Prediabetes: symptoms, risk factors, tests and prevention

Prediabetes is often called a warning stage. Your blood sugar is higher than it should be, but not yet high enough for a diagnosis of type 2 diabetes. Many people do not know they have it, so understanding the basics can help you decide whether to ask for a test.

What is prediabetes?

According to the US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), prediabetes means blood glucose levels are higher than normal but not high enough to be diagnosed as type 2 diabetes. It is closely linked with insulin resistance, a state in which the body's cells do not respond well to insulin. The NIDDK says about 97.6 million adults in the United States aged 18 and older had prediabetes in 2021. The NIDDK also notes that people with prediabetes have a high chance of developing type 2 diabetes within 5 to 10 years, although this is not certain for everyone.

Symptoms

Most people with prediabetes have no symptoms at all, according to the NIDDK. This is why testing matters. You cannot tell from how you feel whether your blood sugar is in the normal range.

Causes and risk factors

The NIDDK says researchers do not fully understand what causes prediabetes. It lists several things that raise the chance of having it:

• Overweight, obesity or a large waist
• Being 35 or older (children and teens can also develop prediabetes)
• A family history of diabetes
• Being African American, American Indian, Asian American, Hispanic/Latino or Pacific Islander
• Not being physically active
• Smoking, using e-cigarettes or being exposed to secondhand smoke
• Having had gestational diabetes, or having given birth to a baby weighing 9 pounds or more
• Conditions such as polycystic ovary syndrome, Cushing's syndrome, acromegaly or sleep apnea
• Long-term use of certain medicines, such as glucocorticoids, some antipsychotics or some HIV medicines

The NIDDK points out that age, family history and ethnic background cannot be changed, while weight, activity level and smoking can.

How is prediabetes diagnosed?

Prediabetes is found with blood tests. The NIDDK gives these ranges:

• A1C test: 5.7% to 6.4%
• Fasting plasma glucose: 100 to 125 mg/dL
• Oral glucose tolerance test (2-hour result): 140 to 199 mg/dL

The NIDDK adds that the A1C test may miss prediabetes in people with certain health conditions. Doctors may also check cholesterol and triglycerides, because these often rise along with prediabetes. A home glucose meter cannot be used to diagnose prediabetes or diabetes.

Who should be tested?

According to the NIDDK, adults may be tested if they are 35 or older, or if they have overweight or obesity plus other risk factors. Children with overweight or obesity may begin testing at age 10 or at puberty. If you have risk factors but your results are normal, you may be retested at least every 3 years. If you have prediabetes, the NIDDK says you should be tested for type 2 diabetes every year.

Steps that may delay type 2 diabetes

The NIDDK describes these general steps. Your doctor can help you decide what suits you.

• Eat healthy foods and drinks.
• Be physically active.
• Manage your weight. In the Diabetes Prevention Program study, losing 5% to 7% of starting weight lowered the risk of diabetes, the NIDDK reports.
• Get enough sleep.
• Ask your doctor whether a medicine could help delay type 2 diabetes. This is a decision for you and your doctor.
• Consider a structured lifestyle change program. The US Centers for Disease Control and Prevention (CDC) describes a recognised lifestyle change program as an evidence-based way to prevent or delay type 2 diabetes. The CDC says about 1 in 3 American adults has prediabetes.

When to see a doctor

Talk to a doctor about testing if you have any of the risk factors above, even if you feel well. Also speak to a doctor if you notice signs that can go with high blood sugar, such as unusual thirst, passing urine more often, tiredness or blurred vision.

Seek urgent care for severe symptoms such as trouble breathing, confusion, fainting, or stomach pain with vomiting. In an emergency, call your local emergency number (112 in India, 911 in the United States).

This article is for education only. It does not diagnose any condition or replace advice from your own doctor.