Tracking nearly 400,000 adults over a median follow-up of 13.3 years, researchers using the UK Biobank prospective cohort examined whether the body roundness index—a mathematical calculation combining waist circumference and height—offers a clearer picture of myocardial infarction risk than conventional body measurements, finding a 52% higher adjusted hazard of heart attack in the highest index quartile.
In Plain English: The Clinical Takeaway
- Beyond the Scale: Traditional body mass index cannot describe regional adiposity, and standard waist measurements cannot distinguish between visceral and subcutaneous abdominal fat.
- The Roundness Metric: The body roundness index uses height and waist circumference to estimate fat accumulation and body roundness, showing a statistically significant association with heart attack risk in this cohort.
- Clinical Caution: While the index showed a slight statistical advantage over other measurements, researchers emphasize that further independent validation is required before changing routine clinical practice.
Evaluating Anthropometric Indices in the UK Biobank Cohort
Obesity remains a complex medical condition carrying multiple health risks. Global data shows that the contribution of high body mass index to disability-adjusted life years climbed from 3.4% in 2010 to 4.9% in 2023. At the same time, ischemic heart disease stood as the number one cause of age-standardized deaths worldwide from 1990 to 2023, interrupted only in 2021 when coronavirus disease 2019 outranked it. Identifying simple, inexpensive screening tools remains critical for assessing myocardial infarction risk in high-risk individuals.
To investigate whether geometric measurements could improve risk assessment, investigators analyzed data from 395,831 participants aged 40 to 70 years. The study categorized individuals into quartiles based on multiple anthropometric indices: body roundness index, body mass index, waist circumference, weight-adjusted waist index, body surface area, and a body shape index. Cox proportional hazards regression models accounted for demographic, lifestyle, and clinical risk factors.
During the 13.3-year median follow-up period, researchers recorded 14,419 myocardial infarction events. Participants who experienced a heart attack tended to be older, were more frequently male, presented with a higher deprivation metric, and reported a more extensive smoking history. They also showed higher rates of hypertension, diabetes, hypercholesterolemia, and family histories of heart disease, alongside elevated serum creatinine and C-reactive protein levels.
Comparative Predictive Performance Across Quartiles
The analysis revealed a 52% higher adjusted hazard of heart attack among participants in the highest quartile of the body roundness index compared to the lowest quartile, demonstrating a progressive increase across quartiles. Each standard deviation increase in the index corresponded to a 13% higher adjusted hazard. Similar trends emerged across other indices, with each standard deviation increase associated with a 9% to 15% higher adjusted hazard, with the sole exception of body surface area.
| Anthropometric Index | Comparison (Highest vs. Lowest Quartile) | Model Area Under ROC Curve (AUC) |
|---|---|---|
| Body Roundness Index (BRI) | 52% higher adjusted hazard | 0.710 |
| Weight-Adjusted Waist Index (WWI) | 46% higher adjusted hazard | Not specified |
| Waist Circumference (WC) | 40% higher adjusted hazard | Not specified |
| Body Mass Index (BMI) | 32% higher adjusted hazard | Not specified |
All measures except body surface area demonstrated significant nonlinear associations with incident myocardial infarction. The body roundness index achieved an area under the receiver operating characteristic curve of 0.710, compared with 0.697 to 0.708 for the other measures. When adjusted for age, sex, and race, the advantage over the next-best metric amounted to just 0.002 AUC points.
Sex-stratified models maintained consistent patterns. In female participants, the body roundness index and the weight-adjusted waist index yielded comparable predictive values that exceeded other metrics. In male participants, the body roundness index remained the top-performing predictor.
Clinical Context
Because anthropometric calculations serve as indirect estimates of body roundness and abdominal adiposity, routine screening measurements should be interpreted by healthcare professionals within the context of a comprehensive metabolic and cardiovascular profile. The study did not evaluate whether using the body roundness index could prevent heart attacks.
The study notes notable limitations, including its observational design, which precludes establishing causality. Because baseline measurements were not updated during follow-up, shifting body compositions went unrecorded. Furthermore, the UK Biobank cohort comprises self-selected volunteers who are not representative of the general UK population, potentially underestimating true risk associations. Independent population cohorts must validate these findings before the body roundness index can be considered for routine clinical use.
References
- Journal of Health, Population and Nutrition: Body roundness index and other anthropometric indices in relation to incident myocardial infarction: a cohort study from the UK Biobank
