Health Inequalities: Lifecourse Approaches

This book is a selection of George Davey Smith's papers on health inequalities published between 1990 and 2002. Not counting the afterword, 39 papers are reproduced, of which a third originally appeared in the BMJ. Davey Smith (or GDS) has made and edited the selection himself, so it provides a good opportunity to catch a glimpse of the man behind this prolific writer and “professional preventive medicine apparatchik” (his words, p 524).

Figure 1.

Ed George Davey Smith

The Policy Press, £25/$37.50, pp 548 ISBN 1 86134 322 1

Rating: ★★★

The book is loosely constructed around the new theme of “lifecourse approaches”—attempts to understand health inequalities from the cumulation and interaction of factors acting early and later in life. Although GDS was originally sceptical about David Barker's work on the early-life origins of adult disease, he soon recognised the potential of lifecourse approaches for understanding health inequalities. Nine of the papers here directly illustrate the lifecourse approach.

In a set of important papers based on the west of Scotland collaborative study—a cohort of almost 6000 men recruited in workplaces between 1970 and 1973—GDS and his co-workers showed that socioeconomic circumstances at different stages of life had independent effects on health in adulthood. By looking at social class at three stages of people's lives (social class of father's job, own first job, and own current job, respectively), he was able to show that each independently affected risks of premature mortality in adulthood, and that they had a cumulative effect on death rates.

Using data from the Renfrew and Paisley study, another large cohort recruited in the west of Scotland between 1972 and 1976, GDS and others analysed how height—a marker of socio-economic circumstances and nutritional status in childhood—related to mortality from various causes. Taller people were found to have lower risks of dying from coronary heart disease, stroke, stomach cancer, and respiratory diseases, but higher risks of dying from colorectal and prostate cancer. Much of the association between height and cardiorespiratory mortality was accounted for by lung function, which is probably partly determined by exposures in childhood. The positive associations between height and several cancers could reflect the influence of calorie intake during childhood.

Both examples not only illustrate the fruitfulness of the lifecourse approach for understanding health inequalities, but also disclose some of the secrets of GDS's success as a researcher. Most of his work is based on secondary analysis of large and rich datasets collected for other purposes (and by other researchers). The collaborative and the Renfrew and Paisley studies are just two examples: he has also worked on the multiple risk factor intervention trial, the Caerphilly and Whitehall studies, and on routinely collected statistical data such as occupational mortality and small-area datasets.

He has not spent much energy on collecting data, one of the few exceptions perhaps being his famous study of the height of obelisks in Glasgow graveyards. The methods section of this paper reads, “The height of each obelisk was measured with a set of chimney sweep rods, each 90 cm long, with gradations added” (p 389).

One of his other strong points is the ability to combine analytic rigour with imaginative interpretation and humour. His study of the (inverse) association between frequency of sexual intercourse and risk of death in middle aged men mocks both epidemiology and health promotion, and, like some of his other papers, contains a number of truly hilarious passages.

But is not only good humour that drives this man. Many of his readers must have wondered to what extent he is politically motivated, and there are a few pieces in this volume that show traces of rather leftist political opinions. The biting sarcasm with which he describes the results of his analyses of voting patterns and premature mortality in Britain, which showed higher mortality rates in areas with a higher proportion of Labour voters, is one example. He writes, “The recent Conservative strategy of encouraging increasing... socio-economic differentials in mortality and increases in death rates among some groups living in the most deprived areas, will in turn consolidate the Conservative electoral advantage by hastening... the death of those who would oppose them in the polls” (p 98).

Figure 2.

Davey Smith: a warrior armed with exceptional brains

However, there is sometimes a one-sidedness in his scientific rigour. For example, he relates widening inequalities in mortality in Britain to widening income disparities, ignoring both time lags and the results of international-comparative studies that show widening mortality inequalities everywhere, some of the largest in countries with the smallest income inequalities in Europe.

The afterword, apparently intended as a biographical note, is a piece about a serious traffic incident GDS was involved in in Nicaragua. The atmosphere is grim, as in a Ludlum novel, and although the story is told with a sense of humour, the portrait is that of a warrior in a hostile world. The good news for all his readers is that this warrior is armed with exceptional brains and great rhetorical gifts, and sees his task as “the fearless description of how the world really is” (p 517). Let's hope he continues to do so for as long as he can.