Research into the link between mortality and inequality has been given a boost by a government that appears to care more. Geoff Watts reports
According to an 1842 report on "the sanitary conditions of the labouring population of Great Britain", the average age at death of the gentry and professional classes of mid-19th-century Bath was 55; for artisans it was 38. In Liverpool, neither toffs nor proles fared so well: they died at 35 and 15 respectively.
Not surprisingly, these huge gaps have since shrunk. More remarkable is that gaps of any significance persist to this day. Yet they do: in Britain, the death rate among male unskilled manual workers is almost three times that found in professionals, a separation that has actually widened in the past couple of decades. Regional differences persist too, and not only in illness; certain treatments, for example, are more freely available in some parts of the country.
But how disturbed are we by inequalities in health? And how much do we really value equity within the health service? Peter Smith and his colleagues in the Centre for Health Economics at the University of York are in the preliminary stages of trying to answer both these questions.
Professor Smith's project is one of some two dozen that make up the Economic and Social Research Council's Health Variations Programme. It was set up in 1996 and grew out of the need to understand more of the age, sex, income, geographical, ethnic and social class factors that influence health inequalities. Now into its second phase, the programme is intended to fill in some of the gaps identified in its earlier work.
"There was a sea-change in political thinking in the early 1990s that signalled that we needed a major research investment in this area," says programme director Hilary Graham, of Lancaster University. "This programme was one of the products of that change."
Another of the programme's grant holders is Sally Macintyre of the Medical Research Council social and public health sciences unit in Glasgow. She is looking at the influence of houses and cars on health and longevity. Researchers have known for years that having a car and owning as opposed to renting a house are both associated with a longer and healthier life. Generally they have assumed that these things are mere proxies for class and income. But Professor Macintyre began to wonder if car and house ownership might actually have a direct effect.
"With a car, if your kids are ill you can take them to the GP or to the hospital, you can go to supermarkets and stock up on bulk food more cheaply - practical things like that. And then there's a series of things in relation to security and a sense of privacy - the psychosocial aspects of car ownership. We're thinking initially about mental health, but there is increasing evidence that psychosocial stress and its relief can have physical health effects as well."
Professor Macintyre and her colleagues have conducted a postal survey of a random selection of adults in Scotland, and also interviewed some of them face to face. The analysis is still incomplete, but several things are already clear.
"We can say that rented homes and owned homes do differ in all sorts of ways that might affect health. But we haven't yet put it all together to see if these things can completely explain the effect of income."
In fact, Professor Macintyre doubts if they will, suspecting rather that house and car ownership will be both direct influences and also markers for other factors.
Even how income affects health is still not completely understood. Michaela Benzeval of The London School of Economics is interested in the influence of changes in income: "What we find is that if your income falls it has a significant harming effect on your health. But while an increasing income does improve health, it's less dramatic. This implies that health can be harmed much quicker than it can be improved."
And income and health are not linked in a simple linear fashion. "There's a much steeper relationship between the two at lower income levels, and then the curve flattens out at higher levels. In other words, the health differences between those just above and just below you get smaller as your income rises."
From his preliminary findings, Professor Smith is already confident that the public cares about inequality. "With major health variations, for example social class differences in child mortality and chronic illness, they express anything from concern to horror. They say they view the reduction of these inequalities as being a major issue. We also have some evidence that they are prepared to sacrifice aspects of efficiency in the NHS in order to pursue greater equity."
But what of the policy-makers? Each of the individual projects in the programme has a short section in its manifesto titled "policy implications". Professor Graham is optimistic: "Since the last election we've been in a different policy context. People in the programme have found that rather than just talking to each other, they're expected to talk to policy-makers. We have a government that has put inequalities right at the centre of its strategy. I haven't witnessed that before in my academic lifetime."