JMIR Publications

ABSTRACT

Background:

Psoriasis, a chronic inflammatory skin disease, is increasingly linked to metabolic disorders, particularly obesity. Traditional anthropometric measures like body mass index (BMI) and waist circumference (WC) have limitations in assessing fat distribution and metabolic risk. The Body Roundness Index (BRI), which integrates height and waist circumference, may offer superior predictive value for psoriasis risk, but its clinical utility remains underexplored.

Objective:

This study aimed to evaluate BRI as a potential digital biomarker for psoriasis risk prediction, comparing its performance with BMI and WC across diverse demographic subgroups using large-scale national health data.

Methods:

We analyzed cross-sectional data from 13,798 adults aged 20–59 years in the National Health and Nutrition Examination Survey (NHANES, 2003–2014). Psoriasis status was self-reported. BRI, BMI, and WC were calculated from standardized measurements. Weighted multivariable logistic regression and restricted cubic spline (RCS) models assessed associations, adjusting for sociodemographic, metabolic, and lifestyle factors. A nomogram model quantified predictive contributions.

Results:

BRI showed a robust linear association with psoriasis risk (OR=1.11 per unit increase, 95% CI=1.05–1.17, p<0.001), outperforming BMI (OR=1.03) and WC (OR=1.01). Tertile analyses revealed a 1.73-fold higher psoriasis risk in the highest BRI group (p=0.003). Subgroup analyses confirmed consistency across age, sex, and metabolic status (p for interaction >0.05). The nomogram highlighted BRI’s dominant predictive contribution (largest score-axis span).

Conclusions:

BRI demonstrates stronger and more consistent associations with psoriasis risk than traditional measures, supporting its role as a digital biomarker for early risk stratification. Integration of BRI into clinical informatics tools could enhance personalized psoriasis prevention and management.