EVERY six seconds a person somewhere in the world dies as a consequence of diabetes, according to estimates by the International Diabetes Federation (IDF). In 2015 5m lives were lost to the disease, more than were claimed by AIDS, tuberculosis and malaria combined. Moreover, the toll is rising faster than forecasters have expected. Nearly half of these deaths are among people younger than 60. In parts of Africa, where the condition is much less likely to be diagnosed, that share is more than four-fifths.

The rise of diabetes has been misjudged repeatedly. In 1995 the World Health Organisation estimated that 135m 20- to 79-year-olds had diabetes, and that this figure would more than double in three decades. But reality outpaced this stark projection by a huge margin: just twelve years later the number of people with diabetes had already nearly doubled. Since then, the rise of diabetes has been so steep that prevalence closed in on projections even faster. In 2015, the estimated global prevalence had reached 8.8%, nearly double that in 1995. By 2040, the IDF reckons that a tenth of humanity will have the condition. Already, diabetes gobbles up 12% of health spending globally; in some countries, the share is as much as a fifth.

Both type 1 and type 2 diabetes are increasing rapidly. The factors contributing to type 2 are well known; poor diets, urbanisation and low physical activity increase susceptibility. It is no surprise that type 2 accounts for 90% of cases in high-income countries. But type 1 diabetes, which is fatal unless treated with daily insulin medication, is also rising at about 3% a year. The reasons are unclear, but the data leave no doubt that diabetes is no longer exclusively a rich-world disease.