The rate of diabetes diagnoses in the United States has increased in recent decades, but a new study shows that between 2008 and 2012, the rate of diagnosed diabetes leveled off among adults ages 20 to 79. While that’s good news, for some groups there was still a significant increase in diabetes during that period.

African-Americans, Hispanics, and adults with a high school education or less had significantly higher rates of diagnosed diabetes compared to non-Hispanic white adults and those who had more than a high school education. The increase in the diabetes rate was also higher for young adults ages 20 to 44 than for older adults ages 45 to 64.

Hoping to fill a gap in existing diabetes data, researchers from the U.S. Centers for Disease Control and Prevention (CDC) examined long-term national trends in diabetes diagnoses. Their findings were published today in the Journal of the American Medical Association.

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Diabetes Rates Leveled Off in 2012, But Don't Pop the Cork Yet

Between 1980 and 2008, overall diabetes rates increased significantly before leveling off between 2008 and 2012.

Furthermore, between 1990 and 2008, the prevalence of type 2 diabetes jumped from 3.5 to 7.9 in every 100 people, before leveling off at 8.3 in 2012. The plateau in the overall population may have to do with a slowdown in the obesity rate, since carrying extra weight is a significant risk factor for type 2 diabetes.

While a leveling off of diabetes prevalence is a good thing, the ramifications of a 20-year period of increased rates will continue. “In light of the well-known excess risk of amputation, blindness, end-stage renal disease, disability, mortality, and health care costs associated with diabetes … diabetes will remain a major public health problem that demands effective prevention and management programs,” the study says.

Obesity Adds to Diabetes Health Risks

More than one-third of adults in the United States are obese, according to the CDC. Some groups have higher rates of obesity than others. Nearly 48 percent of non-Hispanic blacks are obese, followed by 42.5 percent of Hispanics.

Obesity and its added health risks appear to be geographically concentrated. While no state has a prevalence of obesity that is less than 20 percent, the South has the highest prevalence of obesity at just over 30 percent. Mississippi and West Virginia had the highest prevalence of obesity in 2013, with obesity rates of 35 percent or greater, according to the CDC

Obesity is a major risk factor for type 2 diabetes and increases in one parallels increases in the other, the study notes. The upside to a relationship between the two is that if one plateaus, the other may do so as well. The plateau in diabetes that occurred between 2008 and 2012 may have been caused by several factors, including a leveling off of obesity rates. Other factors that have positively influenced diabetes and obesity rates include better healthcare, demographic changes in the American adult population, and lifestyle and environmental changes.

With continued healthy lifestyle modifications, it’s possible that the prevalence of diabetes will continue to hold steady or hopefully even decline. Lifestyle modifications like exercise, better diet, and weight loss can prevent or delay the onset of type 2 diabetes, according to the Obesity Society, an advocacy group for obesity research.