**1. Introduction**

India is currently experiencing an epidemic of diabetes mellitus (DM). According to the World Health Oganization, India has the unique distinction of being the country with the largest number of diabetic patients in the world. Type-2 DM accounts for more than 90% of all patients with diabetes worldwide. The prevalence of diabetes in adults is showing an upward trend world‐ wide [4% in 1995 to 5.4% in 2025 (projected)]. The majority of this increase will however occur in developing countries. Asians, particularly from the Indian subcontinent, will be mostly affected. Reports from different parts of India show a rising trend in the prevalence of diabe‐ tes. In 1995, prevalence of diabetes was 19.4 million and is projected to increase to nearly 80 million in 2030. Migrants have a higher risk of developing type-2 diabetes. The long-term impact of obesity and change in diet are two main causes of increased prevalence of diabetes in migrant Indians. The migrants are shifting from the high-fiber staple diet to polished and milled rice.

Diabetes is a heterogeneous syndrome where it is impossible to formulate a unified etiopa‐ thogenesis. In our country (India), diabetes of the young is often seen. Type-2 diabetes occurs a decade earlier and type-1 occurs a decade later. In type-2, strong genetic basis exists. But the

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time of onset depends on the environmental factors. It is triggered by obesity, increase in age, and diet indiscretion.

In type-1 diabetes, in a susceptible individual (HLA B8), interaction between environmental factors triggers autoimmune response.

Environmental factors play a role in the etiopathogenesis of diabetes. They include polluted air, soil, water, unhealthy diet, stress, lack of physical activity, vitamin-D deficiency, exposure to enteroviruses, and damage to immune cells.
