Sports participation plays a relevant role in the relationship between birth weight and bone mineral content in adolescents.

The Developmental Origins of Health and Disease hypothesis (DOHaD) proposes that growth during the prenatal period might play a critical role in health, affecting the development of diseases, such as osteoporosis. Bone health is particularly affected by human behaviors when sports participation constitutes the main manifestation of physical exercise. The aim of this study is to analyze the relationship between birth weight (BW) and bone mineral content (BMC) among adolescents, as well as to identify if sports participation and maturity can affect this relationship. The sample was composed of adolescents with ages ranging from 11 to 18 years, stratified according to normal birth weight (n = 331), low birth weight (n = 36), and macrosomia (n = 47), extracted from a wider cross-sectional study (ABCD Growth Study). BW was self-reported by the adolescent's parent. Sports participation was assessed by face-to-face interview. BMC was assessed using dual-energy X-ray absorptiometry. In the multivariate models, the relationships between BW and BMC remained non-significant, while sports participation was significantly related to BMC on lower limbs among boys (r = 0.154; p value = .001) and BMC of upper limbs among girls (r = 0.124; p value = .044). APHV was related to BMC of upper limbs among boys (r = 0.137; p value = .001). In conclusion, BMC was not affected by BW, while this phenomenon seems to be significantly affected by the positive impact of sports participation and maturation on it.

Resistance training presents beneficial effects on bone development of adolescents engaged in swimming but not in impact sports: ABCD Growth Study.

BACKGROUND: Sports practice during adolescence is important to enhance bone development, although it may provide different effects depending on the mechanical impact present in the sport. Besides, resistance training (RT) may also induce bone changes directly (via muscle contractions) and indirectly (via myokines). However, there have been no studies analyzing the longitudinal influence of engaging in sport with and without added mechanical load. Thus, this study aims to analyze the combined effects of sports participation and resistance training on areal bone mineral density (aBMD) accrual in adolescent athletes participating in swimming and impact sports for 12-months. METHODS: This was a 12-month longitudinal study. The sample comprised 91 adolescents (21 females) aged 10 to 18 years, engaged in impact sports (basketball, tennis, track & field, baseball and gymnastics, n = 66) and non-impact sport (swimming, n = 25). The sample was divided according to resistance training participation: impact sports only (n = 45), impact sports + resistance training (n = 21), swimming-only (n = 17) and swimming + resistance training (n = 8). aBMD and soft tissues were measured using dual-energy X-ray absorptiometry. Generalized linear models analysis was used for the resistance training (RT) x type of sport interaction in predicting aBMD changes overtime, adjusting for maturation, sex and baseline aBMD. RESULTS: After 12-months, all groups showed a significant increase in aBMD, except for the swimming groups (regardless of resistant training), which showed a significant loss in spine aBMD (-0.045 [-0.085 to -0.004] g/cm2 in swimming-only and - 0.047 [-0.073 to -0.021] g/cm2 in swimming + RT). In comparisons between groups, only swimming + RT group, compared with swimming-only group presented higher upper limbs aBMD (0.096 g/cm2 [0.074 to 0.118] in swimming + RT vs. 0.046 [0.032 to 0.060] g/cm2 in swimming only; p < 0.05) and whole body less head (WBLH) aBMD (0.039 [0.024 to 0.054] g/cm2 in swimming + RT vs. 0.017 [0.007 to 0.027] g/cm2 swimming-only; p < 0.05). CONCLUSION: Despite the significant gain in aBMD in all groups and body sites after 12-months, except for the spine site of swimmers, the results indicate that participation in RT seems to improve aBMD accrual in swimmers at the upper limbs and WBLH.

Overweight and Blood Pressure in Pre-Pubertal Children: A Longitudinal Study.

