Friday, 26 February 2016

The story of the new alcohol guidelines

I've been reading the minutes of the meetings held by the committee that reviewed the alcohol guidelines recently. You may recall that this was the first full review since 1995 and led to the Chief Medical Officer (CMO), Sally Davies, lowering the recommendations for men from 21 to 14 units a week. The female guidelines were left at 14 units. She also claimed that the health benefits derived from moderate drinking were an ‘old wives’ tale’ and claimed that there was ‘no safe level of alcohol’.

The most striking difference between the 1995 review and the 2016 review is the make-up of the panels. Whereas the 1995 committee was dominated by civil servants who had no obvious prejudices for or against alcohol, the meetings held from March 2013 to discuss alcohol guidance were dominated by activist academics and temperance campaigners.

The Institute of Alcohol Studies (IAS), a small but hardline anti-alcohol organisation, was heavily represented on the committee. The IAS was formed in the 1980s as a direct successor to the UK Temperance Alliance which, in turn, had been formed out of the ashes of the UK Alliance for the Suppression of the Traffic of All Intoxicating Liquors, a prohibitionist pressure group. The IAS receives 99 per cent of its income from the Alliance House Foundation whose official charitable objective is ‘to spread the principles of total abstinence from alcoholic drinks’. Its director, Katherine Brown, was on the CMO’s panel, as was its ‘expert adviser’ Gerard Hastings, although he failed to disclose his IAS role in his declaration of interests.

The IAS’s scientific adviser Petra Meier was also on the committee and was joined by her Sheffield University colleague John Holmes. Holmes and Meier are both strong advocates for minimum pricing and helped develop a computer model which has been repeatedly used to promote minimum pricing by producing estimates of the number of lives that will supposedly be saved by the policy.

Another staunch anti-alcohol campaigner, Ian Gilmore (chairman of the Alcohol Health Alliance, of which the IAS is a key member), was unable to attend the first meeting but was involved thereafter. Gilmore has campaigned for many years for higher alcohol taxes, minimum pricing and a total ban on alcohol advertising.

Other members of the committee may have been less strident than Gilmore and the IAS but there was no doubt where their biases lay. Mark Bellis wrote an article for the British Medical Journal in 2011 complaining that existing alcohol guidance was too generous and ‘read more like an alcohol promotion slogan’. Mark Petticrew and Theresa Marteau are both strong advocates of a range of heavily interventionist ‘public health’ policies, including sugar taxes, plain packaging and minimum pricing.

Of those who attended the initial meetings in 2013, only three did not explicitly advocate stricter alcohol control: the health economist Martin Buxton, the health sociologist Sally Macintyre, and the epidemiologist Valerie Beral. The latter appears to have been selected because of her research linking alcohol to breast cancer, which would become a crucial element in the ‘no safe level’ narrative.

The minutes of a meeting in June 2013 indicate that the path towards dismissing the benefits of moderate alcohol consumption was mapped out from an early stage. Mark Petticrew told his new colleagues: ‘The beneficial effects of alcohol consumption, where they are evidenced, are limited to a low consumption level of half a drink per day.’ Moreover, he said, ‘The population cohort who experiences any beneficial health effect from alcohol is very small. Given these limitations, there is an argument that beneficial effects could be considered not to be relevant in the context of an overall population message, advice or guidance.’

These bald assertions were based on private meetings held between Petticrew and two alcohol researchers, Jurgen Rehm and Tim Stockwell, a fortnight earlier. As a result of this information, the minutes of the 25 June meeting state that the group ‘agreed that a key message from the Rehm/Stockwell discussion is that the evidence shows that any amount of alcohol increases the risk of cancer. Therefore it cannot be said that there is such thing as a “safe” limit.’

Here were the two central messages that would be transmitted, almost word for word, to the British public two and half years later — that the benefits of moderate consumption had been much exaggerated and there is no safe level of drinking. This new narrative appears to have arisen from nothing more than a private meeting with two researchers. Rehm has strong views on alcohol policy (he advises governments to ‘treat alcohol like tobacco’) and he is a respected alcohol researcher but his views, as ventriloquised by Petticrew, bear little relationship to what he told the BBC after the guidelines were announced. On BBC Radio 4’s More or Less programme, he made it clear that there was good evidence that moderate alcohol consumption reduced the risk of heart disease and other diseases. Rehm’s own research concluded that the protective effect of alcohol on heart disease was ‘hard to deny’ and not just for those who consume ‘half a drink a day’, as Petticrew claimed, but for larger quantities too. Rehm’s 2012 systematic review found that heart disease risk was at its lowest for men drinking around four units a day, with a lower optimal level for women.

