According to official stats, the number of cases of diabetes has shot up by 60 per cent in the past decade. The vast majority of these cases are type-2 diabetes, which is linked to obesity and leads to a variety of complications including heart disease, stroke, circulation problems that require amputations, and blindness. This rise in diabetes is routinely referred to, alongside obesity, as the central reason why something must be done about our ‘obesogenic environment’, and why we must all eat our five-a-day, dump the fast food and get more exercise.
But there’s always been something rather troubling about the sudden boom in diabetes cases. Chronic conditions don’t normally take off that quickly; that’s something that we would normally associate with an outbreak of infectious disease. Could there be more to the diabetes epidemic than meets the eye?
A research paper published last week in Diabetologia, the journal of the European Association for the Study of Diabetes, offers an explanation. The first thing to note is that diabetes cases are usually referred to according to prevalence – that is, the number of people who are living with the condition. That’s important when it comes to understanding the demands that might be placed on health services, for example. But it’s important to distinguish that from incidence – that is, the number of new cases reported each year. When people refer to an epidemic of diabetes, it is often assumed that the number of new cases is rising rapidly. So, is it?
Apparently not. The new paper looked at 180,290 new cases of type-2 diabetes in Scotland between 2004 and 2013. The authors note: ‘Overall, incidence of type-2 diabetes remained stable over time and was 4.88 and 3.33 per 1,000 in men and women, respectively. However, incidence increased among young men, remained stable in young women, and declined in older men and women. Incidence rates declined in all socioeconomic groups but increased after 2008 in the most deprived groups.’
The authors conclude: ‘Incidence of type-2 diabetes has stabilised in recent years, suggesting that increasing prevalence may be primarily attributed to declining mortality. Prevention of type-2 diabetes remains important, particularly among socioeconomically deprived populations.’ In other words, the rise in the total number of cases is not due to a boom in new cases, but is a product of people with diabetes living longer.