Tag Archives: public health

Don’t treat obesity as physiology or physics

I have a whole bunch of draft and outline blog posts from winter and spring that I was never able to find the time to finish off. To clear them out of the way, I’ve bashed out some half-hearted conclusions, and will post them this month.

Flicking through the pile of Natures that never got read properly, ready to be rid of them, I alighted on Gary Taubes’s opinion piece: Treat obesity as physiology, not physics. Bear with me while I appear to be completely off-topic talking science for a while.

Taubes argues that:

…obesity is a hormonal, regulatory defect… it is not excess calories that cause obesity, but the quantity and quality of carbohydrates consumed. The carbohydrate content of the diet must be rectified to restore health.

Taubes set out his case that it is not useful to think of obesity as a straightforward energy in/out imbalance that causes weight gain, but that it’s in understanding that specific forms of that energy — carbohydrates, and sugars doubly so — activate our body’s own fat accumulation systems (through the well understood insulin process) where solutions lie. You’ll be familiar with it from all that “Atkins diet” and “glycaemic index” stuff: energy in the form of carbs bad; energy from dietary fat not so much.

Taubes thinks this is important stuff because:

…the overeating hypothesis has failed. In the United States, and elsewhere, obesity and diabetes rates have climbed to crisis levels… despite the ubiquity of the advice that if we want to lose fat, we have to eat less and/or move more.

There is an obvious response to this, but Taubes pre-empts it:

Yet rather than blame the advice, we have taken to blaming the individuals for not following it ‘properly’.

Suggesting that Taubes thinks that if only we change the advice from “eat less and exercise more” to his “don’t eat high glycaemic index foods”, the advice will be followed and we will then succeed in defeating obesity.

I imagine any “advice” we give will be useless, whether it’s based on physics or physiology.

Because while obesity is about physics and physiology — and psychology and genetics and half a dozen other fields of science — none of those things explain what is important: why there is more obesity now than in the past, and how to make there be less of it in the future.

The laws of physics haven’t changed in fifty years. Physiology, and the genes that underlie it, can change — but only by evolution over the course of hundreds of generations, not a few decades. Sure, our bodies have a mechanism for turning carbohydrates into fat stores. But they always have.

The focus is on the quantity of energy in and the quantity out because that is what has changed during the rise of the obesity crisis. By all means refine that to a specific focus on an excess of high-glycaemic index foodstuffs and a deficit of burning off specific sugars, but the problem that really matters remains fundamentally not one of physics or physiology but of our environment.

Taubes is right to treat those who “blame individuals for not following the advice properly” with contempt. But not because the advice is wrong. Because any “advice” — right or wrong — is going to be useless. This is not a problem that individuals have created for themselves, and it’s not a problem that individuals can be “advised” to solve for themselves. This is a problem of the environment that we live in: the types of food that are available to us, and the opportunities for an active healthy lifestyle that have been taken away from us.

Taubes later uses an analogy with smoking and lung cancer, and the analogy perfectly describes what’s wrong with the idea that obesity should be treated as a physiology problem. We know a great deal about the physiology of smoking-related lung cancer. We know how all of the many different carcinogenic chemicals within cigarette smoke flow through the lungs and pass through membranes into the cells. We know the chemical reactions that they participate in and how those reactions cause damage to the cells’ DNA. We know exactly which pieces of DNA damage result in the harmful mutations that transform them into cancer cells, driven to grow and divide. We know exactly how those mutations — to genes with names like RAS and RAF, and EGFR and a dozen others — change the shape of the proteins that those genes encode, and why that change of shape causes those proteins to misbehave. We know how these things result in the tumour evading the body’s inbuilt defences, how they hijack the blood supply to allow their expansion, and how they go on to invade and destroy neighbouring tissue and eventually escape and metastasise.

And knowing these things about physiology makes not the slightest difference to solving the smoking problem. Smoking-related lung cancer, like obesity, is a process of physiology. But it’s a problem of environment. And the most important lesson from smoking for obesity is that you can’t solve a problem environment with advice alone. Bad lifestyle choices are not an individual failing. Good lifestyle choices need an infrastructure to support them.

