Do I have a risk of developing diabetes if some of my relatives have it and others don't?

Yes, You Are at Increased Risk for Diabetes

Having relatives with diabetes—even if some relatives don't have it—places you at significantly increased risk for developing type 2 diabetes, and you should be screened and counseled about prevention strategies. 1

Understanding Your Family History Risk

Family history of diabetes in first-degree relatives (parents, siblings) is one of the strongest risk factors for developing type 2 diabetes, even more influential than many other risk factors. 2, 1

Key facts about familial risk:

• If you have a parent with diabetes, your risk of developing diabetes is approximately 4-5 times higher than someone without family history. 3
• Studies show that 14.3% of people with a first-degree relative with diabetes develop the disease, compared to only 3.2% without family history. 3
• The fact that some relatives don't have diabetes does not negate your risk—family history of diabetes in any first-degree relative qualifies you as higher risk. 1
• Between 74-100% of people who develop type 2 diabetes have at least one first- or second-degree relative with the disease. 2

Why Some Relatives Have It and Others Don't

The genetics of type 2 diabetes are complex and poorly understood, involving multiple genes interacting with environmental factors. 2

Important considerations:

• Type 2 diabetes has a strong genetic predisposition, but it requires both genetic susceptibility and environmental triggers (obesity, physical inactivity, aging) to manifest. 2
• Some family members may have undiagnosed diabetes, so the absence of known family history doesn't necessarily mean absence of genetic risk. 1
• Your relatives without diabetes may simply not have developed the environmental risk factors (obesity, sedentary lifestyle) that trigger the disease in genetically susceptible individuals. 2

What You Should Do Now

Screening recommendations based on your family history:

• Begin screening earlier than age 45 if you have a parent or sibling with diabetes. 1
• Get tested regardless of age if you have a first-degree relative with diabetes AND you are overweight (BMI ≥25 kg/m² or ≥23 kg/m² if Asian American). 2, 1
• If initial tests are normal, repeat screening at minimum every 3 years, with consideration for more frequent testing if you have additional risk factors. 2, 1
• Appropriate screening tests include fasting plasma glucose, 2-hour oral glucose tolerance test, or hemoglobin A1C. 2

Risk Factors That Compound Your Family History

Your risk becomes substantially higher if you have family history plus any of these factors:

• Obesity or overweight status (BMI ≥25 kg/m² or ≥23 kg/m² for Asian Americans)—this is the most significant modifiable risk factor. 1, 4
• Physical inactivity or sedentary lifestyle—lack of exercise independently increases diabetes risk. 1, 5
• Age ≥35-45 years—risk increases progressively with advancing age. 2, 5
• High-risk ethnicity (African American, Latino, Native American, Asian American, Pacific Islander). 1, 5
• Hypertension (blood pressure ≥140/90 mmHg). 5
• History of gestational diabetes (if female). 5

Prevention Strategies You Should Implement

Intensive lifestyle modification programs have been proven to significantly reduce diabetes incidence in high-risk individuals like yourself. 2, 4

Specific actions to take:

• Weight management: If overweight, even modest weight loss (5-7% of body weight) substantially reduces diabetes risk. 2
• Regular physical activity: Aim for at least 150 minutes of moderate-intensity exercise per week. 2, 1
• Healthy diet: Focus on whole grains, vegetables, lean proteins, and limiting processed foods and added sugars. 2
• More aggressive interventions: If you develop prediabetes (A1C 5.7-6.4%, fasting glucose 100-125 mg/dL), you need even more vigilant follow-up and intensive lifestyle programs. 1

Critical Pitfalls to Avoid

• Don't assume you're safe because some relatives don't have diabetes—the presence of diabetes in any first-degree relative qualifies you as high-risk. 1, 3
• Don't wait until age 45 to be screened—with family history, screening should begin earlier, especially if you have other risk factors. 1
• Don't ignore borderline test results—if your A1C is 5.7-6.4% or fasting glucose is 100-125 mg/dL, you have prediabetes and face a 25-50% risk of developing diabetes within 5 years. 2
• If you're Asian American, don't use standard BMI cutoffs—use ≥23 kg/m² instead of ≥25 kg/m² to avoid missing your elevated risk. 2, 5

The Bottom Line

Your family history places you at substantially elevated risk regardless of which specific relatives have diabetes. The risk is continuous and becomes disproportionately greater with additional risk factors like obesity and physical inactivity. 1 You should discuss your family history with your doctor, undergo appropriate screening, and implement aggressive lifestyle modifications to prevent or delay the onset of diabetes. 1, 6