Muscular fitness and metabolic and inflammatory biomarkers in adolescents: Results from LabMed Physical Activity Study.

This study aimed to evaluate the associations between muscular fitness and inflammatory biomarkers and to investigate the relationship between muscular fitness and selected clustered inflammatory biomarkers in adolescents. This is a cross-sectional analysis with 529 adolescents (267 girls) aged 12-18 years. Handgrip strength and standing long jump tests assessed MF. Continuous scores of clustered inflammatory biomarkers (sum of Z-scores of C-reactive protein [CRP], C3, C4, fibrinogen, and leptin); metabolic risk factor (MRF) score (sum of Z-scores of SBP, triglycerides, ratio total cholesterol [TC]/HDL, HOMA-IR, and waist circumference [WC]) were computed. Regression analyses showed an inverse association between muscular fitness score (β=-.204; P<.021) and clustered score of inflammatory biomarkers, adjusted for age, sex, pubertal stage, socioeconomic status, adherence to the Mediterranean diet, cardiorespiratory fitness (CRF), MRF score, and body fat. Analysis of covariance showed that adolescents with an adverse inflammatory profile with low levels of muscular fitness exhibit the poorest MRF score (F3,525 =6.461; P<.001), adjusted for age, sex, pubertal stage, socioeconomic status, adherence to the Mediterranean diet, CRF, and body fatness. The inflammatory state seems to explain a significant part of the highest MRF score and in adolescents with high inflammatory status and low muscular strength.