Aptidão física, biomarcadores inflamatórios e metabólicos em adolescentes

A presente tese tem dois objetivos principais; 1) verificar as associações entre vários biomarcadores inflamatórios e metabólicos com o risco cardiometabólico, em adolescentes e 2) verificar as associações entre a aptidão cardiorrespiratória e aptidão muscular e biomarcadores inflamatórios e metabólicos, no risco cardiometabólico, em adolescentes. Para esse efeito, esta tese que faz uso do modelo Escandinavo de tese e apresenta 7 artigos originais, sendo os dois primeiros para responder ao primeiro objetivo e outros 5 artigos para ao segundo objetivo. Este estudo transversal contou com uma amostra de 529 adolescentes entre 12 e 18 anos da região Norte de Portugal que participaram do LabMed Physical Activity Study, em 2011. Procedimentos estandardizados foram utilizados para medir e estimar indicadores da aptidão cardiorrespiratória (teste de vai e vem), aptidão muscular (prensa manual e salto de impulsão horizontal), adiposidade, estagio maturacional, estatuto socioeconómico e adesão à dieta Mediterrânea. Foram avaliados também vários biomarcadores inflamatórios e metabólicos. Os resultados principais deste estudo indicam: i) o potencial de vários fatores de risco não tradicionais (proteína C reativa, C3, C4, leptina, fibrinogénio e a razão adiponectina/leptina) em identificar um risco cardiometabólico mais elevado, bem como a potencial habilidade discriminatória da utilização de um clustered score de biomarcadores inflamatórios (InflaScore); ii) a adiponectina associa-se de forma inversa com a aptidão cardiorrespiratória e a aptidão muscular; iii) os níveis de aptidão muscular e de aptidão cardiorrespiratória estão inversamente associados com o InflaScore; a combinação de um alto perfil inflamatório e baixa aptidão muscular ou cardiorrespiratória aparentam potencializar os efeitos deletérios da saúde metabólica. Os estudos apresentados nessa tese reforçam e sublinham a importância da prevenção e monitorização precoce dos fatores de risco cardiometabólicos. Continuam a ser necessários esforços futuros para identificar características clínicas em crianças e adolescentes que poderiam ser utilizadas em triagem para prevenção de risco de DCV na idade adulta. No entanto, do ponto de vista da saúde pública, a promoção de um estilo de vida saudável continua a ser o foco prioritário. Apesar das limitações impostas pelo desenho transversal deste estudo, as consequências deletérias atribuídas ao processo de inflamação de baixo grau parecem poder ser contrariadas, até certo ponto, pela manutenção dos níveis adequados da aptidão cardiorrespiratória e aptidão muscular. Além disso, a aptidão muscular parece associar-se ao perfil inflamatório e cardiometabólico, independentemente da aptidão cardiorrespiratória e de outros confundidoresThis thesis has two main aims: 1) to verify the associations between several inflammatory and metabolic biomarkers with cardiometabolic risk, in adolescents and 2) to investigate the associations between cardiorespiratory fitness and muscular fitness and inflammatory and metabolic biomarkers on cardiometabolic risk, in adolescents. For this purpose, this thesis makes use of the Scandinavian thesis model and presents 7 original articles, being the first two to respond to the first aim and another 5 articles for the second aim. This cross-sectional study included a sample of 529 adolescents aged between 12 and 18 years, from the Northern region of Portugal, who participated in the LabMed Physical activity study in 2011. Standardized procedures were used to measure and estimate indicators of cardiorespiratory fitness (shuttle-run-test) muscular fitness (handgrip and standing long jump), adiposity, pubertal stage, socioeconomic status, and adherence to the Mediterranean diet. Several inflammatory and metabolic biomarkers were also assessed. In this study, 3 mains results were verified; i) the potential of several nontraditional risk factors (C-reactive protein, C3, C4, leptin, fibrinogen and the adiponectin/leptin ratio) to identify a higher cardiometabolic risk, as well as the potential discriminatory ability of using a clustered score of biomarkers inflammatory (InflaScore); ii) adiponectin is inversely associated with cardiorespiratory fitness and muscular fitness; iii) higher levels of muscular fitness and cardiorespiratory fitness are inversely associated with InflaScore; the combination of a high inflammatory profile and low muscular or cardiorespiratory fitness seems to potentiate the deleterious effects of metabolic health. The results presented in this thesis reinforce and underline the importance of early prevention and cardiometabolic risk factors monitoring. Further efforts are needed to identify clinical features in children and adolescents that could be used in screening to prevent CVD risk in adulthood. However, from the point of view of public health, the promotion of healthy lifestyles should remain the priority focus. Despite the limitations imposed by the cross-sectional design of this study, the deleterious consequences attributed to the process of low-grade inflammation seem to be counteracted to some extent by maintaining adequate levels of cardiorespiratory fitness and muscular fitness. In addition, muscular fitness seems to influence the inflammatory profile and cardiometabolic health, independently of cardiorespiratory fitness and other confounder

