consumption, fibre intake, salt intake, overweight and obesity (Daily Mail readers love this one), physical exercise, infections, post-menopausal hormones, breastfeeding, ionising radiation, ultraviolet light (sun beds and the mandatory trip to Mallorca essentially), and of particular interest to me – occupation.
The main conclusion first – 42.7% of all cancers (that is 134,000 cases last year) can be attributed to less-than-optimal levels of any of these factors. Translated by journalists this means:
Cancers could be prevented by lifestyle changes in over 40% of cases: study
100,000 cancer cases ‘preventable’
It’s not just down to fate: How simple lifestyle changes can prevent four in 10 cancer cases
Cancer can be avoided with ‘four simple lifestyle changes’
Not arguing at all that making these lifestyle changes help in reducing the change of 
getting cancer, but ‘preventable’ and ‘can be avoided’ is a bit optimistic. Remember that this would imply reducing all of these exposures and lifestyle factors to nill (or maxed out if, like fruit, it is in fact good for you).
However, there is something else interesting in these figures that I would like to focus on. Please have a look at the following table which I lifted out of paper number 16 (link) and shows the percentages of cancers attributable to risk factors:
|
Exposure |
All |
Males |
Females |
|
Tobacco |
19.4 |
23.0 |
15.6 |
|
Alcohol |
4.0 |
4.6 |
3.3 |
|
Fruit and vegetables |
4.7 |
6.1 |
3.4 |
|
Meat |
2.7 |
3.5 |
1.9 |
|
Fibre |
1.5 |
1.4 |
1.7 |
|
Salt |
0.5 |
0.9 |
0.2 |
|
Overweight/obesity |
5.5 |
4.1 |
6.9 |
|
1.0 |
0.4 |
1.7 |
|
|
Post-menopausal hormones |
0.5 |
– |
1.1 |
|
Infections |
3.1 |
2.5 |
3.7 |
|
Radiation –ionising |
1.8 |
1.7 |
2.0 |
|
Radiation –UV |
3.5 |
3.5 |
3.6 |
|
Occupation |
3.7 |
4.9 |
2.4 |
|
Reproduction (breastfeeding) |
0.9 |
– |
1.7 |
|
All of the above |
42.7 |
45.3 |
40.1 |
Now this is essentially a summary table of all 16 papers, and I don’t think it comes as big surprise that the usual suspects show up: tobacco smoking as the most important risk factor, overweight and obesity (well, a stroll through Manchester city centre could have told you that), and making sure you eat your veggies.
Much more of a surprise, I suspect, is that in fact the 5th most important factor overall (3.7% of cancers), and the 3rd(!) most important factor in men (4.9% of all cancers) is occupational exposures. Let me re-iterate that in a somewhat different fashion:
Occupational exposures remain to be one of the most important risk factors for getting 
cancer, especially in men, in the UK, in 2010. It has a bigger impact than your consumption of meat, fibres, salt. A bigger impact than physical exercise, and a bigger impact than ionising or non-ionising radiation exposure. More so, if you happen to be a man it also has a comparable impact, one could argue slightly larger, to drinking alcohol or your weight (eat your veggies though!).
Occupation is quite a heterogeneous set of different exposures and circumstances so it is slightly more complicated than trying to reduce a single risk factor such as for example junk food, but in terms of actual reduction of risk – just try and separate a British bloke from his pint and steak‘n’onion pie.
Now how come we never hear of that, and why are relatively few studies done in the UK nowadays to try and reduce these exposures to ‘acceptable’ levels? After all, this is the UK, and it is 2010. Yet, it seems that not all occupational exposure levels have reduced to acceptable levels over here (or that the harmful exposures have been conveniently shipped to the developing world). I don’t have the calculations at hand, but surely it would save us all a lot of money if employees would not get (terminally) ill?
Unfortunately, our own Cameron and Osborne have adopted a somewhat simplistic approach to saving the economy in which improving working conditions and removing carcinogens from the work floor is part of all that damned “Red Tape” that prohibits Uk industry to compete with the Indias and Chinas of the world. That makes sense, given a choice I bet most workers would prefer working in Chinese industry instead of British.
And of course, we can’t all be investment bankers….
Sense about Science
The Fun Police 
Posted on December 8, 2011
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