Body fat distribution and insulin resistance: beyond obesity in nonalcoholic fatty liver disease among overweight men.

OBJECTIVE: The aim of this study was to characterize the relationship between nonalcoholic fatty liver disease (NAFLD) and body fat distribution and insulin resistance in a sample of non-diabetic overweight men.

SUBJECTS AND METHODS: We conducted a cross-sectional survey of 117 overweight men with NAFLD, as well as 117 controls, who were matched with regard to age and body mass index. None of the study subjects exhibited signs of alcohol abuse, hepatitis B or C, diabetes or fasting hyperglycemia, or hypertension. The diagnosis of NAFLD was based on dual findings of elevated alanine aminotransferase levels and sonographically-determined fatty liver. Body fat distribution was assessed via bioelectrical impedance. Insulin resistance was evaluated via homeostasis model assessment (HOMA-IR).

RESULTS: The risk of developing NAFLD was found to be profoundly associated with elevated measurements of waist circumference, fat mass, percentage of body fat and abdominal fat, iron, triglycerides, apolipoprotein B, and results of HOMA-IR. Multivariate analysis revealed that NAFLD was significantly associated with elevated measurements of waist circumference, iron, apolipoprotein B, and HOMA-IR.

CONCLUSIONS: Our study provides evidence for a profound and dose-dependent association of NAFLD with central adiposity, insulin resistance in overweight men lacking complications of metabolic syndrome. Overweight subjects with insulin resistance or central adiposity were at more risk of NAFLD than were those subjects with less insulin resistance or central adiposity, even those with a similar degree of obesity.