摘要
Nonalcoholic fatty liver disease(NAFLD)is the most common liver disease worldwide,with an estimated prevalence of 25% globally.NAFLD is closely associated with metabolic syndrome,which are both becoming increasingly more common with increasing rates of insulin resistance,dyslipidemia,and hypertension.Although NAFLD is strongly associated with obesity,lean or nonobese NAFLD is a relatively new phenotype and occurs in patients without increased waist circumference and with or without visceral fat.Currently,there is limited literature comparing and illustrating the differences between lean/nonobese and obese NAFLD patients with regard to risk factors,pathophysiology,and clinical outcomes.In this review,we aim to define and further delineate different phenotypes of NAFLD and present a comprehensive review on the prevalence,incidence,risk factors,genetic predisposition,and pathophysiology.Furthermore,we discuss and compare the clinical outcomes,such as insulin resistance,dyslipidemia,hypertension,coronary artery disease,mortality,and progression to nonalcoholic steatohepatitis,among lean/nonobese and obese NAFLD patients.Finally,we summarize the most up to date current management of NAFLD,including lifestyle interventions,pharmacologic therapies,and surgical options.