Prevention and cure

While organising notes, I stumbled upon this quote I bookmarked years ago, from the great Harvard cancer biologist Judah Folkman:

A pediatric surgeon in Boston just finished a difficult operation. To relax, he went to the Charles River and sat down on a bench. Suddenly, he heard cries of ‘Help! Help!’ and saw a person drowning. The surgeon jumped into the river and pulled the person to safety. He lay exhausted on the banks of the river and again heard, ‘Help! Help! ’ He glanced at the river and saw another person drowning. Despite his exhaustion, he jumped into the river and pulled the second drowning person to safety. Now, he was truly exhausted and lay on the ground huffing and puffing and again heard, ‘Help! Help! ’ He raised his head to look toward the river and saw a third person drowning, but he also noticed two basic researchers walking by the river. The surgeon shouted, ‘Colleagues, you must help! This is the third drowning person in the river in one afternoon! ’ The researchers looked at the river and then at the surgeon and said, ‘Three people drowning in one afternoon? This is very interesting! We’ll walk upstream to see who’s throwing them in!’.’’

(I think actually that it would work better if cast with public health researchers in place of basic researchers. The basic researchers would be too busy describing in obscure detail of the currents of the river, while translational researchers designed a better buoyancy aid for those currents.)

Folkman was applying the metaphor to his own field, cancer, but it works equally well for death and injury on our streets. The “road safety” approach to the problem has people studying the currents and advocating hi-viz vests and bicycle helmets, while spending billions on air ambulances and major trauma units. The “road danger reduction” approach goes upstream and asks why we are allowing large volumes of fast moving vehicles into the places where we live and work and play and learn. And it’s notable that in medicine, it’s the surgeons who think that preventing injury means bicycle helmets, and the public health researchers who think that preventing injury means calming and removing cars and trucks.

Here are a few of them: Danny Dorling talking about the open sewers of the 21st century; Harry Rutter’s Street Talk on moving towards a healthier city; and Ian Roberts, acting badly, on The Energy Glut. And you can hear Robert Davis talking about “road danger reduction” at London South Bank University on thursday next week.

During the 20th century, life expectancy lengthened by 30 years in the developed world. 25 of those years are attributable to public health intervention — to prevention rather than cure. But prevention disproportionately helps the poor and frequently hinders the rich. Guess which branch of medicine gets all the money.

In which the EU nudge the coalition* to quietly save a lot of lives

To transport nerds like me and Tom, something stood out in Simon Birkett’s Street Talk about air pollution in London:

When you map air pollution levels in central London you get an only very-slightly fuzzy road map, of course. But that other thing — you see the other thing, more polluting than anything else on the map?

You can see it when you look at the whole city — three things that aren’t roads clearly stand out:

Well one of them is obviously Heathrow Airport, way out west, but those other two…

It’s those old Intercity 125s, high speed diesel trains on London’s remaining major non-electrified railways** — the Great Western into Paddington, and the Midland into St Pancras. You might also spot a lesser line, the Chiltern to Marylebone (Waterloo, Euston, and King’s Cross also still get a very small number of diesels, but not enough to leave any obvious trace on the map).

Makes one wonder how bad the air is in Bristol and Cardiff, where all the trains are diesel.

For most of the day, Paddington hosts half a dozen or more old Intercity 125s each hour from the Westcountry and South Wales. That’ll change when lines to Bristol, Cardiff and Oxford go electric over the next few years. The long distance trains will either be electric, or bizarre hybrids that will burn fuel only where the power lines run out on a few routes.

The £1 bn electrification of the Great Western lines is being sold by Philip Hammond and the DfT almost entirely as an investment to improve speed (always the obsession with speed!) and capacity — the electric trains will accelerate faster, cutting perhaps as much as a fifth from the journey time when combined with other line upgrades. (Trains to Swansea will have to be bizarre hybrids, carrying the dead weight of fuel and engines all the way from London, because the final few miles beyond Cardiff won’t be electrified on the grounds that there are other physical constraints on journey times between Swansea and Cardiff — always the obsession with speed!)

