Pancreatic β-cell dysfunction in normoglycemic patients and risk factors

To evaluate pancreatic β-cell function (βf) in patients with normoglycemia (NG) and normal glucose tolerance (NGT) and related risk factors.

An observational and comparative study in 527 patients with NG and NGT that were divided by quartiles of βf according to the disposition index derived from OGTT. Anthropometrical, clinical, nutritional, and biochemical variables were measured and associated with βf.

Quartiles of βf were Q1 = DI < 1.93 n = 131, Q2 = DI 1.93-2.45 n = 134, Q3 = DI 2.46-3.1 n = 133, and Q4 = DI > 3.1 n = 129. There was a progressive reduction in pancreatic β-cell function and it is negatively correlated with age, weight, BMI, total body fat and visceral fat, waist circumference, total cholesterol, LDL, and triglycerides (p < 0.01). Glucose levels during OGTT had a negative correlation with βf; the product of fasting glucose by 1-h glucose had the best correlation with βf (r = 0.611, p < 0.001) and was the best predictor of βdf (AUC 0.816, CI 95% 0.774-0.857), even better than 1-h glucose (r = 0.581, p < 0.001). Energy, fat, and carbohydrate intake were negatively correlated with βf (p < 0.05). Glucose levels at 1-h OGTT > 110 mg/dl were positively associated with pancreatic βdf (OR 6.85, CI 95% 3.86-12.4). In the multivariate analysis, glucose levels during OGTT, fasting insulin, and BMI were the main factors associated with βf.

A subgroup of patients with NG and NGT may have a loss of 40% of their βf. Factors related to this βdf were age, adiposity, glucose during OGTT, and the product of fasting and 1-h glucose, as well as food intake.