Abstract

The aim of this study was to analyze the association between overweight and obesity with high blood pressure (HBP) according to sports practice in young people. Took part in this study 636 young people aged 10 to 17 years of Londrina, Parana State, Brazil. Sex, age, parental education, sedentary behavior, sports practice, nutritional status and blood pressure were analysed. Poisson regression was used to estimate the prevalence ratio (PR) and 95% confidence intervals. Overweight and obesity young people showed higher prevalence of HBP compared to eutrophics when analysed the total sample (25,7 e 29,5 vs 15,2%) and non sport practitioners (29,7 e 33,3 vs 15,1%), which did not occur with sports practitioners (17,1 e 18,2 vs 15,5%). Positive associations were found between overweight and obesity with HBP in total sample (PR = 1,60, 1,02-2,52 and 1,93, 1,15-3,25) and on non sport practitioners (RP = 1,80, 1,05-3,14 and 2,15, 1,10-4,16). For young people sports practitioners were not found associations between overweight and obesity with HBP (PR = 1,01, 0,36-2,82 and 1,09, 0,48-2,48). Weight excess was not associated with HBP in young people sports practitioners, suggesting cardiovascular protection in young people with overweight and obesity.

Key words
Adolescent; Motor activity; Nutritional status; Hypertension

Introduction

High blood pressure (HBP) is an important health risk because it increases the likelihood of being affected by cardiovascular disease in adults¹1. Mancia G, Fagard R, Narkiewicz K, Redón J, Zanchetti A, Böhm M, Christiaens T, Cifkova R, De Backer G, Dominiczak A, Galderisi M, Grobbee DE, Jaarsma T, Kirchhof P, Kjeldsen SE, Laurent S, Manolis AJ, Nilsson PM, Ruilope LM, Schmieder RE, Sirnes PA, Sleight P, Viigimaa M, Waeber B, Zannad F. Task Force Members. Guidelines for the management of arterial hypertension. Eur Heart J 2013; 31(7):1281-1357. and presents the highest risk fraction attributed to mortality²2. Yang Q, Cogswell ME, Flanders WD, Hong Y, Zhang Z, Loustalot F, Gillespie C, Merritt R, Hu FB. Trends in Cardiovascular Health Metrics and Associations With All-Cause and CVD Mortality Among US Adults. Jama 2012; 307(12):1273-1283.. HBP is also an indicator of cardiovascular health in young people because it is positively associated with arterial stiffness, reduced diastolic function, intima-media carotid artery thickness, and cardiac hypertrophy of the left ventricle³3. McNiece KL, Gupta-Malhotra M, Samuels J, Bell C, Garcia K, Poffenbarger T, Sorof JM, Portman RJ; National High Blood Pressure Education Program Working Group. Left ventricular hypertrophy in hypertensive adolescents: analysis of risk by 2004 National High Blood Pressure Education Program Working Group staging criteria. Hypertension 2007; 50(2):392-395.^–66. Urbina EM, Khoury PR, McCoy C, Daniels SR, Kimball TR, Dolan LM. Cardiac and vascular consequences of pre-hypertension in youth. J Clin Hypertens 2011; 13(5):332-342.. As well as presenting health risks to young people, HBP is related to resistance to insulin, leptin and blood pressure in adult life⁷7. Campana EMG, Brandão AA, Pozzan R, Magalhães MEC, Fonseca FL, Pizzi OL, Freitas EV, Brandão AP. Blood pressure in adolescence, adipokines and inflammation in young adults. The Rio de Janeiro study. Arq Bras Cardiol 2014; 102(1):60-69., which suggests the importance of preventing HBP in childhood and adolescence.

Despite the risks that are known to be associated with HBP, a systematic review⁸8. Magalhaes MGP, Oliveira LMFT, Christofaro DGD, Ritti-Dias RM. Prevalência de pressão arterial elevada em adolescentes brasileiros e qualidade dos procedimentos metodológicos empregados : revisão sistemática. Rev Bras Epidemiol 2013; 16(3):849-859. demonstrated that the prevalence of HBP ranged from 2.7 to 30.9% in children and adolescents from different regions of Brazil. Of the 21 studies included in the review, 12 reported a prevalence of HBP higher than 10%⁸8. Magalhaes MGP, Oliveira LMFT, Christofaro DGD, Ritti-Dias RM. Prevalência de pressão arterial elevada em adolescentes brasileiros e qualidade dos procedimentos metodológicos empregados : revisão sistemática. Rev Bras Epidemiol 2013; 16(3):849-859.. Studies conducted after the aforementioned systematic review reported a prevalence of HBP ranging from 12.4 to 19.4%⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^–1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400..