While Rehm’s views may have been misreported by Petticrew, those of Tim Stockwell were not. Stockwell is the world’s most persistent and prominent critic of the evidence showing that moderate alcohol consumption saves lives. His various letters, editorials and studies casting doubt on the benefits of drinking were given a hugely disproportionate prominence in the 2016 guidance. It is telling that Petticrew’s first act was to approach Stockwell and allow his controversial opinion to frame the debate.

The other striking difference between the 1995 review and the 2016 review is the range of evidence put before the respective committees. Whereas the 1995 panel received dozens of submissions, the minutes of a March 2013 meeting show Sally Davies’s team explicitly rejecting a call for evidence, preferring instead to rely on their own wisdom. Several new reports were commissioned, but all were co-authored by members of the committee.

Most of these were commissioned from the Centre for Public Health at Liverpool John Moores University and co-written by Mark Bellis. One of them, entitled ‘A summary of the evidence of the health and social impacts of alcohol consumption’, did its utmost to cast doubt on the benefits of alcohol consumption.

Sceptics such as Stockwell often claim that non-drinkers have a lower life expectancy than moderate drinkers because many of them are unhealthy former drinkers. Despite many studies showing that moderate drinkers also live longer than lifetime abstainers, this zombie argument continues to be made and it reappeared in Bellis’s report for the committee. He was, however, forced to admit that studies which have controlled for this potential confounder still found a protective effect. The draft document concedes: ‘A few meta-analyses have sought to account for such bias, and based on the extent to which this misclassification error can be accounted for, compared with lifetime abstainers a protective association appears to remain for type-2 diabetes, ischaemic heart disease, and ischaemic stroke.’

This was undoubtedly true. The Liverpool report included a summary of epidemiological studies showing that risk from several major diseases is lowest for people drinking between 1.5 and 8.5 units a day and that risk only reverts to that of an abstainer at a level of at least 4 units a day (or 28 units a week). The authors did not dwell on this evidence. Instead, they immediately suggested that there were ‘further reasons to suggest that the beneficial effects of alcohol consumption may currently be overestimated’, a vague claim for which the only citation was an opinion piece by Tim Stockwell.

The Liverpool document has since been made available to the public but the published version has been edited to further obfuscate the benefits of drinking. Whereas it previously acknowledged the evidence that moderate drinking reduces the risk of type-2 diabetes, ischaemic stroke and heart disease, it now only mentions heart disease and Stockwell’s opinion is given added prominence. The passage quoted above has been replaced by the following: ‘A few meta-analyses have sought to account for such bias; for example a recent meta-analysis, which reported that light to moderate alcohol consumption was associated with a reduced risk of cardiovascular outcomes, included lifetime abstainers as a reference category in sensitivity analyses. However, Stockwell et al question the robustness of the conclusions generated from this literature…’

By November 2013, Mark Petticrew had already drafted the committee’s conclusions. He acknowledged that many studies have found a ‘J-shaped relationship between alcohol consumption and total mortality’ but after considering evidence from Liverpool John Moores University and his conversations with Rehm and Stockwell (no other evidence was mentioned) he claimed that the ‘estimates of the size of this protective [effect] are likely to be biased’. Petticrew had no such concerns about flaws in the epidemiology of cancer, however: ‘For cancers there is clear and consistent evidence of a linear relationship. Alcohol is carcinogenic with no safe lower limit.’

The draft guidelines concluded that the benefits of alcohol consumption, such as they were, mainly affected people over the age of 50 and only related to heart disease. The latter is untrue (the evidence before the committee clearly showed a protective effect for other diseases) and the former is largely irrelevant (heart disease is rare among people under 50). Despite portraying the benefits as only applying to older people, Petticrew advised against telling them to drink alcohol. ‘Discussion at previous meetings,’ he wrote, ‘was along the lines of: if someone >65 is not currently drinking, then the evidence is not strong enough to recommend them to start; however if they are currently drinking more than the lower limit, then they should reduce their consumption.’

It was becoming clear that the bar for what constituted good evidence was being set much higher for benefits than it was for risks. The idea that the government should recommend moderate alcohol consumption to people who did not drink was regarded as unthinkable, regardless of the health benefits.

When a second draft of the guidelines was written at the end of January 2014, an even harder line was taken and a new argument had been found. Having whittled away the benefits of drinking until they applied only at a low level to a single disease among one section of the population, Petticrew explained that heart disease in Britain was not the killer it once was and, therefore, ‘irrespective of whether any protective effect is real or artefactual, any positive impact on total mortality is likely to decline as mortality from IHD [ischaemic heart disease] continues to decline’. No one seems to have raised the possibility that heart disease rates have declined in the last 50 years partly as a result of rising alcohol consumption, nor was it pointed out that heart disease — declining though it may be — still kills more people than all the ‘alcohol-related’ cancers combined.

