Saturday, 23 May 2015

God, evolution, global warming and heart disease: a personal reflection on population health

An ‘inaugural’ lecture given in the Nuffield Department of Population Health at the University of Oxford, on 18th May 2015,  for my Professorship in Population Health.  For the slides see: here .

In general I think you should never apologise when giving lectures but I am going to start this lecture with three apologies.

Firstly I know that it is conventional to give lots of acknowledgements in an inaugural lecture but I only have two: firstly to the University of Oxford, and in particular Professor Rory Collins, for awarding me this professorship and secondly to the British Heart Foundation for paying my salary for the last 22 years.   There are too many other people I should thank so to avoid missing people out I will stop there.  Sorry.   I will however in the course of this lecture acknowledge some of the people who have affected my thinking about population health.

Secondly I also know that it is conventional to try to be inspirational in an inaugural lecture.   I would like to be inspirational but my trajectory from DPhil student in the Department of Zoology to Professor of Population Health has hardly been ‘conventional’ and I would not advise anyone else to follow my example.  So I am sorry if you’d come to this lecture hoping to hear some tips on how to become a Professor of Population Health.  I do however hope to inspire you to think differently about population health.

Thirdly this lecture is more valedictory than inaugural.  This seems to inevitable given that I have been working in the field of population health for about 30 years and by my reckoning I have less than ten years left.    I have fought against the consequent temptation to be self-referential and even worse self-indulgent but you’ll see that I haven’t been able to resist these temptations completely.   Sorry.

I have chosen as the title for this lecture God, evolution, global warming and heart disease, not because I am an expert on these four things but because all four topics have figured extensively in my intellectual life: much as particular songs or pieces of music provide the sound track of one’s general life.   Incidentally the actual piece of music which has done this most for me is ‘Without You’ by Nilsson.   Don’t’ worry I won’t be playing you a clip: that would just be too self-indulgent.    I guess we all have many pieces of music that provide the sound track to our lives and there are more topics I could have included in this list: foods and diets being an obvious one. 

These four topics of God, evolution, global warming and heart disease do I think have a relationship with population health and the aim of lecture is merely to persuade you that they do.  It is clearly obvious that heart disease is relevant to population health but, of course, less so when it comes to God, evolution and global warming.

[OHP] Here then are four paintings of God, evolution, global warming and heart disease.  Three of these paintings were painted by my friends for me.  Top left is a painting of Jesus’ miracle of turning water into wide at a wedding at Cana which hangs in my office.  It depicts God in the shape of an actual living person – I don’t know his name - who represents Jesus, second from the left.   God has always been an important topic in my life.  So much so that I became an Anglican priest in 2008 as many of you know.  Theologians have much to say about health.

Top right is a painting by Desmond Morris that illustrates the front cover of the first edition of a book called ‘The Selfish Gene’ by Richard Dawkins.  The Selfish Gene was published in 1976 while I was studying for a degree in Zoology here at Oxford and I had some tutorials with Richard Dawkins.  I think the book has been very important in the way we think about many things including health: perhaps even comparable in its influence to Charles Darwin’s ‘On the Origin of the Species’ published in 1860.   I do not think the influence of either book has been good.

Bottom right is a painting entitled ‘Global Warming’.  Since around the mid 1990’s - through meeting an energy scientist called Alwyn McKay who had worked with Nils Bohr in Copenhagen.  I have increasingly come to see that that global warming is a much bigger problem for the human species than anything else including heart disease.   And this has had an influence on my perspective on population health as I’ll briefly explain later

Finally the last painting, bottom left, is entitled ‘Heart Disease’   Heart disease is a topic that I have been concerned with since 1986 when I joined the staff of a non-governmental organisation called the Coronary Prevention Group.    I guess this picture’s does not make for comfortable viewing but it reminds us that heart disease isn’t in the end a comfortable subject – it affects people we know and love including some of us here.  It is an evil that many in this department of population health are seeking to eradicate or at least to ameliorate.  

This picture obviously has both theological and biological references: the three hooded figures represent – at least to my way of thinking - three of the four horsemen of the apocalypse in the book in the Bible called the Revelation to John – and the yellow gunge the cholesterol laden plaque that clogs up coronary arteries thereby causing heart disease. 

Before moving on the relationship between God, evolution, global warming and heart and population health I fell a need to provide you with a definition of population health. Here is my definition: [OHP] 'The science and art of preventing disease and promoting health through the organized efforts of society, organizations, communities, families and individuals'.

