Clinical Characteristics and Metabolic Profiles of Non-Alcoholic Fatty Liver Disease (NAFLD) in Lean Patients and Their Comparison with Obese and Overweight NAFLD

Abstract

Non -alcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease throughout the world. The spectrum of NAFLD includes a non-serious condition called fatty liver, a more serious condition named non-alcoholic steatohepatitis (NASH) which may lead to severe liver scarring and cirrhosis. Obesity and diabetes mellitus are established risk factors for NAFLD. However, it has been increasingly reported among lean or non-obese and non diabetic patients. The aim of this study was to evaluate the magnitude, clinical and metabolic profiles of NAFLD in normal body mass index (BMI) subjects, defined as lean NAFLD, as compared to overweight or obese NAFLD and lean healthy controls.

Material: 92 consecutive NAFLD and 90 healthy controls were studied between 2021 March to 2021 August, for a period of 6 months. Patients of NAFLD were diagnosed on the basis of ultrasonography features, presence of metabolic syndrome or insulin resistance. Patients with a BMI of less than 23 kg/m2 were defined as lean NAFLD. Alcoholic patients, those with liver diseases of other known causes, patients on medications known to induce fatty liver were excluded. For comparing the characteristics of lean NAFLD patients, we also included 90 lean healthy subjects with normal liver on ultrasonography as control subjects.

Observation: Among the 92 NAFLD patients, 18 (19.56%) were lean or non-obese, while 48 (52.17%) were obese, and 26 (28.26%) were overweight. The lean NAFLD cohort was younger (p<0.001), more commonly female, had a lower prevalence of diabetes (p=0.01) and metabolic syndrome (p<0.001). The serum lipid profile was similar in all the three BMI categories and 82% of the lean NAFLD were dyslipidemic. In comparison to obese subjects, patients with lean NAFLD had significantly less fibrosis. Despite being lean, the mean BMI of lean NAFLD patients was still higher than healthy control group.

Conclusion: Dyslipidemia is frequently associated with lean NAFLD. Lean NAFLD when compared to obese or overweight NAFLD, have lower prevalence of type 2 diabetes mellitus, metabolic syndrome and less fibrosis on fibroscan of liver. They donot have abdominal obesity, but their BMI was higher than healthy controls.