Prediabetes Racial and Ethnic Disparities: Prevalence, Risk, and What to Do About It

How Big Are the Racial Gaps in Prediabetes Prevalence?

The gaps are substantial and well-documented. National Health and Nutrition Examination Survey (NHANES) data show that prediabetes prevalence among non-Hispanic Black adults (40%), Hispanic adults (39%), and Asian Americans (37%) all exceed the 34% rate seen in non-Hispanic White adults, with American Indian/Alaska Native populations estimated above 50% in some regional surveys. [1]

What NHANES Data Actually Show

NHANES cycles from 2017 to 2020 found that age-adjusted prediabetes prevalence differed by as much as 16 percentage points across racial and ethnic subgroups when fasting glucose and HbA1c criteria were applied together. [1] The disparity is not simply a product of age distribution. After adjusting for age, sex, and body mass index, Black and Hispanic adults still showed significantly higher odds of prediabetic glycemia compared with White adults.

The Asian American Paradox

Asian Americans develop insulin resistance and impaired glucose tolerance at lower body weights than other groups. The American Diabetes Association (ADA) 2025 Standards of Care therefore recommend initiating diabetes screening in Asian American adults at a BMI of 23 kg/m² rather than the 25 kg/m² threshold applied to other populations. [2] A 2019 analysis published in Diabetes Care (N=4,033) confirmed that Asian Americans reached equivalent cardiometabolic risk at BMIs roughly 3 to 4 units lower than non-Hispanic White adults. [3]

American Indian and Alaska Native Burden

Federal Indian Health Service surveillance and the Strong Heart Study consistently place prediabetes and undiagnosed diabetes rates among American Indian adults 20 to 30 percentage points above national averages. [4] Structural factors, including limited access to laboratory screening, geographic isolation, and high rates of food insecurity, amplify genetic susceptibility in these communities.

Why Do These Disparities Exist?

The drivers fall into two overlapping categories: biological and structural. Neither category alone explains the full gap. [5]

Biological Contributors

Hepatic insulin clearance, skeletal muscle insulin sensitivity, and pancreatic beta-cell reserve differ measurably across populations. A 2021 study in The Journal of Clinical Endocrinology and Metabolism (N=1,322) found that Black adults had lower hepatic insulin extraction than White adults at identical fasting glucose levels, meaning standard HbA1c cutoffs may under-diagnose prediabetes in this group. [6] Genetic variants in TCF7L2 and SLC30A8, both associated with beta-cell dysfunction, show different allele frequencies across ancestral populations, which may partly explain differential progression rates. [7]

Structural and Social Determinants

Structural inequities shape glycemic risk long before a lab value appears. Neighborhood food environments, chronic stress from discrimination, shift-work schedules tied to economic necessity, and limited green space for physical activity all affect insulin sensitivity independently of individual behavior. [5]

The ADA's 2023 position statement "Social Determinants of Health and Diabetes" explicitly states: "Poverty, food insecurity, and neighborhood disadvantage are associated with higher rates of diabetes and its complications, and these exposures cluster in communities of color due to historical and ongoing structural racism." [8]

Screening: Who Needs to Be Tested, and When?

The USPSTF 2021 recommendation (Grade B) calls for screening all asymptomatic adults aged 35 to 70 who are overweight or obese, with the grade lowered to I (insufficient evidence) for adults under 35. [9] The ADA 2025 Standards go further, recommending screening beginning at any age for adults with a BMI at or above 25 kg/m² (or at or above 23 kg/m² in Asian Americans) plus one or more additional risk factors. [2]

ADA Risk Factors That Trigger Earlier Screening

• First-degree relative with diabetes
• High-risk race or ethnicity (Black, Hispanic, Asian American, American Indian, Pacific Islander)
• History of gestational diabetes or delivery of a baby weighing more than 9 pounds
• Polycystic ovary syndrome
• HDL <35 mg/dL or triglycerides >250 mg/dL
• Hypertension or treatment for hypertension
• Physical inactivity

Because high-risk race or ethnicity appears explicitly on this list, it lowers the effective screening threshold for tens of millions of U.S. Adults. [2]

Which Test to Use

Fasting plasma glucose, 2-hour 75 g oral glucose tolerance test (OGTT), and HbA1c are all acceptable. The OGTT catches the most cases in populations where postprandial hyperglycemia predominates, a pattern more common in Asian and Hispanic adults than in White adults. [3] A study in Diabetes Care (2014, N=5,765) found that HbA1c alone missed 73% of OGTT-diagnosed prediabetes in a multiethnic cohort. [10] HbA1c can also be falsely lowered by common hemoglobin variants (such as HbS trait) prevalent in Black adults, potentially masking true glycemic risk. [6]

Progression to Type 2 Diabetes: Who Is at Greatest Risk?

