Causes and Risk Factors of Prediabetes

Prediabetes affects approximately 96 million adults in the United States and occurs when a person's blood sugar (glucose) levels are abnormally high but below the threshold for a diagnosis of type 2 diabetes.

While the exact cause of prediabetes is unclear, experts believe this complex condition stems from various factors, including genetic makeup, lifestyle, and underlying cardiovascular health.

This article will explore the factors involved in developing prediabetes, from unmodifiable factors like age and family history to modifiable ones like excess weight and a sedentary lifestyle.

Person eating french fries and fried chicken sandwich

Grace Cary / Getty Images

Common Causes

Experts don't know precisely why some people develop prediabetes and others do not. They know that in prediabetes, your body starts producing less insulin, develops insulin resistance, or both.

What Is Insulin Resistance?

Insulin is a hormone made by your pancreas that moves glucose into your cells, where it's converted into energy. When cells become insulin resistant, they become sluggish and stop responding to insulin, causing blood sugar levels to rise even more.

Experts also know that several factors increase your chances of prediabetes, some within your control and others not.

One unmodifiable risk factor for prediabetes is age. The likelihood of developing prediabetes increases with age. At least half of U.S. adults over 65 have prediabetes.

Genetics and cardiovascular factors play a role in developing prediabetes. Lifestyle habits that contribute to elevated blood sugar levels and stress the body's response to make and respond to insulin can also influence the manifestation of prediabetes.

Even though prediabetes affects most racial and ethnic groups, it's diagnosed most often in Black Americans, Hispanic Americans, Asian Americans, and Hawaiian/Pacific Islanders.

It's unclear why this is the case, but it could be due to decreased access to care or other social and health-related disparities. Understanding racial and ethnic differences in prediabetes is essential to optimizing care for all people.

Genetics

Genetic changes within at least 70 genes have been cited in developing type 2 diabetes, which is what prediabetes will become if left untreated. Most of these genes are involved in insulin production and signaling.

Supporting the genetic component of prediabetes is that your chance of developing prediabetes increases if you have a parent or sibling with the disease.

It's essential to understand that prediabetes is not directly inherited. Even if you are genetically predisposed to developing prediabetes, in most cases, other factors like a sedentary lifestyle or poor diet must be present for the condition to manifest.

Lifestyle Risk Factors

Certain lifestyle factors can also increase your chances of developing prediabetes.

Excess Weight

Obesity is a considerable risk factor for prediabetes. Experts have found that obesity is associated with low-grade inflammation in the body and the impaired metabolic activity of fat cells. This inflammation and metabolic dysfunction ultimately cause insulin resistance.

What Is Obesity?

Obesity is a body mass index (BMI) of 30 or higher. BMI approximates body fat based on a person's height and weight.

The good news is that weight loss lowers inflammation in the body and can prevent prediabetes from progressing into diabetes.

One study found that individuals with prediabetes who lost 10% or more of their body weight had an 85% reduction in risk of developing diabetes within three years. Those who lost 5% to 7% of their body weight decreased their risk by 54%.

Diet

Diets high in cholesterol, saturated fats, salt, and carbohydrates, including red and processed meats, eggs, seafood, cheese, fast foods, snacks, chocolates, and alcohol, also increase your risk for prediabetes.

As such, choosing foods that reduce the inflammatory stress in the body may help prevent prediabetes and eventually diabetes. Specifically, plant-based diets like the Mediterranean diet have been found to improve insulin resistance and chronic inflammation.

What Is the Mediterranean Diet?

The Mediterranean diet emphasizes the consumption of unprocessed foods, especially fruits, vegetables, legumes (such as peas, beans, and lentils), nuts, and extra-virgin olive oil.

Lack of Exercise

Physical inactivity is another risk factor for prediabetes. The American Diabetes Association recommends at least 150 minutes of regular physical activity per week to prevent or combat prediabetes.

Increasing daily movement, in general, is also advised—even brief, unstructured three- to 15-minute activities like errands or gardening can be effective.

In the end, any physical activity helps lower blood glucose levels by improving the body's use of insulin. In addition, exercise helps maintain weight loss, which can also help prevent prediabetes and the onset of type 2 diabetes.

Poor Sleep

Poor sleep quality is also associated with prediabetes, and chronic inflammation may explain this link.

In one study, the inflammatory blood marker C-reactive protein (CRP) was higher in individuals with prediabetes compared to a control group without prediabetes. Chronic inflammation leads to insulin resistance by interfering with insulin signaling pathways within fatty tissues, muscle, and the liver.

Interestingly, less sleep also increases a person's risk of progressing from prediabetes to type 2 diabetes, which occurs in 5% to 10% of individuals yearly.

Cigarette Smoking

Cigarette smoking increases your risk for prediabetes by increasing inflammation and oxidative stress in the body.

Oxidative stress is a phenomenon that occurs in the presence of free radicals (highly reactive and unstable molecules). It causes cell damage, leading to insulin resistance and high blood sugar levels.

Exposure to secondhand smoke also increases your risk for prediabetes.

Cardiovascular and Other Health-Related Risk Factors

Various heart or blood vessel (cardiovascular) factors are also associated with an increased risk of prediabetes. These include:

Two other health conditions tied to the development of prediabetes include:

  • Gestational diabetes: This is a type of diabetes that starts during pregnancy. It usually ends after delivery but does increase a person's risk of developing type 2 diabetes (up to 60%) in the future.
  • Polycystic ovary syndrome (PCOS): This lifelong hormonal/metabolic condition is one of the most common causes of infertility in people with ovaries. It's associated with elevated androgen (a class of sex hormones) levels, irregular menstrual cycles, and insulin resistance, increasing the risk for prediabetes.

Summary

Prediabetes is a condition of abnormally elevated blood sugar levels that are not high enough to be classified as diabetes. Individuals with prediabetes are at risk for progressing to type 2 diabetes.

Experts believe that multiple factors, including genetics and lifestyle habits, including poor diet and lack of exercise, play a role in causing prediabetes. In addition, certain health conditions, such as obesity, high blood pressure, and gestational diabetes, increase your chances of developing prediabetes.

A Word From Verywell

If you (or a loved one) have been diagnosed with prediabetes, you may feel anxious about what this means for your future health. Try to keep a positive mindset and focus your energy on engaging in healthy lifestyle habits that can ultimately reverse your prediabetes.

These habits include eating a well-balanced diet rich in fruits and vegetables, staying active, quitting smoking, and ensuring adequate sleep.

Frequently Asked Questions

  • Can prediabetes cause weight gain?

    Yes. The insulin resistance associated with prediabetes can promote weight gain. Excessive weight is also a risk factor for developing prediabetes.

  • Can prediabetes lead to diabetes?

    Yes. If not managed, prediabetes can progress to type 2 diabetes and complications involving vital organs like the eyes, nerves, kidneys, and blood vessels. 

  • Does prediabetes cause neuropathy?

    Yes. Prolonged elevated sugar levels, as seen in prediabetes, can cause nerve damage (neuropathy). This can cause numbness and tingling of the feet, toes, hands, and fingers.

  • What are the main symptoms of prediabetes?

    Most people with prediabetes experience no symptoms. If they do, they are often subtle and may include excessive thirst, a frequent urge to urinate, or blurry vision. 

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.