About half of all Americans have either diabetes or pre-diabetes, according to a new report. And experts in the field say that’s good news.

That’s because the study finds that after two decades of linear growth, the prevalence of diabetes in the United States has finally started to plateau.

In a paper published Tuesday in JAMA, the authors write that their findings are consistent with other studies that show the percentage of people with diagnosed diabetes remained steady from 2008 to 2012.

“Although obesity and Type 2 diabetes remain major clinical and public health problems in the United States, the current data provide a glimmer of hope,” wrote William Herman and Amy Rothberg of the University of Michigan in an article accompanying the paper.


Herman and Rothberg, who were not involved in the research, said the study suggests the implementation of food, nutrition and physical activity policies and regulations by federal, state and local governments as well as other efforts to curb obesity and diabetes have finally started to pay off.

“Progress has been made, but expanded and sustained efforts will be required,” they wrote.

The study is based on data collected by the National Health and Nutrition Examination Survey. The researchers report that from 2011 to 2012 between 12% and 14% of Americans had diabetes, depending on what criteria were used to diagnose them. This percentage has remained stable since 2008.

The research team also found that the proportion of people who had diabetes without knowing it decreased from 40.3% in 1988-1994 to 31% in 2011-2012.


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FOR THE RECORD

A previous version of this post incorrectly stated the beginning year in the period 1988-1994 as 1998.

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This decrease, however, was not seen across all racial and ethnic groups.

The proportion of Mexican Americans who were undiagnosed was higher than their white and black counterparts, and this percentage had not decreased over time. The authors suggest this result may be due to a lower percentage of Mexican Americans with health insurance, leading to lower access to healthcare.

The authors also found that Asian people were more likely than any other racial group to have undiagnosed diabetes.

The prevalence of people with pre-diabetes has grown over time. Previous studies show that between 1990 and 2002, 29% of people had pre-diabetes. Between 2007 and 2010, that number grew to 36%. In 2011 and 2012, the authors report the number grew slightly to 37% to 38%.


Altogether, that means that in 2011-2012, 49% to 52% of the entire U.S. population is estimated to have diabetes or pre-diabetes.

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