Low-grade inflammation and muscular fitness on insulin resistance in adolescents: Results from LabMed Physical Activity Study.

BACKGROUND: Low muscular fitness (MF) and low-grade inflammation has been linked to insulin resistance (IR). OBJECTIVE: To evaluate the associations between MF and a clustered score of inflammatory biomarkers on IR and to investigate the combined impact of MF and inflammation on IR in adolescents. METHODS: This is a cross-sectional analysis with 529 adolescents (267 girls) aged 12 to 18 years. Pubertal stage, socioeconomic status, adherence to the Mediterranean diet, cardiorespiratory fitness, and waist circumference were assessed. Standing long-jump and isometric handgrip dynamometry were used as indicators of MF. Continuous score of clustered inflammatory biomarkers (InflaScore) (sum of Z-scores of C-reactive protein, C3, C4, fibrinogen, and leptin) and IR (homeostasis model assessment of insulin resistance [HOMA-IR] estimated from fasting serum insulin and glucose) were assessed. RESULTS: HOMA-IR and fasting insulin were positively associated with InflaScore and negatively associated with MF, independently of age, sex, pubertal stage, socioeconomic status, adherence to the Mediterranean diet, cardiorespiratory fitness, and waist circumference. Adolescents classified as High InflaScore/Unfit showed significantly higher HOMA-IR when compared than those with High InflaScore/Fit and those with Low InflaScore/Fit (F(3,519) = 4.761, P < .003), after adjustments for potential confounders. Unfit adolescents with high InflaScore had the highest odds of expressing high HOMA-IR (odds ratio, OR = 2.40, 95% confidence interval [CI]: 1.2-5.6) and insulin risk (2.53 95% CI, 1.5-5.9) when compared to those of the Low InflaScore/Fit group, after adjustments for potential confounders. CONCLUSION: Higher levels of MF seem to minimize the deleterious effect of inflammation on IR.

Cardiorespiratory fitness and inflammatory profile on cardiometabolic risk in adolescents from the LabMed Physical Activity Study.

PURPOSE: We investigated the combined effect of cardiorespiratory fitness and the clustered score of inflammatory biomarkers (InflaScore) on the cardiometabolic risk score in adolescents. METHODS: This is a cross-sectional analysis with 529 adolescents (267 girls) aged 12-18 years. The shuttle run test was used to assess cardiorespiratory fitness. Continuous scores of clustered inflammatory biomarkers (high sensitivity C-reactive protein, complement factors C3 and C4, fibrinogen and leptin); cardiometabolic risk score (systolic blood pressure, triglycerides, ratio total cholesterol/HDL, HOMA-IR and waist circumference) were computed. RESULTS: Adolescents with a higher inflammatory profile had the highest cardiometabolic risk score; adolescents with high InflaScore and low fitness had the highest odds of having a high cardiometabolic risk (OR 16.5; 95% CI 7.8-34.5), followed by adolescents with a higher InflaScore but fit (OR 7.5; 95% CI 3.7-8.4), and then by adolescents with a low InflaScore and unfit (OR 3.7; 95% CI 1.6-8.4) when compared to those with low InflaScore and fit, after adjustments for age, sex, pubertal stage, adherence to a Mediterranean dietary pattern and socioeconomic status. CONCLUSIONS: The findings of our study suggest that the combination of high inflammatory state and low cardiorespiratory fitness is synergistically associated with a significantly higher cardiometabolic risk score and thus supports the relevance of early targeted interventions to promote physical activity and preservation as part of primordial prevention.

Association between Leptin, Adiponectin, and Leptin/Adiponectin Ratio with Clustered Metabolic Risk Factors in Portuguese Adolescents: The LabMed Physical Activity Study.

INTRODUCTION: Circulating leptin and adiponectin levels have been associated with impaired vascular function, insulin resistance, and acute cardiovascular evens. This study aimed to evaluate the associations of leptin, adiponectin, and the leptin/adiponectin (L/A) ratio with a clustering of metabolic risk factors (MRF) in adolescents aged 12-18 years. METHODS: This is a cross-sectional analysis with 529 Portuguese adolescents aged 12-18 years. Blood samples were taken to analyze total cholesterol (TC) and high-density lipoprotein (HDL) cholesterol (HDL-c), triglycerides glucose, insulin, leptin, and adiponectin levels. A continuous variable of clustered MRF score (sum of Z-scores of body fat percentage, systolic blood pressure, ratio TC/HDL, triglycerides, homeostatic model assessment insulin resistance, and cardiorespiratory fitness*[-1]) was computed. RESULTS: Regression analyses showed that adiponectin was a significant and negative predictor of MRF score (boys: ß = -0.199; p < 0.001; girls: ß = -0.200; p < 0.001); whereas leptin was a significant positive predictor of MRF score (boys: ß = 0.553; p < 0.001; girls: ß = 0.399; p < 0.001). The L/A ratio was also a significant positive predictor of MRF score in both sexes (boys: ß = 0.593; p < 0.001; girls: ß = 0.461; p < 0.001), after adjustments for age, pubertal stage, adherence to the Mediterranean diet, and socioeconomic status. In addition, adiponectin, leptin, and L/A ratio were accurate to predict MRF among adolescents, but L/A ratio showed the highest area under receiver operating characteristic curve. CONCLUSION: Leptin, adiponectin, and L/A ratio are associated with the clustering of MRF in adolescents after adjustments for age, sex, pubertal stage, adherence to the Mediterranean diet, and socioeconomic status. L/A ratio was more strongly associated with MRF score than adiponectin or leptin.