At this stage, however, there was little to suggest that the male drinking guidelines would be reduced to bring them in line with those of women. The Liverpool report had shown clear differences in risk for men and women, and a presentation viewed by the committee on 10 September 2013 showed different J-curves for both sexes. The draft conclusions of November 2013 noted that alcohol’s ‘cardioprotective effect on total mortality is observed at a much lower level of consumption for women’ and almost every country in the world has higher guidelines for men.

This began to change after the committee, via Public Health England (PHE), commissioned some computer modelling to help formulate the final guidelines. In the minutes of a September 2014 meeting it was noted that ‘the PHE tender exercise had resulted in just one bid and that the bidder would be interviewed in early October to explore their proposals’. We must presume that the lone bidder was Petra Meier and John Holmes’s team at Sheffield University since it was they who won the contract.

It remains puzzling why a theoretical model was deemed necessary when so much epidemiological data exists to show the effect on morbidity and mortality from different levels of alcohol consumption. We may never know how the model was put together — the published Sheffield report does not provide enough data to allow independent replication — but one thing is clear: its risk curves bear no relationship to any risk curves in the published epidemiological literature. Whereas observational epidemiology shows lower rates of mortality for people drinking up to 4-8 units per day, the Sheffield model suggests that drinkers’ mortality risk is lower than abstainers only at very low intakes and exceeds that of abstainers at around two units per day. Moreover, while epidemiological studies find that men can drink more than women before assuming the same risk as a teetotaller, the Sheffield report finds similar limits for both sexes.

It is not even clear what the Sheffield report is measuring. The key criterion for gauging a safe drinking level is the risk of death, ie mortality risk, but the Sheffield report instead focuses on mortality from ‘chronic alcohol-related causes’. It is obvious that non-drinkers are less likely to die from alcohol-related causes, but it tells us nothing about overall mortality.

Moreover, the team stripped out all health benefits from drinking with the exception of heart disease. In their response to a comment from the peer-reviewer (who, interestingly, said ‘I predict that there will be very little, if any, change to the guidelines’), the team stressed that ‘excepting cardioprotective effects, the report focuses exclusively on the negative consequences of drinking’. This was certainly true and, like Petticrew and Bellis, the Sheffield team went out of their way to cast doubt on the cardiovascular benefits. In the space of two sentences, they described the protective effect on the heart as ‘disputed’, ‘overestimated’ and suggested that the scientific consensus was moving towards the view that the benefits barely existed at all. This passage contains ten references, half of which were articles or op-eds written by Tim Stockwell.

In short, the Sheffield team produced a theoretical model that was entirely divorced from the epidemiological evidence. The model appeared to show that a ‘safe’ level of drinking — if defined as carrying no more risk than abstaining from drink — was significantly lower than had been reported in a large body of epidemiological research. The model also deviated from observational epidemiology by showing this ‘safe’ level to be similar for men and women alike. Indeed, it actually reported a higher level for women. When a computer model clashes with observed reality so conspicuously, it is time to bin the model. Instead, the CMO’s committee binned the real world evidence and used the model as the basis of its recommendations.

By April 2015, the only question was how to sell the new advice to the public. Having failed to completely erase the health benefits of drinking, the group were concerned about the public being encouraged to drink even small quantities of alcohol. The group emphasised that there was ‘now no justifiable case to recommend that anyone should choose to start drinking alcohol in the interests of their health’. Their message to those who already drank below the current lower risk limit was that ‘should they wish to reduce their frequency or levels of drinking, [they] need have no health concerns in doing so’. Whatever the evidence might say, there was no doubt that the committee favoured total abstinence: ‘The message is quite clear that any level of drinking can be harmful to health’.

The statistician David Speigelhalter, who acted as an adviser to the committee in the latter stages, told them that ‘a message that “there is no safe lower limit” would risk being at odds with public opinion’, but it barely seemed to matter if the public found the new guidelines credible or realistic. A telling comment in one set of minutes indicates that the real intention was to influence policy: ‘It would be important to bear in mind that, while guidelines might have limited influence on behaviour, they could be influential as a basis for government policies, which could in turn help to alter norms.’

The new guidelines were announced on 8 January 2016. The committee had made every effort to downplay the benefits of moderate drinking, and Sally Davies delivered the final blow by dismissing those benefits as ‘an old wives’ tale’ on the Today programme. Nearly three years after cramming her committee with temperance campaigners and ‘public health’ activists, Davies went further than even Tim Stockwell could ever have hoped when he had that first chat with Mark Petticrew in June 2013. The job was done.

Cross-posted from Spectator Health

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