It has been reported that HBP is associated with behavioral, biological and hereditary characteristics¹²12. Spagnolo A, Giussani M, Ambruzzi AM, Bianchetti M, Maringhini S, Matteucci MC, Menghetti E, Salice P, Simionato L, Strambi M, Virdis R, Genovesi S. Focus on prevention, diagnosis and treatment of hypertension in children and adole scents. Ital J Pediatr 2013; 39(1):20.. One of the behavioral aspects that have been widely studied in young people is physical activity, which can be defined as any bodily movement produced by skeletal muscles that result in expending energy¹³13. Caspersen CJ, Powell KE, Christensen GM. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research. Public Health Rep 1985; 100(2):126-131.. The physical activity of children and adolescents is predominantly conducted via sports¹⁴14. Wickel EE, Eisenmann JC. Contribution of youth sport to total daily physical activity among 6-to 12-yr-old boys. Med Sci Sports Exerc 2007; 39(9):1493-1500._, which are defined as games using rules regulated by a federation and which have various objectives such as education, recreation, health or performance¹⁵15. Tubino MJG. Dimensões sociais do esporte. 2ª ed. São Paulo: Cortez Editora; 2001.. The literature contains controversial findings regarding the association between physical activity and HBP. Some studies have shown an inverse association between physical activity and blood pressure in young people¹⁶16. Carson V, Ridgers ND, Howard BJ, Winkler EA, Healy GN, Owen N, Dunstan DW, Salmon J. Light-intensity physical activity and cardiometabolic biomarkers in US adolescents. PLoS One 2013; 8(8):e71417.^–2020. Christofaro DGD, Ritti-Dias RM, Chiolero A, Fernandes RA, Casonatto J, Oliveira AR. Physical activity is inversely associated with high blood pressure independently of overweight in Brazilian adolescents. Scand J Med Sci Sport 2013; 23(3):317-322._, while others have shown no such association⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^,1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,2121. Silva KS, Lopes AS. Excesso de peso, pressão arterial e atividade física no deslocamento à escola. Arq Bras Cardiol 2008; 91(2):93-101.^–2323. Moreira NF, Muraro AP, Brito FDSB, Gonçalves-Silva RMV, Sichieri R, Ferreira MG. Obesidade: principal fator de risco para hipertensão arterial sistêmica em adolescentes brasileiros participantes de um estudo de coorte. Arq Bras Endocrinol Metab 2013; 57(7):520-526.. A systematic review showed that the number of studies that showed an association between physical activity with blood pressure was lower than the studies that showed no association²⁴24. Corrêa Neto VG, Palma A. Pressão arterial e suas associações com atividade física e obesidade em adolescentes: uma revisão sistemática. Cien Saude Colet 2014; 19(3):797-818..

Among other associated factors, the conditions of being overweight and obese are considered to be the determing factors of HBP because they trigger several physiological mechanisms that result in HBP in young people²⁵25. Flynn J. The changing face of pediatric hypertension in the era of the childhood obesity epidemic. Pediatr Nephrol 2013; 28(7):1059-1066.. For this reason, overweight young people are 1.66 to 4.30 while obese are 5.19 to 5.40 more likely to have HBP compared to eutrophic⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^–1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,1818. Gomes B, Alves J. Prevalência de hipertensão arterial e fatores associados em estudantes de ensino médio de escolas públicas da Região Metropolitana do Recife, Pernambuco. Cad Saúde Pública 2009; 25(2):375-381.^,2222. Pinto SL, Silva RDCR, Priore SE, Assis AMO, Pinto EDJ. Prevalência de pré-hipertensão e de hipertensão arterial e avaliação de fatores associados em crianças e adolescentes de escolas públicas de Salvador, Bahia, Brasil. Cad Saude Publica 2011; 27(6):1065-1075.^,2626. Guimarães ICB, Almeida AM, Santos AS, Barbosa DBV. Pressão Arterial: Efeito do Índice de Massa Corporal e da circunferência abdominal em Adolescentes. Arq Bras Cardiol 2008; 90(6):393-399.. The studies that are available in the literature have not investigated the association between overweight and obesity with HBP according to sports practice. It prevents to infer whether overweight and obese young people are more likely to suffer from HBP even if they practice sports.

