Love Actuaries

When most people want advice longevity, they consult doctors, nutritionists or the latest internet guru. I prefer actuaries. It doesn’t make for thrilling dinner-party conversation, but there is a simple reason. If an actuary consistently gets life expectancy wrong, someone loses a great deal of money. If an influencer gets it wrong, they usually gain another million followers. But that doesn’t stop the new rich embarking on fools’ errands.

There is something faintly comic about wealthy middle-aged men spending fortunes trying to become the oldest corpse in the cemetery.

Healthy living

Every week seems to bring another longevity guru promising to slow ageing, reverse ageing or, if the marketing department has had enough coffee, abolish it altogether. Blood tests, ice baths, fasting regimes, wearable sensors, exotic supplements and enough biometric monitoring to keep a medium-sized hospital occupied. The message is simple: death is no longer inevitable, merely a management problem.

It is a comforting thought. It is also, I suspect, rather optimistic.

Don’t misunderstand me. I’m all in favour of sensible living. Exercise because it keeps you fit. Eat well because food matters. Don’t smoke because it damages almost everything worth keeping. None of that is controversial.

But somewhere between common sense and social media, healthy living has become an industry selling something much bigger than good advice. It is selling control. The promise is that, if only you follow the protocol with sufficient devotion, longevity will obediently follow. While most of us live now, pay later, the ultra-rich pay now and expect to die later.

My doubts about that promise began many years ago, not in a gym or a laboratory, but in an NHS office in the North East.

Near misses

Before that I’d been a medic, where I had become fascinated by an idea that hardly anyone outside professional circles talks about: near misses.

In obstetrics, we spent almost as much time discussing disasters that nearly happened as disasters that actually did. A baby who was almost lost often taught us more than one who sadly was. The aviation industry understood this long before healthcare did. Pilots had developed sophisticated systems for reporting mistakes and near misses because they had a powerful incentive to get better.

When aeroplanes crash, the people making the mistakes have an unfortunate habit of being on board.

Economists call this “skin in the game”.

Medicine, by contrast, has often been less good at learning from its mistakes.

That lesson stayed with me.

Whenever I wanted to know who to trust on a difficult question, I found myself asking a rather simple one. Who pays the price for getting this wrong?

Years later, as a public health physician, I was confronted with a parallel problem. One of the most deprived communities in our area had a markedly lower life expectancy than its more affluent neighbours. We were asked the obvious question. What should we do about it? The standard public health answer was equally obvious. More health promotion. Better diets. More exercise. Less smoking. Encourage healthier lifestyles.

All perfectly sensible.

But I found myself wondering whether we were asking the right people. So I looked somewhere unexpected. Actuaries.

Actuaries or epidemiologists?

Life assurance companies employ actuaries, and pension funds have spent generations trying to estimate how long people will live. Not because they are especially interested in public health but because getting the answer wrong costs them millions of pounds. They have skin in the game.

That immediately intrigued me.

For years afterwards, when teaching trainee epidemiologists, I used to begin one session with a deliberately provocative exercise. I showed them two different ways of thinking about life expectancy. One came from conventional epidemiology; the other reflected actuarial thinking (See appendix for detailed table). I wasn’t interested in the numbers themselves. I was interested in what happened next.

The room would divide.

Why, the trainees asked, did two respectable disciplines appear to give different answers?

The answer, I suggested, lay not in the evidence but in the telescope.

Imagine two people looking at the same landscape.

One deliberately uses the wide-angle end of the telescope. She sees whole populations. Patterns emerge. Smoking rates. Poverty. Education. Housing. This is the epidemiologist’s world, and it has transformed public health.

The other adjusts the telescope to bring a single individual into sharp focus. One applicant for life assurance. Family history. Existing illness. Occupation. Education. Marriage. The accumulated experience of millions of lives is brought to bear on one person sitting in front of him.

Neither observer is wrong.

They are simply asking different questions.

The epidemiologist asks, “How do we make populations healthier?” The actuary asks, “How long is this individual likely to live?”

Confuse those two questions and trouble begins. It certainly did for us.

Advising my health authority, my conclusion was that, if the target population was going to die young anyway, we were better to target them with good health care rather than health promotion. Many of the strongest predictors of life expectancy (education, deprivation, family history and established disease) were not going to change any time soon.

The proposal was politically stillborn. Redistributing healthcare resources towards poorer communities would have been unpopular in wealthier ones. Health promotion was politically much easier to sell.

Whether it was the best intervention for our population was another matter.

Which brings me back to today’s longevity industry. Its great selling point is certainty. Influencers are wonderfully certain. There is always another protocol. Another hack. Another miracle. Another expensive subscription.

Perhaps that explains why I remain mildly sceptical whenever another millionaire announces that he intends to live to 120.

What’s more, the people most obsessed with prolonging life seem, more often than not, to be those who have already enjoyed rather a good one. And if we are being completely honest, one occasionally suspects that the people most determined to live forever are not always those the rest of us are most anxious to keep indefinitely.

So yes, eat sensibly. Walk more. Avoid cigarettes.

But don’t confuse sensible living with immortality.

The older I get, the more I find myself trusting the actuary rather than the influencer.

The actuary understands probability.

The influencer understands marketing.

There is quite a difference.

Appendix

This is a table which compares two life expectancy calculation studies. The principal is the same; various lifestyle and family history factors are weighted to add or to subtract years of life expectancy from standard figures. For example, a person who is aged 35 may have a standard life expectancy of 75 years; but lifestyle and family history factors might add on or remove years to give their actual life expectancy.

In the table below there are the weightings from two different sources: the Buzan & Keene source and the Perls & Silver source. The Buzan & Keene weightings are derived from life assurance company mortality information; whereas the Perls & Silver weightings are derived from epidemiological estimations.

Table of weightings in years:

[i] The Age Heresy Buzan T, Keene R. 1966. Ebury Press. ISBN: 0091851505

[ii] Living to 100 Perls T, Silver MH. 2003. Basic Books. ISBN: 0465041428

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