Monday 5 September 2022

Drinking is not smoking

From the Daily Express...

Cancer warning: Popular drink equivalent to smoking five to 10 cigarettes UK study finds 

CANCER is a terrifying prospect but one that can be mitigated against to some extent. For the first time, a UK study has found knocking back a popular drink is the equivalent of five to 10 cigarettes.

The popular drink is wine. I'm not sure why they don't just say that in the headline.

Drinking a bottle of wine per week may be like smoking five to 10 cigarettes in the same time period, in terms of cancer risk, according to a study from the United Kingdom.

The research, published in the journal BMC Public Health, should serve as a clarion call for the general public to drink in moderation.

The study was published three years ago. It was garbage then and I have no idea why it's being revived now, but since it has been, here's what I said about it at the time on the long gone Spectator Health website...

If you’ve been watching closely, you'll have seen the signs. The campaign to turn alcohol into The New Tobacco happened gradually at first but is now approaching full speed. It accelerated last year when two widely reported studies in The Lancet claimed that there is no safe level of drinking. The evidence in these studies, such as it was, didn't actually support that claim but along with the equally dubious assertion that alcohol is a major cause of cancer, it forms the bedrock of the drive to treat drinkers like smokers.

If there was a turning point, it was in January 2016 when the Chief Medical Officer, Sally Davies, pushed the “no safe level” line to the public whilst announcing the new drinking guidelines. The guidelines didn’t actually say that there was no safe level, but the small band of anti-alcohol activists who created them managed to downplay the health benefits of moderate drinking to such an extent that it only required a little more statistical chicanery to make the benefits disappear altogether.
The Lancet studies made the final push.

By August 2018, decades of evidence showing that moderate drinkers live longer than teetotallers had been debunked, at least as far as the BBC was concerned [the same researchers who made this claim produced a study this year showing that moderate drinkers do live longer after all, but the Beeb didn't cover that one - CJS 2022]. If alcoholic drinks, like cigarettes, are carcinogens that cannot be consumed safely, then the anti-tobacco blueprint of cancer warnings, advertising bans and the endgame of total eradication can be rolled out.

The most shameless example yet of the deliberate conflation of smoking and drinking was published today. A study in BMC Public Health claims that drinking one bottle of wine a week increases the risk of cancer by the same amount as smoking ten cigarettes a week (if you’re a woman) or by five cigarettes (if you’re a man). Its authors say that their intention is to provide ‘a useful measure for communicating possible cancer risks that exploits successful historical messaging on smoking’. They insist that they are ‘not saying that drinking alcohol in moderation is in any way equivalent to smoking’.

Yeah, right. The only reason this study was conducted was to generate headlines to the effect of 'drinking is as bad as smoking' - and it has worked. The 'study' might boost the impact factor of the journal that published it, but it has no academic merit. There is no reason for it to exist other than as propaganda.

Do you know what the cancer risk of smoking ten cigarettes a week is? No, because hardly anyone does it. The authors admit that ‘the risk of smoking approximately five cigarettes per day (35 cigarettes per week), [is] generally the lowest level of risk detailed in [epidemiological] studies’. There is a study that estimates the cancer risk of smoking very few cigarettes, albeit in a low quality journal, but the authors ignore it and choose instead to extrapolate from other data. To put it in plain English, they had a guess.

So much for it being a 'useful measure for communicating possible cancer risks'. They are comparing the risk of drinking one bottle of wine to a risk that most people have never thought about and which even experts cannot reliably quantify. It throws shade, not light. If this is an attempt to 'make advice simpler', as The Times says, then it has failed. Unless, of course, the advice is to not drink at all.

The authors' real aim is laid bare in the study's introduction when they assert, with breathtaking chutzpah, that: 'There is now robust evidence that low levels of alcohol intake do not provide any protective health benefits.' They cite one of the ridiculous Lancet studies as evidence for this, but it could not be further from the truth. Decades of epidemiological studies have shown a strong and consistent association between moderate alcohol consumption and lower mortality, mostly thanks to lower rates of cardiovascular disease. This finding has been tested and retested dozens, if not hundreds, of times by researchers all over the world and has always come up smiling. To claim that there are no health benefits from moderate consumption would make you odd, but to claim that there is 'robust evidence' disproving those benefits puts you in Flat Earth territory.

By contrast, the claim that there is no safe level of alcohol consumption rests on a much smaller, thinner and shakier body of evidence, mostly concerned with the effect of light drinking on breast cancer (which is why the authors' cigarette equivalents for men are half those of women's).

