Prediabetes: What It Is, Symptoms and Signs

Prediabetes is usually imagined as a condition you can feel. In practice, it is the opposite: a person lives for years with elevated glucose and has no idea. Let us go through it in order: what lies behind this word and why the numbers on a test form say more than how you feel.

What prediabetes is

The definition is simple: blood glucose is above normal but not high enough to diagnose type 2 diabetes mellitus. Behind this lies insulin resistance: cells of muscle, adipose tissue, and liver respond poorly to insulin. It is produced by the pancreas, and the hormone's job is to help glucose enter cells. When cells do not respond, the gland may over time fail to produce enough insulin, and blood glucose rises.

The scale is impressive: approximately one in three adults has prediabetes, and in the USA in 2021 — about 97.6 million people over 18. The term "pre-sugar diabetes" is also used — it means the same thing. The condition is often detected retrospectively, already based on the fact of rising glucose.

Causes and risk factors of prediabetes

Researchers do not fully understand the exact mechanism, but the range of causes is outlined. The main factors are considered to be excess body weight and lack of regular physical activity. What increases the likelihood:

• excess body weight or obesity, large waist circumference;
• age: risk rises after 35 years, some recommendations name 45 years as the threshold;
• diabetes in a parent, brother, or sister;
• physical inactivity, smoking and passive smoking, including e-cigarettes;
• gestational diabetes in the past, birth of a child weighing 4.5 kg or more, polycystic ovary syndrome, sleep apnea, long-term use of glucocorticoids and certain other medications.

Some factors cannot be changed — heredity, age, ethnic origin. Some can be corrected.

Symptoms and signs of prediabetes

The most honest answer: there are usually no symptoms. Most people learn about their condition by chance, from a blood test. Some develop skin changes — darkening in the armpits and on the back and sides of the neck, small skin growths in the same areas.

Clinical descriptions also mention nonspecific signs: dry skin, itching, slow-healing injuries, furunculosis, bleeding gums and periodontitis, menstrual irregularities. Each of these alone says nothing, but together with risk factors it becomes a reason to check glucose.

How prediabetes is detected

The diagnosis is made by blood. An insulin resistance test is not used in routine practice — it remains a research tool. Two main tests are used. Fasting glucose (at least 8 hours without food or drink): 99 and below — normal, 100–125 — prediabetes, 126 and above — diabetes. Glycated hemoglobin A1C shows average glucose over the last 3 months: below 5.7% — normal, 5.7–6.4% — prediabetes, above 6.5% — diabetes. There is also a glucose tolerance test: fasting glucose and two hours after a load.

Testing is done for those aged 35 and older, as well as people with excess body weight and other risk factors. Children with excess body weight — from age 10 or from the onset of puberty. If risk factors are present but there is no prediabetes, the test is repeated at least once every 3 years; with confirmed prediabetes — once a year.

Why prediabetes is dangerous

The main risk is progression to type 2 diabetes: the chances of this are high within 5–10 years. But it is not only about the future diagnosis. In some people with prediabetes, blood vessels are already changing, and these are the same complications as with diabetes. The list of associated conditions includes high blood pressure, metabolic syndrome, fatty liver disease, obesity, unhealthy cholesterol and triglyceride levels, and increased risk of heart disease and stroke. At the same time, not everyone with prediabetes progresses to diabetes: many people can delay or prevent it.

When to see a doctor

The reason is not how you feel, but the combination of risk factors and the numbers in tests. If you have relatives with diabetes, excess weight, are over 35, had diabetes during pregnancy in the past, or have darkened skin folds — discuss with your family doctor or endocrinologist what examinations are needed. The doctor takes a history, orders blood tests, and determines how often to repeat monitoring.

Prediabetes by itself is not a reason to call an ambulance. 103 or 112 — if signs of stroke or heart attack appear, conditions that threaten life.

And lastly: reference text is a guide, not a diagnosis. Only a doctor during an appointment can make sense of your test results.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer