The Epidemiological Survey Of Non-alcoholic Fatty Liver In Fuzhou And The Role Of Free Fatty Acids In The Pathogenesis Of NAFLD

Objective To investigate the prevalence and major risk factors of non-alcoholic fatty liver(NAFLD) among adult residents in Fuzhou, explore the role of free fatty acids in NAFLD and the relationship between insulin resistance and the free fatty liver(FFA) in NAFLD patients, and provide the new theory for the pathogenesis and prevention of NAFLD.Methods In first part, a cross-sectional survey with multiple-stage stratified cluster and random sampling was performed. All residents aged 16 years and above were invited to participate in the survey; they came from 2 streets of Fuzhou. Ques-tionnaire, physical examination, serum lipid-profile, 75 gram oral glucose tolerance test, and ultrasonographic examination of liver were undertaken; in second part, case-control study was perfoemed, NAFLD and conctol group, all the above were undertaken, also including serum insulin, FFA by ELISA. Analysis of data was performed by SPSS13.0 for Windows statistical package.Results A total of 2850 adult residents took part in the survey,which was 87.31% of residents of the investigated communities and 17.59/10000 of Fuzhou municipal residents. Of the 2850, 1350 were males and 1500 were females. The mean age of the participants was 52.40±16.20 years and ranged from 16~82 years. Fatty liver was detected with ultrasound examination in 729 participants(25.58%),among which 17.28% had alcoholic fatty liver, 3.43% had suspected alcoholic fatty liver, and 79.29% had NAFLD.The age-adjusted, sex-adjusted prevalence of fatty liver in Fuzhou residents was 25.58%, the prevalence of alcoholic fatty liver,suspicious alcoholic fatty liver,and NAFLD in Fuzhou residents were 4.42%, 0.88%, and 20.28% respectively. The prevalence of NAFLD was increased with aging in males and in females.Among participants younger than 55 years,the prevalence of NAFLD in males was significantly higher than that in females(χ2= 25.708, P<0.001), but in participants older than 55 years the case was just the opposite, higher in females(χ2= 4.320, P<0.05). The body mass index(BMI), waist circumference, blood pressure, fasting blood glucose level, triglyceride(TG), Total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), and the incidence of obesity, diabetes2 mellitus, hypertension, dyslipidemia in NAFLD group were significantly higher than those in the group without fatty liver(all P<0.001), but the high-density lipoprotein cholesterol(HDL-C) level was lower in NAFLD group (P<0.001). Logistic regression analysis demonstrated that the prevalence of fatty liver was only closely correlated to nine factors, including waist circumference, WHR, BMI, FBG, TG, hypertension, abnormal hepatic function and diabetes mellitus. The level of FFA in NAFLD patients was higher than that of the control group, P<0.01, the difference was statistically significant. In NAFLD patients FFA levels was significantly negatively correlated with insulin sensitivity index(ISI), the level of FFA was positively related to insulin resistance.Conclusion 1. The prevalence of fatty liver among residents in Fuzhou is 25.58%, and NAFLD(20.28%) is the major type. 2.The hypertension, type 2 diabetes, TG, waist circumference, BMI, FBG, WHR and abnormal hepatic function are positively related to NAFLD,which are risk factors; HDL-C is negatively correlated with NAFLD,which is protective factor; 3. FFA concentration is closely associated with NAFLD, in NAFLD patients FFA is positively related to IR.