Without intervention, people with prediabetes progress to type 2 diabetes at roughly 5 to 10% per year. The Diabetes Prevention Program (DPP) baseline cohort (N=3,234) confirmed a 4-year cumulative incidence of 37% in the placebo arm. [11] Progression risk is not uniform across ethnicities even within a prediabetic population.

DPP Subgroup Findings by Ethnicity

The DPP enrolled participants across five racial and ethnic groups: non-Hispanic White (45%), Black (22%), Hispanic (16%), Asian American (5%), and American Indian (5%). Subgroup analyses published in Diabetes Care found that American Indian participants had the highest placebo-arm progression rate, while Asian American participants showed the steepest absolute risk reduction from lifestyle intervention relative to their baseline rate. [12]

HbA1c Level as a Progression Predictor

Within the prediabetes range (HbA1c 5.7 to 6.4%), the risk of progression varies sharply. Adults with an HbA1c of 6.0 to 6.4% have a 25% 3-year progression rate, compared with roughly 9% for those at 5.7 to 5.9%. [11] Clinicians managing high-risk ethnic groups should treat HbA1c at the upper end of the prediabetic range as a near-emergency for intervention initiation.

Evidence-Based Interventions That Work Across Racial Groups

The Diabetes Prevention Program

The DPP remains the gold standard. Lifestyle intervention (goal: 7% weight loss, 150 min/week of moderate activity) reduced progression by 58% (P<0.001) compared with placebo over 2.8 years. [11] Metformin 850 mg twice daily reduced progression by 31% (P<0.001). Critically, lifestyle intervention outperformed metformin in every subgroup except adults aged 25 to 44 and those with BMI above 35, where metformin was roughly equivalent. [11]

Cultural Adaptations of the DPP

The CDC-recognized National Diabetes Prevention Program (NDPP) operates in community settings and has been adapted for specific populations. YMCA DPP studies in predominantly Black and Hispanic communities show 1-year weight loss of 4 to 5% and reduced progression risk, though absolute weight loss is modestly lower than in the original DPP trial. [13]

A 2020 systematic review in Diabetes Care (k=22 studies) found that culturally tailored DPP adaptations produced statistically significant HbA1c reductions in Black and Latino participants, with a mean HbA1c reduction of 0.27% (P<0.001) relative to standard care. [13]

Metformin in Racial Subgroups

Metformin is FDA-approved for prevention of type 2 diabetes in high-risk adults, though it carries an off-label nuance in this specific indication. The ADA 2025 Standards recommend considering metformin for adults with prediabetes who are aged 25 to 59, have a BMI of 35 or above, have higher fasting glucose (110 to 125 mg/dL), or have a history of gestational diabetes. [2] Because those criteria overlap heavily with high-risk ethnic populations, metformin is a reasonable adjunct option after shared decision-making.

GLP-1 Receptor Agonists: Emerging Role

Semaglutide has not been studied specifically in a prediabetes-prevention trial at the scale of the DPP. The STEP-1 trial (N=1,961) demonstrated 14.9% mean weight loss with semaglutide 2.4 mg weekly versus 2.4% with placebo at 68 weeks (P<0.001), and a proportion of participants with prediabetes at baseline reverted to normoglycemia. [14] Post-hoc analyses have not yet been stratified by race and ethnicity with adequate power, but the absolute weight-loss benefit may be particularly meaningful for Asian American patients who develop metabolic dysfunction at lower BMIs. GLP-1 agents are not currently a first-line ADA recommendation for prediabetes in any ethnic group, but their use in comorbid obesity is consistent with ADA 2025 obesity-management guidance. [2]

A Practical Screening and Management Framework for High-Risk Populations

The following decision pathway applies the ADA and USPSTF criteria with race-specific adjustments:

Step 1: Identify eligibility. Screen any adult aged 35 to 70 who is overweight or obese (USPSTF). For Asian American adults, apply BMI <23 threshold. For any adult of Black, Hispanic, Asian, American Indian, or Pacific Islander ancestry with one additional ADA risk factor, begin screening regardless of age.

