Study On The Prevalence And Risk Factors Of NAFLD Based On Physical Examination People In A Hospital

Objective:To evaluate the prevalence of non-alcoholic fatty liver disease (NAFLD) among physical examination population in Tianjin, and explore its risk factors and the relationship between NAFLD and obesity.Methods:Both cross-sectional study and case-control study were used in this research.9523of subjects aged18-69yrs and taken physical examination during September23th in2010to September22th in2011in a central hospital of Tianjin were sellected in the cross-sectional study and their check-up data were collected to describe the NAFLD prevalence and NAFLD-related diseases. Then160cases and160controls were selected from the population to conduct the case-control study. All subjects in both groups were investigated on their lifestyle, diseases history and diseases family history, etc. Unconditional logistic regression was used for analysis of the risk factors of NAFLD.Results:1. the cross-sectional study results showed that the prevalence of NAFLD was27.3%(standard rate was25.4%),33.7%for male and16.6%for female. Most of the patients were mild degree of NAFLD (62.9%). The NAFLD prevalence of female was rising with age. In male, NAFLD prevalence rates were at a high level from30to60-year-old, and then there was a slight decline after the age of60. The rates of overweight/obesity, DM, hyperlipidemia, hypertension, hyperuricemia, abnormal blood viscosity and abnormal liver function were all higher in NAFLD group than in the normal controls (69.1%v.s26.1%,13.1%v.s5.2%,65.2%v.s32.8%,43.4%v.s25.5%,19.0%v.s8.0%,12.4%v.s8.4%and23.3%v.s7.0%, respectively)(all p<0.05).2. The risk factors for NALFD by univatiate analysis included no tea-drinking, travel in car or by bus, family history of hypertension, family history of diabetes, family history of cardiovascular disease, hypertension, impaired fasting glucose, DM, hypertriglyceridemia, hypercholesterolemia, low HDL-c hyperlipidemia, abnormal LDL-c, hyperuricemia, BMI, WC, WHR, triceps brachii muscle subcutaneous fat thickness, scapular subcutaneous fat thickness, periumbilical subcutaneous fat thickness, dining out, eating night snack frequently, partial greasy daily diet, high salt diet and fried food. The protective factors of NALFD by univatiate analysis were heavy manual labor occupations, physical exercise, no significant increase of body weight, and nuts intake. With interaction analysis, periumbilical subcutaneous fat thickness was interacted with WC and removed, then the multivariate logistic regression showed that BMI, WC, eating night snack frequently, fried food, abnormal fasting glucose, hyperuricemia, hypertriglyceridemia, family history of hypertension, family history of cardiovascular disease were independent risk factors for NAFLD, and the independent protective factors for NAFLD were heavy manual labor occupations, nuts intake, no significant increase of body weight.3. BMI and WC were combined as a simple test to screen NAFLD, the results showed that the sensitivity was83.7%, the specificity was32.5%, and the kappa value was0.529.Conclusions:1. The NAFLD prevalence of physical examination people in Tianjin was higher than that of the national general level; more attention should be taken to focous on the prevention and treatment of NAFLD.2. The occurrence of NAFLD was influenced by multiple factors. So it is recommended for residents, especially the people with high risk for NAFLD, to take some comprehensive preventive controlling measures on NAFLD, including reasonable diet, weight contol, and improving the status of metabolic disorders. The people with family history of hypertension and cardiovascular disease should focus on monitoring and take primary prevention measures to prevent the occurrence of NAFLD.3. This study didn’t found that subcutaneous fat thickness was one of independent risk factors for NAFLD, while neither BMI nor WC can accurately determine the body fat content and describe the relation between obesity and NAFLD comprehensively. Therfore we need to explore other accurate indicators for obesity and to describe the content and distribution of fat objectively, such as subcutaneous fat and visceral fat, etc, furthermore to explore the relationship of body fat and NAFLD.