OBJECTIVE: To analyze the longitudinal relationship between overweight and hypertension in school children. METHODS: This cohort study enrolled children 6-8 years of age who were then prospectively followed up over a 24 months period with repeat assessments performed at an interval of 11-13 months. Information on participation in physical education classes in school, sports practice outside of school, and economic status were obtained through questionnaires answered by parents/guardians. The measurement of blood pressure, weight, height, and waist circumference was performed during the serial follow-up visits in school. RESULTS: The proportion of hypertension did not change significantly over the 24 months (7.1% to 8.2%; P = 0.690). However, children with overweight and obesity throughout the period, had a 198% [HR (95% CI) 2.98 (1.40, 6.35)] higher risk of having hypertension diagnosed during follow-up when compared to eutrophic children in the same period. CONCLUSION: The development trajectory of overweight and obesity in children aged 6-8 years was associated with hypertension.

Impact of cycling and walking on adiposity and healthcare costs among adults: longitudinal study.

Leisure-time physical activity seems relevant to prevent the development of chronic diseases and obesity. However, not much is known about the economic burden of these healthy behaviors, mainly in longitudinal designs. This study aimed to analyze the impact of walking and cycling on leisure-time on adiposity and healthcare costs among adults. This longitudinal study was conducted at a medium-size Brazilian city and included 198 participants with no missing data attended in the Brazilian Unified National Health System. Cycling and walking were assessed by a questionnaire with a face-to-face interview at four time-points (baseline, 6-month, 12-month, and 18-month). Healthcare costs were assessed using medical records. Adiposity markers included waist circumference and body fatness. Over the follow-up period, participants who were more engaged in cycling presented lower body fatness (p-value = 0.028) and healthcare costs (p-value = 0.038). However, in the multivariate model, the impact of cycling on costs was not significant (p-value = 0.507) due to the impact of number of chronic diseases (p-value = 0.001). Cycling on leisure-time is inversely related to adiposity in adults, whereas its role on preventing chronic diseases seems the main pathway linking it to cost mitigation.

The impact of early sports participation on body fatness in adulthood is not mediated by current physical activity.

OBJECTIVE: The aim was to analyze the relationship between early sports participation (ESP) and body fatness (BF) in adults, as well as to identify whether this possible relationship is directly influenced by the current physical activity (PA) level. METHODS: This cross-sectional study combined baseline data of two cohort. The BF estimated by DXA. The ESP, the subjects reported the engagement in sports during childhood (7-10 years) and adolescence (11-17 years) through two yes/no questions and current PA (described as steps) was device-measured using pedometers. Were identified as potential covariates and therefore adjusted the multivariate models: age, ethnicity, alcohol consumption, smoking, and sleep quality. Statistical analysis consisted of the chi-square test, analysis of variance/covariance, and structural equation modeling (software BioEstat version 5.0; p-value < .05). RESULTS: Adults engaged in ESP had lower BF; among women, the variance in BF explained by ESP was 25.5%; among men, it was 9.2%. Sports participation in early life (r = -.436 [95% CI: -0.527 to -0.346]) and current PA (r = -.431 [95% CI: -0.522 to -0.340]) were inversely related to BF, as well as positively related to each other (r = .328 [95% CI: 0.226 to 0.430]). In the mediation model, current PA partially mediated (18.5%) the impact of ESP on BF, while current PA and ESP remained relevant determinants of BF. CONCLUSION: Early sports participation and current PA have a significant impact on BF in adulthood, which is of similar magnitude and independent of each other.

Impact of cycling and walking on adiposity and healthcare costs among adults: longitudinal study / Impacto do ciclismo e da caminhada na adiposidade e nos custos de saúde em adultos: estudo longitudinal / Impacto de andar en bicicleta y caminar sobre la adiposidad y los costos de salud en adultos: estudio longitudinal

Abstract: Leisure-time physical activity seems relevant to prevent the development of chronic diseases and obesity. However, not much is known about the economic burden of these healthy behaviors, mainly in longitudinal designs. This study aimed to analyze the impact of walking and cycling on leisure-time on adiposity and healthcare costs among adults. This longitudinal study was conducted at a medium-size Brazilian city and included 198 participants with no missing data attended in the Brazilian Unified National Health System. Cycling and walking were assessed by a questionnaire with a face-to-face interview at four time-points (baseline, 6-month, 12-month, and 18-month). Healthcare costs were assessed using medical records. Adiposity markers included waist circumference and body fatness. Over the follow-up period, participants who were more engaged in cycling presented lower body fatness (p-value = 0.028) and healthcare costs (p-value = 0.038). However, in the multivariate model, the impact of cycling on costs was not significant (p-value = 0.507) due to the impact of number of chronic diseases (p-value = 0.001). Cycling on leisure-time is inversely related to adiposity in adults, whereas its role on preventing chronic diseases seems the main pathway linking it to cost mitigation.

