1. The "fasting level" is the amount of glucose in blood after 8 hours of fasting (e.g. in the morning, before the first meal of the day). Normal fasting blood sugar is between 70 to 100 mg/dL.
   
2. The "2-hour post prandial level" is the level of blood glucose two hours after eating a meal. A normal value is less than 140 mg/dL.
   
3. The "Random blood sugar (RBS) level" is blood glucose level at random times of the day, regardless of the last meal.  Random blood sugar levels in healthy individuals usually stay somewhere between 70-140.  A few mg/mL fluctuation is acceptable, but wide variations may indicate a problem.

Prediabetes is a state of “impaired fasting glucose” or “impaired glucose tolerance.” It is a warning sign for upcoming diabetes. Without treatment, prediabetes can develop into diabetes in ten years or even less, depending upon genetic predisposition and lifestyle.

Impaired fasting glucose is diagnosed if your fasting blood sugar is between 110- 125mg/dl. Impaired glucose tolerance is diagnosed if your blood sugar two hours post glucose load is 140-199 mg/dl.

Even before developing into frank diabetes, prediabetes can cause damage and compromise your cardiovascular health.

There are some physical traits that are grouped together as “metabolic syndrome” that increase your risk to both heart diseases and diabetes-2. People who have 3 or more of the following conditions qualify for this diagnosis:

1. Bad waist size: If you are a man, this means a waist circumference of 40 inches or more. If you are a woman, this means a waist circumference of 35 inches or more.
   
2. Impaired Fasting glucose or Type 2 Diabetes
   
3. Triglyceride levels greater than 150 mg/dL
   
4. “Good” cholesterol (HDL) levels below 40 mg/dL for men and below 50 mg/dL in women.
   
5. Blood pressure over 130/85 mmHg.

Diabetes mellitus is a condition of abnormally high glucose levels in the blood.

To understand why blood glucose levels rise to abnormally high levels, it is important to understand how the body deals with blood glucose normally.  The glucose that is formedby the digestion of carbohydrates is absorbed in the intestines and enters the blood stream. The presence of this glucose in the blood signals the pancreas to release the hormone insulin. Insulin stimulates the body’s cells to absorb glucose from the blood, thus reducing the overall glucose level. Any excess glucose is converted to glycogen and stored in the liver.

Diabetes occurs when there is insufficient insulin activity. It may happen because the pancreas does not produce sufficient insulin. Or it may happen because the cells of the body do not respond normally to insulin. Thus excess glucose accumulates in the bloodstream, resulting in a range of symptoms that characterize diabetes.

There are many types of diabetes.

Type 1 diabetes occurs when the pancreas does not release sufficient insulin. This condition is also known as "insulin-dependent diabetes mellitus.”Type 1 diabetes is fatal unless insulin is injected regularly into the blood stream.

Type 1 diabetes is most commonly an autoimmune disease – occurring because the body’s immune system attacks and destroys insulin producing beta cells of the pancreas.

The cause for type 1 diabetes is not yet fully understood. There are other plausible explanations.
The body may be programmed to attack and destroy insulin producing cells as a response to certain stress factors. It is believed that viral attack can cause the immune system to respond and destroy the pancreatic cells. Some types of drugs and chemicals can preferentially damage the insulin producing cells. For example, Vacor, a rat poison, and streptozotocin, a chemotherapy drug, are known to kill pancreatic cells leading to insulin deficiency, and consequently, type 1 diabetes.

Type I diabetes was previously called juvenile diabetes because it was a common chronic disease noticed in children. However, it has been subsequently found that a majority of type 1 diabetics are adults. Other names for this type of diabetes include brittle diabetes, unstable diabetes, and ketosis-prone diabetes.

Diabetes mellitus type 2 is a condition of insulin resistance. It happens when the pancreas is not able to keep up with the amount of insulin required by the body’s tissues and then eventually “burns out”. This most often happens in states of obesity – where the pancreas is not able to produce enough insulin to deliver to the excess fat cells. This condition is sometimes referred to as non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes.

Type 2 diabetes is the most common form of diabetes found in India; almost 95% of diabetes patients fall under this category. Type 2 diabetes is caused by a number of factors. The leading reasons for type2 diabetes in India are heredity and obesity.

There is a definite genetic component to the disease, making it a hereditary malady. People with first-degree relatives with type 2 diabetes (parents, siblings) have higher risk of developing it than those with diabetes-free relatives.

Obesity is the other very common risk factor for developing type 2 diabetes. Unhealthy lifestyle habits – including unhealthy diets and a sedentary life – can lead to this condition.

Less commonly, Type 2 diabetes may develop as part of diseases like acromegaly, Cushing's syndrome, thyrotoxicosis, pheochromocytoma, chronic pancreatitis, certain cancers and some medications.

Gestational diabetes, also known in the medical circle as gestational diabetes mellitus, (GDM), is seen in some women during the third trimester of pregnancy.It is caused when the hormones released by the placenta increase insulin tolerance in the mother. These women may or maynot have a history of diabetes. Gestational diabetes affects 3-4% of pregnancies in India.

Mothers with gestational diabetes face an increased risk of developing type 2 diabetes after delivery. Babies born to mothers with gestational diabetes also face risk of problems such as being large, leading to complications during delivery, low blood sugar, and jaundice. The children are also prone to childhood obesity with possible type 2 diabetes later in life. Gestational diabetes can be controlled through diet and exercise and if needed, insulin injections..

There are other rarer forms of diabetes such as congenital (“present at birth”) diabetes, cystic fibrosis-related diabetes, steroid diabetes induced by high doses of glucocorticoids, and several forms of monogenic diabetes, caused by genetic mutations.

