Systematic review with meta‐analysis: risk factors for non‐alcoholic fatty liver disease suggest a shared altered metabolic and cardiovascular profile between lean and obese patients

Summary Background The pathogenesis of non‐alcoholic fatty liver disease ( NAFLD ) is closely associated with the co‐occurrence of multiple pathological conditions characterising the metabolic syndrome (MetS), obesity in particular. However, NAFLD also develops in lean subjects, whose risk factors remain poorly defined. Methods We performed a meta‐analysis of 15 studies, along with the data pertaining to our own population (n = 336 patients). Data from lean (n=1966) and obese (n=5938) patients with NAFLD were analysed; lean (n=9946) and obese (n=6027) subjects without NAFLD served as controls. Results Relative to the lean non‐ NAFLD controls, lean patients with NAFLD were older (3.79±0.72 years, P =1.36×10 −6 ) and exhibited the entire spectrum of the MetS risk factors. Specifically, they had a significant ( P =10 −10 ) increase in plasma glucose levels (6.44±1.12 mg/dL) and HOMA ‐ IR (0.52±0.094‐unit increment), blood lipids (triglycerides: 48.37±3.6, P =10 −10 and total cholesterol: 7.04±3.8, mg/dL, P =4.2×10 −7 ), systolic (5.64±0.7) and diastolic (3.37±0.9) blood pressure (mm Hg), P =10 −10 , and waist circumference (5.88±0.4 cm, P =10 −10 ); values denote difference in means± SE . Nevertheless, the overall alterations in the obese group were much more severe when compared to lean subjects, regardless of the presence of NAFLD . Meta‐regression suggested that NAFLD is a modifier of the level of blood lipids. Conclusion Lean and obese patients with NAFLD share a common altered metabolic and cardiovascular profile. The former, while having normal body weight, showed excess of abdominal adipose tissue as well as other MetS features.