Early-onset diabetes on the rise, but hope for reduced long-term impact
medwireNews: Two independent studies published in The New England Journal of Medicine explore the epidemiology of diabetes and its long-term impact from different perspectives, the first showing an increase in the prevalence of diabetes among youths in the USA, and the second a decline in the incidence of all-cause and cardiovascular mortality among adults with diabetes in Sweden.
In the first study, Elizabeth Mayer-Davis (University of North Carolina, Chapel Hill, USA) and colleagues used data from the SEARCH for Diabetes in Youth study to examine changes in the incidence of diabetes from 2002 to 2012 among children and adolescents aged 0 to 19 years.
The researchers estimated that approximately 15,900 youths were diagnosed with type 1 diabetes annually in 2002–2003, rising significantly to 17,900 in 2011–2012. After adjustment for factors including age, gender, and ethnicity, the annual incidence of type 1 diabetes increased by 1.8% per year.
The prevalence of type 2 diabetes also rose significantly over the time period studied, from an estimated 3800 cases diagnosed annually in 2002–2003 to 5300 in 2011–2012, with an adjusted annual increase of 4.8%.
In subgroup analyses, the adjusted annual increase in prevalence of type 1 diabetes was significantly higher among Hispanic than non-Hispanic White people (4.2 vs 1.2%). And for type 2 diabetes, the rate of increase was greater for all other racial and ethnic subgroups compared with non-Hispanic White people (0.6%), with the largest increase seen for Native Americans (8.9%).
The authors of an accompanying editorial, Julie Ingelfinger and John Jarcho, Deputy Editors of The New England Journal of Medicine, note that “[a]lthough it is not surprising that the incidence of type 2 diabetes among youths is increasing, the differing rates among racial and ethnic groups is somewhat unexpected.”
Mayer-Davis and colleagues observe that “[v]ariations in the underlying prevalence of obesity over time may contribute to variations in insulin resistance and to the increasing incidence of type 2 diabetes,” noting an increasing prevalence of obesity among Hispanic girls and non-Hispanic Black boys specifically over the study period.
But the editorialists were concerned by “the fact that the incidence of type 1 diabetes appears to be increasing, with apparent disparities among ethnic groups that are not likely to be explained by the obesity epidemic,” and pose the question: “What will happen to the increasing number of persons with early-onset diabetes as they age?”
They believe that the second study, an analysis of data on 36,869 patients with type 1 diabetes and 457,473 with type 2 diabetes from the Swedish National Diabetes Register, provides some insight into this question.
Aidin Rawshani (University of Gothenburg, Sweden) and fellow researchers found that from 1998 to 2014, the rate of all-cause mortality decreased by 31.4 deaths per 10,000 person–years among patients with type 1 diabetes, and by 69.6 deaths per 10,000 person–years among those with type 2 diabetes.
Similarly, the incidence of cardiovascular mortality decreased by 26.0 and 110.0 deaths per 10,000 person–years, respectively.
While the reduction in rates of fatal outcomes was comparable between patients with type 1 diabetes and matched nondiabetic controls, the rates decreased significantly less among those with type 2 diabetes compared with controls.
The authors note that the observed decreases in mortality rate among patients with diabetes “likely reflect a combination of advances,” for example in integrated care for patients with chronic disease and patient education in disease management.
However, Ingelfinger and Jarcho believe that “even though mortality and the rate of cardiovascular disease are decreasing among persons with diabetes, the overall adverse effect of diabetes on public health is actually increasing” as a consequence of the rising incidence of diabetes among youths as demonstrated by Mayer-Davis and colleagues, as well as “the aging and growth of the population.”
And the editorialists conclude: “It is clear that we are far from controlling the negative effects of diabetes on health worldwide.
“As the prevalence increases, we clearly need new approaches to reduce the burden of this disease on public health.”
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