Resumo: A atividade física no lazer parece relevante para prevenir o desenvolvimento de doenças crônicas e obesidade. No entanto, pouco se sabe sobre o impacto econômico destes comportamentos saudáveis, principalmente em estudos longitudinais. O objetivo deste estudo foi analisar o impacto da caminhada e do ciclismo como atividades de lazer na adiposidade e nos custos de saúde em adultos. Este estudo longitudinal foi realizado em uma cidade brasileira de médio porte e incluiu 198 participantes sem dados indisponíveis atendidos no Sistema Único de Saúde brasileiro. A caminhada e o ciclismo foram avaliados por meio de questionário e entrevista presencial em quatro momentos (linha de base, 6 meses, 12 meses e 18 meses). Os custos de saúde foram avaliados por meio de prontuários médicos. Os marcadores de adiposidade incluíram circunferência da cintura e gordura corporal. Durante o período de acompanhamento, os participantes que praticavam mais ciclismo apresentaram menos gordura corporal (p = 0,028) e custos de saúde (p = 0,038). Porém, no modelo multivariado, o impacto do ciclismo nos custos deixou de ser significativo (p = 0,507) devido ao impacto do número de doenças crônicas (p = 0,001). O ciclismo no momento de lazer está inversamente relacionado à adiposidade em adultos, enquanto o seu papel na prevenção de doenças crônicas parece ser o principal aspecto que o liga à redução de custos.

Resumen: La actividad física en el ocio parece relevante para prevenir el desarrollo de enfermedades crónicas y la obesidad. Sin embargo, poco se sabe sobre el impacto económico de estos comportamientos saludables, especialmente en estudios longitudinales. El objetivo de este estudio fue analizar el impacto de caminar y andar en bicicleta como actividades de ocio sobre la adiposidad y los costos de salud en adultos. Este estudio longitudinal se llevó a cabo en una ciudad brasileña de tamaño mediano e incluyó a 198 participantes sin datos indisponibles atendidos en el Sistema Único de Salud brasileño. Se evaluaron los hábitos de caminar y andar en bicicleta mediante un cuestionario y una entrevista cara a cara en cuatro momentos (inicial, 6 meses, 12 meses y 18 meses). Los costos de atención médica se evaluaron utilizando registros médicos. Los marcadores de adiposidad incluyeron la circunferencia de la cintura y la grasa corporal. Durante el período de seguimiento, los participantes que practicaban más ciclismo presentaron menos grasa corporal (p = 0,028) y costos de salud (p = 0,038). Sin embargo, en el modelo multivariado, el impacto del ciclismo en los costos dejó de ser significativo (p = 0,507) debido al impacto del número de enfermedades crónicas (p = 0,001). El hábito de andar en bicicleta en los momentos de ocio está inversamente relacionado con la adiposidad en los adultos, mientras que su papel en la prevención de enfermedades crónicas parece ser el principal aspecto que lo vincula con la reducción de costos.

Physical activity and sedentary behaviour of adolescents and their parents: a specific analysis by sex and socioeconomic status.

