Wednesday 16 November 2016

Alcohol and prostate cancer - the wizard strikes again

Tim Stockwell has established himself as the man who can turn black into white in the neo-temperance movement.

There is a mass of evidence showing that moderate drinkers live longer than teetotallers but Stockwell managed to persuade the Chief Medical Officer that this evidence shouldn't be taken seriously.

Conversely, there is no evidence whatsoever to suggest that hiking the minimum price on alcohol reduced alcohol-related deaths in British Columbia. Stockwell's own department in the province put out data showing as much, and yet he was able to create a model which convinced the world that alcohol-related deaths fell by a third.

Is there no end to this wizard's talents? Apparently not, for he has now decided that drinking causes prostate cancer. The British government doesn't think it causes prostate cancer. The International Agency for Research on Cancer doesn't think it does. Plenty of researchers who have conducted meta-analyses don't think it does.

But Tim 'no safe level' Stockwell reckons it does, and he's done what he did with the health benefits of drinking; he's looked at the evidence, thrown out the studies he doesn't like, adjusted the figures to within an inch of their lives, and claimed to have found a link. And not just with drinking, but with moderate drinking. And it paid off with headlines like this:

Prostate cancer risk soars by a quarter if men drink just one or two beers 

As in his previous work on moderate drinking, the supposed presence of 'sick quitters' is Stockwell's excuse for conjuring with the data.

Part of the problem with most previous studies comes from what scientists call "abstainer bias," where former drinkers were lumped together with people who have never touched a drop.

This practice can disguise the association between alcohol intake and health problems like prostate cancer by making drinkers "look good" in comparison with a group containing unhealthy former drinkers.

This would be a legitimate concern if you were looking at the overall mortality of drinkers and non-drinkers, but in a study of prostate cancer it doesn't matter if ex-drinkers are classified as abstainers unless alcohol consumption causes that form of cancer. You would only need to adjust for it if drinking was a known risk factor, which it isn't, but Stockwell assumes it is. Having made that assumption, he not only adjusts for it, but also boots out 90 per cent of the literature...
The research team identified all 340 previously published studies on alcohol and prostate cancer and found 27 that attempted to measure the risk at different levels of consumption.

You can read his study here. After ripping up most of the studies because they don't meet his standards, he is left with a pitifully small association between drinking and prostate cancer of 1.08, ie. an 8% increase in lifetime risk.

He then makes a bunch of largely unspecified adjustments and is still left with an relative risk of 1.08, but he managed to get a dose-response relationship and somehow got his results for moderate drinkers to achieve statistical significance.

He was then able to triumphantly announce that moderate drinkers have an 8% greater risk of prostate cancer, rising to 18% for heavy drinkers. Both are too small to bother most men but they were enough for the docile media to talk about how a man's prostate cancer risk would 'soar by a quarter [sic]' after 'one or two beers'.

Stockwell's evidence is as shaky as it gets, and people who know a thing or two about prostate cancer are not convinced. You may recall Diabetes UK politely putting down Action on Sugar when they claimed that sugar consumption directly caused diabetes. Well, Prostate Cancer UK issued a similarly gentle, but clearly sceptical, response to Stockwell's propaganda in The Times...

Iain Frame, director of research at Prostate Cancer UK, said: “It is already well known that alcohol plays a role in development of some cancers. However, the impact is unclear when it comes to prostate cancer specifically. This systematic review comparing previous research looking at possible links between alcohol consumption and prostate cancer serves to highlight just how difficult it is to undertake studies which provide conclusive evidence as to the true impact of one item in the diet over any other.”

This measured response was enough to get another member of the temperance fantasy modelling community - a goon from the Sheffield Alcohol Research Group called Colin Angus - to launch an extraordinary outburst on a venerable cancer charity. In a now-deleted tweet, he said...

I see no way to interpret this remark other than to conclude that Angus thinks that Prostate Cancer UK are deliberately lying about - or covering up - the risks of prostate cancer because they have worked with a beer company. This is quite an allegation.

Follow-the-money squealing and anti-industry paranoia come so naturally to people in the 'public health' racket that they make such accusations almost instinctively but, even so, this is a scurrilous claim to make.

It really is all about money with these people isn't it? It's what Carl Phillips calls the mirror-image delusion. They can't imagine anybody saying something just because it's true, or doing something without being paid for it, and so they can't imagine anybody else doing it either.


Another one who thinks that if you're not raging against alcohol, you're promoting it...

Mark Petticrew is not some Twitter loony. Or rather he is not just a Twitter loony. He was a key figure in the Chief Medical Officer's review into the alcohol guidelines which commenced with him having a private meeting with Stockwell and announcing from the outset that there is no safe level of drinking.    

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