Background and aims: non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in the western world. Although NAFLD prevalence is higher in patients with a BMI > 25 kg /m2, it is unclear if there are differences between overweight and obese patients. The associated biochemical, dietary and genetic parameters were compared between overweight and obese patients with NAFLD.
Methods: patients with biopsy-proven NAFLD (n = 203) were enrolled in a cross-sectional study. The MEDAS questionnaire was used to assess adherence to the Mediterranean diet. Biochemical, anthropometrical parameters and the I148M variant (rs738409) of the PNPLA3 gene and rs180069 of the TNF-α gene were evaluated.
Results: overweight patients had higher serum adiponectin levels (22.5 ± 21.9 vs 11.2 ± 18.1 ng/ml; p < 0.05) and lower resistin (3.3 ± 1.7 vs 8.1 ± 8 ng/ml; p < 0.001) and leptin concentrations (22.9 ± 21.9 vs 55.8 ± 45 ng/ml; p < 0.001) than obese patients. Non-alcoholic steatohepatitis (NASH) was more frequent in the obese group (59.3% vs 41.3%; p = 0.02). The multivariate analysis showed adherence to the Mediterranean diet to be an independent protective factor for NASH and liver fibrosis in overweight patients (OR 0.7, 95% CI 0.5-0.8).
Conclusions: NASH was more prevalent in obese patients than in overweight subjects. HOMA-IR and adherence to the Mediterranean diet provided protection against fibrosis in overweight patients. Adherence to the Mediterranean diet was the only independent factor associated with NASH in these patients.