The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study

Background The aim of this prospective cohort study was to examine whether the association between the cardiorespiratory fitness (CRF) at baseline and blood pressure (BP) at follow‐up is mediated by adiposity in adolescents. Materials and methods The sample comprised 734 adolescents (349 girls) aged 12‐18 years from the LabMed Physical Activity Cohort Study. The variables of interest were measured in 2011 (baseline) and in 2013 (2‐year follow‐up). CRF was assessed by the 20‐m shuttle run test. Body mass index, waist circumference, body fat percentage, pubertal status and resting BP were assessed according to standard procedures. Boot‐strapped mediation procedures were performed, and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant. Results After adjusting for potential confounders, body mass index acted as a mediator of the relationship between CRF and systolic BP (IE = −0. 023; CI = −0.039; −0.009), pulse pressure (IE = −0.023; CI = −0.034; −0.012) and rate product pressure (IE = −2.839; CI = −5.329; −0.340). Similar results were obtained for waist circumference as mediator for systolic BP (IE = −0.019; CI = −0.033; −0.005), pulse pressure (IE = −0.017; CI = −0.028; −0.007) and rate product pressure (IE = −3.793; CI = −6.097; −1.689). Likewise, body fat percentage mediated the association for: systolic BP (IE = −0.029; CI = −0.048; −0.010), pulse pressure (IE = −0.027; CI = −0.041; −0.013) and rate product pressure (IE = −4.280; CI = −7.488; −1.264). Conclusions Adiposity mediated the association between CRF and BP in adolescents. Therefore, both optimal CRF and adiposity levels are important to maintain normal BP ranges throughout adolescence

Serum adiponectin levels and cardiorespiratory fitness in nonoverweight and overweight Portuguese adolescents: The LabMed Physical Activity Study

Purpose: This study examined the independent associations between cardiorespiratory fitness and circulating adiponectin concentration in adolescents, controlling for several potential covariates. Methods: This is a cross-sectional study in Portuguese adolescents. A sample of 529 (267 girls) aged 12-18 years were included and categorized as overweight and nonoverweight. Cardiorespiratory fitness was assessed by 20 meters shuttle run test. We measured serum adiponectin, high-sensitivity C-reactive protein, fasting glucose, insulin and HDL-cholesterol. Results: After adjustment for age, sex, pubertal stage, adherence to the Mediterranean diet, socioeconomic status, body fat percentage, insulin resistance, HDL-cholesterol and C-reactive protein, regression analysis showed a significant inverse association between adiponectin and cardiorespiratory fitness in nonoverweight participants (B=-0.359; p \u3c .042). Analysis of covariance showed a significant difference between the highest cardiorespiratory fitness Healthy zone (above healthy zone) and the Under and the Healthy cardiorespiratory fitness zones in nonoverweight adolescents (p = .03) (F (2, 339) = 3.156, p \u3c .001). Conclusion: Paradoxically, serum adiponectin levels are inversely associated with cardiorespiratory fitness in nonoverweight, but not in overweight adolescents. In nonoverweight adolescents, those with highest levels of cardiorespiratory fitness (above healthy zone) presented lower levels of adiponectin compared with those in Under and Healthy cardiorespiratory fitness zones