Nearly everyone is at risk for diabetes. The primary risk factor for all forms of diabetes is heredity. Having close family members – parent, sibling or grandparent - with diabetes increases risk of developing it.

Augmenting genetic predisposition to diabetes is an interplay of lifestyle and environmental factors. Some deciding factors include

1. Obesity: The most important lifestyle factor that triggers diabetes (especially type 2) is obesity.
   Since body fat interferes with the body’s ability to use insulin, abnormal weight gain increases risk of diabetes.
   
2. Lack of exercise/sedentary lifestyle: Inactivity, coupled with obesity increases risk of type 2. The World Health Organization reports that sedentary lifestyle is one of the 10 leading causes of death and disability.Lack of exercise has assumed importance among children. Television, computers, video games, cell phones and homework has reduced the time spent running around and physical games, resulting in earlier onset of diabetes in genetically predisposed children.
   
3. Bad eating habits: Eating junk food with too much fat, not enough fiber, and higher amounts of simple carbohydrates (e.g. sugar) contribute to diabetes.
   
4. Age: Older people are at a greater risk of diabetes, especially if they have a hereditary link to the disease. It is believed that the ability of the pancreas to release insulin decreases with age, and cells also lose their ability to use the insulin fully.
   
5. Hypertension and cholesterol: There is a clear connection between these two diseases and diabetes. It is sometimes thought to be a vicious cycle, with one triggering the other. Having both diabetes and high blood pressure can exponentially increase the risk of heart disease, stroke, and eye, kidney and nerve complications.
   
6. Gestational diabetes: Women with abnormal blood glucose levels during pregnancy are more likely to develop type 2 diabetes later in life. The placental hormones may permanently damage the insulin sensitivity in the mother, leading to diabetes two or more years after delivery.
   
7. Some diseases can cause diabetes. Type 1 diabetes can be triggered by certain diseases of pancreas (e.g. Chronic Pancreatitis and Exocrine pancreatic insufficiency) that inhibit the generation of insulin. A range of viral infections and other types of illness can also cause type 1 diabetes. Certain food-borne chemicals, recreational drugs such as steroids and medicinal drugs such as alloxan, streptozocin, and thiazide diuretics can also lead to insulin resistance. Syndromes such as Prader-Willi, Down's, Progeria, Shwachman-Diamond’s and Turner's may result in diabetes. Diabetes is also commonly associated with cystic fybrosisand polycystic ovarian syndrome. Hemochromatosis (abnormal build up of iron in cells) can also cause diabetes.
   
8. Ethnic origins: There is a clear relationship between ethnic background and diabetes. The International Journal of Diabetes in Developing Countries has labeled India the diabetes capital of the world with 40.9 million known diabetic patients in the country in 2007. The genetic predisposition coupled with carbohydrate-rich diet and lack of exercise has made diabetics almost a pandemic in the country. Other ethnic groups with higher risk of type 2 diabetes include Hispanics, Latinos, Native Americans, Africans and Asians. Caucasians are at a higher risk of type 1 diabetes.
   
9. Environmental factors: There is now an increasing concern among the medical and scientific community on the effect of pollution on insulin activity. Recent research with mice have shown that air pollution caused inflammation, increased body fat and interfered with processing of insulin, a hallmark of diabetes. The effects were strongest when combined with poor diet.

As with any disease, prevention is better than cure. This particularly important for diabetes because there is no known cure for the disease. Preventive steps are critical when there is a genetic risk factor.

The following simple steps will play an important role in preventing or delaying the onset of diabetes:

1. Awareness: Knowledge is power. Awareness of family health history will help in proactive prevention of the disease.
   
2. Weight Maintenance: Excessive weight and body fat, especially around the midsection of the body, increases the risk of diabetes.
   
3. Exercise: Regular physical exercise can help prevent diabetes by active weight control and improving blood flow. This is particularly important if there is a hereditary risk factor.
   
4. Diet: A balanced diet is key to good health. There is no “magic” diet to prevent diabetes, but common-sense approaches such as consumption of low fat, low sugar, high fiber food will go a long way to protect the body. Increased uptake of fruits and vegetables has a beneficial effect since bioflavonoids have been found to trigger insulin production and prevent the conversion of glucose into protein-bound products that can damage the body.
   
5. Routine checkup: Since the risk of diabetes increases with age, adults above 40 years of age should test blood sugar regularly. In the presence of hereditary history of diabetes, regular testing should begin much earlier than 40.
   
6. Blood pressure: Monitoring blood pressure and keeping it under control through lifestyle changes (meditation, yoga, exercise) or medication is important to ward off diabetes.

Diabetes may or may not be associated with obvious symptoms. It is important to test blood sugar periodically even in the absence of symptoms, especially with old age or hereditary.

The most common symptoms include:

1. Frequent urination: When insulin is unable to remove glucose from the blood, the body starts eliminating the excess glucose through urine. Kidneys draw out extra water from the blood to dissolve and eliminate the excess glucose.
   
2. Thirst: With the kidneys drawing more and more water from the blood to eliminate the glucose, the body is dehydrated leading to unquenchable thirst.
   
3. Unusual weight loss: This is more common with type 1 diabetes. Since the cells do not get sufficient glucose for energy, the muscle and fat cells are broken down for energy and result in weight loss.
   
4. Weakness and fatigue: Lack of energy producing glucose in the cells cause a drop in energy levels and cause fatigue and weakness. Extreme hunger also results from the drop in energy of the cells.
   
5. Numbness of extremities: Consistently high glucose levels damage the nervous system, especially at the extremities.
   
6. Other symptoms: Vision problems (blurring), itchy or flaky skin, unhealing wounds, and frequent infections of the gum, skin and bladder are other classic symptoms of diabetes.