A Novel Metabolic Risk Classification Incorporating Body Fat, Waist Circumference, and Muscle Strength in Young Mexican Adults: A Cross-Sectional Study

Background: The rising prevalence of metabolic diseases requires new risk assessment tools beyond BMI and waist circumference (WC). A phenotyping system combining body fat percentage (%BF) and WC has been proposed to better stratify cardiometabolic risk, but muscle strength, a key metabolic health predictor, remains underexplored. This study introduces a novel risk classification system integrating %BF, WC, and grip strength (GS) to enhance risk identification in young adults in Mexico. Methods: In this cross-sectional study, 300 young adults (18-22 years) from Mexico City were assessed for %BF, WC, and GS using standardized protocols. Participants were classified into risk categories using both traditional and new criteria, including the novel phenotyping system. Results: The existing %BF-WC system categorized 29.8% of males and 22.2% of females as "no risk." Slightly increased risk included 19% of males and 25% of females, while increased risk comprised 34.5% of males and 24.5% of females. High and very high risks included 16.6% of males and 28.2% of females. The new system, including GS, reduced "no risk" to 15.5% of males and 11.6% of females and increased those at higher risk (70.2% of males, 69% of females). The system also identified a protective condition group. Significant reclassification was observed (p < 0.001). Conclusions: Integrating muscle strength into metabolic risk assessment alongside %BF and WC provides a more refined understanding of metabolic health, effectively identifying at-risk individuals who may be overlooked by existing methods.