Thus, the aim of this study was to analyze the association between overweight and obesity with HBP according to sports practice in young people.

Methods

This transversal study was conducted in state schools in the city of Londrina, Paraná, Brazil from April to July 2012. According to the Regional Education Center, the number of students in the sixth year of elementary school to the third year of secondary school was 55,475. The students who participated in the study were aged 10-17. The study sample was performed using the probabilistic method utilizing two clusters (school and classroom), which were stratified by regions of the city (north, south, east, west and center) and gender. The study was performed in two stages. In the first stage, one school was randomly chosen from each region. In the second stage, the number of students in each school was evaluated in order to select the ratio that represented the region.

The sample calculation was performed using the following parameters: population of 55475 students; 14.1% prevalence of of high blood pressure²²22. Pinto SL, Silva RDCR, Priore SE, Assis AMO, Pinto EDJ. Prevalência de pré-hipertensão e de hipertensão arterial e avaliação de fatores associados em crianças e adolescentes de escolas públicas de Salvador, Bahia, Brasil. Cad Saude Publica 2011; 27(6):1065-1075._; sampling error of 4%; 97% confidence interval and design effect of two. The sample of students required to perform the study was 636 participants. The calculations were performed using OpenEpi, version 3.03a software.

The inclusion criteria were as follows: to be enrolled in a state school, in schools selected for the study; to be aged between 10-17; to agree to participate voluntarily in the study; and to present authorization and informed consent to participate in the study. The exclusion criteria were to have any physical, metabolic or neurological injury that would prevent the implementation of the procedures of the study.

After authorization by the Londrina Regional Education Center and the direction of the selected schools, prior to the start of data collection the study objectives and the procedures to be performed were described. All those who were responsible for the young people who participated in the study signed an informed consent form which set out all procedures, as well as the possible risks and benefits of the study. The study was approved by the Ethics Committee for Research Involving Human Beings of the State University of Londrina, in accordance with resolution 196/96 of the National Health Council. At the end of the study the results were presented to each participating school through an individual report.

All the research procedures were performed in the school in which the students were enrolled. The questionnaires were completed in the classroom as well as anthropometric and blood pressure measurements. The data collection was performed in the schools in which the participants were enrolled during a single day. All the information was collected by six researchers who were previously trained to perform all the procedures in a standardized manner, which was carried out under the supervision of the coordinator of the study.

The sports practice was estimated by the following question, which referred to the previous 12 months: In terms of leisure activities and occupation of your free time do you practice sports? The options for reply were as follows: never; rarely; sometimes; often and always²⁷27. Baecke JAH, Burema J, Frijters JER. A short questionnaire for the measurement of habitual physical activity in epidemiological studies. Am J Clin Nutr 1982; 36(5):936-942.. The young people were considered to practice sports if they answered often or always. At the time of data collection the study participants were informed that practicing sports was defined as any formal or informal sport which demanded physical effort.

Sedentary behavior was estimated by the following question: How many hours on average do you watch TV, play video games or use the computer? The options for reply were as follows: less than one hour per day; one hour per day; two hours per day; three hours per day; four hours per day; and five or more hours per day. The level of education of the head of the household was analyzed by the questionnaire used by the Brazilian Association of Research Companies²⁸28. Associação Brasileira de Empresas de Pesquisa [homepage na Internet]. Critério de Classificação Econômica do Brasil, 2012. [acessado 2015 Dez 07]. Disponível em: http://www.abep.org/criterio-brasil.
http://www.abep.org/criterio-brasil... .

Nutritional status was assessed by body mass index. A tape measure attached to the wall (Sanny, São Paulo, Brazil) with an accuracy of 1 mm, and an electronic weighing machine, which was accurate to 100 g and had a capacity of 150 kg (Plenna, model MEA-03140, São Paulo, Brazil), were used to perform the height and weight measurements respectively. The measurements were performed according to previously described standardizations²⁹29. World Health Organization (WHO). Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee. Geneva: WHO; 1995. (Technical Report Series, n° 854). The cut-off points for being overweight and obese that were adopted were those proposed by the International Obesity Task Force (IOTF)³⁰30. Cole TJ, Lobstein T. Extended international (IOTF) body mass index cut-offs for thinness, overweight and obesity. Pediatr Obes 2012; 7(4):284-294._.

