Is Diabetes Incidence Flat or Declining?

Good news seems a bit rare these days. So reading that a robust new analysis says type 2 diabetes incidence is dropping in high-income countries prompts more questions. Is this trend real? Or is it an artifact of this one, very large dataset? Does this represent progress? Or merely a shift in the global patterns of this relentless chronic disease?

These findings run counter to a popular narrative about a global diabetes epidemic. So  they will surely stir debate. This is the mark of good, provocative research.

Five Billion Person-Years

No doubt about it, this analysis was a massive effort. A large team of researchers assembled data on 22 million diagnoses of type 2 diabetes in 21 countries. They used 24 different data sources. In sum, the data represents five billion person-years of follow-up. This research is ambitious indeed.

The patterns in the data are pretty clear. In fact, most of the data showed a stable or downward trend in new diagnoses. Declines ranged from 1.1 to 10.8 percent annually. From 2010 onward, only four data sources showed an increasing trend. Those ranged from 0.9 to 5.6 percent annually.

These researchers are cautious, but they express an inclination to attribute declines to prevention efforts:

“Preventive strategies and public health education and awareness campaigns and other factors might have contributed to declining trends.”

Yes, But

In a commentary alongside this new study, Mohammed K. Ali, Jacqueline Seiglie, and K.M. Venkat Narayan advise caution:

“It would be a big leap of faith to attribute changes in incidence at the population level, even if real, to diabetes prevention efforts, without more rigorous examination of causality. Furthermore, the current and projected increase in overweight and obesity globally, which are major drivers of type 2 diabetes, represent a more dire prediction of future trends in metabolic disease.”

After all, these data represent the trend in new cases. As these study authors note right up front, diabetes prevalence is increasing in most places all over the world. A slowdown in new cases would be welcome, but it does not mean that the problem is solved.

And, in fact, these findings leave out a substantial portion of the problem – diabetes in low and middle income countries. Roughly 80 percent of the global population with diabetes reside in those countries. Obesity, which drives the epidemic of diabetes, is only getting started in those countries.

So this finding of a decline in new diabetes cases for high-income countries is important. However, it raises more questions than it answers.

Click here for the study and here for the commentary. For a recent systematic review of diabetes incidence, click here.

Human Islet-Like Organoids, image by the Salk Institute via NIH Image Gallery / flickr

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February 24, 2021