Aeromedical Issues in Diabetic Aviators

I Diabetes mellitus is a common disease that poses a serious health and safety threat to civilian aviators. Complications secondary to diabetes can be severe and result in sudden incapacitation. The Federal Aviation Administration (FAA) has developed regulabons for certifLrng aviators with diabetes, as well as guidelines for in-flight management of blood glucose levels. Advances in medical technology have led to treatments and countermeasures for diabetes that enable many individuals to engage in physically and mentally demanding activities. This paper presents a basic overview of the pathophysiology, diagnosis, and maaagement of diabetes mellitus in civil aviators. In addition, current FAA regulations for medid certification and blood glucose management will be outlined. BACKGROUND In order to understand the hazard that diabetes poses to a pilot's health and flying safety, one must understand the nature of this condition. Diabetes is a metabolic condition that usually presents with symptoms of uncontrolled blood sugar, such as increased urination, persistent thirst, hquent urination at night, and weight loss (Braunstein, G.D., Friedman, T., Herman-Bonert, V., Peters, A.L., 1997). A random blood sugar level greater than 200 mgldl usually confirms the diagnosis. Diabetes mellitus is a lifelong disease that can lead to blindness, heart and blood vessel disease, strokes, kidney failure, amputations, nerve damage, and death. Diabetes is generally the result of the body's inability to produce enough insulin, resistance to insulin, or both (Braunstein et al., 1997). Insulin is a polypeptide hormone secreted by the islets of Langerhans, located in the pancreas. Its primary function is to regulate the metabolism of carbohydrates and fats, especially the conversion of glucose to glycogen. This conversion is what lowers the blood glucose level. In addition, insulin allows nutrients to enter the muscle were it can be stored and later used for energy. How does this process unfold during our daily consumption of food? Food is digested in the stomach and the intestines where carbohydrates are broken down in to sugar molecules, or glucose. At this point glucose is absorbed into the circulatory system, causing the blood glucose levels to rise. In response to elevated blood glucose levels, the pancreas releases insulin from beta cells. There are 18.2 million people in the United States, or 6.3% of the @tion, who have diabetes (American Diabetes Association, 2003). While an estimated 13 million have been diagnosed, unfortunately, 5.2 million people (or nearly onethird) are unaware that they have the disease (ADA, 2003). on xi mat el^ 2,200 people are diagnosed with diabetes each day. Almost 800,000 people will be diagnosed each year. Diabetes is the seventh leading cause of death and sixth-leading cause of death by disease in the United States (ADA, 2003). TYPE I DIABETES Diabetes is generally classified into two basic categories: type I and type 11. Type I diabetes, or insulin dependent diabetes, usually presents at a young age and is characterized by the inability of beta cells in the pancreas to produce adequate levels of insulin. Without the appropriate level of insulin in the bloodstream, glucose levels increase and cannot be converted into energy. After five to ten years, the beta cells of the pancreas are completely destroyed. The exact process leading to type I JAAER, Winter 2004 Page 15 1 Keegan and Bradshaw: Aeromedical Issues in Diabetic Aviators Published by Scholarly Commons, 2004