Cardiorespiratory fitness cut-points are related to body adiposity parameters in Latin American adolescents

Background and Objectives: A deficiency exists in the criterion-referenced cut-points for field-based cardiorespiratory fitness (CRF) in Latin American youths. The aims of the present study were two-fold: (1) To identify the ability of CRF estimated by the 20-m shuttle-run test (20mSRT) to differentiate between 'healthy' and 'unhealthy' phenotypes (by adiposity) in adolescents; (2) to assess the association between obesity and relative peak oxygen uptake (VO2peak) in a large and diverse sample of Latin American youths. In total, 72,505 adolescents aged between 13 and 15 years were recruited from Chile and Colombia (47.5% girls). Materials and Methods: The waist circumference (WC) and waist-to-height ratio (WHtR) were used to identify body adiposity markers. CRF was measured using the 20mSRT (VO2peak). Receiver operating characteristic curves and logistic regression were used to determine the discriminatory ability of CRF to predict body adiposity parameters. Results: For boys and girls, VO2peak showed a significant predictive capacity to detect body fat (area under the curve [AUC] > 0.62). The sensitivity of VO2peak was medium (>63%) for all age- and sex-specific cut-points, with optimal cut-points in 13- to 15-year olds for obesity identified as 43.77 mL·kg-1·min-1 and 38.53 mL·kg-1·min-1 in boys and girls, respectively. Conclusions: According to these cut-points, adolescents with low CRF were more likely to be obese either by WC or WHtR. The CRF cut-points can be used as quantitative markers for a healthier body in Latin American adolescents.This study (Colombia sample) is supported by Secretaria de Educación Distrital-SED (ID Convenio N◦ CDP 3381, Project N◦ 893 'Pensar en Educación' date 02-Oct-2014). Mikel Izquierdo is funded in part by a research grant PI17/01814 of the Ministerio de Economía, Industria y Competitividad de España (ISCIII, FEDER)

Fruit, vegetable consumption and blood pressure in healthy adolescents: A longitudinal analysis from the LabMed study

Background and aims: The associations between fruit and vegetable consumption and high blood pressure among adults are well studied. Nonetheless, data on the influence of a low consumption of fruit and vegetables on cardiovascular disease risk, particularly blood pressure, among healthy adolescents are scarce. Therefore, we aim to analyse the associations between fruit and/or vegetable intake and blood pressure over a two-year period in healthy adolescents.Methods and results: As part of a cohort, 606 adolescents from the LabMed Physical Activity study were evaluated in 2011 (baseline) and 2013 (follow-up). Blood pressure was measured according to standardized procedures and fruit and vegetable consumption was assessed with a food frequency questionnaire. Anthropometric variables, socioeconomic status, pubertal stage and lifestyle determinants were gathered and used as confounders. Prospective associations between fruit and/or vegetable intake and blood pressure were examined using generalized linear models. Girls who consumed more fruit at baseline had a significant decrease in diastolic blood pressure at follow-up [unstandardized beta: -0.005 mmHg (95% CI: -0.01; -0.0002) (p = 0.038)].Conclusion: In apparently healthy adolescents, fruit intake may already start to have an effect in blood pressure. Girls who consumed more fruit exhibited lower levels of diastolic blood pressure. (C) 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.This study was supported by the Research Centre on Physical Activity Health and Leisure (CIAFEL) of the Faculty of Sport, University of Porto and by FCT grant BD88984/2012 (J. Oliveira-Santos); The Research Centre on Physical Activity Health and Leisure (CIAFEL) is supported by UID/DTP/00617/2013 (FCT); the author C. Agostinis-Sobrinho was given Doctoral scholarship from the Brazilian government by CAPES (Coordination of Improvement of Higher Education Personnel) (Proc: 9588-13-2).The authors gratefully acknowledged the participation of all adolescents and their parents, teachers and schools of the LabMed Study. They also acknowledge the cooperation of volunteer's subjects and the Research Centre in Physical Activity, Health and Leisure (University of Porto) for the sponsoring the LabMed Study