For those of you familiar with definitions of population health and what it used to be called - public health - you’ll note that this definition is basically the same as that of Charles-Edward Winslow dating back to the 1920s[i] and also that of the Faculty of Public Health – the standard setting body for specialists in population health in the United Kingdom - although with some modifications of my own.  

An important thing to note about this definition is that it regards population health as both a science and art which suggests that the arts have just as much to contribute to population health as the sciences.   By arts I do mean art, but also literature, myth and history which I’ll come on to later.  The definition also makes it clear that, when it comes to disease, population health is about prevention rather than cure.   This definition also begs the questions of what we mean by disease and health. Here the World Health Organization’s definition of health is, I think, useful. [OHP]t hat is that: ‘Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.’

The word to note here is social.   From this definition it follows that health is not just something individuals might aspire to but also groups or populations i.e. families, organisations – such as this department, communities and indeed societies and from this it can be argued that: [OHP] The health of a population is not just the sum of the health states of the individuals within that population.

Now I know it will sounds odd to some of you to suggest that groups rather than individuals can be healthy or unhealthy, and even odder to suggest that the health of a population is not just the sum of the states of health of the individuals of which it is composed.  But for me these ideas are at the heart – forgive the pun – of population health and distinguishes it from medicine which might be defined as the ‘science and art of treating and alleviating the disease of individuals’.  

Do we have any evidence to suggest that the health of a group is not just the sum of the health states of the individuals within that group?   Well I think we do in the work of various population health scientists and most strikingly in the analyses of Richard Wilkinson and colleagues.    To take just one example: [OHP] Here is a graph of income inequality against infant mortality in rich countries.   Each point represents a country.  The countries with the greatest income inequality such as the US are to the right.  The countries with the least income inequality such as Sweden and Japan are to the left.  It shows that there is a relationship between income inequality and infant mortality with countries having the greatest income inequality experiencing the greatest infant mortality.

Now it is important to note that the X and Y variables on this graph are not the properties of individuals but of societies.  Income inequality can only be measured when you have two people at least, in relationship with one another.   Income inequality can be experienced by an individual but only when another individual is present.   Similarly, but perhaps less obviously, the infant mortality rate of a county can only be measured when there is a group of individuals in which more than one child dies and the same may be said of any disease rate. 

I think the properties of groups and their relationship to health is an important area for future research.   Of course societies are clearly not merely defined by how unequal they are.   But this area of research has been hampered by the notion that there is no such thing as society – as articulated by Margaret Thatcher in a famous interview given to Women’s Own in 1987. [OHP]

She said in this interview: "They are casting their problems at society. And, you know, there's no such thing as society.. There are individual men and women and there are families. And no government can do anything except through people, and people must look after themselves first. It is our duty to look after ourselves and then, also, to look after our neighbours."

Of course population health does not merely aim to describe the healthiness or otherwise of individuals and populations but to do something about what is observed.   In addition it is worth emphasising [OHP] that population health aims to improve the health of groups: societies, communities, organisations, families and not just individuals.  Public health is therefore concerned with both problems and solutions.   Incidentally some of us think that population health research spends much too much time on the problems and not enough on the solutions but I do not have time to go into that issue today.

Turning again to my definition of population health.  Another important couple of words in this definition are ‘organised efforts’.   What are organised efforts?  At this point I can’t resist the temptation to show you my favourite diagramme of the complexity with which population health must deal.  [OHP]  This is a map of the causes and possible solutions of just one population health problem: obesity.  It was produced by the UK Government’s Foresight Programme for the Government Office for Science in 2007.   I say favourite but actually I think it obfuscates rather than enlightens.  To me the solution to the problem of obesity is simple as many of you will know.   My solution is to tax sugary drinks.   Although I acknowledge that this isn’t going to be the only measure necessary.

There is no mention of sugary drinks in this map let alone sugary drinks taxes.  The closest you get to that is ‘the market price of food offerings’ circled here.   Rather strangely you get a whole section of the map devoted to ‘self-esteem’ and ‘psychological ambivalence’ shown here.  There is even a box for ‘genetic and epigenetic predisposition’ shown here.   But how, I ask, does knowing that there is a genetic predisposition to obesity – which there probably is - help generate a solution?

