Non-alcoholic fatty liver disease's prevalence and impact on alanine aminotransferase associated with metabolic syndrome in the Chinese

Background and Aim: Non‐alcoholic fatty liver disease (NAFLD) is becoming a major public health hazard in China. The present study aimed to estimate the prevalence of NAFLD, NAFLD with abnormal serum alanine aminotransferase (ALT) levels, and determine the potential associations of ALT levels with the components of metabolic syndrome (MetS) in the absence or presence of NAFLD in Chinese adults. Methods: A population‐based cross‐sectional survey was conducted with 2226 participants. Physical examinations, laboratory tests and hepatic ultrasounds were performed. Individuals were further stratified into higher or lower ALT subgroups with the upper quartiles of ALT in this population. The MetS was identified according to the criteria of the Chinese Joint Committee for Developing Chinese Guidelines (JCDCG). Results: The standardized prevalence of NAFLD was 23.3% (NAFLD with abnormal ALT levels, 3.1%), 26.5% (NAFLD with abnormal ALT levels, 5.1%) in males, and 19.7% (NAFLD with abnormal ALT levels, 0.9%) in females. Multivariate logistic analysis revealed that higher ALT was significantly associated with elevated triglyceride (TG) in the non‐NAFLD participants, independent of age, smoking status, drinking status, and other MetS‐related measures with odds ratios (95% confidence intervals) of 3.4 (1.6–7.1) and 2.3 (1.4–3.7) in males and females, respectively. On the other hand, the higher ALT was statistically associated with elevated TG and hyperglycemia in the NAFLD cases with odds ratios of 2.2 to 2.5 (P < 0.05). Conclusions: The prevalence of NAFLD has become epidemic in Shanghai adults. NAFLD combined with ALT levels may be used to identify the individuals at the different risk levels of metabolic disorders.