What are the risk factors for diabetes type II?

Risk Factors for Type 2 Diabetes

The risk of developing type 2 diabetes is driven by a combination of non-modifiable factors (age, genetics, race/ethnicity) and modifiable factors (obesity, physical inactivity, diet), with obesity and family history being the strongest predictors. 1

Non-Modifiable Risk Factors

Age

• Age ≥35 years is a major independent risk factor, with screening recommended to begin no later than age 35 for all individuals 1
• Risk increases progressively with advancing age, making it one of the most consistent predictors 1

Genetics and Family History

• First-degree relatives (parents or siblings) with diabetes confer strong genetic risk, more so than for type 1 diabetes 1
• Having a parent with diabetes warrants earlier screening regardless of other factors 2
• The genetic mechanisms remain poorly understood despite intense investigation 1

Race and Ethnicity

• Higher risk populations include African American, Native American, Hispanic/Latino, and Asian American individuals 1
• Asian Americans develop diabetes at lower BMI thresholds (≥23 kg/m² vs ≥25 kg/m² for general population) 1
• African Americans have equivalent diabetes risk at BMI 26 kg/m² compared to BMI 30 kg/m² in non-Hispanic whites 1
• One-third to one-half of diabetes in Asian Americans remains undiagnosed, suggesting inadequate screening at appropriate BMI cutoffs 1

Modifiable Risk Factors

Obesity and Body Composition

• BMI ≥25 kg/m² is a primary risk factor (≥23 kg/m² for Asian Americans) 1
• Central/abdominal adiposity carries particularly high risk, even in individuals without elevated BMI by traditional criteria 1
• Excess weight causes insulin resistance, the fundamental metabolic defect in type 2 diabetes 1

Physical Inactivity

• Lack of physical activity independently increases diabetes risk 1
• Sedentary behavior compounds risk when combined with other factors 3
• Conversely, moderate physical activity is protective even without weight loss 4

Prior Gestational Diabetes and Reproductive History

• Women with prior gestational diabetes mellitus (GDM) have substantially elevated risk 1
• History of delivering a baby weighing ≥9 lbs indicates increased risk 1
• Polycystic ovary syndrome (PCOS) is an independent risk factor 1

Comorbid Conditions and Clinical Indicators

Cardiovascular Risk Factors

• Hypertension (≥140/90 mmHg) significantly increases diabetes risk 1
• Dyslipidemia, specifically HDL cholesterol ≤35 mg/dL and/or triglycerides ≥250 mg/dL, are strong predictors 1
• History of vascular disease indicates elevated risk 1

Prediabetes

• Impaired fasting glucose (100-125 mg/dL) or impaired glucose tolerance (2-hour OGTT 140-199 mg/dL) markedly increase progression risk 1
• HbA1c 5.7-6.4% identifies individuals at high risk 1
• Risk is continuous across the prediabetes range, becoming disproportionately greater at the upper end 1

Metabolic Indicators

• Insulin resistance, manifested by acanthosis nigricans, is a key risk factor 1, 5
• Fatty liver index is a particularly strong predictor (OR = 6.14) 4
• Signs of insulin resistance include skin tags and central adiposity 5

Medication-Induced Risk

High-Risk Medications

• Glucocorticoids are well-established diabetes risk factors 1
• Thiazide diuretics increase risk 1
• Atypical antipsychotics elevate diabetes risk 1
• Certain HIV antiretroviral therapies (protease inhibitors and NRTIs) cause insulin resistance and may lead to β-cell apoptosis 1

Psychosocial Factors

Mental Health

• Depression increases progression risk from prediabetes to diabetes (OR = 1.88) 4
• Anxiety is associated with elevated risk (OR = 2.61) 4
• Social deprivation correlates with increased diabetes incidence 4

Pediatric and Adolescent Risk Factors

Youth-Specific Considerations

• Testing should be considered in youth with overweight (≥85th percentile) or obesity (≥95th percentile) plus one additional risk factor 1
• Maternal history of diabetes or GDM during the child's gestation is a major risk factor 1
• Testing should begin after puberty onset or after age 10 years, whichever occurs earlier 1
• Signs of insulin resistance (acanthosis nigricans) or small-for-gestational-age birth weight increase risk 1

Clinical Pitfalls to Avoid

• Do not use standard BMI cutoffs for Asian Americans—use ≥23 kg/m² instead of ≥25 kg/m² to avoid missing high-risk individuals 1
• Do not rely on HbA1c for diagnosis in individuals with HIV—it may underestimate glycemia 1
• Do not assume absence of family history eliminates genetic risk—undiagnosed diabetes in family members is common 2
• Do not overlook medication-induced risk—review all medications, particularly glucocorticoids, antipsychotics, and antiretrovirals 1
• Do not screen only at age 45—begin at age 35 for all individuals, and earlier for those with risk factors 1