But crucial to the electrification project are EU carbon emissions and air pollution regulations, both of which are tightened again next year: they make it more expensive to build and buy compliant diesel engines, and they mean that money is thrown away on mitigation and fines, costs which seal the case for electrification. Without such regulations pushing up the cost of diesel, the current occupants of the Treasury would never have agreed to spending the money on wires.

And yet the fact that electrification will reduce the incidence of childhood asthma and horrible deaths from respiratory diseases in Cardiff and Bristol and West London doesn’t seem to be something that the government wants to boast about. To boast about solving air pollution would require first that the government publicly acknowledge the frightening scale of the air pollution problem — and then that they acknowledge that, without the EU, they never would have bothered solving it.

* After six Labour transport secretaries did nothing, the final one, Adonis, succeeded in getting electrification announced, only for an unfortunate general election to fall between the announcement and his being able to implement it.

** Yes, I know they are both electrified within London for some commuter services.

Second hand; unused

Thinking about how the Cycling Embassy might go about trying to generate political will to progress cycling, I’ve been researching previous failed attempts to advance cycling in this country.  So on Amazon I snapped up a second-hand copy of an out-of-print British Medical Association book written in 1992: Cycling: towards health and safety.

People in Public Health are very interested in the bicycle because it keeps you fit — thus reducing incidence of obesity, cardiovascular disease, cancer, diabetes, dementia, depression, etc, etc — in a way that can be effortlessly integrated into everyday routines.  And because it provides an alternative to transport modes that cause thousands of hideous traumatic deaths and injuries, even more air pollution-related deaths, isolation-related mental ill-health, and so on.

From a quick flick through, I’m expecting all that to be covered, in addition to a section on “barriers to cycling” which looks like it might cause a cardiovascular event itself by chatting about the weather while ignoring the elephant in the room.

But also when I quickly flicked through, I noticed I was breaking the spine.  This second-hand book has never been read, never been opened except to stamp “date of cataloguing 14 May 1992″ and “disposed of by authority” on the inside cover.  Where does this never-before-read book make its way to me from?

Perhaps it’s for the best.

A vaccine for road safety

I stumbled upon this infomercial from BBC World while looking for something to entertain me over dinner:

It’s always fascinating to see how a television documentary treats a subject that one has spent some time looking at — in this case, motor vehicles and public health.

The one little specific aspect of motor vehicles and public health that the documentary looks at is the problem of “road safety”, particularly in the poorer parts of the world.  Well over a million people die on the world’s roads each year, disproportionately poor people killed by or in the name of rich people, putting road danger alongside those similarly neglected poor people’s problems, malaria and tuberculosis, in the public health league tables.

The documentary looked at the sort of interventions that can be made to reduce road deaths.  They are interventions that the UN has backed as part of the “decade of action” on road safety, and which the World Bank is now helping to fund.  They seem to fall into two categories: engineering and education.

The reasoning behind an engineering campaign is that it has been observed that some road designs see more deaths than other road designs.  Motorways, with their regimented traffic, central reservations and hard shoulders, have fewer fatalities than roads that pitch opposing traffic head on, separated only by a bit of paint.  Therefore, the World Bank will replace the dangerous streets and roads of the developing world with motorways.  Some of you might already be mumbling something about confounding variables, and safety being achieved simply by driving vulnerable road users away with hostile environments, but shut up you ingrates, it’s a gift, for their safety.

Unfortunately, they are discovering that even when you build these fantastic new eight-lane highways, no matter how much you teach the kids the green-cross code, the bloody fools still misuse them. “The irony is, that freeway is supposed to serve the people, in whatever form that takes.” So the kindly international road safety folk are building pedestrian overpasses. They’re not even going to ask why people are trying to cross their shiny new road. Are they trying to get to their workplaces? Their school, or shops, or market? Their few remaining fields? What kind of a moron builds their house on one side of a motorway and their school on the other?  You might ask whether it’s worth expending money on people who make such an elemental mistake.  But the road safety folk are so nice they will provide a foot bridge just like that — no awkward questions asked.

