Impaired glucose tolerance in healthy men with low body weight

We included three groups of low weight, normal weight, and obese subjects comprising 15 healthy male participants each. All participants underwent a standardized hyperinsulinemic-euglycemic glucose clamp intervention to determine glucose tolerance. In addition, insulin sensitivity index (ISI) was calculated by established equation.ISI values were higher in low and normal weight than in obese subjects (P < 0.010) without any difference between low and normal weight groups (P = 0.303). Comparable to obese participants (P = 0.178), glucose tolerance was found decreased in low weight as compared with normal weight subjects (P = 0.007). Pearson's correlation analysis revealed a positive relationship between glucose tolerance and BMI in low (P = 0.043) and normal weight subjects (P = 0.021), an effect that was found inverse in obese participants (P = 0.028).Our study demonstrates that not only obese but also healthy people with moderate underweight display glucose intolerance. It is therefore suggested that all deviations from normal BMI may be accompanied by an increased risk of developing T2DM in later life indicating that the maintenance of body weight within the normal range has first priority in the prevention of this disease.Type 2 diabetes mellitus is a global epidemic. A considerable body of evidence indicates that impaired glucose tolerance and body mass index represent risk factors for developing T2DM. To date, the association between BMI and impaired glucose tolerance is well documented in case of overweight and obesity [1] but little is known about the relationship between low weight and IGT. However, studies show a linear relationship between low birth weight and the prevalence of T2DM in adult life [2]. Moreover, IGT has been observed in severe malnutrition [3], certain forms of cancer [4], and anorexia nervosa [5], i.e. diseases accompanied by extremely low BMI within the scope of a pathologic state. These findings indicate that, apart from obesity, also a