Impaired Glucose Tolerance

Impaired glucose tolerance (IGT) is a pre-diabetic state of hyperglycemia that is associated with insulin resistance and increased risk of developing type 2 diabetes and cardiovascular disease.

Definition

Impaired glucose tolerance is defined as a condition where the blood glucose level is higher than normal but not high enough to be classified as diabetes. According to the World Health Organization (WHO), IGT is diagnosed when the 2-hour plasma glucose value during an oral glucose tolerance test (OGTT) is between 7.8 and 11.0 mmol/L.

Causes and Risk Factors

The causes of impaired glucose tolerance are multifactorial and include:

• Insulin resistance: a condition where the body's cells become less responsive to insulin, leading to high blood sugar levels
• Genetic predisposition: family history of diabetes or IGT
• Obesity: particularly central obesity
• Physical inactivity
• Aging: risk increases with age
• Other medical conditions: such as hypertension, dyslipidemia, and polycystic ovary syndrome (PCOS)

Symptoms

Impaired glucose tolerance may not always produce noticeable symptoms. However, some people may experience:

• Increased thirst and urination
• Fatigue
• Blurred vision
• Cuts or wounds that are slow to heal
• Recurring skin, gum, or bladder infections

Diagnosis

Impaired glucose tolerance is typically diagnosed using an oral glucose tolerance test (OGTT). The test involves:

• Fasting for at least 8 hours
• Drinking a sugary drink containing 75g of glucose
• Measuring blood glucose levels after 2 hours

Treatment and Management

The primary goal of treatment is to prevent the progression to type 2 diabetes and reduce the risk of cardiovascular disease. Lifestyle modifications include:

• Weight loss: if overweight or obese
• Increasing physical activity: aiming for at least 150 minutes of moderate-intensity aerobic exercise per week
• Healthy diet: focusing on whole, unprocessed foods and limiting sugary drinks and saturated fats

In some cases, medication may be prescribed to help manage blood glucose levels.

Complications

If left untreated or poorly managed, impaired glucose tolerance can increase the risk of developing:

• Type 2 diabetes
• Cardiovascular disease: including heart attacks, strokes, and peripheral artery disease
• Kidney damage
• Nerve damage
• Eye damage

Early diagnosis and treatment can help prevent or delay the onset of these complications.

Frequently Asked Questions (FAQs)

What is impaired glucose tolerance?
A pre-diabetic state where blood sugar levels are higher than normal but not high enough to be classified as diabetes.

What causes impaired glucose tolerance?
Insulin resistance and impaired insulin secretion.

What are the symptoms of impaired glucose tolerance?
Often none, but may include increased thirst and urination.

How is impaired glucose tolerance diagnosed?
Through an oral glucose tolerance test (OGTT) or a fasting plasma glucose test.

What are the risks associated with impaired glucose tolerance?
Increased risk of developing type 2 diabetes and cardiovascular disease.

Can impaired glucose tolerance be treated?
Yes, through lifestyle changes such as diet and exercise.

What dietary changes can help manage impaired glucose tolerance?
Eating a healthy, balanced diet low in sugar and saturated fats.

Is exercise important for managing impaired glucose tolerance?
Yes, regular physical activity can improve insulin sensitivity.

Can medication be used to treat impaired glucose tolerance?
In some cases, yes, but lifestyle changes are usually recommended first.

Is impaired glucose tolerance reversible?
Yes, with lifestyle changes and weight loss, it is possible to reverse impaired glucose tolerance.