Role of Hyperinsulinemia and Glucose Intolerance in the Pathogenesis of Nonalcoholic Fatty Liver in Patients with Normal Body Weight

OBJECTIVES: The pathogenesis of nonalcoholic fatty liver in non-obese persons is poorly understood. We aimed to elucidate whether hyperinsulinemia and glucose intolerance are associated with development of fatty liver in patients with normal body weight METHODS: Forty-seven patients with fatty liver were divided into non-obese (n=25) and obese groups (n=22) according to age adjusted body mass index. Inclusion criteria were as follows: (1) elevated transaminase levels during more than 3 months of follow up period, (2) no detectable HBsAg or anti-HCV in the serum, (3) alcohol consumption less than 40 gm/week, (4) no use of potential hepatotoxic drugs within 3 months and (4) sonographic evidence of fatty liver(moderate to severe degree). Baseline insulin levels and oral glucose tolerance test using 75gm of glucose were performed and the results were compared in each group of patients. RESULTS: Mean baseline insulin levels were elevated in both groups above the reference value, 9.3±3.5 μU/L in non-obese group and 9.9±3.5 μU/L in obese group (p=0.26). Seventeen of non-obese patients (68%) had elevated basal insulin level and 16 of obese patients (73%) had elevated basal insulin level (p=0.39). In oral glucose tolerance test, there was no difference in glucose level between non-obese and obese groups from O minute to 180 minutes (p > 0.05). Eleven patients from the non-obese group (44%) and 8 patients from the obese group (36%) had either impaired glucose tolerance or diabetes (p=0.29). CONCLUSION: Our data suggest that hyperinsulinemia and glucose intolerance may play a role in the pathogenesis of fatty liver in patients with normal body weight as well as in patients with obesity.