BACKGROUND: The association of lifestyle habits of parents and of their children has been widely investigated as an important determinant for healthy habits in youth. Although parental sociodemographic characteristics are potential confounding factors in parent-child physical activity (PA) and sedentary behaviour (SB), it is still unclear whether these factors have a moderating role in this association. This study aimed to analyze the association of parent-child PA and SB according to parental sex and economic level in adolescents. METHODS: The study sample was made up of 1231 adolescents (15.6 ± 1.1 years, 58.2% of girls), 1202 mothers and 871 fathers. The leisure-time and commuting PA was assessed by the Baecke questionnaire, while sedentary behaviour (SB) was assessed according to hours per week of television viewing and computer use, by both adolescents and their parents. Economic status was analyzed using a questionnaire and classified as low, medium, and high. Linear models were used to assess the association of parent-child PA and SB in the different domains according to parental sex and economic level. RESULTS: Leisure time was associated between boys and their fathers in high (ß = 0.23, p = 0.044) and low economic classes (ß = 0.31, p < 0.001), and girls and their mothers in low economic class (ß = 0.38, p < 0.001). Commuting PA was associated between adolescents and both parents in low economic class (fathers ß = 0.21, p = 0.005; mothers (ß = 0.15, p = 0.020). TV time of boys was associated with TV time of fathers in low economic class (ß = 0.13, p = 0.022) and with TV time of mothers in medium economic class (ß = 0.13, p = 0.046). Among girls, TV time was associated with TV time of both parents only in low economic class (fathers ß = 0.28, p < 0.001; mothers ß = 0.25, p < 0.001). Computer use of girls was associated with computer use of fathers in high economic class (ß = 1.72, p = 0.043) and mothers in low economic class (ß = 0.57, p = 0.014), while no association was observed among boys. CONCLUSION: Economic status was shown to be an important moderator of the association between parent-child PA and SB in adolescents.

Interrelationship between arterial hypertension, health service costs, therapeutic treatment and physical activity.

BACKGROUND: Arterial hypertension is a high prevalence disease that increase healthcare costs and affects physical activity level. This study aimed to analyse the interrelationship between arterial hypertension, health service costs, therapeutic treatment, and physical activity in patients with cardiovascular diseases. METHOD: Cross-sectional study that evaluated 306 patients from a hospital in Presidente Prudente-Brazil. Based on their medical diagnosis, they were classified into multiple groups to access primary care and hospital-related costs variations. Then, using data from medical records and face to face interviews, they were examined on their treatment adherence and physical activity practice. Healthcare costs were accessed using medical records. Finally, the generalised linear model was used to analyse the interrelationship between treatment adherence, physical activity, health care costs and arterial hypertension. The data were analysed with Stata/MP4 16, and a p-value of less than 5% was used to determine statistical significance. RESULTS: The group that adhered to the arterial hypertension treatments but were physically inactive presented higher costs with consultation (US$=24.1, 95%CI = 1.90;46,3)​​ medication (US$=56.60, 95%CI = 1.65; 111.5) and total primary health care costs (US$=71.60, 95%CI = 19.2; 123.9) even after adjusting for confounding variables, meanwhile those participants that adhered to the treatments and were physical active did not present difference in healthcare cost when compared to normotensive and physical active participants. CONCLUSION: To be adherent to hypertension treatment were related to higher health care costs meanwhile been physical activity were related to lower health care costs and the combination of both showed that be adherent and physical activity represent the same cost with health than those normotensive and active emphasizing the importance of adherence and physical activity in the hypertensive treatment.

Interrelationship between muscle fitness in childhood and bone mineral density in adulthood: mediation analysis of muscle fitness in adulthood.

