Geography and life expectancy

The Guardian makes the usual mistake here:

The latest life expectancy data for the UK is out and reveals a north-south divide in ages of death – of four-years.

The data from the Office for National Statistics shows that for men in the south-east of England it is 79.4 years, while in Scotland the figure is 75.4, according to the Office for National Statistics. For women the gap is slightly less: 83.3 in south-east and south-west England against 80.1 in Scotland.

Health areas with lowest life expectancy are Greater Glasgow and Clyde (which has a lower rate than Albania for men), Hartlepool, Western Isles, Liverpool and Blackburn with Darwen. The pattern in the geographic age gaps remains similar to those of previous years, showing just how stubborn social and economic inequalities remain.

There\’s a nice map with the same problem.

The problem is that these figures fail to take account of internal migration.

There are indeed people who are born, live and then die in the same house, let alone the same health care area (which these numbers are based upon).

But there are also those who move across such health care areas.

For example, a not unlikely life path is to be born somewhere or other, work as an adult in another place and then finally retire to a third area.

As the old saying went (back when we still had Indian Army Colonels) Cheltenham is where Indian Army Colonels go on retirement and Eastbourne is where their widows move to to die: forgetting why they went there when they get there.

Think of this in the American sense: would anyone at all be surprised by the idea that Florida has longer life spans than, say, Michigan? Part of which is explained by the way in which people who survive 60 odd Michigan winters move to Florida?

Or a more exact UK example: the reason that lifespans are long in Frinton Upon Sea is not that living in Frinton creates a long life span: it\’s that old people move to Frinton.

Are there social and economic inequalites? Yup, there sure are. One of them is that it is those at the higher end of those inequalities who do the moving around as they age.

Which means that this data does not show what it is purported to show: lifespans at birth for each health care region. Rather, at least in part, it shows the life span effects of the inequalities that allow or do not allow people to move from their health care region of birth.

It\’s that well known, survivorship bias, all over again.

It\’s like looking at Chelsea Pensioners and remarking that military men without wives seem to live an awfully long time. Without noting that you have to be a long lived and without a wife military man to become a Chelsea Pensioner.

Toss in short.

8 comments on “Geography and life expectancy

  1. Thing is, what is it about making it to (and beyond) retirement that makes people want to live in Frinton-on-sea?

    I will quite probably retire to Manchester, and not just to be contrarian.

  2. In similar vein, 20 year old have lower life expectancy than 30 year olds. Is this because
    A) those wicked tory NHS cuts mean we’re all going to die young
    or
    B) 30 year olds have learnt how not to crash the car

  3. And what about the sex difference? Should the State be bumping off women in their 70s to even out the life expectancies?

  4. It may be the pensioners who feel fittest who move off to the coast or wherever; those who already feel frail might feel that they lack the energy, or want the comfort of staying near friends, family and a familiar GP.

  5. If I remember correctly, life expectancy is just an average “age at death” calculated across the population. This means that child mortality rates act to pull the average down, as do drug overdoses and all the other grotty stuff that happens rather more in the dodgy bits of Glasgow than in leafy Esher.
    So I don’t thinks it’s entirely survivorship bias.

  6. Seems to me that the places with the lowest life expectancy are all solid Labour, so obviously voting Labour will lead to an early death.

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