Study and Comparison of Metabolic Profile of Lean and Obese Subjects with Non Alcoholic Fatty Liver Disease

Background and objective: Nonalcoholic fatty liver disease (NAFLD) is conventionally considered to be a disease of obese subjects. Recent data suggests increasing incidence of NAFLD among lean subjects also. The aim of this study was to evaluate the metabolic profile of lean subjects with NAFLD and compare it with obese subjects with NAFLD. We also aimed to compare the same with lean subjects without NAFLD.

Methods: This study included 250 subjects with NAFLD and 500 non-NAFLD controls. Clinical, anthropological and biochemical data were collected. Subjects with body mass index (BMI) >= 25 kg/m2 were taken as obese and subjects with BMI <25 kg/m2 were taken as lean. Study population was divided into four groups i.e. lean subjects with NAFLD (LN), obese subjects with NAFLD (ON), lean subjects without NAFLD (LNN) and obese subjects without NAFLD (ONN).

Results: Out of 250 NAFLD subjects, 69 (27.6%) were lean. Out of 69 lean subjects with NAFLD, 54 (78.3%) were having diabetes mellitus. Metabolic profile (including lipid profile, diabetic profile) of lean subjects with NAFLD was significantly abnormal in comparison to lean non-NAFLD subjects. Proportion of subjects with metabolic syndrome was also comparable in both lean and obese NAFLD groups. Despite having comparable BMI, LN groups had significantly higher waist circumference (WC) than LNN. Mean total cholesterol, triglyceride, LDL were significantly higher in obese NAFLD in comparison to lean NAFLD. Mean HDL and VLDL were comparable among both groups. Mean FBS, HbA1c, fasting insulin and HOMA-IR were significantly higher among lean NAFLD group in comparison to obese NAFLD group. Obese NAFLD group had significantly higher levels of SGPT and SGOT as compared to lean NAFLD group.

Conclusion: Lean NAFLD has significantly higher WC in comparison to non-NAFLD counterparts suggesting possible association with central adiposity. Lean and obese NAFLD share common set of metabolic abnormalities, albeit with varying intensity. Lean NAFLD has more severe insulin resistance in comparison to obese NAFLD. Lean NAFLD subjects appeared to have less severe transaminasemia.