BACKGROUND: This study was aimed to examine the relationship between muscular fitness indicators in childhood and areal bone mineral density (aBMD) in adulthood and to verify whether the relationship is mediated by performance on muscular fitness indicators in adulthood. METHODS: A sample of 138 healthy adults (69 males; 22.3 years) were followed after a previous assessment at the age of 7-10 years. Stature, body mass and muscular fitness indicators (handgrip strength, standing long jump and sit-ups tests) were assessed in childhood and adulthood. Additionally, total body, upper limbs, lower limbs, right femoral neck and lumbar spine aBMD was assessed in adulthood using dual X-ray absorptiometry. Analysis included descriptive statistics; t-test or Mann-Whitney U-test for comparison between males and females, multiple linear regression for the prediction aBMD from muscular fitness indicators in childhood, mediation analysis of the respective muscular fitness indicators in adulthood and the relationship between muscular fitness indicators in childhood and aBMD. RESULTS: Males were stronger compared to females regarding muscular fitness indicators in childhood and adulthood, and presented higher mean values for aBMD in adulthood, except for lumbar spine (p < 0.05). Regression analysis revealed that some muscular fitness indicators in childhood showed significant positive relationship with bone health indicators in adulthood, such as: handgrip strength and total body aBMD (ß = 0.005; R2 = 0.35; p = 0.040) and upper limbs aBMD (ß = 0.005; R2 = 0.55; p = 0.019); and sit-ups test was a significant predictors of lumbar spine BMD (ß = 0.003; R2 = 0.06; p = 0.039). Mediation analysis pointed out the following: adulthood handgrip strength mediated relationships between childhood handgrip strength and total aBMD (indirect effect (IE) = 0.0025; 95%CI = 0.0005-0.0048), and upper limbs aBMD (IE = 0.0040; 95%CI = 0.0017-0.0069). CONCLUSIONS: Muscular fitness indicators in childhood showed significant relationship with bone health indicators in adulthood and the sit-ups test in childhood had direct effect on lumbar spine aBMD in adulthood. Adulthood handgrip strength mediated the relationship between childhood handgrip strength and total body and upper limb aBMD, pointing out that muscular fitness in childhood may be a aBMD determinant in adulthood, especially when higher muscle fitness performance is maintained in adulthood.

Qualidade de vida e comportamentos durante a pandemia da COVID-19: Um estudo transversal / Quality of life and behaviors during the COVID-19 pandemic: A cross-sectional study

Pesquisa transversal com objetivo de analisar a associação entre qualidade de vida e comportamentos desenvolvidos por indivíduos hipertensos durante o período de isolamento social, devido à pandemia da COVID-19. O estudo foi realizado através de ligações telefônicas e avaliou adultos cadastrados na atenção primária de saúde. A prática de atividade física foi avaliada pelo Questionário Internacional de Atividade Física, sendo somadas a duração e a frequência das atividades e o tempo total sentado durante a semana e fim de semana. A qualidade de vida foi analisada através do Sistema Descritivo ­ EQ-5D, considerando o score utilidade e o estado geral de saúde. Presença de doenças e comportamentos durante o isolamento social, assim como aspecto emocional e ambiente para realização de atividades físicas foram analisados. Foram utilizados os testes t de Studant e ANOVA one way para comparação de grupos e ANCOVA para comparações entre os grupos ajustadas. A significância estatística foi pré-fixada em valores inferiores a 5%. Foram entrevistados 659 hipertensos, com idade entre 41 e 93 anos. Observou-se maior qualidade de vida naqueles que praticaram exercício físico (p = 0,015), que não relataram ter a saúde emocional afetada pela pandemia (p = 0,001) e que responderam ter ambiente favorável em casa para prática de atividade física, (p = 0,001). Em conclusão, a qualidade de vida associou-se aos comportamentos positivos dos participantes durante a pandemia, como a prática de atividade física, contudo é necessário que os órgãos públicos se atentem aos baixos níveis de atividade física da população provocados pela pandemia

Cross-sectional research with the objective of analyzing the association between quality of life and behaviors developed by hypertensive individuals during the period of social isolation, due to the COVID-19 pandemic. The study was carried out through telephone calls and evaluated adults registered in primary health care. The practice of physical activity was assessed by the International Physical Activity Questionnaire, adding the duration and frequency of activities and the total time sitting during the week and weekend. Quality of life was analyzed using the Descriptive System ­ EQ-5D, considering the utility score and general health status. Presence of diseases and behaviors during social isolation, as well as the emotional aspect and environment for carrying out physical activities were analyzed. Student's t-test and one-way ANOVA were used for group comparisons and ANCOVA for adjusted between-group comparisons. Statistical significance was pre-set at values below 5%. 659 hypertensive adults aged between 41 and 93 years were interviewed. A better quality of life was observed in hypertensive individuals who practiced physical exercise (p = 0.015), who did not report having their emotional health affected by the pandemic (p = 0.001) and who responded that they had a favorable environment at home for the practice of physical activity, (p = 0.001). In conclusion, QoL was associated with the positive behaviors of the participants during the pandemic, such as the practice of physical activity, however, it is necessary for public agencies to pay attention to the low levels of PA in the population caused by the pandemic

Effect of Resistance Training on Body Composition of Adolescents: ABCD Growth Study.