The reasoning behind an education campaign is that it has been observed that many of the people who are dying are pedestrians and “two-wheeler” users, doing silly reckless things like running from one side of the road to the other, or putting themselves in the way of vehicles without first encasing themselves in armour.  Did you know that in some of these countries they don’t even have hi-viz?  Even some drivers are endangering themselves by not wearing a seatbelt.  The only possible conclusion is that these people are ignorant of the risks that come with running across a motorway, and the benefits to be had from wearing helmets and seatbelts.  If only we could reach out and let them know…

“Enforcing drink driving laws, making people wear seatbelts, toughening up on vehicle maintenance standards, these are all basic affordable things,” the presenter tells us.  If only our own government thought so.

Unfortunately, enforcement seems to be a slip of the tongue.  This doesn’t appear to be about enforcing drink-driving and seatbelt laws, but about educating people about the dangers of drink-driving and the merits of seatbelts.  And simply telling people how to do something that they don’t want to do is at best an inefficient route to behavioural change.  This has been shown time and time again, study after study shows that telling people — whether child pedestrians or experienced drivers — to do specific things in order to be safe on roads just doesn’t work.  (See e.g. the review drawn up for NICE, the UK body which decides whether proposed health interventions are worthwhile.)

The one thing that road safety education does achieve, of course is good PR for the company that is funding it.

The BBC documentary doesn’t say who is behind all this stuff. A few representatives of development NGOs pop up, we visit the UN, who have put their name to the “decade of action”, and we know that the World Bank will be amongst those building roads. But we don’t really hear from the concerned and benevolent folk who persuaded the UN and World Bank to spend all this money on bigger safer roads.

Michelle Yeoh, presenter of the BBC item, is global ambassador for road safety at the “Make Roads Safe” campaign.  That campaign is the public facing side of the “Commission for Global Road Safety”, itself a part of the FIA Foundation.  The FIA Foundation in turn being the independent charity funded by the Fédération Internationale de l’Automobile, the international automobile lobby.

Ian Roberts describes who the commissioners on the Commission for Global Road Safety are:

Canada is represented by an Executive Director at General Motors, Japan by a Board Member of the Bridgestone Corporation, the major trans-national tyre maker. Russia is represented by the President of the Russian Automobile Federation and Italy by a former president of the Automobile Club of Italy. Michael Schumacher represents Germany and France is represented by Gerard Saillant, Deputy President of the FIA Institute, another FIA creation and responsible for the medical aspects of Formula One. The UK Commissioner is the Chief Economist at Lehman Brothers, a US investment bank with financial links to Formula One. The US Commissioner is Director of the Global Road Safety Forum, an organization funded by the FIA and one of the ‘implementation partners’ that the Commission works with. The Commission’s Patron is Prince Michael of Kent, a former racing driver, now a member of the British Racing Drivers Club and the Bentley Drivers Club. Lord Robertson himself is Deputy Chairman of the Board of TNK-BP, a Russian oil company. According to the Lords’ Register of Interests, which shows that the FIA paid for Robertson to attend the 2006 Monaco Grand Prix, the Commission meets at the races.

In a response to Roberts’ paper about the Commission, the FIA Foundation reminded us that it “has no relationship with industry whatsoever”.

At Bath Skeptics, Ian Walker, referring to British road conditions, stated that anybody who has to use the roads as part of their job is working in Dickensian conditions.  Health and Safety regulation means that death in the workplace is exceptionally rare in Europe today, and when it does occur, it is typically followed by extensive investigation to discover what went wrong, whether anybody was to blame, and how to prevent it ever happening again.  Unless the workplace is a road, in which case death is routine, nobody is to blame, and nothing can be done about it.  If you drive as part of your job, you are expendable labour.

