High prevalence of non-alcoholic fatty liver disease in the Chinese – results from The Hong Kong Liver Health Census

Abstract

Background and Aims: To determine the prevalence and risk factors of non-alcoholic fatty liver disease (NAFLD) in a healthy Chinese population. Methods: Participants of the Liver Health Census were recruited from two sources – blood donors from the Hong Kong Red Cross Blood Transfusion Service and volunteers from the general population. All participants included in the census were screened negative for hepatitis B surface antigen, antibody to hepatitis C virus, and antibody to human immunodeficiency virus. All subjects underwent weight, height, and hip and waist circumference measurements. Blood pressure was also recorded. A detailed questionnaire of medical history, alcohol, medicine, and herbal intake was undertaken. Laboratory blood testing, ultrasonography and transient elastography were performed on the same day. Results: A total of 2,493 subjects were recruited into the census. The prevalence of NAFLD was 42% (1,054 patients). Univariate analysis identified male gender, increasing age, weight, height, body mass index, waist circumference, hip circumference, waist-hip ratio, systolic and diastolic blood pressure, fasting cholesterol and glucose levels to be significant factors associated with NAFLD. Using multivariate analysis, gender, age, waist circumference, systolic blood pressure, fasting cholesterol and glucose levels remained significant factors. The relative risk of NAFLD in those with high waist circumference (current recommendation: male 90cm, female 80cm), diabetes, hypertension, and hypercholesterolemia was 2.99, 2.01, 1.79, and 1.54 respectively. The degree of steatosis increased with levels of fasting glucose, cholesterol, systolic blood pressure and waist circumference (all p<0.001). The optimal waist circumference was found to be 84 and 74cm for male and females respectively, with a relative risk of 5.16 for those above this limit. 1.2% and 0.002% of subjects with NAFLD had advanced liver fibrosis and cirrhosis respectively. Conclusions: NAFLD was found to be highly prevalent in the Chinese population. Despite this, the prevalence of severe liver disease was low. Increasing levels of risk factors were associated with increasing severity of NAFLD. Lower cut-off levels of waist circumference to predict NAFLD should be adopted for Chinese population.