OBJECTIVE: To analyze the relationship between resistance training and body composition in adolescents. METHODS: A longitudinal 12-month follow up of 190 adolescents of both sexes categorized into three groups according to resistance training practice, as non-engagement (n=121), irregular engagement (n=44), and frequent engagement (n=25). The outcomes adopted were bone mineral density (BMD), lean soft tissue (LST), and body fatness (BF). RESULTS: Adolescents frequently engaged in resistance training presented higher gains in mean (95 CI) LST [6.1 (3.7 to 8.5) kg vs 2.4 (1.4 to 3.4) kg; P= 0.027] and BMD-upper limbs [0.096 (0.072 to 0.121) g/cm2 vs 0.046 (0.036 to 0.056) g/cm2; P=0.002] than adolescents who were not engaged in resistance training, respectively. Findings were more consistent for boys than girls (models were not significant among girls: LST P= 0.721; BMD-upper limbs P= 0.053). CONCLUSION: Regular engagement in resistance training was related to higher gains in muscle mass and bone density, especially among boys.

Physical Activity Levels in Brazilian Adolescents: A Secular Trend Study (2007-2017/18).

Only a small proportion of Brazilian adolescents practice sufficient physical activity (PA). However, it is not clear whether this proportion has been decreasing over time. This study aimed to examine the 10-year trends of sufficient PA in adolescents and to investigate differences by sex and age. Using a standard protocol, we compared two cross-sectional cohorts of adolescents aged 15 to 18 years, recruited in 2007 (n = 1040) and in 2017/18 (n = 978). Using the International Physical Activity Questionnaire-Short Form (IPAQ-SF), the adolescents reported moderate-to-vigorous PA (MVPA) performed in the last seven days. Sufficient PA was defined as engaging in at least 60 min/day of MVPA. In the subgroups, investigated by sex or age, there was an increase in the prevalence of sufficient PA. Overall, sufficient PA declined by 28.1% from 2007 to 2017/18. Boys in 2007 were more active than their 2017/18 peers, and this was equally observed in girls in 2007 compared to those in 2017/18. The findings show decreasing secular trends in sufficient PA in the investigated adolescents. Not only are public health authorities in Brazil witnessing an escalation of insufficient PA, but they are also losing ground with the most active adolescents.

The Combined Relationship of Vitamin D and Weight-Bearing Sports Participation on Areal Bone Density and Geometry Among Adolescents: ABCD - Growth Study.

Osteoporosis is a public health problem, which negatively impacts society and national health services worldwide. Altered mineralization of the skeleton can be caused by persistent vitamin D deficiency. However, the combined impact of both on bone health is still under investigation. In fact, although there is compelling evidence in the literature about the positive effect of weight-bearing sports participation on bone mineral density, its impact on bone geometry gains more attention in pediatric population. The sports modalities that we evaluated were artistic gymnastics and track and field. Nonsports group was composed of 43 adolescents. Bone density was assessed using dual-energy X-ray absorptiometry. Vitamin D concentration was assessed by blood analysis. In the crude comparison of bone outcomes, the sport group presented higher aBMD only in the trochanter (p-value = 0.040). Considering the combination of the engagement in sports and vitamin D, adolescents in the sports group presented significantly higher values of aBMD in lower limbs, whole body, trochanter, shaft, and femur whole body (p-value = 0.024, 0.035, 0.001, 0.019 and 0.003 respectly). In contrast, only the sport group with high vitamin D presented a higher CSA (p-value = 0.015) and femur neck aBMD compared to the non-sport/low vitamin D group. Only adolescents with a combination of sports participation and higher serum concentrations of vitamin D presented better bone geometry, denoting the relevance of the combination of both factors to bone health.

Impact of sports participation on cardiovascular health markers of children and adolescents: Systematic review and meta-analysis.

