Type 2 diabetes risk factors: who is at risk, and how to lower it

The main risk factors

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says your chances depend on a combination of risk factors. You are more likely to develop type 2 diabetes if you (NIDDK) (NIDDK):

• have overweight, obesity or a large waist size
• are age 35 or older; children and teens can also develop type 2 diabetes, but the risk goes up with age
• have a family history of diabetes
• are African American, American Indian, Asian American, Hispanic/Latino or Pacific Islander
• are not physically active, because of physical limits, a sedentary lifestyle or a job that requires sitting for long periods
• smoke, including tobacco products and e-cigarettes, or are exposed to secondhand smoke
• have prediabetes
• had gestational diabetes (diabetes during pregnancy), or gave birth to a baby weighing 9 pounds or more (see gestational diabetes risk factors)

Children and teens are also at higher risk if, on top of these, they were born with a low birth weight or their parent had gestational diabetes while pregnant with them (NIDDK). NIDDK also suggests asking your doctor whether any medicines you or your child take might increase the risk (NIDDK).

MedlinePlus says type 2 diabetes may come from a mix of factors: overweight or obesity, not being physically active, and genetics and family history. It usually starts with insulin resistance, when your cells do not respond normally to insulin (MedlinePlus).

Risk factors you can and cannot change

You cannot change your age, family history, race or ethnicity. NIDDK says you may be able to change others, and prevent or delay type 2 diabetes, by keeping a healthy weight, being physically active and stopping smoking (NIDDK). Talking with a doctor about conditions that need treatment may also help, because managing health problems may reduce your chances (NIDDK).

Does your weight put you at risk?

NIDDK says most adults with a body mass index (BMI) of 25 or higher are overweight and have a higher risk of type 2 diabetes. Asian Americans are overweight at a BMI of 23 or higher, and Pacific Islanders at 26 or higher (NIDDK). Work out yours with the BMI calculator.

Waist size matters too. Men have a higher risk if their waist is more than 40 inches, and women who are not pregnant if it is more than 35 inches. A large waist is a risk factor for diabetes and heart disease even with a normal BMI (NIDDK). See the waist circumference check.

Why it can go unnoticed

Symptoms of type 2 diabetes can develop slowly, over several years. Many people have no symptoms, or symptoms so mild they do not notice them (NIDDK). MedlinePlus also lists numbness or tingling in the feet or hands and unexplained weight loss among possible symptoms (MedlinePlus).

Common symptoms of diabetes listed by NIDDK include increased urination, feeling very thirsty, feeling very hungry even after eating, blurred vision, fatigue, sores that do not heal, and frequent infections (NIDDK). These have other causes too, so they are a reason to talk with a health care professional and ask about testing, not a diagnosis.

The tests that check for it

NIDDK lists these results as diabetes for people who are not pregnant, and says your doctor will usually use a second test to confirm it (NIDDK):

• Fasting blood glucose: 126 mg/dL or above. See fasting blood sugar levels.
• Hemoglobin A1C: 6.5% or above. See A1C levels.
• Oral glucose tolerance test: 200 mg/dL or above, 2 hours after glucose intake.

Results that are higher than normal but below these lines are called prediabetes, which NIDDK says raises your chance of developing type 2 diabetes. About 1 in 3 Americans has prediabetes, and you will not know unless you are tested (NIDDK).

Who should get tested

The US Preventive Services Task Force recommends screening for prediabetes and type 2 diabetes in adults aged 35 to 70 years who have overweight or obesity (USPSTF 2021). The diabetes screening age check shows what the US Preventive Services Task Force advises for you.

No blood test yet? The diabetes risk test asks 7 questions to show whether testing is worth asking about.

Steps that may lower your risk

NIDDK says research such as the Diabetes Prevention Program shows you can do a lot to lower your chances (NIDDK):

• Lose weight and keep it off. Losing 5 to 7 percent of your starting weight may prevent or delay diabetes. If you weigh 200 pounds, that is about 10 to 14 pounds.
• Move more. Get at least 30 minutes of physical activity 5 days a week. If you have not been active, ask your health care professional which activities are best, and start slowly.
• Eat healthy foods most of the time. Eat smaller portions, choose foods with less fat, and drink water instead of sweetened beverages.

NIDDK also says to ask your doctor whether the diabetes drug metformin could help prevent or delay type 2 diabetes for you (NIDDK).

Common questions

What is the biggest risk factor for type 2 diabetes?

NIDDK does not rank them; your chances depend on a combination of risk factors (NIDDK). Overweight, age 35 or older, family history and prediabetes are all on its list.

Can thin people get type 2 diabetes?

Yes. Weight is only one risk factor. Age, family history, prediabetes and a large waist are others, and NIDDK says a large waist is a risk factor even with a normal BMI (NIDDK).

Does type 2 diabetes run in families?

A family history of diabetes is a risk factor, and MedlinePlus names genetics and family history among the causes (NIDDK) (MedlinePlus).

Can type 2 diabetes be prevented?

NIDDK says it can be delayed or even prevented, mainly by losing a modest amount of weight and being physically active (NIDDK).