Association of Aldehyde Dehydrogenase 2 ( ALDH2 ) rs671 Polymorphism and Alcohol-Related Liver Outcomes in Studies from China and Taiwan: A Systematic Review

Alcohol-related liver disease (ALD) is a major public health concern in East Asia, where alcohol consumption and genetic susceptibility jointly influence disease risk. This systematic review evaluated the association between aldehyde dehydrogenase 2 (ALDH2) polymorphisms, alcoholism, and ALD susceptibility among Chinese and Taiwanese populations. We searched PubMed, Scopus, and Web of Science and identified 1,743 records, followed by PRISMA guidelines. After screening and eligibility assessment were conducted, nine studies comprising 3,586 cases from China and Taiwan were included. Evidence was categorized into ALD severity, hepatocellular carcinoma (HCC), and longitudinal outcomes. Associations were summarized using odds ratios (ODs), Hardy-Weinberg equilibrium (HWE) was reassessed, overlapping reports were carefully considered, and bias was calculated. Individuals carrying ALDH2 polymorphisms showed an increased risk of ALD, odds ratio 2.28 (95% Cl: 1.01–5.15. Significant associations were observed for cirrhosis (ODs = 2.02, 95% Cl:1.10–3.71), HCC (ODs = 19.59, 95% Cl: 4.38-87.68), and hepatitis B-related liver disease (ODs = 5.59, 95% Cl: 2.42–12.90). The association was stronger among studies from China (ODs = 4.00, 95% Cl:1.74–9.20), whereas the Taiwan subgroup showed a lower frequency of the genetic variant in liver disease associated with chronic alcohol consumption cases. Allele frequencies and drinking behaviors were observed between the two countries. Taiwanese populations have lower frequencies of the ALDH2 Glu and one variant Lys allele, and higher rates of alcohol dependence and liver disease compared with Chinese populations. The interaction of genetic predisposition, alcohol consumption, and sociocultural factors appears to play an important role in ALD progression.