A better way of explaining the organised efforts necessary to prevent obesity and indeed the organised efforts necessary to prevent disease and promote health as a whole is a poem called ‘The Fence or the Ambulance?’ by Joseph Malins written in 1895.  I’ll read it to you.

Twas a dangerous cliff, as they freely confessed,
Though to walk near its crest was so pleasant;
But over its terrible edge there had slipped
A duke and full many a peasant.
So the people said something would have to be done,
But their projects did not at all tally;
Some said, "Put a fence 'round the edge of the cliff,"
Some, "An ambulance down in the valley."

But the cry for the ambulance carried the day,
For it spread through the neighboring city;
A fence may be useful or not, it is true,
But each heart became full of pity
For those who slipped over the dangerous cliff;
And the dwellers in highway and alley
Gave pounds and gave pence, not to put up a fence,
But an ambulance down in the valley.

"For the cliff is all right, if you're careful," they said,
"And, if folks even slip and are dropping,
It isn't the slipping that hurts them so much
As the shock down below when they're stopping."
So day after day, as these mishaps occurred,
Quick forth would those rescuers sally
To pick up the victims who fell off the cliff,
With their ambulance down in the valley.

Then an old sage remarked: "It's a marvel to me
That people give far more attention
To repairing results than to stopping the cause,
When they'd much better aim at prevention.
Let us stop at its source all this mischief," cried he,
"Come, neighbors and friends, let us rally;
If the cliff we will fence, we might almost dispense
With the ambulance down in the valley."

"Oh he's a fanatic," the others rejoined,
"Dispense with the ambulance? Never!
He'd dispense with all charities, too, if he could;
No! No! We'll support them forever.
Aren't we picking up folks just as fast as they fall?
And shall this man dictate to us? Shall he?
Why should people of sense stop to put up a fence,
While the ambulance works in the valley?"

But the sensible few, who are practical too,
Will not bear with such nonsense much longer;
They believe that prevention is better than cure,
And their party will soon be the stronger.
Encourage them then, with your purse, voice, and pen,
And while other philanthropists dally,
They will scorn all pretense, and put up a stout fence
On the cliff that hangs over the valley.

Better guide well the young than reclaim them when old,
For the voice of true wisdom is calling.
"To rescue the fallen is good, but 'tis best
To prevent other people from falling."
Better close up the source of temptation and crime
Than deliver from dungeon or galley;
Better put a strong fence 'round the top of the cliff
Than an ambulance down in the valley.

But to return to my title: what have God, evolution, global warming and heart disease got to do with population health?  I’ll take each in turn.

The easiest of these topics to deal with is heart disease because it is self-evidently a population health problem.  And I am going to take it as read that it can be prevented by improving our diets, increasing our levels of physical activity, smoking less and reducing our consumption of alcohol.

As I said heart disease is an issue that I have been concerned with since 1986 when I joined the staff of the Coronary Prevention Group.  In that year coronary heart disease was responsible for about 180,000 deaths a year in the UK and we could confidently say that coronary heart disease was the UK’s Number 1 killer.   In 2012 coronary heart disease was responsible for 74,000 deaths and now even the British Heart Foundation concedes that cancer is the UK’s Number 1 killer with nearly 166,000 deaths a year.  

Can we explain this success story?  Here are some slides from a paper I contributed to.   It was published in the British Medical Journal in 2012 and the first author was one of my DPhil students – Kate Smolina.  The first slide [OHP] shows this decline in deaths from heart attack – the most acute form of coronary heart disease - between 1999 and 2007.  The blue line shows the decline in deaths from heart disease overall, the green line shows deaths from heart disease in hospital and the red line deaths out of hospital.  So the decline in overall deaths has had nothing to do with improving hospital care.  Your chance of dying from a heart attack if you reach hospital hardly changed over that time.

So what was happening which led to this rapid decline in people dying from heart disease out of hospital.  This slide [OHP] shows that it was two things: the number of actual heart attacks was falling – the event rate as described in this slide - and people were living longer after their heart attacks: case-fatality, as it’s called here, was improving.   So why was event rate declining and case fatality improving?   I still think this question lacks an entirely satisfactory explanation.   My friend Simon Capewell has tackled it but I don’t think he, or anyone else, as yet has given us the full answer.