Blood pressure was measured according to the guidelines contained in the “Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents”³¹31. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Pediatrics. 2004; 114(2):555-576.. Prior to the implementation of the measures, all the young people were instructed not to use any stimulating substance¹²12. Spagnolo A, Giussani M, Ambruzzi AM, Bianchetti M, Maringhini S, Matteucci MC, Menghetti E, Salice P, Simionato L, Strambi M, Virdis R, Genovesi S. Focus on prevention, diagnosis and treatment of hypertension in children and adole scents. Ital J Pediatr 2013; 39(1):20.. They remained seated with their feet on the floor and the lower back supported by a chair for five minutes. Two measurements were performed with an interval of 10 min between them, using an oscillometric device (Omron^® model HEM 742), which was validated in a sample similar to the present study³²32. Christofaro DGD, Fernandes RA, Polito MD, Romanzini M, Ronque ERV, Gobbo LA, Oliveira AR. A comparison between overweight cutoff points for detection of high blood pressure in adolescents. J Pediatr 2009; 85(4):353-358.. The young people were considered to have HBP if they had blood pressure above the 90th percentile, according to their gender, height and age group.

The description of the results was performed using the absolute and relative frequency. The bivariate association was performed using the chi-square test, adopting Fisher's exact test when necessary. Poisson regression was used to estimate the crude and adjusted prevalence ratio (PR), as well as the confidence intervals of 95% of the association between nutritional status and HBP. The independent variables that presented an association that was P < 0.20 in the bivariate analysis were included in the adjusted analysis. Because of the complex sample design used in the study and analysis according to practicing sports, the design effect (deff) was estimated. The analyses were performed considering the stratum, the primary sampling unit, and the sample weight, using the “survey” (svy) of Stata 11.0 software.

Results

Of the 965 young people who were invited to voluntarily participate in the study, 78% accepted and performed all the procedures. Table 1 shows the characteristics of the study participants. There was a similar frequency of students in terms of gender and age in the total sample. The prevalence of youngsters who were overweight and obese was respectively 14.5 and 5.9%, while 17.5% had HBP.

Higher proportions of male participants, aged 10 to 12, were found to have sedentary behavior less than two hours per day in young people sports practitioners (P <0.001). The frequency of young people who were overweight (14.2 vs 14.7%), obese (6.5 vs 4.5%) and with high blood pressure (18.4 vs 15.8%) were similar between the two groups (P > 0.05). The young people practitioners and those who did not practice sports did not differ with respect to paternal education.

The bivariate association between the independent variables with HBP in the total sample is presented in Table 2. The female participants had a negative association (PR = 0.55, 0.40 to 0.76) while the variables age (PR = 1.46, 1.02-2.10), overweight (PR = 1.62, 1.03-2.56) and obesity (PR = 1.91, 1.11-3.28) were positively associated with HBP.

Table 3 shows the bivariate associations between the independent variables of the study with HBP in relation to practising sports. The female participants had a negative association (PR = 0.47, 0.32-0.68) while overweight (PR = 1.92, 1.03-3.61) and obese (PR = 2.22, 1.13-4.42) were positively associated with HBP in young people who did not practice sports. None of the analyzed variables was significantly associated with HBP in young people sports practitioners.

After the adjustment of the models, the associations were upheld between overweight and obesity with HBP in the total sample (PR = 1.60, 1.02-2.52; and 1.93, 1.15-3.25) and in the young people who did not practice sports (PR = 1.80, 1.05-3.14; and 2.15, 1.10-4.16). There were no significant associations between overweight (PR = 1.01, 0.36-2.82) and obesity (PR = 1.09, 0.48-2.48) with HBP in those who practice sports (Table 4).

Discussion

To the best of our knowledge, this was the first study that has examined whether an association between overweight and obesity with HBP occurred in both young people who practiced sports and those who did not practice sports. The main result was that overweight and obesity was positively associated with HBP in the total sample and also in the young people who did not practice sports, whereas the same was not true for those sports practitioners.

