Data sources and research subjects
We conducted a cross-sectional study using data from the sixth wave (2013-15), seventh wave (2016-18), and eighth wave (2019) of KNHANES conducted by the Agency for Disease Control and Prevention, Ministry of Health, Korea and Welfare. All participants were selected through multistage cluster probability sampling and included a representative sample of South Korea’s non-institutionalized civilian population.All participants provided written informed consent before participating in the study23.25.
Between 2013 and 2019, a total of 55,327 participants filled out the KNHANES questionnaire. Of these, we included 44,029 adults aged 19 years and older. We excluded 5,618 respondents who lacked liver enzyme testing information and completed the weight control questionnaire. In addition, we excluded 306 respondents diagnosed with hepatitis B, hepatitis C, or cirrhosis. We also excluded 1,736 respondents with a history of various cancers, including stomach, liver, colorectal, breast, cervical, lung, thyroid, etc. Finally, we excluded 110 respondents diagnosed with renal failure (Fig. 3).
learning process. aspartate aminotransferase aspartate aminotransferase; alanine aminotransferase Alanine transferase.
ethics
This study complied with the Declaration of Helsinki, and the Asan Medical Center Institutional Review Board (2021-1666) exempted this study from ethical review and approval requirements because the KNHANES database contains anonymized data that does not identify patients. All participants provided written informed consent before participating in the study. However, due to the observational nature of the study and the fact that patient identifiers were fully encrypted prior to data analysis, written or verbal consent was not required.
weight control methods
We extracted data on participants’ experiences with weight management over a one-year period and the strategies they employed. The data were collected through a questionnaire that asked: “In the past year, have you made a conscious effort to control your weight?” and “Please list all methods you have used to lose weight or maintain weight in the past year. ” We recorded attempts to control weight, including no control, efforts to gain weight, and efforts to lose or maintain weight. Only those participants who said they had tried to lose weight or maintain weight answered subsequent questions. We recorded weight control methods including exercise, fasting, reducing food intake, skipping meals, using prescription diet pills, using over-the-counter diet pills, using herbal remedies, consuming functional foods, and adhering to the diet. Single food diet. We divided weight control methods into two categories: use of weight loss medications (prescription and over-the-counter diet pills, traditional herbal medicines, and dietary supplements) and other methods (exercise, fasting, reduced food intake, skipping meals, single meals). -Food diet, etc.)3.
Liver enzymes
Liver aminotransferases (ALT and AST) are commonly used markers in routine serum liver enzyme testing. Levels of these enzymes increase when liver cells are damaged in conditions such as hepatitis, cholestasis, severe steatosis, etc. ALT and AST levels were obtained from venous blood samples and measured using a Hitachi automatic analyzer 7600-210 (Hitachi, Tokyo, Japan). The assay was carried out using the International Federation of Clinical Chemistry method, using UV light without pyridoxal 5′-phosphate and using Pureauto S series reagents (Sekisui, Tokyo, Japan).25.26.Although lower cutoffs are recommended to define status with elevated AST or ALT, we primarily use the traditional cutoff of >40 IU/L to classify elevated liver enzymes27. Sensitivity analyzes were performed on several cutoff points to investigate the robustness of the results, as follows: 1) American College of Gastroenterology Clinical Guidelines (ACG CG): AST > 43 IU/L and ALT > 33 IU/L, AST in men >32 IU/L and ALT >25 IU/L in women, 2) above borderline elevation defined using 2 times the upper limit of normal (ULN) using traditional cutoff levels: AST or ALT >80 IU/L, and 3) above borderline Elevated, use 2x ACG CG ULN: AST > 80 IU/L and ALT > 86 IU/L for men, AST > 64 IU/L and ALT > 50 IU/L for women28.
variable
To fully assess potential confounders and account for their effects, we included demographics, behavioral factors, comorbidities, and family history in our analyses. Demographic variables we considered included age, gender, year of survey, household income (categorized as low, lower-middle, upper-middle, or high), occupation type (categorized as unemployed or economically inactive, non-manual worker, manual worker, service or sales worker , or unknown/no response), marital status (married or single) and educational status (divided into junior high school or below, high school or college and above). Behavioral factors included perceived stress level (categorized as high, moderate, low, or unknown/no response), BMI, obesity, smoking status (categorized as non-smoker, ex-smoker, current smoker, or unknown/no response), alcohol consumption (categorized as severe, light to moderate, not drinking, or unknown/no response), and engaging in moderate-intensity physical activity (yes, no, or unknown/no response). We define obesity as a BMI of 25 kg/m2 or higher, Asia-Pacific standards based on World Health Organization guidelines29. We also considered participants’ history of comorbidities, including hypertension, hyperlipidemia, diabetes, depression, and thyroid disease. In addition, we collected information on family history of hepatitis B virus infection because it was considered a relevant confounder in the analyses.
Statistical Analysis
Data for continuous variables are presented as mean ± standard deviation (SD) and for categorical variables as percentage of the number of cases. Analysis of variance and chi-square tests were used to examine differences between weight control methods. We analyzed the association between elevated liver enzymes and weight control methods using logistic regression models. To adjust for founders, we selected variables that demonstrated statistical differences between exposure groups. We then used logistic regression to identify statistically significant risk factors for elevated liver enzymes. p– A value < 0.1 serves as the significance threshold.We also stratified the data by sex, age group (under 40 years or 40 years and over) and BMI (non-obese < 25 kg/m2)2Obesity ≥ 25.0 kg/m2), because susceptibility to elevated liver enzymes and attempts at weight control vary by sex, age, and body mass index30,31,32. We also performed a sensitivity analysis using a linear regression model treating AST and ALT as continuous variables. All statistical analyzes were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA).arrive p– Values <0.05 were considered to indicate statistical significance.