TYPE 2 DIABETES MELLITUS: INTRODUCTION

Formerly known as non-insulin dependent diabetes mellitus (NIDDM) is the commonest form of diabetes mellitus accounting for about 90% of all diabetes. It is considered as diagnosis exclusion, that is patients are assumed to have type 2 diabetes because thy do not demonstrate typical features of type 1 diabetes. Most patients acquire the disease after 40 years of age (insidious onset) but occur in young people. Here 50% of those with the condition remain undiagnosed. T-2 diabetes in children and adolescent is an emerging significant problem.

Fig. Diabetes symptoms

Here there is both insulin resistance (primary cause) and relative insulin deficiency (due to beta cell dysfunction which is inability of pancreas to produce sufficient insulin to compensate for insulin resistance) or both. Some patient with T2 diabetes will revert of type 1 LADA. Here ketosis develops late in the disease but patients are likely to go to hyperosmolar coma and are at increased risk of developing macrovascular and microvascular complications. The typical patient with type 2 diabetes present with overweight BMI 25-29.9 kg/m² with central obesity (most conveniently assessed by waist circumference or waist-hip ratio). The marked increase in the prevalence of obesity is an important contributor to the increased prevalence of type 2 diabetes. Increase in abdominal fat mass, weight gain since young adulthood and sedentary lifestyle are additional obesity related risk factors. Other environmental risk factors include being born to a mother with gestational diabetes mellitus, having exceptionally high birth weight and low birth weight.

The burden of type 2 diabetes is increasing exponentially due to epidemic of obesity and other conditions. The incidence of type 2 diabetes in children is approaching type 1 diabetes and will outstrip type 1 diabetes in coming years.

The need of insulin during puberty in type 2 may be due to double diabetes effect where the risk of having type 1 diabetes increased by prior existence of type 2 diabetes or insulin resistance.