New research from the University of Eastern Finland and Rutgers University's Robert Wood Johnson Medical School announced on Apr. 14 shows that waist-to-height ratio (WHtR) cut-offs are more effective than body mass index (BMI) in predicting the risk of hypertension. The study aimed to validate new WHtR-based fat mass cut-offs for assessing elevated blood pressure and hypertension risk among a diverse population of children and adults in the United States.
Obesity is a complex disease marked by excess fat, with BMI currently used as the standard diagnostic tool. However, BMI has notable limitations, such as its inability to differentiate between fat and muscle mass. This distinction is important because higher muscle mass can reduce risks associated with cardiometabolic diseases like type 2 diabetes and bone fractures.
The waist-to-height ratio has gained attention as an alternative measure for obesity assessment. A WHtR cut-off of 0.5 is already recommended by the UK National Institute for Clinical Excellence for diagnosing central obesity, with other values suggested for different groups. Researchers recently proposed new WHtR thresholds that have outperformed BMI in identifying risks related to prediabetes, type 2 diabetes, fatty liver disease, and bone fractures.
Using data from the US National Health and Nutrition Examination Survey between 2015-2023—which included over 19,000 participants aged twelve or older—the study evaluated how well these WHtR thresholds could predict elevated blood pressure (defined as ≥120/70 mm Hg) and hypertension (≥140/90 mm Hg). In the most recent survey cycle from 2021-2023 involving over seven thousand participants with an average age of nearly forty-five years, elevated blood pressure was present in more than sixty percent while about fourteen percent had hypertension.
Results showed that individuals classified by WHtR as having high fat mass were fifty percent more likely to have elevated blood pressure and eighty-two percent more likely to be hypertensive; those with excess fat had even higher likelihoods—ninety-one percent for elevated blood pressure and one hundred sixty-one percent for hypertension. Among people under twenty-five years old, increased fat according to WHtR raised chances of high blood pressure but did not show a statistically significant link with hypertension due to its rarity at younger ages.
Dr Mahidere Ali, lead author from the University of Eastern Finland, said: "BMI failed to detect the independent effect of adiposity, likely because it does not isolate the confounding influence of muscle mass, which may inflate its association with blood pressure at earlier stages while obscuring its relationship with established hypertension." Dr Ali also stated: "After demonstrating consistent associations across ethnic backgrounds, age categories and survey cycles, it is safe to conclude that WHtR-based estimates of fat mass provide a more precise and clinically meaningful indicator of hypertension risk. WHtR is a simple, scalable tool that can strengthen early screening and improve detection of adiposity-related cardiovascular risk."
