Association of leptin with type 2 diabetes in non-obese subjects.

South asians have a high tendency to develop type 2 diabetes even at low bmi. we evaluated serum leptin levels in a group of non-obese type 2 diabetics. an observational study conducted on 90 subjects,55 with type 2 diabetes mellitus,and 35 normal controls (non-diabetics). bmi,waist circumference,serum leptin,and serum glucose were measured. the correlation between these variables was studied by multiple regression analysis. serum leptin levels were positively correlated with bmi in obese (r = 0.976) and non-obese diabetics (r = 0.956). serum leptin was related with diabetes (r = -0.153,p = 0.001). serum leptin was highly correlated with waist circumference in obese than non-obese diabetics,(r = 0.753). mean serum leptin level was 21.4 etag/ml in non-obese diabetics and 34.9 etag/ml in diabetic group. it is even lower than the non-obese,non-diabetics (23.3 etag/ml). multivariate linear regression analysis between leptin and age,weight,bmi,waist circumference in patients shows only a strong association with bmi in diabetics (p = 0.0001),while in non-diabetic it was not significant (p = 0.07). serum leptin was high in diabetics taking oral hypoglycaemic (37.8 +/- 19.1 etag/ml),while it was low in diabetics taking insulin injections (29.3 +/- 24.2 etag/ml). low leptin levels are associated with type 2 diabetes mellitus independent of changes in bmi.