Abstract:
Purpose: Body mass index (BMI) and waist circumference (WC) are the most widely used anthropometric indices for identifying obesity. This study aimed to compare and clarify the usefulness of BMI, WC, and the combination of these two indicators in predicting non-alcoholic fatty liver disease (NAFLD).
Methods: This cross-sectional study included 15,267 Korean adults. We defined four obesity categories using BMI and WC as follows: BMI non-obese and WC non-obese (BNWN); BMI obese and WC non-obese (BOWN); BMI non-obese and WC obese (BNWO); BMI obese and WC obese (BOWO). ANOVA was used to compare fatty liver severity across each category. The odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD were calculated using multiple logistic regression.
Results: Compared with BNWN, participants with BNWO were 3.235 (95% CI, 2.774–3.773) times more likely and participants with BOWN were 2.344 (95% CI, 2.045–2.687) times more likely to have NAFLD. Participants with BNWO had higher OR for NAFLD than those with BOWN. Moreover, BOWO participants had the highest OR of 4.788 (95% CI, 4.350–5.270) for NAFLD among all obesity categories.
Conclusion: Combined obesity classification by BOWO is the most reliable indicator for NAFLD presence in Korean adults.
Audience take-away:
- This study showed that a combination of BMI and WC can be a useful screening tool for NAFLD in Korean adults. Moreover, WC obesity has more powerful association with NAFLD incidence than BMI obesity. People should maintain a healthy diet and exercise and closely observe changes in visceral adipose distribution. It is important to maintain WC within a normal range to prevent abdominal obesity, which could increase the risk for NAFLD. This study emphasizes the need to use BMI and WC simultaneously to better identify obese individuals and predict NAFLD incidence. People should focus on reducing their WC, not just on losing weight.
- This study has several limitations. First, this was a single-center study with a homogenous ethnic cohort of Korean adults. Second, there is potential for selection bias, because study participants were self-referred for health screenings. Third, because this study had a retrospective cross-sectional design, it cannot confirm a causal relationship between each obesity group and NAFLD incidence. Future subsequent studies should include heterogeneous populations to ensure generalizability to other ethnicities.
