Diabetes and Spinal Cord Injury

Published: August 17, 2008  |  Source: unitedspinal.org
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People with spinal cord disorders are more Prone than most to developing type 2 diabetes. But the condition can be managed and even reversed with diet, exercise and medications.

“You are diabetic.” No one wants to hear these words and when they do, they are likely to be in shock or disbelief. “Sure, I’m in a wheelchair, overweight and I don’t get much exercise, but nobody in my family has diabetes,” may be a typical response.

Surprisingly, genetics plays only a limited role in the development of type 2 diabetes, but diabetes now afflicts almost 1 in 10 Americans and a recent study showed that 2 in 10 spinal cord injured veterans are diabetic.

Diabetes mellitus is characterized by elevated blood glucose levels that are due to an inability of the pancreas to produce adequate amounts of insulin. Type 1 or insulin dependent diabetes often occurs in adolescence and results in a complete failure of the pancreas to produce insulin. Type 2 diabetes, formerly called “adult onset diabetes” usually occurs later in life and is characterized by inadequate insulin production that can often be treated with oral medications or lifestyle changes. But oftentimes, type 2 diabetes progresses to the point that insulin injections are required.

At Risk

The risk of developing diabetes is increased if you are sedentary or obese, which are more common among persons with spinal cord injury. Obesity, especially abdominal fat, is closely correlated with type 2 diabetes because fat cells tend to nullify the effects of insulin, resulting in a condition called insulin resistance. With insulin resistance the pancreas works overtime to produce lots of insulin but glucose levels remain high. Eventually the pancreas fails and insulin production falls to extremely low levels. Now the individual may be in a diabetic crisis that can only be treated with insulin injections.

In addition to being sedentary or obese, the other risk factors for Type 2 diabetes include older age, ethnicity, a history of gestational (pregnancy) diabetes, and rarer forms of impaired glucose metabolism. Unfortunately, paraplegics and quadriplegics tend to carry more abdominal fat than able-bodied individuals of equal waist circumference. Thus, body weight and waist circumference tend to underestimate the risk for development of type 2 diabetes in person with spinal cord injury.

Do You Have Diabetes?

It is possible to have diabetes (or pre-diabetes) and not know it. The American Diabetes Association estimates that one third of individuals with diabetes have not been diagnosed. This is because the early signs and symptoms of diabetes are subtle and may go unnoticed for years. The classic symptoms of diabetes include excess thirst, hunger, and urination. There are two different tests that can be used to determine whether you have diabetes: the fasting plasma glucose (FPG) test or the oral glucose tolerance test (OGTT). When FPG is 126 or greater or the OGTT (at 2 hours) is 200 or greater a diagnosis of diabetes is made. However, an FPG of 110-126 is diagnostic of a prediabetic condition.

Although the immediate effects of mildly elevated blood glucose may be minimal, the long-term effects can be devastating. The risk of heart disease and stroke are 2 to 4 times greater in diabetics. High blood pressure is present in three-fourths of individuals with diabetes. Diabetes is the leading cause of blindness in individuals aged 20 to 74 years. It is also the leading cause of kidney failure leading to the need for chronic dialysis. Nervous system disease is seen in 60 to 70% of people with diabetes. More than 60% of non traumatic lower-limb amputations occur in people with diabetes. The damage caused by elevated blood glucose levels may proceed at such a barely visible rate as to be unrecognized until the damage has become irreversible.

The treatment options for type 2 diabetes include dietary modification, exercise, weight loss, oral medications and injectable medications. The goal of diabetic treatment is to control blood glucose levels. The fastest way to achieve control in the newly diagnosed diabetic is to initiate a medication regimen. Most of the oral medications control blood glucose levels by increasing the ability of the pancreas to produce insulin or by making target tissues more sensitive to insulin (reducing insulin resistance). The effect can be immediate and dramatic. Unfortunately, many newly diagnosed diabetics may see medications as a miraculous cure and their interest in pursuing lifestyle changes dissipates. But, as the underlying factors that cause type 2 diabetes progresses, so does the severity of the disease leading to the need for injectable insulin.

Many doctors consider the lowering of Fasting Plasma Glucose (FPG) alone an adequate goal. However, the concept of controlling blood glucose at all times has been gaining popularity. This is because the marked elevations in blood glucose that occur after eating can be more damaging than the elevated

fasting plasma glucose levels. High blood glucose levels cause oxidative stress that damage blood vessels and other sensitive tissues. Many doctors and scientist also believe that elevated FPG is also a relatively late diagnostic finding. The oral glucose tolerance test (OGTT), however, can provide more data when incremental blood glucose and insulin levels are drawn which can diagnose early or pre-diabetic conditions.

Controlling (or Reversing) the Disease

The primary lifestyle changes that control or reverse diabetes are diet and exercise leading to weight loss. In addition to restricting calories, dietary modification should focus on controlling blood glucose levels. Avoiding sweets is a common theme in diabetic diets, but many carbohydrates raise blood glucose levels more than table sugar (when comparing calorie for calorie).

The glycemic index (GI) is a useful tool for comparing the blood glucose raising effect of different carbohydrates. The glycemic index of glucose is assigned a value of 100. The blood glucose raising effect of other carbohydrates have been measured and compared to glucose. Instant mashed potatoes have a GI of 85 and the GI of table sugar is 68. This means that when equal calories are consumed, the mashed potatoes will raise blood glucose levels more than table sugar. Black beans have a GI of only 30, which clearly has a much lower propensity for raising blood glucose levels compared with either table sugar or mashed potatoes. Glycemic index is a dietary tool for controlling blood glucose levels and the need for insulin that can also help with weight loss.

Exercise reduces the risk of developing type 2 diabetes. It is beneficial for people with diabetes as it reduces insulin resistance, and also helps with weight reduction and weight control. Exercise also helps regulate mood so that unhealthy food cravings and binge eating are reduced.

Medication remains the mainstay of diabetic management. All medications, especially those for diabetes should be taken under the close supervision of your physician. Oral diabetic medications, when combined with dietary modification and exercise can slow or prevent the need to progress to the use of insulin. Exenatide (marketed as Byetta) is a newer injectable medication derived from the saliva of the Gila monster lizard that not only regulates blood glucose levels but can also lead to weight loss.

If you are a person with Paraplegia, Quadriplegia or you have some other chronic disabling condition and are concerned that you may have diabetes or pre-diabetes, then it’s highly recommended you see your doctor. If testing shows that you are pre-diabetic or diabetic then follow your physician’s instructions and remember that dietary modification and exercise leading to weight loss can be enough to prevent diabetes or reverse pre-diabetes and early diabetes.

By Jerome Stenehjem, M.D.
Jerome Stenehjem, MD, is Medical Director of the Sharp Rehabilitation Center in San Diego, California.