Saturday, 6 March 2021

That World Obesity Federation scatter plot

It was World Obesity Day recently so we got the inevitable press release from the World Obesity Federation, with the inevitable COVID-19 tie-in. 
 
The media picked up on one striking claim in particular...
 
Obesity warning as report shows nine out of 10 COVID-19 deaths have been in countries with high rates of obesity
 
 
The correlation cited in the report is actually with overweight, not obesity, but journalists nearly always get those two mixed up. Obesity is a risk factor for COVID-19 mortality, especially morbid obesity. Being overweight, not so much. 


Nevertheless, the claim is that 90 per cent of COVID-19 deaths have taken place in countries where more than 50 per cent of the population is overweight. The, er, 'correlation' between the two is shown in the WOF report in a graph that is the stuff of statisticians' nightmares.

 
I'm not quite sure where the trend line is meant to go there.

For those who are still not convinced, we were given some examples of countries with low rates of obesity and low rates of COVID-19.
 

Author of the report Dr Tim Lobstein, who is a senior policy adviser to the World Obesity Federation and visiting professor at the University of Sydney, said: "We now know that an overweight population is the next pandemic waiting to happen.

"Look at countries like Japan and South Korea where they have very low levels of COVID-19 deaths as well as very low levels of adult obesity."

 
The Guardian reported... 

Among countries where more than half the adult population is overweight, Belgium has the highest level of deaths, followed by Slovenia and the UK. Italy and Portugal are 5th and 6th, while the US is 8th.

Vietnam, by contrast, has the lowest lowest level of overweight in the population and the second lowest Covid death rate in the world.

 
But these Asian countries didn't have many deaths because they didn't have many cases. Unless the WOF is claiming that being slim stops you catching and spreading the virus, these examples are meaningless. 

If you look at the maps from the WOF report, you can see that the countries with low Covid mortality are nearly all in Asia and Africa. The death rate is low in these countries because they had low infection rates (China, Vietnam, etc.) and/or a young population (India, most of Africa). Obesity had, at best, a marginal impact.



I wrote a quick letter to the Times about this. 
 

Sir, Tim Lobstein says “there is no escaping the clear correlation between some of the world’s worst Covid death rates and worst obesity rates”. The correlation may be clear, but we should not infer causation from the fact that 90 per cent of Covid-19 deaths take place in countries where more than 50 per cent of the population is overweight. The lowest death rates have been in places that have controlled the virus, such as Vietnam and Japan, or have a young population. In India, only 5 per cent of the population is aged over 65. In Africa, the average age is 20. Such places have had relatively few Covid deaths despite high infection rates.

Obesity certainly increases the individual’s risk of dying from Covid-19 but it is not a decisive factor when comparing nations, as the cases of New Zealand and Australia (both of which have a higher rate of obesity than the UK) can confirm.

Christopher Snowdon
Head of lifestyle economics, Institute of Economic Affairs

 
Naturally, the letter printed below mine calls for a 50 per cent tax on 'burgers, ketchup, ready meals (unless the individual has a genuine physical or medical reason for exemption) biscuits, cakes, fruit yogurts, gentlemen’s relish, etc.'


Friday, 5 March 2021

Fantasy modelling and a 70p minimum alcohol price

Is the Sheffield Alcohol Research Group aware that minimum pricing has been in force in Scotland for nearly two years?
 
Their latest study suggests not. Using their computer model (what else?), they conclude that minimum pricing has more of an effect on men than on women.
 
For example, a £0.50 MUP led to a 5.3% reduction in consumption and a 4.1% reduction in admissions for men but a 0.7% reduction in consumption and a 1.6% reduction in hospitalisations for women.
 
The problem here is that it is an indisputable fact that the number of alcohol-related hospitalisations has not fallen since the £0.50 minimum unit price was introduced. There were 35,544 of them in 2017/18 and 35,781 in 2019/20.


If you want to split hairs, there was a minuscule decline in the rate of admissions, from 668.8 per 100,000 people in 2017/18 to 666.6 per 100,000 people in 2019/20, but that is just 0.3%, nowhere near the 3% implied in the new Sheffield study nor the 4% predicted in the model they produced before the policy came into effect.

In the press release, lead author Petra Meier (who is now at Glasgow University) gives further indications that she hasn't heard about the policy being introduced.

