A S IN POST-SOVIET Russia or opioid-ravaged parts of America, stalling growth in life expectancy is often a sign of a sickly society. Diagnosing the sickness, however, can be difficult. Researchers seeking to explain why Britons have recently stopped living longer have been hampered by a lack of data. Information is often out of date and tends to cover broad swathes of the country, making it hard to spot underlying trends. In the absence of a better explanation, some experts have argued that the slowdown can be attributed to a squeeze on health and social-care spending.

A study published on October 24th suggests that the picture may be more complicated. From 2006-07 to 2015-16, the number of premature deaths decreased faster in the most-deprived tenth of local authorities than in the least-deprived tenth, according to estimates published by the Lancet and the Global Burden of Disease Study, based at the University of Washington. Moreover, in 2013-15 premature mortality did not just fall more slowly in affluent areas—it increased. In other words, the slowing gains in life-expectancy seem to be attributable more to rich areas than to poor ones. John Ford of the University of East Anglia, a co-author of the analysis, says it is the first research to find something like this, in Britain or anywhere else.

One possibility is that illnesses like cardiovascular disease are following an “epidemic curve”, says John Newton of Public Health England, a government agency which helped to fund the research. Such illnesses were at their worst in the 1970s and 1980s and have since become less common. Further improvements will be hard to achieve among rich folk who already smoke little, eat healthily and exercise. Complicating the picture, however, is other evidence which suggests that health inequalities between rich and poor have slightly widened in recent years. It may be that poor people living in rich areas have, for some reason, fared worst of all.

Whatever the cause, the trend has helped reduce regional health inequalities—albeit not in a way policymakers would like. Not only has the improvement in premature mortality slowed in poor areas, too, but poor areas still suffer vastly more than wealthy ones. The number of years of life lost to premature deaths was more than 14,000 per 100,000 people in Blackpool, a deprived seaside resort in the north-west, compared with less than 7,000 in Wokingham, a market town in the south.

The research also identified the main source of the slowdown as more gradual improvements in cardiovascular disease and breast, colorectal and lung cancers. By contrast, the rate of improvement for Alzheimer’s disease and other forms of dementia did not change much.

Those who argue that a complex mix of factors, rather than trimmed care budgets, is to blame for stalling gains in life-expectancy point out that a similar stall is also apparent in countries like France and Germany, which have not experienced spending cuts on the scale of Britain’s. The new estimates do not end the debate. But the nuanced picture they present, with improvements varying by disease and area, further bolsters this case.