we should have a worldwide epidemic of one of the world’s oldest diseases is a bombshell. Whereas all other diseases, from smallpox to influenza to tuberculosis to AIDS, have been controlled over time, the diseases associated with diabetes are increasing at an alarming rate.
But the question still remains: Why? Why are we powerless to stop the spread of type 2 diabetes? Why are we powerless to stop the spread among our children? Why are we powerless to stop the ravages of type 2 diabetes on our bodies? Why are we powerless to prevent the heart attacks, strokes, blindness, kidney disease, and amputations that accompany it? More than 3000 years after its discovery, why is there no cure?
The answer is that we have fundamentally misunderstood the disease called type 2 diabetes. To design rational treatments that have a chance of success, we must begin again. We must understand the root causes of the disease, or in medical terms, the aetiology. What is the aetiology of type 2 diabetes? Once we understand that, we can begin. Let us begin.
THE DIFERENCES BETWEEN TYPE 1 AND TYPE 2 DIABETES
DIABETES MELLITUS COMPRISES a group of metabolic disorders characterized by chronically elevated blood glucose, or hyperglycemia. The prefix hyper means “excessive,” and the suffix emia means “in the blood,” so this term literally means “excessive glucose in the blood.”
There are four broad categories of diabetes mellitus: type 1, type 2, gestational diabetes (high blood glucose associated with pregnancy), and other specific types.1 Type 2 diabetes is by far the most common, making up an estimated 90 percent of cases. Gestational diabetes, by definition, is not a chronic disease, though it increases the future risk of developing type 2 diabetes. If hyperglycemia persists after pregnancy, it must be reclassified as type 1, type 2, or another specific type. Other specific types of diabetes, listed in Table 2.1, are rare. We will not discuss these types of diabetes or gestational diabetes any further in this book.
Table 2.1 Classifications of diabetes mellitus
| Type 1 |
| Type 2 |
| Gestational |
| Other specific types: |
| - Genetic defects |
| - Pancreatic disease |
| - Drug or chemical induced |
| - Infections |
| - Endocrinopathies |
DIABETES SYMPTOMS
HYPERGLYCEMIA, OR HIGH blood glucose, characterizes all forms of diabetes. When blood glucose levels rise above the kidney’s ability to reabsorb the glucose (the renal threshold), it spills over into the urine, causing frequent, excessive urination and severe thirst. The chronic loss of glucose may lead to rapid weight loss and also stimulate the appetite. The most typical symptoms seen in diabetes therefore include
•increased thirst,
•frequent urination,
•rapid, unexplained weight loss,
•increased hunger despite weight loss, and
•fatigue.
These symptoms of hyperglycemia are common to all forms of diabetes, but they occur more frequently in type 1 diabetes, since the onset of type 2 diabetes is typically very gradual. Today, type 2 diabetes is most often diagnosed during routine blood testing, before patients have symptoms.
In severe cases, patients—typically those with type 1 diabetes—may present with diabetic ketoacidosis. Dangerously high levels of acid build up in the blood due to the severe lack of insulin. Symptoms include confusion, rapid breathing, abdominal pain, a fruity smell to one’s breath, and loss of consciousness. This is a true emergency situation, which needs immediate treatment with insulin.
Severe cases of type 2 diabetes may present with hyperosmolar non-ketotic syndrome. High blood glucose stimulates excessive urination, leading to severe dehydration, seizures, coma, and even death. Since insulin levels are normal or high in type 2 diabetes, ketoacidosis does not develop.
DIAGNOSING DIABETES
DIABETES MAY BE diagnosed by one of two blood tests: the hemoglobin A1C (often abbreviated to A1C) or the blood glucose. The A1C, which has been accepted as a diagnostic criterion by the American Diabetes Association since 2009, is the most convenient screening test for diabetes because it does not require fasting and can therefore be done at any time of the day.
Hemoglobin A1C
HEMOGLOBIN IS A protein found inside red blood cells that carries oxygen to the entire body. Over the average three-month lifespan of a red blood cell, glucose molecules attach to the hemoglobin in proportion to the prevailing blood glucose levels. The amount of glucose attached to the hemoglobin can be measured with a simple blood test called the hemoglobin A1C. The A1C thus reflects the body’s average level of blood glucose over three months.
In North America, the A1C is given as a percentage, while in the U.K. and Australia, the units are expressed as mmol/mol. The American Diabetes Association defines an A1C level of 5.7 percent or less to be normal. A level above 6.5 percent is considered diabetic (see Table 2.2).
Table 2.2. Classification of diabetes and prediabetes according to A1C blood glucose levels
| A1C | Classification |
| < 5.7% | Normal |
| 5.7%–6.4% | Prediabetes |
| > 6.5% | Diabetes |
Prediabetes is the in-between stage, where blood glucose levels are abnormally high, but not quite high enough to be considered diabetic. It denotes a state of very high risk of future progression to full-fledged type 2 diabetes. A patient with a baseline A1C of 6.0–6.5 percent (42– 48 mmol/mol) has an estimated 25–50 percent risk of developing diabetes within five years. That’s more than twenty times the risk of a person with an A1C of 5.0 percent (31 mmol/mol).2
Blood glucose
THE SECOND TEST to diagnose diabetes is the blood glucose test, which is also known as the blood sugar or plasma glucose test. It is measured using either a fasting blood sugar test or an oral glucose tolerance test (OGT).
For the fasting blood glucose test, a patient is asked to have no caloric intake for at least eight hours. A blood sample is then taken and the amount of glucose in the blood is measured. A level above 7.0 mmol/L (or 126 mg/dL) is considered diabetic.
For the OGT, a patient is asked to ingest a standard test dose of 75 grams of glucose. A blood sample is taken two hours later and the amount of glucose in the blood is
