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Objective: To measure the graded relation between cardiorespiratory fitness and sum of skinfolds, waist circumference, and blood pressure in children and adolescents participating in the European youth heart study. Methods: The participants were 4072 children and adolescents (aged 9 and 15) from Denmark, Portugal, Estonia, and Norway. Cardiorespiratory fitness was indirectly determined using a maximal ergometer cycle test. The sum of four skinfolds, waist circumference, and blood pressure were assessed with a standardised protocol. Linear regression analysis was used to test the graded relation between cardiorespiratory fitness and the dependent variables adjusted for pubertal stage, sex, and country. Results: A significant curvilinear graded relation was found between cardiorespiratory fitness and waist circumference and sum of skinfolds (partial r² for cardiorespiratory fitness was 0.09-0.26 for the different sexes and age groups). Systolic and diastolic blood pressure also showed a curvilinear relation with cardiorespiratory fitness, and fitness explained 2% of the variance in systolic blood pressure. The difference in systolic blood pressure between the least and most fit was 6 mm Hg. Conclusion: A curvilinear graded relation was found between cardiorespiratory fitness and waist circumference, sum of skinfolds, and systolic blood pressure. The greatest difference in these health variables was observed between low and moderate fitness levels. [ABSTRACT FROM AUTHOR]

Objectives: In this study we examined the association between leptin and blood pressure in a population-based study of Danish and Norwegian children and adolescents. Because of the putative bidirectional relationship between leptin and adiposity we formally tested (i) the mediating effect of body mass index in the association between leptin and blood pressure, and (ii) the mediating effect of leptin in the association between body mass index and blood pressure., Methods: To examine these aims we used a cross-sectional random sample of children and adolescents from Denmark and Norway (n = 1993) who had measures of leptin, anthropometry, blood pressure and other personal and biological risk factors for raised blood pressure available., Results: Both body mass index and leptin were positively associated with blood pressure (P < 0.001). The association with leptin was stronger in pre- and early-pubertal children compared to late- and post-pubertal adolescents (P < 0.01 for interaction). The association between leptin and blood pressure was almost completely mediated by body mass index, whereas the association between body mass index and blood pressure was modestly mediated by leptin., Conclusion: Leptin was strongly associated with blood pressure, a relationship that to a large extent was mediated by body mass index. Conversely, the association between body mass index and blood pressure was only modestly mediated by leptin. This indicates that the influence of adiposity on blood pressure is also driven by other biological risk factors beyond leptin. Such factors could include insulin, glucose, and triglycerides although residual confounding also could account for the observed relationships.

Background: The rising prevalence of obesity in children may be due to a reduction in physical activity (PA)., Objective: Our aim was to study the associations of objectively measured PA volume and its subcomponents with indicators of body fatness., Design: A cross-sectional study of 1292 children aged 9-10 y from 4 distinct regions in Europe (Odense, Denmark; the island of Madeira, Portugal; Oslo; and Tartu, Estonia) was conducted. PA was measured by accelerometry, and indicators of body fatness were the sum of 5 skinfold thicknesses and body mass index (BMI; in kg/m(2)). We examined the associations between PA and body fatness by using general linear models adjusted for potential confounding variables., Results: After adjustment for sex, study location, sexual maturity, birth weight, and parental BMI, time (min/d) spent at moderate and vigorous PA (P = 0.032) and time (min/d) spent at vigorous PA were significantly (P = 0.015) and independently associated with body fatness. Sex, study location, sexual maturity, birth weight, and parental BMI explained 29% (adjusted R(2) = 0.29) of the variation in body fatness. Time spent at vigorous PA explained an additional 0.5%. Children who accumulated <1 h of moderate PA/d were significantly fatter than were those who accumulated >2 h/d., Conclusions: The accumulated amount of time spent at moderate and vigorous PA is related to body fatness in children, but this relation is weak; the explained variance was <1%.