Combined Body Mass Index And Waist-to-height Ratio For Risk Assessment Of Non-alcoholic Fatty Liver Disease

Objective:With the increasing prevalence of obesity on all continents,Non-alcoholic Fatty Liver Disease(NAFLD)has become a major global health problem.It is the largest liver disease in the world and may become the main cause of end-stage liver disease in the coming decades.A combination of Body Mass Index(BMI)and Waistline Circumference(WC)has been demonstrated in previous studies to enhance detection of individuals at high risk for obesity-related diseases.Recently,scholars have proposed a new method to determine obesity,which is based on the joint determination of BMI and waist-to-height Ratio(WHt R).However,the effectiveness of the combined index in assessing the risk of NAFLD still needs to be further clarified,and whether the combined ability of BMI+WHt R is better than that of the single index and the combined effect of BMI+WC also needs to be further verified.The aim of this study is to explore the risk factors for NAFLD and to determine whether a combination of BMI+ WHt R could more accurately identify people at high risk for NAFLD than BMI,WHt R,WC or BMI+WC.Methods:A cross-sectional study is conducted on the data of 1 276 people from the Health Management Center of the Second Affiliated Hospital of Dalian Medical University.Mann Whitney U test,χ2 test and t test are used to screen out related factors of NAFLD between groups.Among the related factors,ROC(receiver operating characteristic)curve analysis is used to screen out the high risk factors of NAFLD.Independent risk factors are determined by binary logistic regression analysis(using risk odds ratio and 95% confidence interval).Participants are then divided into five groups based on the cut-off values for BMI,WHt R,and WC values: WC abnormality(male WC≥90cm,female WC≥85cm),BMI abnormality(BMI≥24.0kg/m2),WHt R abnormality(WHt R≥0.5),BMI+WC abnormality(BMI≥24.0kg/m2 and male WC≥90cm,female WC≥85cm),and BMI+ WHt R abnormality(BMI≥24.0kg/m2 and female WC≥85cm).Spearman correlation analysis is used to compare the correlation between BMI abnormality,WHt R abnormality,WC abnormality,BMI+WC abnormality,BMI+WHt R abnormality and NAFLD.ROC curve is used to analyze and compare the diagnostic efficacy of BMI abnormality,WHt R abnormality,WC abnormality,BMI+WC abnormality and BMI+ WHt R abnormality for NAFLD risk,that is,the area under the receiver operating characteristic curve(AUC)of them is compared..Results:1.The prevalence of NAFLD in this study population is 28.21%,and the prevalence of NAFLD in males is higher than that in females(77.8% vs 22.2%).It tends to appear in individuals with high blood pressure,diabetes,gallbladder polyps,or thyroid nodules.2.When used as continuous variables,BMI,WC,WHTR,Alanine Aminotransferase(ALT),body weight,Triglycerides(TG),γ-glutamyl transpeptidase(GGT),Serum Uric Acid(SUA),Red Blood Cell(RBC),Hemoglobin(HGB),Fasting Blood Glucose(FBG),and Aspartate Aminotransferase(AST)are risk factors for nonalcoholic fatty liver disease(both AUC values were > 0.7).The AUC values of BMI,WC and WHt R are the highest among all variables,which were 0.843,0.830 and 0.823 respectively.3.The odds ratios of WHt R,BMI and WC for NAFLD were 4.060 × 1011(95% CI: 1.224 × 1010 ~ 1.347 × 1013,P < 0.001),1.595(95% CI: 1.504 ~ 1.692,P < 0.001)and 1.157(95% CI: 1.136 ~ 1.179,P < 0.001).After adjusting for age,height,alt,AST,GGT,FBG,TC and TG,WHt R,BMI and WC were still significantly correlated with NAFLD(all P < 0.001).4.The correlation coefficients of WC abnormality,BMI abnormality,WHt R abnormality,BMI+WC abnormality and NAFLD are 0.427,0.436,0.416,0.448,0.470,respectively.The correlation between BMI+WHt R abnormality and NAFLD is strongest.5.The diagnostic efficacy(AUC value)of WC abnormality,BMI abnormality,WHt R abnormality,BMI+WC abnormality and BMI+WHt R abnormality for NAFLD are 0.721,0.742,0.729,0.727,0.751,respectively.BMI+WHt R has the best diagnostic efficacy for NAFLD.Conclusion:BMI,WC,WHt R,ALT,Weight,TG,GGT,SUA,RBC,HGB,FBG and AST are high risk factors for NAFLD.WHt R,BMI and WC were the independent risk factors of NAFLD.The combined index of BMI and WHt R improved the ability of body fat classification and detection of individuals at risk for NAFLD,and provided a more accurate method for early identification of patients with high and low risk NAFLD.The risk identification ability of the combined index is better than that of BMI,WHt R,WC alone or combined BMI+WC.