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Is Diabetes Becoming Mainly a Third World Problem?

Global rates of incident diabetes seem to be on the decline in some populations, researchers reported, although experts questioned whether the evidence could be considered “definitive.”

Based on a systematic review of 47 studies, 36% of age- and ethnicity-defined populations in nations around the world saw drops in incident total diabetes or type 2 diabetes rates from 2006 to 2014, according to Dianna Magliano, PhD, of Baker Heart and Diabetes Institute in Melbourne, Australia, and colleagues.

Populations with declines in diabetes incidence after 2005 included the U.S., Israel, Switzerland, Hong Kong, Sweden, and South Korea, they wrote in The BMJ.

During the same 2006-2014 time period, incident diabetes held steady for 30% of global populations, including Canada, Italy, Scotland, Norway, non-Hispanic white people in the U.S., and the U.K.

A third of populations saw an increase in diabetes, including Portugal, Denmark, and Germany, Magliano’s group reported.

However, most of this data is almost exclusively reflective of high-income countries, pointed out Mike Lean, MD, of the University of Glasgow, and colleagues in an accompanying editorial.

Also, “stricter and more accurate diagnostic criteria” will inevitably reflect an even greater decline in incident diabetes, Lean’s group suggested.

“While we all long for signs that diabetes is in retreat, this sensibly optimistic systematic review does not provide definitive evidence that true incidence is finally falling,” the editorialists cautioned. “Conditions are very different in low and middle income countries, less than 5% of the populations studied, where type 2 diabetes develops at lower body weights and the impact of marketing Western food on diabetes incidence has not yet peaked.”

The review drew upon population-based cohort studies, administrative and health insurance databases, and other diabetes registries to accumulate data on 121 specific adult populations. Not all populations had available trend data for all the time points assessed by Magliano’s group, particularly low income countries. Although some studies included in the review reported trends on both type 1 and type 2 diabetes, the researchers pointed out that these findings “apply predominantly to type 2 diabetes.”

“Although the lack of data for non-Europid populations leaves global trends in incidence unclear, these findings suggest that trends in the diabetes epidemic in some high income countries have turned in a more encouraging direction compared with previous decades,” the group wrote.

They noted that from the years 1990 to 2005, 66% of global populations saw an increase in incident diabetes rates — accounting for the biggest spike of diabetes rates — juxtaposed by only 2% of populations noting a decline. During these years, 32% of populations saw a stable rate of incident diabetes.

Regarding the spike in diabetes incidence from 1990 to 2005, the researchers explained that the diagnostic threshold for fasting plasma glucose dropped from 140 mg/dL to 126 mg/dL (7.8 to 7.0 mmol/L) in 1997, potentially contributing to an increase in incident diabetes cases at this time.

Additionally, around 2009 and 2010, HbA1c was introduced as a new diagnostic tool for diabetes. “Evidence from some studies suggests that the HbA1c diagnostic threshold detects fewer people with diabetes than do the thresholds for fasting plasma blood glucose, potentially leading to a lowering of incidence estimates,” the researchers noted. “However, across multiple studies, prevalence estimates based on fasting plasma glucose only versus HbA1c definitions are similar.”

From 1960 through 1989, 36% of populations saw an increase, while most populations held stable with new diabetes diagnoses during this time (55%). And only 9% of populations saw a drop in diabetes rates during these years.

Some of the reasons for the current fall in diabetes incidence may be attribute to heightened prevention efforts, increased awareness, and reduced sugar intake, according to the authors.

“Another potential explanation for declining or stable diabetes incidence after the mid-2000s is a reduction in the pool of undiagnosed diabetes through the intensification of diagnostic and screening activities and changing diagnostic criteria during the previous decade,” they acknowledged.

Last Updated September 11, 2019

The study was funded by the CDC.

Magliano and co-authors disclosed support from the CDC.

Lean disclosed relevant relationships with Novo Nordisk and Roche.

Source: MedicalNewsToday.com