One of the reasons that Europe’s workplaces are so safe, of course, is because we have simply outsourced the dangerous jobs.  The poor of Africa and Asia, free from health and safety laws, are mining our minerals and weaving our clothes for pennies, working in real Dickensian conditions, and the World Bank needs to build big roads so that they can drive the products to the docks.  Like Victorian mill-workers, the third world should be grateful for the kindness showed by their new bosses in providing such safe new roads, servants of the people.

Passive driving

“The ideal of the ethical man,” wrote the great Victorian scientist and liberal Thomas Henry Huxley, “is to limit his freedom of action to a sphere in which he does not interfere with the freedom of others.”

At Bath Skeptics in the Pub in April, Ian Walker talked about transport-related (ir)rational behaviour and policy.  One of the ideas he talked about was “passive driving”.  The analogy, of course, is to passive smoking.  Every time a smoker lights up in a restaurant or pub or club, the health and life expectancy of all the diners, punters, and staff around that smoker takes a tiny hit.  And those people get nothing positive in return.  In a liberal society, we defend the right of smokers to give themselves horrible slow fatal diseases.  But we expect them not to interfere with the rights of everyone else to their health.  And on the occasions when they can not show that restraint voluntarily, we have to resort to legislation banning smoking in restaurants and pubs and clubs.

Similarly, every time you get into your car and fire up the engine, my health and life expectancy takes a hit, and I get nothing in return.  You get to work or to the shops or to a day out, but I get nothing except a reduced life expectancy. Every time you get in the driving seat, you are making the decision that your journey is worth more than my and everybody else’s health and wellbeing. How big a problem is it?

Well, before the ban on smoking in enclosed public spaces and workplaces, estimates were that around 600 people in the UK were dying prematurely each year because of exposure to second-hand  tobacco smoke in those environments.

Exposure to driving in the UK annually causes:

  • over 2,000 deaths in what the DfT describe as road “accidents”, of which less than half are of car users (stats for drivers and passengers are, sadly, all combined). Around 500 pedestrians, just over 100 cyclists, around 500 motorcyclists and a few bus and coach passengers are killed in “accidents”.  A few of those deaths will have nothing to do with cars — indeed, some genuinely will be “accidents” — but most are in some way the consequence of other people choosing to get in a car, a choice that would never bring any benefit to the person killed. As Harry Rutter pointed out at Street Talks, pedestrian deaths are particularly high in children, the elderly, and the lowest socio-economic groups: people to whom the benefits of car use are often out of reach, but who have to suffer the negative consequences regardless.  Motor vehicles are the biggest cause of death in teenagers, who should have a large proportion of their lives ahead of them, arguably making road “accidents” a more important issue than diseases which kill late in life and thus take away fewer quality life years.
  • Air pollution is not a fashionable topic, yet estimates of UK deaths attributable to it are even higher than for crashes, ranging from 12,000 to 35,000. Motor vehicles are not the only contributor to air pollution, but they are the major one.  Air pollution is especially a problem in cities, paradoxically the places that usually have the highest proportion of non-car users.  People living happily in cities without a car — who have perhaps even made the conscious decision to live somewhere within walking or cycling distance of employment and shops and services — again have to deal with the negative consequences of people driving into and through their city.
  • Diseases associated with obesity and sedentary lifestyles are amongst the biggest killers of our time: cardiovascular disease, cancers, diabetes, even dementia.  We know that these diseases can be prevented or delayed by regular exercise — cycling, for example — and that exercise is therefore one of the biggest predictors of life expectancy.  But while a great many people in the UK would like to be able to make their regular short journeys by bicycle (not so much because they worry about their health, but because it’s cheap and simple), very few do.  The overwhelming reason people give for not cycling is that the roads are far too uninviting: because they’re full of fast moving and badly driven motor vehicles.  Every time somebody chooses to drive a car, the rest of us get none of the benefit, but we do get dangerous, intimidating, noisy and smelly streets, in which normal people will never want to ride a bicycle.

