Epidemiology of non‐alcoholic fatty liver disease and non‐alcoholic steatohepatitis in Japan: A focused literature review

Abstract

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) represent a growing unmet medical need and an increasingly prevalent cause of cirrhosis, hepatocellular carcinoma (HCC), and death in Japan. The aim of this review was to characterize the epidemiology of NAFLD and NASH in Japan. An English and Japanese literature search was conducted in PubMed, Embase, and ICHUSHI Web, identifying 6553 studies, 67 of which were included. Prevalence of NAFLD in the Japanese population rose from the early 1990s (12.6-12.9%) to the early 2000s (24.6-34.7% of the population). Japanese NASH prevalence is estimated to be 1.9-2.7%. NAFLD and NASH are more common among males than females; however, females experience more severe disease than males. While obese patients had higher prevalence of NAFLD/NASH, nonobese individuals (body mass index [BMI] <25 kg/m 2) consistently comprised 20% to >35% of NAFLD and NASH patients. The evidence shows that, despite obesity being linked with worse disease stages, "lean-NASH" also plays an important role in NASH epidemiology. Besides obesity, diabetes and metabolic syndrome appeared to be reliably associated with disease severity. The prevalence of advanced fibrosis or cirrhotic disease was the highest in patients with NASH-HCC (44-80% with stage F3/F4 disease), while 21-50% of patients with NASH had F3/F4 disease. NAFLD/NASH is common in the Japanese population, and the prevalence of these conditions has tripled in the last two decades. Furthermore, these NAFLD/NASH patients have a high comorbidity burden. Early and efficient identification of safe and effective treatments for NAFLD/NASH patients is urgently needed.

Efficacy of lenvatinib for unresectable hepatocellular carcinoma based on background liver disease etiology: multi-center retrospective study

“…Although there was no significant difference in OS (P = 0.057), OS in the NAFLD/NASH-HCC patients treated with lenvatinib was very favorable (20.5 months) and tended to be better than that in the Viral/Alcohol HCC cases (16.9 months). It was recently proposed by Hessheier et al that metabolic factors may be risk factors for development of liver diseases and cirrhosis 32 , while Eguchi et al found “lean-NASH” (non-obese NASH, body mass index: BMI < 25 kg/m 2 ) existing in 20% to > 35% in patients in Japan 33 . Of the present cryptogenic HCC patients (n = 26), diabetes was observed in 44.4% (n = 12), hypertension in 51.9% (n = 14), and overweight (BMI ≥ 25 kg/m 2 ) in 25.9% (n = 7), while 70.4% (n = 19) had at least one of those co-factors (Supplemental Table S2 ).…”

Efficacy of Lenvatinib for Unresectable Hepatocellular Carcinoma Based on Background Liver Disease Etiology: Multi-center Retrospective Study

“…It was recently been proposed by Hessheier et al that metabolic factors may be risk factors for development of liver diseases and cirrhosis 29 , while Eguchi et al found "lean-NASH" (non-obese NASH, body mass index: BMI <25 kg/m 2 ) existing in 20% to >35% in patients in Japan 30 . Of the present cryptogenic HCC patients (n=26), diabetes was observed in 44.4% (n=12), hypertension in 51.9% (n=14), and overweight (BMI ≥25 kg/m 2 ) in 25.9% (n=7), while 70.4% (n=19) had at least one of those co-factors (Supplemental Table S2).…”

Epidemiology of non-alcoholic fatty liver disease and hepatocellular carcinoma

“… [9] , [10] , [11] , [12] , [13] Risk factors for NAFLD are metabolic in nature and include obesity, insulin resistance, type 2 diabetes, hypertension, and dyslipidaemia. 9 , 10 , [13] , [14] , [15] , [16] Male sex and older age are also risk factors for NAFLD. 17 , 18 …”