Diabetes mellitus is a complex metabolic disorder with multiple factors which acts as etiology of diabetes. Diabetes mellitus is caused by a complex interaction of genetics and environmental factors. Diabetes mellitus is associated with disturbances in carbohydrate, fat and protein metabolism which are due to defects in secretion of insulin, defects in action of insulin, or both. Most important is disturbances in carbohydrate metabolism, which results in chronic hyperglycemia (higher than normal blood sugar level), which is the characteristic feature of diabetes mellitus.

The characteristic symptoms of diabetes are polyuria (frequent or excess urination), polydypsia (excessive thirst and excessive drinking of water) and polyphagia (over eating). The effects of diabetes mellitus are weight loss, blurring of vision and long-term damage, dysfunction and failure of various organs, such as kidney, nervous system, blood vessels and heart.

Diabetes is one of the most common (with worldwide distribution) and most important metabolic diseases that are one of the leading causes of morbidity and mortality worldwide. Practically any organ system of the body can be affected by diabetes and has become a major health problem in most of the parts of the world. Long standing inadequately managed or untreated cases of diabetes leads to complications which cause blindness, end stage renal disease, increase risk for stroke, ischemic heart disease, peripheral vascular disease, peripheral neuropathy, lower extremity amputations due to involvement of foot etc.

The World Health Organization has already declared that diabetes has reached epidemic proportions, as number of diabetes patients or prevalence have gone up dramatically over last few decades, from only 30 millions in 1985 to 135 millions in 1995, 177 millions in 2000 and more than 200 millions by 2010 and World Health Organization (WHO) estimates by current trend that by 2025 the number of diabetes patients will be more than 300 millions. The increase in number of diabetes patients will be mainly in developing countries such as India, China and other highly populated developing countries.

Diabetes is a group of complex metabolic disorders. In diabetes there is complete or partial insufficiency of insulin secretion. There is also various degree of insulin resistance in diabetes mellitus. Diabetes is generally of two major types of diabetes, the type 1 - the insulin dependent diabetes mellitus (IDDM) and type 2 - non-insulin dependent diabetes mellitus (NIDDM).

Diabetes is a common non-communicable chronic disease which affects up to 5% to 10% of the adult population in the western world and it is becoming very common in developing countries too, such as India. The number of diabetes patients is increasing in India in such a way that within few decades India will be the Diabetes Capital, with largest number of diabetes patients in the world.

Some major landmarks in the history of diabetes:

• 1552 B.C. – Polyuria or frequent urination is a symptom of diabetes, described by Egyptian physician Hesy-Ra.
• In first century A.D.-Diabetes is described as “melting down of flesh and limbs into urine”.