Roughly 1.4 million Americans are diagnosed with diabetes every year, and 96 million Americans over the age of 18 had prediabetes in 2019. It’s a major public health issue, and early diagnosis can prevent serious complications from the disease.

However, when it comes to diagnosis, a study published March 24 in the American Journal of Preventive Medicine found that focusing on age and not weight captures the greatest number of people in all ethnic and racial groups who have prediabetes and diabetes. The team found that this age-focused approach will also maximize the ability to diagnose prediabetes and diabetes.

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Currently, the US Preventive Services Task Force (USPSTF) recommends screening those who are 35 to 70 years-old who have a body mass index (BMI) above 25 for diabetes, partially because BMI is considered a risk factor and predictor for the disease. But different racial and ethnic groups develop diabetes at lower body weights, so making screening decisions solely based on weight alone can miss them, according to this study

“All major racial and ethnic minority groups develop diabetes at lower weights than white adults, and it’s most pronounced for Asian Americans,” Matthew O’Brien, a co-author of the study and physician with Northwestern University Feinberg School of Medicine, said in a statement. “It might sound counterintuitive because we think of being overweight or obese as the primary cause of diabetes.”

In the study, the team examined the clinical performance of the 2021 USPSTF prediabetes and diabetes screening recommendation, as well as alternate age and BMI cutoffs. The performance was assessed in the entire US adult population and also separately by race and ethnicity.

When looking at a national survey of blood sugar levels, the team found that 2021 guidelines do detect a greater share of people with people with prediabetes or diabetes, but the percentage of cases found in Asian Americans is significantly lower than from other groups. The study found an estimated 6 million Asian Americans have prediabetes or undiagnosed diabetes.

The study then examined the number of cases that would have been detected if all adults ages 35-70 were screened, regardless of BMI. Using age as a criteria detects the most cases within a broad population, hitting closer to an equal percentage point across racial groups.

When looking at lowering the minimum screening age to 18, they found that it increases the amount of cases, which results in large differences in diabetes detection. However, when expanding a test pool for screening, there is also a greater chance of testing those who do not have prediabetes or diabetes.

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”Diabetes is a condition in which unacceptable racial and ethnic disparities persist,” O’Brien said. “That’s why we need a screening approach that maximizes equity. If we can find everyone earlier, it helps us reduce these disparities and the bad outcomes that follow.” 

Some scientists say that there is evidence that health care providers are already doing a good job at screening and diagnosing diabetes in the United States. Elizabeth Selvin, an epidemiologist at Johns Hopkins Bloomberg School of Public Health adds that this new study also did not take into account the costs associated with expanding screening, in an interview with STAT News. A 2022 study she conducted found that the proportion of undiagnosed cases has declined substantially over the last three decades. 

Additionally, the USPSTF guidelines do suggest that clinicians consider earlier screening in racial and ethnic groups with high diabetes risk at younger ages or lower BMI. Still,  these alternatives were not formally included in their list of recommendations. 

“It’s imperative that we identify a screening approach that is equitable across the entire U.S. population,” O’Brien said. “Our findings illustrate that screening all adults aged 35 to 70 years, regardless of weight or body mass index, performs equitably across all racial and ethnic groups.”