Higher cardiorespiratory fitness levels may attenuate the detrimental association between weight status, metabolic phenotype and C-reactive protein in adolescents - a multi-Cohort study

Results from several studies show that only obese, unfit subjects, but not obese, fit subjects, are at higher mortality risk than are normal-weight fit subjects. The aim of the study was two-fold: (1) to examine the differences in C-reactive protein levels across different metabolic phenotypes (healthy and unhealthy) of weight status and (2) ascertain whether high levels of cardiorespiratory fitness (CRF) attenuate the association of C-reactive protein and metabolic phenotypes of weight status. This was a pooled study, which included data from three cross-sectional projects (1706 youth (921 girls) aged 12–18 years). We used a Shuttle run test to assess CRF. Adolescents were classified into six metabolic phenotypes (healthy and unhealthy) of weight status (non-overweight, overweight and obese), based on age- and sex-specific cutoff points for triglycerides, systolic blood pressure, HDL-cholesterol, glucose and body mass index. High-sensitivity assays were used to obtain the C-reactive protein as inflammatory biomarker. After adjustment for potential confounders (age, sex, pubertal stage and country), the analysis of covariance (ANCOVA) shows that C-reactive protein is directly associated with metabolic phenotypes of weight status. Subjects with obesity, regardless of their metabolic profile, had higher levels of C-reactive protein Z-score. In addition, (after adjustments for potential confounders) a two-way ANCOVA showed that high levels of CRF attenuated the associations of C-reactive protein levels in metabolic healthy non-overweight and in adolescents with obesity. In conclusion, higher CRF levels may attenuate the detrimental association between obesity and C-reactive protein independently of metabolic phenotype. Findings from this study are important for prevention, clinical practice on issues associated with adiposity and metabolic disorders.The Research Centre on Physical Activity Health and Leisure (CIAFEL) is supported by UID/DTP/00617/2013 (FCT). R.S. has a Discovery Early Career Research Award from the Australian Research Council (DE150101921). The FUPRECOL Study was carried out with the financial support of Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología “Francisco José de Caldas” COLCIENCIAS (Contract Nº 671-2014 Code 122265743978). The authors are grateful to the Bogota District Education Secretary for the data used in this study. The authors also thank the participating Bogota District students, teachers, schools and staff. This study was funded by the Department of Education (Grand number: CENEDUCA1/2019) of the Government of Navarra (Spain). A.G.-H. is a Miguel Servet Fellow (Instituto de Salud Carlos III—CP18/0150). R.R.-V. is funded in part by a Postdoctoral Fellowship Resolution ID 420/2019 of the Universidad Pública de Navarra

Relationship between insulin resistance and adipocytokines: the mediator role of adiposity in children

Background: Leptin and adiponectin interact with each other in the modulation of obesity and insulin resistance (IR) and it is also important to consider the role of cardiorespiratory and muscular fitness in these relationships. Aim: To analyse the relationship between IR with adipocytokines in children, and to test the mediation effect of %BF (percentage of body fat) in the association of IR with leptin, adiponectin, and L/A ratio. Subjects and methods: This cross-sectional study comprised a sample of 150 schoolchildren, aged 6–11 years, from school in Porto Alegre, Brazil. The following variables were evaluated: cardiorespiratory fitness (CRF), muscular fitness (MF), percentage of body fat (%BF), and biochemical variables (leptin, adiponectin, glucose, and insulin). Results: IR was associated with leptin and L/A ratio, after adjustments for age, sex, sexual maturation, and CRF. When adjusted for age, sex, sexual maturation, and MF, an association was found between IR with leptin and L/A ratio. Moreover, %BF was a mediator in the association between IR and leptin, as well as IR and L/A ratio, explaining 54% and 57% of these associations, respectively. Conclusion: Leptin and L/A ratio are positively associated with IR after adjustments. Also, %BF is a mediator in the associations between IR and leptin and L/A ratio