What we can say is that it wasn't just down to the increasing use of statins and other drugs that reduce your risk of a heart attack.   Here is a slide I have borrowed from Richard Peto [OHP].  It shows the decline in vascular mortally as a whole: i.e. deaths from both heart attacks and strokes for the past 50 years.   And here is the date of the publication of the first major study showing the effectiveness of statins as a drug that reduces your level of blood cholesterol and thereby your risk of vascular disease [OHP].   You can see that this trial was published long after the decline in vascular mortality began.

Oh here [OHP] is the Daily Mail’s explanation of our results published in the British Medical Journal.  For once I think they got it about right but we didn’t actually say this in our paper.  Their headline was – for those who can’t read it – ‘Heart attack deaths halve in eight years due to fewer smokers, better diet and improvements to care.

We have come a long way – in past 30 years - in our understanding of the causes of and remedies for heart disease as illustrated by this bill-board advert from 1994 [OHP] – when I’d just left the Coronary Prevention Group – to start what has become the British Heart Foundation Centre for Non-Communicable Disease Prevention.   The advertising campaign used statistics from a compendium of statistics on heart disease which the Centre had produced for the BHF.  We have continued to produce such a compendium since 1993, but it is inconceivable that the BHF would use the slogan ‘Cross your heart and hope not to die’ nowadays

How we explain things brings me to the next issue in my title: God or rather theology.   But firstly I want to say something about other ologies besides theology and their contribution to population health. 

I think we often suffer from a limited understanding of what counts as an explanation.   Scientific explanations are not the only sort of explanations we need to help us live our lives. A framework for thinking about different types of explanations is provided by the philosopher Ken Wilber in his book ‘A theory of everything’ [OHP].    Wilber divides theories into four types: individual objective, group/objective, group/subjective and individual/subjective.    An easier way of understanding this classification of theories is to show how different disciplines or ‘ologies’ can be classified by this framework [OHP]. 

So physiological theories are archetypical individual/objective theories – aiming objectively to study individual bodies.  Modern day psychological theories are generally of the individual/objective type though in the past they were more subjective [OHP].   Epidemiology is the discipline that is most associated with population health.   It too seeks objectively to study individuals – in particular their health status – but as I have suggested earlier – sometimes seeks objectively to study the health of groups – and indeed in my opinion it should do more of that.   In this it touches upon group/objective theories such as those generated by sociology [OHP].  Sociology is a discipline that seeks to explain – largely objectively (at least almost everywhere except France) the characteristics of groups and in particular societies.

So In the two right hand quadrants we find disciplines that primarily rely on objective knowledge and on empirical data, preferably quantified and ideally from experiments.  In the two left hand quadrants we have disciplines that rely primarily on subjective understanding and on story rather than numbers.

Theology - top left – within which I would include atheistic theologies (if that isn’t a contradiction in terms) as well as theistic theologies – generates the archetypical individual/subjective type of theory.  But there are also theories which can be described as group/subjective theories: such as historical theories – bottom left.  Theology is generally thought of as seeking to explain the individual’s subjective experience of their place in nature, his/her relationships with others including God, etc. but it, like epidemiology should, in my view, be more concerned with the collective experience.

Of course this classification of ologies is hugely simplistic and many of you will object to where I have put your favourite disciplines.

So how does all this relate to the problem of heart disease?  Well firstly different types of theories to explain the problem, in actual fact, seek to address superficially similar but actually very different questions [OHP].  For example in relationship to heart disease, individual objective theories might address the question: Why does he/she have heart disease?  Group objective theories: Why do they (as a group) have heart disease?  Group subjective theories: Why do we (as a group) have heart disease?  And individual subjective theories: Why do I have heart disease?    

[OHP] Physiology tells us how heart disease is a result of cholesterol laden plaque building up in arteries sometimes breaking away to form a clot that blocks a coronary artery bringing oxygen to the heart.  [OHP] Epidemiology gives us some answers to the question of why heart disease is more prevalent in certain groups rather than others (incidentally these are some results – published only the other day – but similar to those I showed you earlier about income inequality and infant mortality).  OHP] History explains how we as a society – such as that of the UK - have become defined by our patterns of consumption – many of which turn out to be bad for us – for example our tendency to over consume high sugar foods, leading to overweight and obesity and in turn to heart disease.   [OHP] Theology seeks to explain why human beings suffer: suffer from diseases such as heart disease.   In Christian theology the reasons for suffering are addressed in the book of Job and in the sayings and stories of Jesus – both his parables and the narrative of his life.  