That’s just to list the obvious ways that other people choosing to drive has negative health consequences for you and me.

I was reminded of all this because today the Association of British Nutters Drivers are back in the news demanding their freedoms.  Nurse turned Tory MP, and now parliamentary under-secretary of state for health, Anne Milton said last week that allowing residents to close their residential streets to motor vehicles on sundays so that their kids can go out and play might be a good thing.  The ABD are said to be amazed that their freedom to drive wherever and whenever they like might, for just one day a week, come second to other people’s freedom to choose how to use just a little bit of their own neighbourhood. Once again, the ABD behave like spoiled children, throwing their toys around when told it’s somebody else’s turn to play.

The ideal of the ethical man is to limit his freedom of action to a sphere in which he does not interfere with the freedom of others.  The Association of British Drivers fail at this most basic principle of ethics.

@bengoldacre on bicycles

Like my googlereader and my drafts folder, my podcast app has a frighteningly large backlog.  This evening while on random play it stumbled on an episode of Little Atoms from 2008, with Ben Goldacre, in which he talks about the media’s obsession with simple, glamorous and individualistic quick fixes to complex social problems:

The idea that food, and particularly very specific individual types of food or specific molecules in food, are the most important lifestyle risk factors for ill-health is itself a very political and I think bogus project. The reason that people in Hampstead live ten years longer than people in Kilburn isn’t because they’re careful to eat a handful of brazilnuts every day to make sure sure they’re not deficient in selenium, it’s because of a whole complex nexus of complex interlocking social and political issues involving, you know, work exposure, social support, stability and all of that stuff.

To profess to people that these commodifiable lifestyle interventions — because it’s always those, it’s never, you know, walking schoolbuses or cycle paths, it’s always, you know, cherry juice, something that a press agency can put a release out about — to pretend that diet is the biggest lifestyle risk factor for ill-health is to my mind a very right-wing individualist manifesto.  It’s the deserving sick in the way that people used to talk about the deserving poor.  You’ll be chatting to somebody and they’ll say, “well, I have to walk past this council estate every day on the way to the tube and you can say what you like but I think it’s got to be diet because you see some of these people and they’re feeding their kids crisps for breakfast and they’re only three and it’s got to be diet hasn’t it?”  Well, yeah, diet might be part of it, but I think you’ll find it’s a bit more complicated than that.

[…]

All the evidence shows that public health interventions that have an effect on the health of a whole population are things that you do or change at the level of the whole population.  You know, change what’s available in the supermarket.  People eat what’s available to them easily and people behave in ways that are easy for them to behave.  So, say, if you make London a really hostile environment to cycle in then people won’t cycle in it.  If you design stupid cycle paths, some of which — I could show you photographs — are shorter than the length of a bicycle; if you put bicycle paths right next to a set of parked cars, so that if you cycled in it then every time somebody opened a door you would just die, but if you cycle outside it then all the cars get really indignant and beep their horns because they think that you should be in the little green cycle path then, if you do all of that then people will cycle less and people will be less healthy in your capital.  Whereas if you make excercise something that can be integrated naturally into people’s everyday lives then people will become healthier.

But fascinatingly all over the country there will be people who are working as public health professionals who will be sending out press releases saying, oh, we’re trying to get a walking schoolbus scheme together locally so that people don’t have to drive their children into obesity by driving them to school, and they’ll maybe use a little pun like that and feel really pleased with themselves, but they’ll be ignored and local papers won’t cover it and national papers won’t cover it, because newspapers want the goji berries, they want the glamorous easy quick fix.

It seemed an appropriate thing to share ahead of tonight’s Street Talk at the Yorkshire Grey, where Harry Rutter will be talking about the relationship between urban design and public health.

Sadly we have a society — or a media, at least — that does not merely ignore these projects in favour of glamorous miracle cures: we actively cry “state intervention” at anything that might make the world a better or nicer place.