Step 2: Choose the right test. Use the OGTT (75 g, 2-hour) when HbA1c may be unreliable due to hemoglobin variant prevalence (particularly in Black adults). Use fasting glucose plus HbA1c together in Asian American patients to capture postprandial risk.

Step 3: Stratify within prediabetes. HbA1c 6.0 to 6.4% or fasting glucose 110 to 125 mg/dL signals high short-term progression risk. Intervene immediately rather than waiting for a recheck.

Step 4: Refer to NDPP. The CDC NDPP has more than 2,000 recognized sites, including telehealth delivery. Evidence supports NDPP effectiveness in Black and Hispanic participants. [13]

Step 5: Consider metformin. For adults meeting ADA metformin-consideration criteria, discuss 850 mg twice daily with titration from 500 mg once daily to reduce GI side effects. Recheck renal function (eGFR) before initiation.

Step 6: Rescreen annually. The ADA recommends annual rescreening for people with prediabetes. [2] Quarterly or semi-annual HbA1c may be appropriate in adults with HbA1c of 6.0 to 6.4% who have not yet enrolled in a structured program.

Access Barriers That Perpetuate Disparities

Even when screening guidelines are clear, access barriers prevent equitable implementation. Community health center data show that Black and Hispanic adults with prediabetes are 30 to 40% less likely to be referred to a structured prevention program than White adults with the same diagnosis. [15]

Insurance Coverage Gaps

Medicare covers the CDC NDPP for beneficiaries with a prediabetes diagnosis or a high-risk score. Many Medicaid programs have lagged in formal coverage, creating a gap that disproportionately affects lower-income Black and Hispanic adults who make up a large share of Medicaid enrollees.

Language and Literacy

CDC survey data show that limited English proficiency is associated with significantly lower rates of prediabetes awareness (19% overall; lower still in Spanish-dominant and non-English-speaking households). [1] NDPP delivery in Spanish, Mandarin, and other languages is available through some providers but remains geographically inconsistent.

Telehealth as an Equalizer

A 2022 analysis in JAMA Network Open (N=10,948) found that telehealth-delivered DPP achieved comparable weight loss to in-person delivery (4.7% vs. 5.0% at 12 months) and showed stronger retention in participants from majority-minority zip codes. [16] Telehealth delivery may reduce transportation and scheduling barriers that fall more heavily on hourly workers, a group disproportionately composed of Black and Hispanic adults.

What Clinicians Should Do Differently Right Now

Clinical inertia is a documented driver of persistent disparities. A 2021 retrospective cohort study in Annals of Internal Medicine (N=23,230) found that fewer than 4% of adults newly diagnosed with prediabetes received a formal referral to a structured prevention program within 12 months, with referral rates lower for uninsured and Medicaid patients. [15]

Three concrete changes improve outcomes for high-risk populations:

1. Use electronic health record (EHR) alerts to flag Asian American patients with BMI above 23 for prediabetes screening at routine visits.
2. Co-locate NDPP referrals with the prediabetes diagnosis in the clinical workflow so referral happens at the point of care rather than at a follow-up visit.
3. Document hemoglobin variant status before relying on HbA1c alone in Black patients, and supplement with fasting glucose or OGTT when variant status is unknown.

The ADA 2025 Standards of Care state: "Clinicians should consider the patient's race/ethnicity when interpreting HbA1c results, as certain hemoglobin variants and conditions that affect red blood cell turnover may interfere with some HbA1c assays." [2]

Prediabetes in high-risk racial and ethnic groups is a preventable condition. The DPP showed 58% risk reduction is achievable. The NDPP delivers that intervention at national scale. Referral at the point of diagnosis, not six months later, is the single highest-yield action a clinician can take today.