A higher prevalence of HBP was found in young people who were overweight and obese compared to those who were eutrophic within the total sample (25.7 and 29.5 vs 15.2%) and those who did not practice sports (29.7 and 33.3 vs 15.1%), respectively. With regard to the participants who practiced sports, the prevalence of HBP was similar in young people who were overweight and obese compared to the eutrophic participants (17.1 and 18.2 vs 15.5%). In the adjusted analysis, young people who were overweight and obese in the total sample and those who did not practice sports showed a prevalence ratio of HBP which ranged from 1.60 to 2.15 higher than their eutrophic counterparts, results that corroborate those in previous studies⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^–1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,1818. Gomes B, Alves J. Prevalência de hipertensão arterial e fatores associados em estudantes de ensino médio de escolas públicas da Região Metropolitana do Recife, Pernambuco. Cad Saúde Pública 2009; 25(2):375-381.^,2222. Pinto SL, Silva RDCR, Priore SE, Assis AMO, Pinto EDJ. Prevalência de pré-hipertensão e de hipertensão arterial e avaliação de fatores associados em crianças e adolescentes de escolas públicas de Salvador, Bahia, Brasil. Cad Saude Publica 2011; 27(6):1065-1075.^,2626. Guimarães ICB, Almeida AM, Santos AS, Barbosa DBV. Pressão Arterial: Efeito do Índice de Massa Corporal e da circunferência abdominal em Adolescentes. Arq Bras Cardiol 2008; 90(6):393-399.. No significant associations were found for young people who practice sports. These results epidemiologically demonstrate the cardiovascular protection presented by the overweight and obese individuals who practice sports compared to their peers who did not practice sports.

When the total sample was analyzed the results of this study corroborated previous studies that showed no association between physical activity and HBP in young people⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^,1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,2121. Silva KS, Lopes AS. Excesso de peso, pressão arterial e atividade física no deslocamento à escola. Arq Bras Cardiol 2008; 91(2):93-101.^–2323. Moreira NF, Muraro AP, Brito FDSB, Gonçalves-Silva RMV, Sichieri R, Ferreira MG. Obesidade: principal fator de risco para hipertensão arterial sistêmica em adolescentes brasileiros participantes de um estudo de coorte. Arq Bras Endocrinol Metab 2013; 57(7):520-526.. The present study examined the practice of sports because the physical activity of young people is largely performed through sports¹⁵15. Tubino MJG. Dimensões sociais do esporte. 2ª ed. São Paulo: Cortez Editora; 2001.. Although no association was found between the practice of sports and HBP in young people, the present study showed a similar prevalence of HBP among young people sports practitioners who were overweight and obese compared to their eutrophic counterparts. This result may explain the lack of association between physical activity and HBP described in previous studies⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^,1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,2121. Silva KS, Lopes AS. Excesso de peso, pressão arterial e atividade física no deslocamento à escola. Arq Bras Cardiol 2008; 91(2):93-101.^–2323. Moreira NF, Muraro AP, Brito FDSB, Gonçalves-Silva RMV, Sichieri R, Ferreira MG. Obesidade: principal fator de risco para hipertensão arterial sistêmica em adolescentes brasileiros participantes de um estudo de coorte. Arq Bras Endocrinol Metab 2013; 57(7):520-526.. Thus, the following two aspects should be considered in relation to the ways in which physical activity may protect young people from HBP: the protection independent of overweight¹⁸18. Gomes B, Alves J. Prevalência de hipertensão arterial e fatores associados em estudantes de ensino médio de escolas públicas da Região Metropolitana do Recife, Pernambuco. Cad Saúde Pública 2009; 25(2):375-381.^,2020. Christofaro DGD, Ritti-Dias RM, Chiolero A, Fernandes RA, Casonatto J, Oliveira AR. Physical activity is inversely associated with high blood pressure independently of overweight in Brazilian adolescents. Scand J Med Sci Sport 2013; 23(3):317-322. and the protection that only occurs in overweight and obese individuals who practice sports.

