Diabetes is one of the biggest global health threats we face, spanning both developed and developing nations. The International Diabetes Federation that there are now 415 million adults with the condition and by 2040 there will be 642 million. The vast majority of cases are type 2 diabetes, the form often linked to diet, sedentary lifestyles and obesity.
Amid these gloomy figures comes some very encouraging news. There has been a decline in the number of new cases of diabetes in US adults at a time when most of us were despairing of the relentless upward trend of this epidemic.
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Last week, the US Centers for Disease Control and Prevention (CDC) estimated that there are close to 30 million Americans with diabetes. But its is also the first to demonstrate a reversal of what appeared to be a rise without an end in sight.
After more than 25 years, new cases are on a downward trajectory. They fell from 1.7 million in 2008 to 1.4 million in 2014 – the first consistent drop in diabetes numbers since 1990. The latest figures prove this trend is real; before, it was not considered statistically significant.
Declines in the prevalence and incidence of this condition are rare. Cuba bucked the trend amid an economic crisis from 1991 to 1995, but that was a time of severe food rationing when rapid reductions in obesity were observed. When the economy picked up, weight regain among the Cuban population was associated with the opposite effect.
Tracking the trend
How can the US reversal be explained? There are a number of possibilities that could, individually or together, explain this phenomenon.
Firstly, there have been changes in the way that diabetes is diagnosed. The traditional use of blood sugar levels is gradually being replaced by . This method reflects average blood sugar over longer periods of time, such as three months. However, the criteria used for diagnosis via this metabolite have not been applied consistently across the US, so there may have been some underdiagnosis.
Another possibility is that because type 2 diabetes has a strong genetic basis, we are now reaching a saturation point in the number of people in the US who were predestined to develop this disorder in our current “obesogenic” environment. This would seem less likely given the significant migration into the US of people whose ethnic background predisposes them to developing type 2 diabetes. People of Hispanic origin, for example, who tend to have a higher risk, with .
It is also unlikely that screening for diabetes in the US has been so effective that new cases have reached a plateau, considering that there is still thought to be at least one undiagnosed case for every known person with diabetes in the US.
But the most hopeful explanation for the trend is that public health messages aimed at obesity and diabetes that address food policy and healthier environments for the community are beginning to hit home.
There is increased recognition in the public health arena that obesity has been driving the diabetes epidemic. Evidence makes clear that diabetes prevention is possible through healthier eating and reduced sedentary behaviour.
If such messages are getting through, it would be a triumph for both the government and the US public health movement. It would represent a milestone in the prevention of a condition that creates huge personal and national costs from premature illness and death.
(Frank Siteman/Superstock)
