ABC | Volume 115, Nº1, July 2020

Original Article Tozo et al. Hypertensive measures and childhood obesity Arq Bras Cardiol. 2020; 115(1):42-49 Table 7 – Odds ratios for the risk of high blood pressure between anthropometric variables and level of physical activity HA OR (CI 95%) PAS elevada OR (CI 95%) PAD elevada OR (CI 95%) Sex=Boys 1.40(0.88-2.22) 1.35(0.85-2.14) 0.84(0.40-1.77) PA-mv= sufficiently active 1.15(0.72-1.84) 1.21(0.76-1.93) 0.33(0.15-0.72) WC= Central obesity 6.11(2.59-14.42) 4.64(2.10-10.23) 2.50(1.04-6.03) BMI-z= General obesity 2.91(1.76-4.79) 2.75(1.68-4.52) 2.09(0.99-4.40) M: male; AF-mv: moderate-vigorous physical activity; WC: waist circumference; BMI-z: body mass index z-score; AH: arterial hypertension; SBP: systolic blood pressure; DBP: diastolic blood pressure; OR: odds ratio; CI: confidence interval; p values with significance level at p <0.005. In view of this situation, anthropometric measurements represent relevant predictors of AH, which are justified as a simple, quick, easily interpreted and cost-effective alternative. 24,25 Several reports demonstrate an association between blood pressure, BMI and WC, suggesting obesity as a strong risk factor for the development of AH in adulthood. 9,16 Excessive distribution of visceral fat is accompanied by changes in various inflammatory and endothelial markers, 26 which stimulate the increase of insulin resistance events, endothelial dysfunction and increased fluid retention, which can then stimulate variations in BP levels and growth of cardiovascular risk. 27 It was found that 40.5% of the adolescents had AH, with half of overweight students and two-thirds with highWC diagnosed as AH, in a greater proportion in adolescent relationships with adequate measures. In a study of national and regional representativeness that evaluated 73,399 students aged 12–17 years in the southern region of Brazil, the estimated prevalence of AH was 12.5% and that of prehypertension was 17%;excess weight varied between 29.8% 1 and 35.5% 28 of South Brazilian adolescents. It is suggested that, in addition to genetic and environmental factors, obesity and AH may be related to metabolic disorders. 27 Regarding the differences between sexes, a prevalence of AH and similar SBP among boys and girls was identified, however, girls had higher mean DBP. Similar results have been found in the literature. 9 A possible explanation may the fact that girls practice less physical activities per day compared to boys, which demonstrated a protective effect for high DBP. In addition, it was observed that overweight girls practice longer physical activities, as well as adolescents considered active had higher averages of anthropometric indicators. This data may reflect participation in physical activities as a strategy to reduce body weight. 14 It was found that high WC and BMI-z were associated with higher risk of AH, however, those considered sufficiently active showed one-third reduction in the risk of high DBP, which suggests that AF-mv may interfere with blood pressure levels, in addition to reducing metabolic risk. 29 However, another study 30 demonstrated that only overweight and obesity were directly associated with AH, but not the practice of AF-mv. 31 Most adolescents were considered sufficiently active, which may be related to socioeconomic level, as physical activities are offered out of school periods. 32 The urbanization process, technological advances in modern society and the increase in violence are associated with changes in behavior in children and adolescents. 33 The increase in time spent doing sedentary activities and less AF- mv practice favor weight gain and diseases associated with obesity, including HA. 1 At least 300 minutes of AF-mv per week is recommended to provide additional health benefits. 34 In this regard, an aspect of relevance found in this study refers to the association between lower DBP in adolescents who practice AF-mv, suggesting that the practice of AF-mv may interfere with blood pressure levels in the juvenile population. 30 A recent study found that adolescents with better muscle skills exhibited lower levels of DBP. 35 Thus, interventions that encourage the transition from physical inactivity to activity promote immediate impacts on the increase of physical activity among schoolchildren, 36 which can be considered a protective factor for AH. Therefore, effectively detecting risk factors early can contribute to the prevention of cardiovascular diseases in adulthood, since changing established habits and attitudes can represent complex tasks and often lead to unsatisfactory results. However, health policies directed at schoolchildren, as well as social investments to improve the practice of AF- mv, may eventually determine significant changes in the population. In this regard, the presence of education and support from health professionals is of great importance, contributing to the control and prevention of AH, among other risk factors associated with cardiovascular diseases. The present study has some limitations, such as the small sample size, and measurement of blood pressure must be performed on at least three different occasions to better diagnose hypertensive students. Another limitation is the use of a recall questionnaire to assess the level of physical activity, however the IPAQ has an excellent association with AF-mv. 23 The variables of socioeconomic level, sexual maturity, dietary salt intake and family history of hypertension were not verified either. However, it is noteworthy that the strong point was to associate AH with the diagnosis of central and general obesity, as well as to highlight the importance of the practice of AF-mv as a protective factor against changes in BP in children and adolescents. Such assessments are important as a prevention in public health, as many children and adolescents do not have the opportunity to have their blood pressure assessed at school. 47