BACKGROUND: Cardiovascular diseases have a high prevalence in adults and their development begins in the first decades of life. On the other hand, sports participation in childhood and adolescence provides benefits which can delay the onset of these diseases. AIM: To synthesize the available literature on the impact of sports participation on cardiovascular outcomes in children and adolescents. METHODS: This systematic review was conducted on studies of children and adolescents (aged 8-18 years) who regularly practiced a sport and had reported cardiovascular outcomes (blood pressure and intima-media thickness) recorded. The Medline/PubMed, SciELO, Reference Citation Analysis (https://www.referencecitationanalysis.com/) and Bireme databases were searched. RESULTS: In total, 3314 publications for blood pressure and 122 publications for intima-media thickness were identified in the databases. After exclusions (e.g., duplicate articles, animal studies and those that did not meet the inclusion criteria), four publications for blood pressure (449 adolescents) and two publications for intima-media thickness were included (402 adolescents). For blood pressure, all publications were longitudinal in design (follow-up ranging from 12 wk to 12 mo) and involved adolescents aged from 8 years to 18 years of age. For intima-media thickness, both publications were longitudinal in design and involved adolescents aged from 11 years to 18 years of age. CONCLUSION: Sports participation seems to promote benefits to cardiovascular structure and function in adolescents. However, studies with adolescents are scarce and further research is needed to understand this phenomenon.

Association between patterns of sedentary time and academic performance in adolescents: the mediating role of self-concept.

OBJECTIVE: To analyze the association between the pattern of sedentary time (bouts and breaks) with academic performance, with an emphasis on the mediating role of self-concept. METHODS: Participants in the cross-sectional study were 394 adolescents (208 girls), aged 10-14 years, from sixth grade from Londrina, Paraná, Brazil. The sedentary time pattern was measured through accelerometry. Definitions: sedentary bouts - uninterrupted periods of sedentary behavior; breaks - non-sedentary period between two sedentary bouts. The self-concept was estimated using the Piers-Harris II Inventory. Academic performance was obtained by school grades. RESULTS: Short sedentary bouts were associated with higher academic performance in boys (1-4 minutes: ß=0.035, p=0.007) and girls (1-4 minutes: ß=0.031, p=0.014; 5-14 minutes: ß=0.054, p=0.001). Long bouts (30 minutes) were associated with lower academic performance in boys (ß=-0.023; p=0.011) and girls (ß=-0.032; p<0.001). For girls, total and intellectual self-concept mediated the association between all sedentary pattern and academic performance (bouts 1-4 minutes [total: 39% and intellectual: 42.8%]; bouts 5-14 minutes [total: 21.5% and intellectual: 35.4%]; bouts ≥30 minutes [total: 22.6% and intellectual: 32.3%]; and breaks [total: 38.9% and intellectual: 40.7%]). For boys, the total (56.4%) and intellectual (82.9%) self-concept mediated only the association between bouts of 5-14 minute and academic performance. CONCLUSIONS: The pattern of sedentary time is associated with academic performance in adolescents and this association is mediated by self-concept, especially in girls.

Relationship between vigorous physical activity and health care costs among adolescents: ABCD Growth Study.

BACKGROUND: The relationship between physical activity and health care costs among adolescents is not yet clear in the literature. OBJECTIVE: To analyze the relationship between physical activity and annual health care costs among adolescents. METHODS: The present sample was composed of 85 adolescents of both sexes with ages ranging from 11 to 18 years (mean age 15.6 ± 2.1). Health care costs were self-reported every month for 12 months, and information on health care values was verified with local pharmacies, private health care plans, and the National Health Service. The time spent in different physical activity intensities was objectively measured by accelerometers. Confounding variables were: sex, age, somatic maturation, body fatness, blood pressure, and components of dyslipidemia and insulin resistance. Multivariate models were generated using generalized linear models with gamma distribution and a log-link function. RESULTS: The overall annual health care cost was US$ 733.60/ R$ 2,342.38 (medication: US$ 400.46 / R$ 1,278.66; primary and secondary care: US$ 333.14 / R$ 1,063.70). The time spent in vigorous physical activity (minutes/day) was negatively related to health care costs (r = -0.342 [95% CI: -0.537,-0.139]; ß = -0.06 cents (95% CI: -0.089, -0.031). CONCLUSION: Vigorous physical activity seems to be associated with lower health care costs among adolescents.

