Waist-to-height ratio found to predict liver damage better than BMI

Excess fat mass estimated by waist circumference-to-height ratio predicts the risk of liver damage better than body mass index (BMI) estimated obesity, a new study shows. Waist-to-height ratio is a cheap and universally accessible tool to detect the risk of fatty liver disease both in the young and adult population. The study was conducted at the University of Eastern Finland, and the results were published in the Journal of the Endocrine Society.

In the present study, 6,464 children, adolescents and adults between 12 and 80 years of age were drawn from the United States National Health and Nutrition Examination Survey (NHANES) conducted between 2021 and 2023. Non-invasive liver scans were conducted in all participants by transient elastography, based on which their risk of liver steatosis or fibrosis was classified. The prevalence of significant or advanced liver fibrosis was 7.1%, while 4.9% had liver cirrhosis. More than 1 in 4 (26.1%) participants had suspected liver steatosis, while less than 1% had severe liver steatosis.

Previous studies in adults have shown that BMI-diagnosed obesity is a risk factor for liver steatosis. However, recent clinical consensus statements have recommended that obesity should not be diagnosed with BMI alone but confirmed with another measure such as waist-to-height ratio.

In a recent study, waist-to-height ratio was discovered as a highly sensitive and specific predictor of dual-energy Xray absorptiometry-measured total body fat mass and abdominal fat mass in the pediatric and young adult population. Waist-to-height ratio cutpoints for normal, high and excess fat mass were established and have since been validated to detect the risk of type 2 diabetes and bone fracture. The present study examined if these cutpoints can predict liver steatosis and fibrosis in a multiracial population.

The prevalence of waist-to-height-ratio-estimated normal fat mass (0.40 - <0.50), high fat mass (0.5 - <0.53) and excess fat mass indicating obesity (≥0.53) was 20.3%, 13.6% and 64.5%, respectively. After full adjustments for covariates, normal fat mass had a 48% protective effect against liver steatosis and a 52% protective effect against liver fibrosis or cirrhosis. High fat mass predicted 63% higher odds of liver steatosis and 31% higher odds of liver fibrosis or cirrhosis. Excess fat mass predicted four-fold higher odds of liver steatosis and 61% higher odds of liver fibrosis or cirrhosis.

Waist-to-height-ratio-estimated high fat mass and excess fat mass separately predicted higher odds of liver steatosis nearly two-fold and six-fold, respectively, better than BMI-overweight and BMI-obesity. The study accounted for age, sex, systolic blood pressure, heart rate, educational status, smoking status, race, sedentary time, moderate physical activity, fasting insulin, glucose, total cholesterol and high-sensitivity C-reactive protein.

Remarkably, the findings were consistent regardless of sex and age. In addition, the findings were similar across the studied White, Black, Mexican-American and Hispanic populations. The simple and universally accessible waist-to-height measurement is useful in clinical and public health practice for liver disease screening, prevention, diagnosis and management globally."

Andrew Agbaje, physician and associate professor (docent) of Clinical Epidemiology and Child Health, University of Eastern Finland

Based on his previous research, Agbaje has also developed a waist-to-height ratio clinical calculator.

Agbaje's research group (urFIT-child) is supported by research grants from Jenny and Antti Wihuri Foundation, the Finnish Cultural Foundation Central Fund, the Finnish Cultural Foundation North Savo Regional Fund, the Orion Research Foundation, the Aarne Koskelo Foundation, the Antti and Tyyne Soininen Foundation, the Paulo Foundation, the Yrjö Jahnsson Foundation, the Paavo Nurmi Foundation, the Finnish Foundation for Cardiovascular Research, Ida Montin Foundation, Eino Räsänen Fund, Matti and Vappu Maukonen Fund, Foundation for Pediatric Research, Alfred Kordelin Foundation, and Novo Nordisk Foundation.