“Our modelling suggests that men’s drinking and risk of alcohol-related hospital admissions would decrease substantially more than women’s for both duty increases and minimum unit pricing policies."

But did it, Petra? We have the empirical data now, surely? Judging by the overall admission figures, minimum pricing had an effect on both sexes that could most charitably be described as minimal. 

Perhaps the most significant aspect of the study is that it also modelled the impact of a 70p minimum price. Brace yourself, Scottish drinkers.


Thursday, 4 March 2021

Smoking and COVID-19: new update

As North Carolina announces that smokers and ex-smokers can jump the queue for the SARS-CoV-2 vaccine, it's time to take another look at the evidence on smoking and COVID-19.

Regular readers will recall the evidence showing smokers heavily under-represented in Covid wards around the world. It made a few headlines last spring, but it has since faded away as a news story. Public Health England's false claim about smokers being 14 times more likely to develop severe COVID-19 remains online.

That doesn't mean the studies have dried up. The ongoing meta-analysis by the UCL academics is now in its eleventh edition and the song remains the same. With 121 studies under review, smokers are still less likely to get COVID-19. 
 
Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR = 0.71, 95% Credible Interval (CrI) = 0.61-0.82, τ = 0.34). Data for former smokers were inconclusive (RR = 1.03, 95% CrI = 0.95-1.11, τ = 0.17) but favoured there being no important association (4% probability of RR ≥1.1).
 
 
My understanding of the evidence last year was that smokers were less likely to be hospitalised with Covid but more likely to suffer severely when they did. That wouldn't be surprising given the impact of underlying health conditions in worsening outcomes. But even that now looks doubtful. The outlook for ex-smokers is worse than for never-smokers, but it's far from clear that current smokers do any worse.
 
Former compared with never smokers were at increased risk of hospitalisation (RR = 1.19, CrI = 1.1-1.29, τ = 0.13), greater disease severity (RR = 1.8, CrI = 1.27-2.55, τ = 0.46) and mortality (RR = 1.56, CrI = 1.23-2, τ = 0.43). Data for current smokers on hospitalisation, disease severity and mortality were inconclusive (RR = 1.1, 95% CrI = 0.99-1.21, τ = 0.15; RR 1.26, 95% CrI = 0.92-1.73, τ = 0.32; RR = 1.12, 95% CrI = 0.84-1.47, τ = 0.42, respectively) but favoured there being no important associations with hospitalisation and mortality (49% and 56% probability of RR ≥1.1, respectively) and a small but important association with disease severity (83% probability of RR ≥1.1).

I'm not sure how 'important' that last finding is given that the result is not statistically significant. Since current smokers don't have a higher rate of Covid mortality, perhaps not much.

Fair play to the UCL researchers for sticking with this when a lot of people in 'public health' would have run a mile. Not that many people are paying attention to these inconvenient facts. 

There is a surprisingly large amount of evidence on this stuff once you start looking. This study from New York didn't find smoking to be a factor in any Covid outcomes. This study from Turkey found that there were fewer smokers with COVID-19 than would be expected from the general smoking rate and that smokers did no worse than nonsmokers if they contracted it. This meta-analysis found smokers to be 82 per cent less likely to be hospitalised with COVID-19! 
 
This study of grocery workers in the USA found 21 symptomatic cases, only one of whom was a smoker. The authors say: 

Our finding of fewer current smokers with a positive SARS-CoV-2 assay result, while in agreement with recent epidemiological studies, contradicts common perception and clinical recommendation on risks and effects of cigarette smoking on lung health warranting further research investigations.

It sure does. All sorts of possible explanations have been advanced for this.
 
On the other hand, this study from Brazil found smokers to be three times as likely to be hospitalised with Covid. And yet it found them no more likely to die from Covid and - most unusually - nor did it find obese people being more likely to die from it.

See this post of mine from last year for more studies or, if you want a deep dive, go through the studies listed in the living meta-analysis.

'What about vaping?' you may ask. Most vapers are former smokers so there is an obvious confounding factor waiting to trip up the sloppy epidemiologist. There hasn't been much research in this area, but a study published last month gives vaping the all clear. 

There were no differences in diagnosed/suspected Covid-19 between never, current and ex-vapers... Among UK adults, self-reported diagnosed/suspected Covid-19 was not associated with vaping status.
 