The protection in relation to HBP presented by the overweight individuals who practiced sports can be explained by the chronic reduction in blood pressure caused by physical exercise³³33. Farpour-Lambert NJ, Aggoun Y, Marchand LM, Martin XE, Herrmann FR, Beghetti M. Physical Activity Reduces Systemic Blood Pressure and Improves Early Markers of Atherosclerosis in Pre-Pubertal Obese Children. J Am Coll Cardiol 2009; 54(25):2396-2406.^–3636. Torrance B, McGuire KA, Lewanczuk R, McGavock J. Overweight, physical activity and high blood pressure in children: a review of the literature. Vasc Health Risk Manag 2007; 3(1):139-149.. As a result, there was a decrease in the prevalence of HBP in obese children³³33. Farpour-Lambert NJ, Aggoun Y, Marchand LM, Martin XE, Herrmann FR, Beghetti M. Physical Activity Reduces Systemic Blood Pressure and Improves Early Markers of Atherosclerosis in Pre-Pubertal Obese Children. J Am Coll Cardiol 2009; 54(25):2396-2406.. Although there were methodological differences between the two studies, the present study corroborated previous results³³33. Farpour-Lambert NJ, Aggoun Y, Marchand LM, Martin XE, Herrmann FR, Beghetti M. Physical Activity Reduces Systemic Blood Pressure and Improves Early Markers of Atherosclerosis in Pre-Pubertal Obese Children. J Am Coll Cardiol 2009; 54(25):2396-2406., given that overweight and obese individuals reduced the prevalence of HBP from 50% to 37% in three months and to 29% in six months after physical activity intercention. Consequently, regular sports practice means that it was possible for young people exposed to one of the main determinants of HBP, overweight and obesity, to be able to present a similar prevalence to their eutrophic counterparts.

Although the cross-sectional design of this study, the results partially corroborated the experimental studies and randomized clinical trials that had previously been conducted. Significant reductions in blood pressure in training programs lasting three months³³33. Farpour-Lambert NJ, Aggoun Y, Marchand LM, Martin XE, Herrmann FR, Beghetti M. Physical Activity Reduces Systemic Blood Pressure and Improves Early Markers of Atherosclerosis in Pre-Pubertal Obese Children. J Am Coll Cardiol 2009; 54(25):2396-2406. and six months³⁴34. Farah BQ, Ritti Dias RM, Balagopal P, Hill JO, Prado WL. Does exercise intensity affect blood pressure and heart rate in obese adolescents? A 6 month multidisciplinary randomized intervention study. Pediatric obesity 2014; 9(2):111-120. have been reported. Exercise programs that are effective in reducing the blood pressure of young people have consisted of at least three weekly sessions that lasted more than one hour³⁵35. García-Hermoso A, Saavedra JM, Escalante Y. Effects of exercise on resting blood pressure in obese children: a meta-analysis of randomized controlled trials. Obes Rev 2013; 14(11):919-928.. The young people who practice sports in the present study probably practice on a daily basis similar to those described in previous studies³³33. Farpour-Lambert NJ, Aggoun Y, Marchand LM, Martin XE, Herrmann FR, Beghetti M. Physical Activity Reduces Systemic Blood Pressure and Improves Early Markers of Atherosclerosis in Pre-Pubertal Obese Children. J Am Coll Cardiol 2009; 54(25):2396-2406.^,3535. García-Hermoso A, Saavedra JM, Escalante Y. Effects of exercise on resting blood pressure in obese children: a meta-analysis of randomized controlled trials. Obes Rev 2013; 14(11):919-928., given that in the present study the participants were categorized as young people who stated that they practiced sports either often or always.

The lack of an association between overweight and obesity with HBP in young people sports practitioners in the present study occurred because young people who were overweight and obese presented a prevalence of HBP similar to the eutrophic participants. Similarly, the prevalence of HBP in the eutrophic participants was similar, regardless of sports practice, and was approximately 15%. This result was contrary to a previous study which showed that physical activity protected non-obese young people from HBP³⁷37. So HK, Li AM, Choi KC, Sung RYT, Nelson EA. Regular exercise and a healthy dietary pattern are associated with lower resting blood pressure in non-obese adolescents: a population-based study. J Hum Hypertens 2013; 27(5):304-308.. One aspect that should be considered is that there is a greater reduction in blood pressure resulting from physical activity in young people who have HBP³³33. Farpour-Lambert NJ, Aggoun Y, Marchand LM, Martin XE, Herrmann FR, Beghetti M. Physical Activity Reduces Systemic Blood Pressure and Improves Early Markers of Atherosclerosis in Pre-Pubertal Obese Children. J Am Coll Cardiol 2009; 54(25):2396-2406.. This can be explained by the attenuation that physical activity exerts on sympathetic activation mechanisms, insulin resistance, arterial stiffness, endothelial dysfunction, increased heart rate and vascular resistance that occur on overweight³⁶36. Torrance B, McGuire KA, Lewanczuk R, McGavock J. Overweight, physical activity and high blood pressure in children: a review of the literature. Vasc Health Risk Manag 2007; 3(1):139-149.. Overweight and obese young people who participated in the present study probably benefited from a reduction in blood pressure resulting from regularly practicing sports.