So, on the one hand, we have decades of epidemiological evidence backed up by biological experiments which show that moderate alcohol consumption reduces the risk of death from heart disease by 15-30 per cent, and, on the other hand, we have a slimmer body of epidemiological evidence which suggests that moderate alcohol consumption might have a small effect on breast cancer risk. It speaks volumes about the 'public health' lobby that they have spent years denying, doubting and ultimately dismissing the former finding while treating the latter as gospel.

Let us take a moment to look at the evidence. A meta-analysis of prospective cohort studies (which track people’s drinking habits and health status over a number of years and are the most reliable studies in observational epidemiology) found that drinkers were 25 per cent less likely to die from coronary heart disease than teetotallers. The 31 studies reviewed are shown below. Note that most of them show a statistically significant reduction in risk.

By contrast, here are the results from a similar meta-analysis of cohort studies looking at moderate/light drinking and breast cancer risk. Of the 25 studies, only six produced statistically significant results and the overall estimate was an increased risk of just nine per cent.

That’s breast cancer incidence. If we look at breast cancer mortality, the evidence is even less scary. For 'very light drinking' - defined as consuming up to five units a week - the risk of dying from breast cancer actually decreases, as does the risk of dying from lung cancer, as the authors of the meta-analysis note:

Very light drinking reduced the mortality of both female and male lung cancer (RR, 0.81; 95% CI, 0.69 to 0.94; I2=0.0%; n=2), female lung cancer (RR, 0.70; 95% CI, 0.56 to 0.89; n=1) and female breast cancer (RR, 0.79; 95% CI, 0.64 to 0.97; I2=0.0%; n=2). There was no significant association between very light drinking and the mortality of colorectal cancer, gallbladder cancer, prostate cancer, and hematologic malignancy.
'Light drinking' - defined as drinking up to eleven units a week, ie. a bottle of wine - is also associated with lower cancer rates in some sites and is not associated with breast cancer mortality...
.. light drinking reduced the mortality of female stomach cancer (RR, 0.65; 95% CI, 0.44 to 0.98; n=1) and male lung cancer (RR, 0.79; 95% CI, 0.70 to 0.87; I2=0.0%; n=5). There was no significant association between light drinking and the mortality of oropharyngeal cancer, esophageal cancer, larynx cancer, colorectal cancer, liver cancer, female gallbladder cancer, pancreatic cancer, breast cancer, cervical cancer, prostate cancer, and hematologic malignancy.
Only when we get to 'moderate drinking' - consuming between 11 and 22 units a week - is there any increased risk of dying from any form of cancer, although it was associated with a lower risk of dying from kidney cancer.
...overall moderate drinking was not associated with the mortality of most cancers. However, it increased the mortality of female colorectal cancer (RR, 2.51; 95% CI, 1.31 to 4.82; n=1) and female breast cancer (RR, 1.04; 95% CI, 1.01 to 1.07; I2=0.0%; n=2), while it reduced the mortality of male kidney cancer (RR, 0.46; 95% CI, 0.23 to 0.93; n=1).

The claim that there is no safe level of drinking makes no sense unless there are risks from very light drinking. We know that very light drinking confers significant health benefits to the heart, and the strongest epidemiological evidence suggests that very light drinking makes breast cancer slightly more likely to occur (+4 per cent) while making fatal breast cancer considerably less likely to occur (-21 per cent).

In the face of seemingly contradictory findings like this, you might be inclined to dismiss observational epidemiology as quackery with mathematics. You might say that meta-analyses are a way of spinning gold out of garbage. If so, I can't wholeheartedly disagree, especially when dealing with ultra-low relative risks of this order, but whatever your view of the science, you can’t have it both ways. You can’t cling to a handful of studies which show a tiny relationship between light/moderate drinking and a few (mostly rare) cancers while dismissing a much larger body of evidence showing a strong, large and clinically relevant protective association between light/moderate drinking and coronary heart disease, nor can you ignore the protective effect of alcohol on the most important health metric of them all: mortality.
The fact remains that the positive effects of moderate drinking on heart disease and other conditions exceed and outweigh the negative effects on cancer risk. To focus on the risks while ignoring the benefits is to lie by omission. 

Given that coronary heart disease is the most common cause of death in the UK, and that the risks of not drinking are more serious than the risks of drinking a little, perhaps we should put a cigarette equivalent on the heart disease risk of teetotalism. Five minutes with PubMed and a pocket calculator tell me that abstaining from alcohol is as risky as smoking five cigarettes a week. Stay safe. Cheers!

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