[Epidemiological survey of prevalence of fatty liver and its risk factors in a general adult population of Shanghai].

Objective: To investigate the prevalence and major risk factors of fatty liver among adult residents in Shanghai.

Methods: A cross-sectional survey with multiple-stage stratified cluster and random sampling was performed. All residents aged 16 and above were invited to participate in the survey; they came from four communities of Yangpu District and Pudong New District. Questionnaire, physical examination, serum lipid-profile, and 75 gram oral glucose tolerance test and ultrasonographic examination of liver were undertaken. Analysis of data was performed through SPSS 11.0 for Windows statistical package.

Results: A total of 3175 residents took part in the survey, which was 75% of adult residents of the investigated communities and 2.26/10 000 of Shanghai municipal residents. Of the 3175, 1218 were males and 1957 were females. The mean age of the participants was 52.4+/-15.1 years and ranged from 16 to 88 years. Fatty liver was detected with ultrasound examination in 661 participants (20.82%), among which 3.48% had alcoholic fatty liver, 4.08% had suspected alcoholic fatty liver, and 92.43% had nonalcoholic fatty liver. The age-adjusted, sex-adjusted prevalence of fatty liver in Shanghai adult residents was 17.29%, the prevalence of alcoholic fatty liver, suspicious alcoholic fatty liver, and nonalcoholic fatty liver in Shanghai adult residents were 0.79%, 1.15%, and 15.35%, respectively. The prevalence of fatty liver was increased with aging in males and in females. Among participants younger than 50 years old, the prevalence of fatty liver in males was significantly higher than that in females, but in participants older than 50 years the case was just the opposite, higher in females. The mean age (years), body mass index (BMI), waist circumference, blood pressure, fasting and two hour serum glucose level, triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and the presence of obesity, diabetes mellitus, hypertension, dyslipidemia, and gallstones in the fatty liver group was significantly higher than those in the group without fatty liver, but the high-density lipoprotein cholesterol (HDL-C) level and the educational level were both lower in the fatty liver group. Logistic regression analysis demonstrated that the prevalence of fatty liver was only positively correlated to nine risk factors, including male sex, educational level, waist circumference, BMI, fasting glucose level, HDL-C, TG, hypertension and diabetes mellitus. In heavy drinkers, obesity increased the risk for fatty liver by 4.8-fold, but heavy drinking only increased the risk for fatty liver 1.5-fold (95% CI 0.9-2.6, P=0.1685).

Conclusion: There is a high prevalence of fatty liver among adult residents in Shanghai, and nonalcoholic fatty liver is the major type. Metabolic disorders such as obesity and diabetes mellitus, hypertension and hyperlipidemia are more closely associated with fatty liver than heavy drinking in Shanghai.