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.

Although the prevalence of type-1 diabetes as well as type-2 diabetes is increasing worldwide, the rise of type-2 diabetes is occurring much faster than type-1 diabetes, may be because of increasing obesity and sedentary lifestyle (reduced activity levels) as countries become more industrialized.

According the Centers for Disease Control and Prevention (CDC), the prevalence rate of diabetes in United States was approximately 7% of the population or more than 20 millions; in 2005 (approximately 30% of individuals with diabetes do not know they have diabetes). CDC also estimated that the prevalence of diabetes among individuals below 20 years was 0.22%, 9.6% among individuals above 20 years of age and 20.9% among individuals above 60 years of age. The prevalence of diabetes among men and women was not significantly different.

The prevalence of prevalence of type-1 diabetes and type-2 diabetes has considerable geographic variation. Scandinavian countries have the highest incidence of type-1 diabetes e.g. in Finland, the incidence is 35/100,000 per year and Pacific Rim has lowest rate type-1 diabetes (e.g. in Japan and China, the incidence is 1–3/100,000 per year). North Europe and North America has intermediate rate (8–17/100,000 per year) of type-1 diabetes. Prevalence of type-2 diabetes and IGT (impaired glucose tolerance, which is prediabetic state), is highest in certain Pacific islands, intermediate in India and the United States, and low in Russia, which may be due to genetic, behavioral, and environmental factors.

Prevalence of diabetes can also vary among different ethnic populations within a given country or geographical area, e.g. in the United States according to CDC estimate in 2005, among individuals of age above 20 years of age, the prevalence was 13.3% in African Americans, 9.5% in Latinos, 15.1% in Native Americans (American Indians and Alaska natives), and 8.7% in non-Hispanic whites and Asian-American or Pacific-Islander ethnic groups in Hawaii have twice the risk of diabetes compared to non-Hispanic whites.

The Indian Diabetes Scenario:

India already has the largest number of diabetes patients in the world and the number is only going up steadily, although in terms of total population it is second to China. Hence many experts term India as “diabetes capital” of the world.

At present there are more than 20 million diabetic patients in India, which is estimated to go up to more than 55 millions by 2025. Among the Indians migrated to Europe and United States, the prevalence of diabetes and insulin resistance (which is considered pre-diabetic state) is very high, compare to local population.

In 1970s the prevalence of diabetes was approximately 2% among urban populations in India, but at present the prevalence is more than 12%. A recent study conducted in 6 different cities support the prevalence rate, which shows very high prevalence in Chennai (13.5%), Bangalore (12.4%), Hyderabad (16.6%), Mumbai (9.3%), Delhi (11.6%) and Kolkata (11.7%).

In the last two decades there is marked increase in the prevalence of diabetes among Indians, especially in urban areas. Among rural and semi urban areas there is increase in prevalence in diabetes, but the increase is slower. The reason of dramatic increase in prevalence in diabetes has been attributed to:

· Lifestyle change due to modernization and industrialization.

· Ageing of population.

· Lower birth weight. Statistics have shown that more than 25% of the children born in India are of low birth weight. Low birth weight with stunting growth and muscle wasting which is followed by overweight and obesity in later life have been postulated to contribute for diabetes and the insulin resistance syndrome.

In India the prevalence of diabetes is highest among affluent class, unlike in developed countries where the prevalence is highest in low socioeconomic class. The difference in prevalence among different socioeconomic classes is due to difference in the stage of epidemiological transition between India (and other developing countries) and developed countries.