New Statistics Shed Light on 'Worrisome' Diabetes Epidemic

Marlene Busko

May 15, 2013

The prevalence of diabetes among US adults grew by 45% over the past 20 years, with the greatest increase seen among seniors aged 65 and over, according to a new study based on surveillance data from the US Centers for Disease Control and Prevention (CDC).

Obesity explained most of the increase in the prevalence of diabetes in younger adults but only part of the increase in older adults.

"We provide…solid evidence that there is a severe epidemic of diabetes, by using National Health and Nutrition Examination Survey [NHANES] data…[the] only US national representative survey data capable of calculating total diabetes, including self-reported diagnosed [diabetes as well as] undiagnosed diabetes [that was] defined by 2 common diagnostic tests: fasting plasma glucose and HbA1c," Yiling J Cheng, MD, from the CDC, in Atlanta, Georgia, told Medscape Medical News.

Finding this increase in diabetes was not especially surprising, Dr. Cheng said, but "the magnitude of the increase [was] significant and worrisome."

These results "underscore the urgent need for planning and delivering primary prevention to the US population and providing quality healthcare for this growing segment of the aging population" — older individuals with diabetes, he stressed.

The study was published online May 1 in Diabetes Care.

Comparing 2 Snapshots of Diabetes, 20 Years Apart

It is well-known that the rates of diabetes and obesity have ballooned over the past 2 decades, but the prevalence of diabetes and the role of obesity in different age groups were unknown, the authors write.

They investigated these relationships using NHANES data from 3 periods:

  • 1988 – 1994 (7950 participants).

  • 1999 – 2004 (6756 participants).

  • 2005 – 2010 (7880 participants).

The survey participants were classed as having diabetes if they had self-reported it or having undiagnosed diabetes (defined as an HbA1c 6.5% or higher or a fasting plasma glucose 126 mg/dL or higher based on a 1-time test).

The researchers looked at the prevalence of diabetes as well as body mass index (BMI), waist-to-hip ratio, waist circumference, and other measures in 3 age groups:

  • Younger adults (aged 20 to 34).

  • Middle-aged adults (aged 35 to 64).

  • Older adults (aged 65 and older).

In the first period, 8.4% of the survey participants had diagnosed or undiagnosed diabetes, but by the third period this had increased to 12.1%.

Based on the total population of the United States at those 2 times, the researchers estimated that diabetes prevalence grew from 14.9 million cases at the first time point to 26.1 million cases approximately 20 years later — an increase of 75%.

The prevalence of diabetes increased significantly in the most recent period vs the earliest period for all ages. However, the increase was greater in the oldest age group (10%) than in the middle-aged group (2.7%) or younger group (1%).

Over the 3 periods, the prevalence of obesity (BMI 30.0 or higher) increased from 22% to 30% to 34.6%, and the prevalence of individuals with a BMI 40.0 or higher rose dramatically from 2.7% to 4.9% to 6.4%.

Obesity, as measured by BMI and waist-to-hip ratio, was strongly associated with the increase in diabetes prevalence, especially in younger and middle-aged adults. "We think [obesity] is a primary factor contributing to the increase in the prevalence" of diabetes, Dr. Cheng said.

The group acknowledges there are limitations to the work: it was a cross-sectional study, it did not distinguish between type 1 and type 2 diabetes, and it relied on a 1-time measurement to establish undiagnosed diabetes.

Nevertheless, the expected ongoing increase in people with diabetes is likely to "significantly stretch" the already-tightened financial and labor resources in the United States, Dr. Cheng concluded, so stakeholders need to work together and focus their efforts on primary prevention.

The authors have reported no relevant financial relationships.

Diabetes Care. Published online May 1, 2013. Abstract


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