Hurrah! And...

Bayes factors indicated there was sufficient evidence to rule out small negative (protective) associations between vaping status and diagnosed/suspected Covid-19.

Intriguing.

In conclusion, there isn't any obvious justification for making smokers a priority group for the vaccine, although there is a stronger case for ex-smokers. The system in North Carolina says that anyone who has smoked more than 100 cigarettes in their lives can jump the queue. It is impossible for authorities to verify this, so I guess they're relying on North Carolinians being very honest.


Wednesday, 3 March 2021

Lockdown libertarianism?

I was on the Accad and Koka podcast this week talking about why I support the current UK lockdown.
 


Friday, 26 February 2021

The lockdown debate with Toby Young

I had an hour long debate about lockdown policy with Toby Young on TalkRadio yesterday. You can watch the whole thing below. Apologies for the sound quality a times. Skype didn't seem to work as well Zoom for me in this.


Much of what was discussed has appeared in more detail on this blog before - and also on the Quillette article that started all of this. I expected a disproportionate number of smileys in the online audience so I started off with the basics. SARS-CoV-2 is a virus that spreads from human to human. If humans don't interact with others, it can't spread. The claim that lockdowns don't reduce the number of infections therefore requires extraordinary evidence.

Florida has recently joined Sweden as the place that has supposedly proved that lockdowns don't work. Neither has had a lockdown in the last six months and although they've had a lot of COVID-19 deaths, they haven't had an exceptionally high number. 

There are more restrictions in both Sweden and Florida than the smileys acknowledge. Even if there weren't, it obviously wouldn't prove that lockdowns don't work. At best, it would show that some places can keep cases down to a manageable number level (debatable in the case of Sweden) without resorting to lockdown. 

Good for them. I've always wished Sweden well. If Britain could have kept the virus at a manageable level through voluntary measures, I would have never supported lockdown. The problem is that we could not and manifestly did not. We had reached an NHS-busting level of infections by the end of December - higher than the peaks in both Sweden and Florida pro rata - and suffered the consequences in January. We couldn't sustain those kind of levels, let alone allow them to rise.

It would have been a suicidal gamble for the government to do nothing and simply hope that people would radically change their behaviour of their own accord or that the virus would somehow go away at the start of January. 

I mentioned the Google Mobility data in the debate. I find it fascinating. In Sweden, you can almost see the exact moment at which people's behaviour changed in late December, thereby leading to the decline in cases in January. You can also see the subsequent rise in movement which correlates with the current increase in cases.


 


 
This is evidence that people can change their behaviour voluntarily (albeit with a lot of nudging and a few regulations) in a way that brings case numbers down. But there are two things I find particularly interesting about this data.

Firstly, mobility fell to a record low in Sweden in late December. Even the current level is lower than it was last spring when rates were falling. In other words, the kind of behavioural change that was sufficient to bring case numbers down in the spring no longer seems to be enough, presumably because winter makes it less congenial to meet outdoors.

Secondly, look at the graph below, particularly November and December.


In the UK, mobility was more than 30 per cent below normal levels in December and yet rates of infection were rising rapidly. In Sweden, they fell to that level in late December, but that was sufficient to bring rates down. 

This is just one measure of mobility, but all the others show a similar trend and a similar disparity between the two countries. It strongly suggests that even if the British had been able to reduce their mobility to Swedish levels voluntarily, it wouldn't have been enough to stop the rise in infections. This might be because of the B117 virus which is dominant in Britain or it might be something else. It could be any number of things. It is a reminder than Sweden and the UK are different countries. You cannot assume that what happens in one place will happen in another.

As I said in the debate, we tried a more 'Swedish' approach in December and unfortunately it didn't end well.


Wednesday, 24 February 2021

Zero tolerance for Zero Covid

Years ago I debated Gabriel Scally on the issue of plain packaging. He was wrong then and he's wrong now. He thinks the UK should pursue 'Zero Covid'. I explain why I disagree in this New Statesman article.
 

There is a belief among some people that the first lockdown could have achieved total suppression of the virus if it had only been kept in place a little longer. This is delusional. Lockdowns do not have a universal definition, but mine is the period between pubs being closed and pubs being open (along with the rest of the hospitality industry and it no longer being illegal to meet friends and family indoors). By this measure, the first lockdown in England lasted three and a half agonising months. Throughout this period, the case rate fell, but with diminishing returns. We never really got below 500 positive tests a day (and you can double that number because half the infections were not reported). The lowest number of total infections in England estimated by the Office for National Statistics was 14,000 on 9 July. 

