The term borderline diabetes refers to a condition called prediabetes. Prediabetes is a condition in which blood sugar levels are higher than normal but not high enough to be classed as type 2 diabetes.

Prediabetes is to be considered a risk factor for type 2 diabetes. It is estimated that 10 to 23 percent of people with prediabetes will go on to develop type 2 diabetes within 5 years.

Prediabetes can be accompanied by other risk factors. It is associated with conditions such as obesity, especially abdominal obesity, high blood pressure, high blood fat levels and low levels of “good” cholesterol.

When these risk factors “cluster” together in a person, there is a higher risk of not just type 2 diabetes but heart disease and stroke as well.

Other medical terms used when talking about prediabetes include:

Symptoms of borderline diabetes

Prediabetes is not the same as diabetes. However, neither prediabetes nor diabetes have clear symptoms. Both can go unnoticed until prediabetes has progressed to type 2 diabetes, or until another complication such as a heart attack occurs.

Some people may experience symptoms as their blood sugars remain high. Passing urine more often and increased thirst can be symptoms of type 2 diabetes before it is diagnosed and treated.

Prediabetes is not found unless testing is done for it. Testing is carried out when there are risk factors that make prediabetes more likely.

Causes and risk factors of borderline diabetes

The main risk factors for prediabetes are being overweight or obese, not getting enough exercise, and having a family history of type 2 diabetes. Other risk factors include:

  • Raised stress levels
  • Smoking
  • Drinking too much alcohol
Soda with many spoons of sugar.
Drinking a lot of sugary drinks like sodas can lead to prediabetes.

Drinking a lot of high-sugar drinks may also increase the risk. One study found that people who regularly drink sugary products – 1 or 2 cans of soda a day, for example – are at an increased risk of type 2 diabetes as well as prediabetes.

People who consume sugary drinks at this level, or more, are at 26 percent higher risk of developing diabetes than people who rarely drink a can.

The risk of getting diabetes from too much soda is even higher for young adults or Asians who are consuming this amount.

Consuming too much sugar also increases the risks for related problems such as obesity, heart disease, and gout.

The problem with cans of soda is that the high levels of calories they contain do not reduce appetite and lead to people eating less at mealtimes. There are 15 to 18 teaspoons of sugar in a typical 20-ounce can of soda.

Inactive lifestyles also worsen the risks of taking in too many calories.

There are other risk factors in addition to these reasons for prediabetes screening. They include polycystic ovary syndrome (PCOS) and having had abnormal blood sugar levels in the past.

Diagnosis of borderline diabetes

Prediabetes is typically diagnosed with a blood draw or with a glucose tolerance test. Fasting or random blood sugar levels can be used, or the doctor can use an A1C test.

The A1C test is an indirect but reliable way of measuring the average blood sugar levels over the past 2 to 3 months.

A hand holding an A1C blood sample.
The A1C test is one of the best tests for diagnosing diabetes.

Unlike fasting blood sugar tests, there is no need to be stop eating food for the A1C test. The blood sample is taken from a vein in the arm at the doctor’s office.

Prediabetes is diagnosed when higher blood sugar levels are shown by an A1C test result of between 5.7 and 6.4 percent.

Fasting blood sugar levels in the range of 100-125 mg/dL (milligrams per deciliter) indicate prediabetes, as do non-fasting levels of 140-199mg/dL. These readings need to be confirmed on another day to confirm the diagnosis of prediabetes.

The World Health Organization (WHO) say the A1C test is the best way to diagnose full diabetes, although the test is not available in all countries around the world. However, the A1C test is not accurate for some people, such as people who are anemic.

WHO recommend the A1C test because it:

  • Avoids the problem of day-to-day variability of blood sugar levels – it takes the average level for the past 2-3 months
  • Avoids the “need for the person to fast” or to take any “dietary preparations.”

Being tested for prediabetes is recommended for certain people by the U.S. Department of Health and Human Services and the American Diabetes Association.

Anyone overweight from the age of 45 years onward should get screened if they have one or more of the risk factors listed below. Also recommended for testing is anyone who has:

  • High blood pressure
  • Physical inactivity
  • High blood fat levels
  • Low “good” cholesterol levels
  • History of high blood sugar levels
  • Signs of insulin resistance such as polycystic ovarian syndrome
  • A first-degree relative with diabetes
  • An ethnic background of African-American, Asian-American, Latino or Hispanic-American, Native American, or Pacific Islander
  • Previously had diabetes during pregnancy (gestational diabetes)
  • Previously given birth to a baby weighing more than 9 pounds

Other risk factors such as those mentioned above may also trigger a screen for blood glucose levels.

Treatments for borderline diabetes

Prediabetes is often a reversible problem. It can be reversed through diet and exercise, and so the main treatment of prediabetes is making lifestyle changes. Sometimes, doctors may consider drug treatments to help, such as metformin.

A woman is holding a glucometer and an apple.
Healthy eating and exercising more can reverse the effects of prediabetes.

Lifestyle changes are the key to preventing progression to type 2 diabetes. They can cut the chance that full type 2 diabetes will develop.

Examples of lifestyle changes include 150 minutes of activity per week and 5 to 7 percent weight loss.

Dietary change can include reducing the intake of sugary foods. Diets should focus on unprocessed high-fiber carbohydrates, increasing fruit and vegetable intake, and lowering saturated fat and processed meat intake. A diet that helps people avoid progression to type 2 diabetes is also a heart-healthy diet.

In a study known as the Diabetes Prevention Program, for example, the people taking part who lost 7 percent of their body weight and maintained this loss also managed to:

  • Cut their risk of developing diabetes by 58 percent
  • Had the same benefit whether they were male or female, and regardless of ethnic group
  • Older participants had greater benefit from lifestyle changes
  • Those aged 60 or more cut their diabetes risk by 71 percent

The people in the lifestyle intervention group had “intensive individual counseling and motivational support on effective diet, exercise, and behavior modification.” They were compared with a group that made no lifestyle changes.

The participants reduced their risk of diabetes and achieved their weight loss by:

  • Eating less fat and fewer calories
  • Doing 150 minutes of exercise each week

Diet and exercise continue to be important for people who do develop full type 2 diabetes.

Monitoring borderline diabetes

In addition to recommending lifestyle changes, doctors may offer advice about the potential development of diabetes and how this can be managed.

Medical management may include addressing risk factors and treating other related conditions such as obesity and heart disease.

Managing prediabetes also involves ongoing monitoring of the risk factors and getting further regular testing of blood sugar levels.

If lifestyle changes can be successfully made, monitoring tests in future may show that the condition has been reversed.