Different ologies bring different answers to the problem of heart disease but also propose different solutions.  [OHP] Physiology suggests tackling the build up of cholesterol in arterial plaque through dietary change or pharmacological treatment.  [OHP] Epidemiology suggests that policies which affect income distribution may have the additional benefit of reducing overall rates of heart disease.   This is a picture of students celebrating the fact that the University of Oxford has signed up to being a Living Wage employer.   [OHP] History suggests that we need to tackle the over-consumption of particular consumer goods such as sugary drinks through for example increasing their price.  This is a billboard urging people in Berkeley, California to vote for a sugary drinks tax there, which in fact they did.   [OHP] Theology tells us of the importance of eating together and if we do we will lead happier healthier lives (to cut a rather long story short).  

Now these ologies are complementary not competitive in both their analysis of problems and generation of solutions.  This is one reason why the Nuffield Department of Population Health, at the University of Oxford needs more than just epidemiologists, but also psychologists and sociologists (as being researchers in neighboring ologies in my conceptual framework) and dare I say it theologians.

So that was God – or at least theology – what about evolution and global warming?   I don’t have time to give them much attention but I will briefly say something about them.

Firstly evolution or rather evolutionary biology.  I mentioned earlier that particular theory of evolution that was summarised in Richard Dawkin’s book, ‘The Selfish Gene’, published in 1975.  This theory called Neo-Darwinism and its fore-runner Darwinism has, I think, had a profound effect on our thinking in all disciplines not just biology.   The influence of Darwinism on other disciplines including psychology, sociology, economics and of course theology is brilliantly laid out in this book [OHP] entitled Darwin’s Metaphor, by Robert Young, and published in 1985, from which I have taken just one quote, but I could have taken many. 

A particular effect of Neo Darwinism on our ideas, and relevant to my personal perspective on population health, is its influence upon our ideas about the nature of societies and whether they might be described as healthy, irrespective, at least to some degree, of the health of the individuals of which they are composed. 

You’ll remember that Margaret Thatcher said that: ‘There is no such thing as society’.  In, to my mind, an extraordinary interview with Eddie Mayer on Radio 4’s iPM Programme in April 2013, Ian Swingland, now Emeritus Professor in Conservation Biology at the University of Kent says: “Thatcher eschewed the idea of society because of a high table dinner at Magdalen College at Oxford [in March 1978.  [At this dinner] ‘Richard Dawkins convinced her there was no such thing as society just individual.”  Swingland himself had attended this dinner.  Here is a transcript of that interview which you can read at your leisure.  I am looking forward to the second volume of Richard Dawkin’s autobiography to see whether Dawkin’s confirms Swingland’s view.

And secondly global warming.   Now anthropogenic global warming is a problem which is similar to heart disease.   It, like heart disease, threatens our physical, mental and societal well-being.   To be concerned about human health and not about the health of the planet seems increasingly absurd, given that, if the predictions of those who are tracking climate change are correct, human health will, in the future, be profoundly affected by global warming.   

Anthropogenic global warming, like heart disease, can be explained in various ways and will require different types of solution.   But explanations for and solutions to global warming seem extraordinarily similar to those for heart disease: we would reduce our risk of heart disease and save on fossil fuels if ate more plant based foods and less meat and walked and cycled more rather than travelling by car.   Moreover, like population health problems, global warming will only be solved through the organized efforts of society, organizations, communities, families and individuals.

So finally I would like to close with some words of a hymn which I we sung in my church yesterday.   They seems peculiarly apt to what I have been saying.

Spirit of truth arise
Inspire the prophet’s voice
Expose to scorn the tyrant’s lies
And bid the poor rejoice
O Spirit, clear our sight,
All prejudice remove,
And help us to discern the right,
And covet only love.

Give us the tongues to speak
The words of love and grace
To rich and poor, to strong and weak
In every time and place
Enable us to hear
The words that others bring
Interpreting with open ear
The special song they sing

I know I said I would only give two acknowledgements in this lecture but I have a few more.  Thank you all for coming and thank you for listening.  And thank you too to Charlotte Payne for providing some sushi made with edible insects to eat as snacks after this lecture.  I’ll leave you to work out the connections between insect sushi and God, evolution, global warming, heart disease and indeed population health.

[i] Winslow, Charles-Edward Amory (Jan 9, 1920). "The Untilled Fields of Public Health". Science 51 (1306): 23–3. doi:10.1126/science.51.1306.23. PMID 17838891.