On the other hand, the similar prevalence of HBP among the eutrophic young people in this study, regardless of sports practice, may have been due to the fact that HBP is a multifactorial risk factor in young people. In addition to overweight, HBP is positively associated with heredity, low birth weight, high salt intake and alcohol consumption¹²12. Spagnolo A, Giussani M, Ambruzzi AM, Bianchetti M, Maringhini S, Matteucci MC, Menghetti E, Salice P, Simionato L, Strambi M, Virdis R, Genovesi S. Focus on prevention, diagnosis and treatment of hypertension in children and adole scents. Ital J Pediatr 2013; 39(1):20., factors which were not analyzed in the present study.

Another important result that should be considered is the similar prevalence of young people who were overweight, obese and with HBP, independent of sports practice (Table 1). Although the relationship between physical activity and HBP has previously been discussed¹⁶16. Carson V, Ridgers ND, Howard BJ, Winkler EA, Healy GN, Owen N, Dunstan DW, Salmon J. Light-intensity physical activity and cardiometabolic biomarkers in US adolescents. PLoS One 2013; 8(8):e71417.^–2020. Christofaro DGD, Ritti-Dias RM, Chiolero A, Fernandes RA, Casonatto J, Oliveira AR. Physical activity is inversely associated with high blood pressure independently of overweight in Brazilian adolescents. Scand J Med Sci Sport 2013; 23(3):317-322., the largest body of evidence indicates no association between physical activity and HBP²⁴24. Corrêa Neto VG, Palma A. Pressão arterial e suas associações com atividade física e obesidade em adolescentes: uma revisão sistemática. Cien Saude Colet 2014; 19(3):797-818.. The results of the present study corroborated previous studies that indicated no association between practicing sports and HBP in young Brazilians⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^,1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,2121. Silva KS, Lopes AS. Excesso de peso, pressão arterial e atividade física no deslocamento à escola. Arq Bras Cardiol 2008; 91(2):93-101.^–2323. Moreira NF, Muraro AP, Brito FDSB, Gonçalves-Silva RMV, Sichieri R, Ferreira MG. Obesidade: principal fator de risco para hipertensão arterial sistêmica em adolescentes brasileiros participantes de um estudo de coorte. Arq Bras Endocrinol Metab 2013; 57(7):520-526.. As already mentioned, the main determinant of HBP in young people is being overweight and obese²⁵25. Flynn J. The changing face of pediatric hypertension in the era of the childhood obesity epidemic. Pediatr Nephrol 2013; 28(7):1059-1066., and overweight young people are more likely to present HBP⁹9. Corrêa Neto VG, Sperandei S, Silva LAI, Maranhão Neto GA, Palma A. Hipertensão arterial em adolescentes do Rio de Janeiro : prevalência e associação com atividade física e obesidade. Cien Saude Colet 2014; 19(6):1699-1708.^–1111. Silva DAS, Lima LRA, Dellagrana RA, Bacil EDA, Rech CR. Pressão arterial elevada em adolescentes: prevalência e fatores associados. Cien Saude Colet 2013; 18(11):3391-3400.^,1818. Gomes B, Alves J. Prevalência de hipertensão arterial e fatores associados em estudantes de ensino médio de escolas públicas da Região Metropolitana do Recife, Pernambuco. Cad Saúde Pública 2009; 25(2):375-381.^,2222. Pinto SL, Silva RDCR, Priore SE, Assis AMO, Pinto EDJ. Prevalência de pré-hipertensão e de hipertensão arterial e avaliação de fatores associados em crianças e adolescentes de escolas públicas de Salvador, Bahia, Brasil. Cad Saude Publica 2011; 27(6):1065-1075.^,2626. Guimarães ICB, Almeida AM, Santos AS, Barbosa DBV. Pressão Arterial: Efeito do Índice de Massa Corporal e da circunferência abdominal em Adolescentes. Arq Bras Cardiol 2008; 90(6):393-399.. Thus, a similar proportion of overweight and obese young people in both strata of sports practice may explain why the the prevalence of HBP was also similar.

