Blood Sugar Limbo

In general, type 2 diabetes is not a condition that develops out of the blue. A diagnosis of diabetes is often made after many years of slight abnormalities in glucose levels. This period of blood sugar limbo between normal readings and full-blown diabetes has become known as prediabetes.

You may be told that you are prediabetic based on the results of two key blood tests. The fasting blood glucose test (FBG) measures the amount of sugar in your blood on an empty stomach. The oral glucose tolerance test (OGTT) goes one step further: blood sugar is measured both before and after drinking a standardized sugary solution to track the body’s response to glucose.

In prediabetics, the results of one or both tests are elevated, but not quite high enough to be classified as diabetes. Although the OGTT is more time-consuming than the FBG, requiring a two hour lab visit, both tests in conjunction will most accurately detect abnormalities.

As we digest a meal or drink containing carbohydrates, blood levels of glucose begin to rise. In nondiabetics, insulin is released quickly, assisting the transport of glucose into the cell. When blood levels fall as glucose is absorbed, insulin release slows to prevent uncomfortable dips in blood sugar.

This delicate balance is compromised in prediabetics, and a state known as insulin resistance develops. Rather than being absorbed, glucose stays in the blood, shut out behind the impenetrable walls of cells that can no longer respond to insulin. Aging, obesity, high calorie diets, and lack of exercise all contribute to insulin resistance, while genetic and environmental factors play a role as well.

To further complicate the issue, prediabetics may release insulin in an abnormal pattern, resulting in a see-sawing of blood sugar levels. The overall effect of this abnormal glucose handling is higher levels of free glucose in the blood, which can cause permanent damage to nerves and blood vessels.

What are the risks?

The greatest risk to Canada’s six million prediabetics is that of developing type 2 diabetes in the future—a reality for a staggering 65 percent of those with abnormal FBG and OGTT results.

Diabetes, though common in our society, is not a condition to be taken lightly. Risks of perpetually high blood sugar levels are dramatic and life altering. Unmanaged diabetes ultimately leads to nerve and kidney damage, blindness, and death from cardiovascular disease.

Recent studies have found that irreversible damage to blood vessels and nerves may happen long before diabetes is diagnosed. It now appears that prediabetics are also at risk for complications previously associated with much higher blood sugar levels. In addition, the risk of cardiovascular disease doubles in the prediabetic state, and studies suggest poorer prognoses for prediabetics with cancer.

Do I have prediabetes?

As prediabetes is a condition that often has no symptoms, many sufferers don’t know that their glucose levels are putting them at risk. Blood testing is the only way to diagnose prediabetes and those with risk factors for diabetes should ensure their blood sugar is checked every year.

The diagnosis of other common conditions may indicate that a blood glucose assessment is required. A recent study found two-thirds of patients with coronary artery disease also had blood glucose abnormalities. The association between polycystic ovarian syndrome (PCOS), impaired glucose tolerance, and the risk of diabetes is well documented. Also, a history of gestational diabetes is known to increase the chance of poor glucose control postpregnancy. If you have any of these conditions, insist upon regular screening for prediabetes.

Metabolic syndrome is the name given to a constellation of symptoms that include high FBG, blood pressure, and triglycerides; low levels of good cholesterol (HDL); and abdominal obesity—and 50 percent of prediabetics with an abnormal OGTT meet the criteria for metabolic syndrome.

Having metabolic syndrome can double or even triple the risk of death from cardiovascular disease, and is seen as a prediabetic condition even if FBG is normal. For that reason, those with metabolic syndrome require regular blood sugar testing.

What’s the good news?

While undiagnosed prediabetes poses real risks to our health, early detection and treatment will delay or even prevent the development of diabetes. Stopping the escalation of blood glucose levels is key to avoiding the complications of prediabetes. In many people, changes to diet and lifestyle can have profound benefits and are more effective than drug-based treatments.

Increasing dietary fibre, avoiding refined carbohydrates, and choosing foods with a lower glycemic index help to keep blood sugar levels in the healthy range. Losing as little as five to 10 percent of body weight reduces blood glucose and improves cholesterol levels, and exercising for 30 minutes most days supports weight loss while protecting the heart. Both exercise and supplemental vitamin D have been shown to improve insulin sensitivity

Although small, the blood sugar elevations of prediabetes pose a significant risk to our overall health. Proactive blood glucose testing and lifestyle choices can delay or even prevent these complications.