Waist-hip ratio is superior to BMI in predicting liver-related outcomes and synergizes with harmful alcohol use

Commun Med (Lond). 2023 Sep 6;3(1):119. doi: 10.1038/s43856-023-00353-2.

Abstract

Background: Obesity is associated with liver disease, but the best obesity-related predictor remains undefined. Controversy exists regarding possible synergism between obesity and alcohol use for liver-related outcomes (LRO). We assessed the predictive performance for LROs, and synergism with alcohol use, of abdominal obesity (waist-hip ratio, WHR), and compared it to overall obesity (body mass index, BMI).

Methods: Forty-thousand nine-hundred twenty-two adults attending the Finnish health-examination surveys, FINRISK 1992-2012 and Health 2000 studies, were followed through linkage with electronic healthcare registries for LROs (hospitalizations, cancers, and deaths). Predictive performance of obesity measures (WHR, waist circumference [WC], and BMI) were assessed by Fine-Gray models and time-dependent area-under-the-curve (AUC).

Results: There are 355 LROs during a median follow-up of 12.9 years (509047.8 person-years). WHR and WC emerge as more powerful predictors of LROs than BMI. WHR shows significantly better 10-year AUC values for LROs (0.714, 95% CI 0.685-0.743) than WC (0.648, 95% CI 0.617-0.679) or BMI (0.550, 95% CI 0.514-0.585) both overall and separately among men and women. WHR is predictive also in BMI strata. Absolute 10-year risks of LROs are more dependent on WHR than BMI. Moreover, WHR shows a significant supra-additive interaction effect with harmful alcohol use for liver-related outcomes (excess 10-year cumulative incidence of 2.8% from the interaction), which is not seen between BMI and harmful alcohol use.

Conclusions: WHR is a better predictor than BMI or WC for LROs, and WHR better reflects the synergism with harmful alcohol use. WHR should be included in clinical assessment when evaluating obesity-related risks for liver outcomes.

Plain language summary

Obesity has been linked to liver disease, but the most accurate measure for predicting obesity-related liver disease outcomes remains uncertain. In this study, we analyzed data from over 40,000 adults to compare the extent to which different measures of obesity can predict liver-related outcomes, such as severe liver disease, liver failure, or death from liver disease. The measures of obesity were the ratio of waist circumference to hip circumference (waist-hip ratio, WHR), waist circumference (WC), and body mass index (BMI). Our findings reveal that WHR and WC are stronger predictors of these outcomes than BMI. In particular, WHR demonstrated superior predictive ability and this predictive ability was influenced by harmful alcohol use. This study suggests that WHR may be a relatively simple but useful measure for clinicians to use when predicting obesity-related risks for liver health.