Lean Patients with Non-Alcoholic Fatty Liver Disease Have a Severe Histological Phenotype Similar to Obese Patients

Abstract

A small proportion of lean patients develop non-alcoholic fatty liver disease (NAFLD). We aimed to report the histological picture of lean NAFLD in comparison to overweight and obese NAFLD patients. Biopsy and clinical data from 466 patients diagnosed with NAFLD were stratified to groups according to body mass index (BMI): lean (BMI ≤ 25.0 kg/m², n confirmed to be appropriate = 74), overweight (BMI > 25.0 ≤ 30.0 kg/m², n = 242) and obese (BMI > 30.0 kg/m², n = 150). Lean NAFLD patients had a higher rate of lobular inflammation compared to overweight patients (12/74; 16.2% vs. 19/242; 7.9%; p = 0.011) but were similar to obese patients (25/150; 16.7%). Ballooning was observed in fewer overweight patients (38/242; 15.7%) compared to lean (19/74; 25.7%; p = 0.014) and obese patients (38/150; 25.3%; p = 0.006). Overweight patients had a lower rate of portal and periportal fibrosis (32/242; 13.2%) than lean (19/74; 25.7%; p = 0.019) and obese patients (37/150; 24.7%; p = 0.016). The rate of cirrhosis was higher in lean patients (6/74; 8.1%) compared to overweight (4/242; 1.7%; p = 0.010) and obese patients (3/150; 2.0% p = 0.027). In total, 60/466; 12.9% patients were diagnosed with non-alcoholic steatohepatitis (NASH). The rate of NASH was higher in lean (14/74; 18.9% p = 0.01) and obese (26/150; 17.3%; p = 0.007) compared to overweight patients (20/242; 8.3%)). Among lean patients, fasting glucose, INR and use of thyroid hormone replacement therapy were independent predictors of NASH in a multivariate model. Lean NAFLD patients were characterized by a severe histological picture similar to obese patients but are more progressed compared to overweight patients. Fasting glucose, international normalized ratio (INR) and the use of thyroid hormone replacement may serve as indicators for NASH in lean patients.

Non-alcoholic fatty liver disease in lean individuals

“…Furthermore, with economic development, there has also been a surge of adiposity even within the normal BMI category, and lean individuals with NAFLD often have increased visceral adipose tissue and sarcopenia. 54…”

Lean Nonalcoholic Fatty Liver Disease and Risk of Incident Diabetes in a Euglycemic Population Receiving Health Checkups: A Cohort Study

“…[33] Consistently, a study of 466 Caucasian subjects with biopsy-proven NAFLD demonstrated that lean NAFLD is characterized by a severe histological picture similar to that of obese NAFLD and the former cases are more progressed compared to overweight cases. [34] In our study, we attempted to evaluate the association between lean NAFLD severity and future diabetes risk. Numerous noninvasive scoring systems, including the NAFLD brosis score, BAAT score, and BARD score, have been proposed to stage NAFLD, though there is no consensus to date.…”

Non‐alcoholic fatty liver disease in Asia: How is it different from the West?

“…20 On the other hand, a recent European study demonstrated that non-obese NAFLD patients had a severe histological picture similar to obese patients but were even more progressive (with a higher rate of cirrhosis) compared with overweight patients who had NAFLD. 21 The different observations in the above studies may be partly explained by selection bias. The threshold to perform liver biopsy examination may be different in obese and non-obese NAFLD patients in some centers-non-obese group was older than the obese group (49.9 vs 40.5 years; P < 0.01).…”

“…A Chinese cohort of histologically proven NAFLD patients showed that non‐obese NAFLD patients had less severe disease and may have a better prognosis than obese patients . On the other hand, a recent European study demonstrated that non‐obese NAFLD patients had a severe histological picture similar to obese patients but were even more progressive (with a higher rate of cirrhosis) compared with overweight patients who had NAFLD . The different observations in the above studies may be partly explained by selection bias.…”