We tried a lengthy lockdown, and we never came close to defeating the virus. Case numbers were roughly halving every four weeks. It takes a long time to get from a thousand to zero at that rate. A massive, Wuhan-style effort could have sped it up but there are a lot of people who cannot work from home and a lot more who are prepared to break the rules when they last for too long. We don’t have the geographical advantages of New Zealand or the ruthlessness of the Chinese Communist Party. We can’t even stop people entering the country on dinghies. 

Perhaps in June 2020, Boris Johnson could have persuaded a weary public to accept another few months of lockdown, along with even tougher restrictions. I somehow doubt it, but it doesn’t matter. We are not in that situation now. 

 




Tuesday, 23 February 2021

Nicotine pouches

The Observer has noticed nicotine pouches and it isn't happy.
 

Flashing an ice-white smile for her 50,000 followers on TikTok, a fresh-faced young woman pops a flavoured nicotine pouch into her mouth, as one of Pakistan’s most popular love songs plays in the background.

More than 3,000 miles away, in Sweden, another social media starlet lip-syncs for the camera, to a different pop tune. The same little pouches, made by British American Tobacco, appear in shot.

Critics say that such viral videos, even if they aren’t paid-for adverts, are the consequence of a global marketing push designed to offset dwindling cigarette consumption by recruiting the nicotine consumers of the future.

 
By that standard, I guess any social media post that shows a product counts. I don't know what the law is in Pakistan, but you can advertise snus in Sweden so I'm sure you can advertise a tobacco-free equivalent.
 

BAT makes much of how such products are helping adult smokers switch to less harmful alternatives, under the slogan “A Better Tomorrow”.

By 2023, the company expects to be targeting 500 million nicotine consumers with £100bn a year to spend. Products other than cigarettes are driving much of that growth.

 
Good! 

Financial results released last week showed an annual pre-tax profit of £8.7bn as “non-combustible” products began contributing to earnings for the first time. The number of customers using them jumped by 3 million to 13.5 million, as the pandemic sparked a migration from cigarettes to more lung-friendly nicotine-delivery methods.

 

Happy days. It's a win-win for business, consumers and 'public health'. 

But not in Observer world...
 

However, such products are far from risk-free and the trend for promoting them via social media and popular influencers is causing concern.

 
Not just not risk-free, but far from risk-free! So what, exactly, are the risks? Alas, the lengthy article never gets round to saying. Nor does it get round to naming the 'critics' who are 'concerned' about this, except someone from an organisation called Corporate Accountability which seems to be against big businesses in general.
 
The Observer article is based on an article from the 'Bureau of Investigative Journalism', the organisation that famously got Newsnight in a lot of trouble over Lord McAlpine and which is now funded by Mike Bloomberg to write anti-vaping pieces and be generally negative about tobacco harm reduction. It finds a critic from within 'public health', but it's just the corpulent know-nothing Martin McKee whose opinion is worthless.

The gist of it is that BAT markets its nicotine pouches and people under the age of 18 might try to buy them.

Lyft has no tobacco in it but does contain nicotine, making it an over-18s product. Yet multiple TikTok videos feature Swedes who appear to be of school age using them.
 
Do they, aye?

In Spain, a campaign for BAT’s heated tobacco product Glo has been fronted by boy band Dvicio, via Instagram and a series of concerts. The “boys” are all in their late 20s or early 30s, but were last year’s summer cover stars for tween magazine Like
 
This is lame stuff and BAT have responded with some fairly obvious points.

"Our social media accounts are age-gated so they are only visible to those users who have confirmed that they are 18+ (or other applicable minimum age),” it said.

The company added it was essential it marketed “reduced-risk” products so smokers were aware of them.

 
To be clear, these are good products. If anything, they should be advertised more. Everyone knows what cigarettes are but I bet most smokers are unaware of nicotine pouches. They are not 'far from risk-free'. They are as risk-free as nicotine patches, the only 'risk' being a caffeine-level increase in heart rate, as far as I can tell. They can't be sold to children and if adults want to buy them, that is up to them. End of story.