Risk Factors and Primary Prevention

Non-Modifiable Risk Factors

• Age — risk rises with age, and age is a direct input into screening decisions
• Family history of diabetes in a first-degree relative
• Race/ethnicity — higher risk in Black or African American, Hispanic or Latino, American Indian or Alaska Native, Asian American, and Native Hawaiian or Pacific Islander populations
• History of gestational diabetes, or delivering an infant weighing more than 9 lb
• Polycystic ovary syndrome (PCOS)
• Genetic susceptibility, such as HLA genotypes that confer type 1 diabetes risk

Modifiable Risk Factors

• Overweight or obesity — BMI ≥25 kg/m² (≥23 kg/m² in Asian American individuals, reflecting elevated risk at a lower BMI threshold in this population)
• Physical inactivity
• Hypertension — blood pressure ≥140/90 mmHg, or already on antihypertensive therapy
• Dyslipidemia — HDL cholesterol <35 mg/dL and/or triglycerides >250 mg/dL
• Prediabetes itself — A1C ≥5.7%, IFG, or IGT, which is both a risk marker and a diagnosis in its own right
• Other markers of insulin resistance, such as acanthosis nigricans, and modifiable cardiovascular risk factors such as smoking

Several of these modifiable factors cluster together as metabolic syndrome — central obesity, hypertension, dyslipidemia, and insulin resistance — which independently predicts progression to type 2 diabetes and cardiovascular disease, and is often what prompts a risk-factor-based screening conversation even before formal diabetes testing is ordered. By contrast, type 1 diabetes risk factors are almost entirely non-modifiable — genetic susceptibility and autoimmune triggers — and no proven primary prevention strategy currently exists, which is why prevention-focused content like the rest of this section centers on type 2 diabetes and prediabetes.

Who and When to Screen

Per the ADA, adults with overweight or obesity and at least one additional risk factor from the lists above should be screened for prediabetes and type 2 diabetes at any age. For everyone else, screening begins at age 35; if results are normal, screening should be repeated at a minimum of 3-year intervals, sooner if risk changes, such as with significant weight gain or a new diagnosis of hypertension. This age-35 threshold reflects a deliberate lowering from the prior age-45 recommendation, made in response to rising rates of type 2 diabetes diagnosed in younger adults. Many clinics use the ADA's validated online Type 2 Diabetes Risk Test, which scores age, sex, history of gestational diabetes, family history, hypertension, physical activity level, and weight-for-height, to flag people who should be tested even outside the standard schedule.

Primary Prevention and the National DPP

Type 2 diabetes is substantially preventable in high-risk individuals through structured lifestyle intervention. The landmark Diabetes Prevention Program (DPP) trial found that intensive lifestyle change reduced progression from prediabetes to type 2 diabetes by 58% overall, and by 71% in adults age 60 and older, outperforming metformin in the same trial.

This evidence underlies the CDC-recognized National Diabetes Prevention Program (National DPP), a year-long, CDC-approved structured lifestyle change program delivered in person, online, or through distance learning. Its core goals for participants:

The National DPP curriculum runs a full year, with more frequent core sessions in the first six months followed by less frequent maintenance sessions, delivered by a CDC-trained lifestyle coach, and is covered as a preventive benefit by Medicare and many private insurers, which removes a common cost barrier to referral.

Participants who reach both the weight-loss and activity goals see the greatest reduction in diabetes risk, and outcomes scale with dose: every additional session attended and every 30 minutes of reported activity is associated with measurably more weight loss. Metformin can be considered as an adjunct or alternative for especially high-risk individuals, such as those with a BMI ≥35 kg/m², age under 60, or a prior history of gestational diabetes, who cannot access or sustain a lifestyle program, but structured lifestyle change remains first-line for primary prevention.

The CDCES Role in Prevention

Referral to the National DPP, or an equivalent evidence-based lifestyle change program, is a core CDCES intervention for anyone meeting prediabetes criteria. Effective referral goes beyond a hand-off: the educator should reinforce the specific 5%-7% and 150-minute goals in terms the person finds meaningful, help identify and address barriers to participation such as transportation, cost, work schedule, food access, and health literacy (see Chapter 3's social determinants of health content), and track progress at follow-up visits. Because National DPP outcomes correlate directly with session attendance and reported activity minutes, ongoing encouragement and problem-solving around adherence are where an educator adds the most value beyond the initial referral itself, and this same lifestyle-first framework carries forward into full self-management education once a person progresses to a diabetes diagnosis. Many National DPP programs now integrate wearable activity trackers and mobile apps to log food intake and exercise minutes in real time, giving both the participant and the coach an early signal when engagement drops — a data stream the CDCES can reference during follow-up visits to problem-solve before a person disengages entirely.