The promotion of physical activity and sports practice is an aspect of lifestyle that has been strongly recommended in order to prevent overweight and obesity in young people³⁸38. Hills AP, Andersen LB, Byrne NM. Physical activity and obesity in children. Br J Sports Med 2011; 45(11):866-870.. However, a systematic review gathered together studies that examined the association between sports practice with overweight and obese, and the results were inconclusive³⁹39. Nelson TF, Stovitz SD, Thomas M, LaVoi NM, Bauer KW, Neumark-Sztainer D. Do youth sports prevent pediatric obesity? A systematic review and commentary. Curr Sports Med Rep 2011; 10(6):360.. A study that was conducted after the aforementioned review found that participation in sports teams protected adolescents from overweight and obesity⁴⁰40. Drake KM, Beach ML, Longacre MR, MacKenzie T, Titus LJ, Rundle AG, Dalton MA. Influence of sports, physical eduation, and active commuting to school on adolescent weight status. Pediatrics 2012; 130(2):e296-e304., a result which was contrary to that found in the present study. One aspect to be considered is that in both the systematic review³⁹39. Nelson TF, Stovitz SD, Thomas M, LaVoi NM, Bauer KW, Neumark-Sztainer D. Do youth sports prevent pediatric obesity? A systematic review and commentary. Curr Sports Med Rep 2011; 10(6):360. and in the present study, sports practice was considered on both the formal and informal levels, while in the study by Drake et al.⁴⁰40. Drake KM, Beach ML, Longacre MR, MacKenzie T, Titus LJ, Rundle AG, Dalton MA. Influence of sports, physical eduation, and active commuting to school on adolescent weight status. Pediatrics 2012; 130(2):e296-e304. sports practice was defined as as the amount of participation by young people in sports teams during the previous year. One characteristic that may explain the differences between these studies is that participation in sports teams is performed systematically and probably present higher volume of training.

Considering that being overweight and obesity are two major public health problems in young people, given that they are the main factors associated with HBP²⁵25. Flynn J. The changing face of pediatric hypertension in the era of the childhood obesity epidemic. Pediatr Nephrol 2013; 28(7):1059-1066. and that HBP results in different threats to the health of young people and adults³3. McNiece KL, Gupta-Malhotra M, Samuels J, Bell C, Garcia K, Poffenbarger T, Sorof JM, Portman RJ; National High Blood Pressure Education Program Working Group. Left ventricular hypertrophy in hypertensive adolescents: analysis of risk by 2004 National High Blood Pressure Education Program Working Group staging criteria. Hypertension 2007; 50(2):392-395.^–77. Campana EMG, Brandão AA, Pozzan R, Magalhães MEC, Fonseca FL, Pizzi OL, Freitas EV, Brandão AP. Blood pressure in adolescence, adipokines and inflammation in young adults. The Rio de Janeiro study. Arq Bras Cardiol 2014; 102(1):60-69., the results of the present study demonstrated that sports practice protects young people with overweight and obesity from HBP compared to eutrophic counterparts. Thus, it is suggested that sports practice is one of the strategies that can be used within intervention programs designed to prevent HBP in young people. As a result, the complications associated with HBP in overweight and obese young people may be prevented.

The limitations of this study should be considered in order to analyze its results with caution and also to provide guidance for future studies. Some variables that have previously been described as being associated with HBP¹²12. Spagnolo A, Giussani M, Ambruzzi AM, Bianchetti M, Maringhini S, Matteucci MC, Menghetti E, Salice P, Simionato L, Strambi M, Virdis R, Genovesi S. Focus on prevention, diagnosis and treatment of hypertension in children and adole scents. Ital J Pediatr 2013; 39(1):20. were not analyzed, which restricts estimating whether the results would hold true if they were entered in the analysis. Similarly, no physiological mechanism that might explain the results of this study was analyzed. Furtermore, the size of the sample meant that it was not possible to perform analyses using other cut-off points for HBP such as the 95th and 99th percentiles. This study considered sports practice both formal and informal, which was a limitation that made it difficult to identify whether practicing sports under supervision provided greater protection against HBP compared to informal sports practice. Finally, due to the fact that this was a cross-sectional study there is a need for experimental and longitudinal studies to confirm these results.

Conclusion

According to the results presented in this study it can be concluded that overweight and obesity were not associated with high blood pressure in adolescents who practice sports. The prevalence of overweight and obese young people who had HBP was similar to their eutrophic counterparts, which suggested that there was a cardioprotective effect of sports practice in individuals who were overweight. Thus, it is suggested that overweight individuals regularly practice sports in order to prevent future health risks that result from HBP at a young age.

References

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