Association of parents' physical activity and weight status with obesity and metabolic risk of their offspring.

Our aim was to analyze the joint association of parental characteristics and offspring obesity indicators with metabolic risk in adolescents. A cross-sectional study was carried out with 972 adolescents and their parents. We observed that overweight adolescents who have a normal weight mother show lower metabolic risk in comparison with their counterparts with overweight mothers. In conclusion, mother's weight status moderates the relationship between offspring' obesity indicators and metabolic risk in adolescents.

Impact of sports participation on components of metabolic syndrome in adolescents: ABCD growth study.

OBJECTIVES: This study aimed to analyze the impact of sports participation (12 months of practice) on the components of metabolic syndrome (MetS) in both sexes. METHODS: This is an observational longitudinal study, a part of which is entitled "Analysis of Behaviors of Children During Growth" (ABCD Growth Study), Presidente Prudente, São Paulo, Brazil. The sample was composed of 171 adolescents (112 boys and 59 girls), divided into non-sports and sports groups. High-density lipoprotein-cholesterol (HDL-c), triglycerides, and glucose were analyzed by the colorimetric method of dry chemistry and processed biochemically. Systolic blood pressure and diastolic blood pressure were measured using an automatic device. Body fat was estimated using a densitometry scanner. RESULTS: Adolescents who practiced sports were younger (p-value=0.001) and had a lower peak height velocity (p-value=0.001) than the non-sports group. The differences (Δ) after 12 months were of greater magnitude for the sports group when compared to the non-sports group (p-value=0.013), glucose (moderate magnitude in favor of the sports group; p-value=0.001), HDL-c (small magnitude in favor of the sports group; p-value=0.0015), and MetS (moderate magnitude in favor of the sports group; p-value=0.001). CONCLUSIONS: The practice of sports in adolescents had a protective effect on the metabolic components of MetS.

Impact of Moderate-To-Vigorous Sports Participation Combined with Resistance Training on Metabolic and Cardiovascular Outcomes among Lean Adolescents: ABCD Growth Study.

BACKGROUND: To investigate the combined impact of being engaged in resistance training (RT) and meeting the physical activity guidelines through sports participation (SP) on cardiovascular and metabolic parameters in lean adolescents. METHODS: A longitudinal study, part of the ongoing study entitled "ABCD Growth Study" (Analysis of Behaviors of Children During Growth), assessed data from 64 adolescents (23 from the sport group, 11 from the sport + RT group, and 30 from the control group). Metabolic and cardiovascular outcomes were analyzed as dependent variables. For the independent variables, sports participation and resistance training were considered, and for the covariates, sex, chronological age, body weight, height, and somatic maturation. RESULTS: After 12 months of follow-up, the RT + SP presented improvements in triglycerides (TG) and the SP presented a reduction in LDL-c, TG, and glucose when compared to the control group. CONCLUSIONS: Being engaged in RT and SP is a good strategy to improve health in eutrophic adolescents, with a great impact on TG from the lipid profile.

Relationship Between Muscle Strength, Body Composition and Bone Mineral Density in Adolescents.

Adolescence is an important period for the acquisition of bone mass, which can be enhanced by several factors. This study aimed examine the relationships of handgrip strength, free-fat mass, and fat mass with bone mineral density in adolescents. 118 adolescents (60 girls), aged 10 to 14 years, participated in the study. Information on sex, age, handgrip strength, free-fat mass, fat mass and bone mineral density were collected. Multiple linear regression analyses were conducted to examine possible relationships between bone mineral density and handgrip strength, free-fat mass and fat mass. There was a relation between handgrip strength and free-fat mass with bone mineral density in both sexes. Fat mass was correlated with bone mineral density only in girls (r= 0.314, p< 0.014). The final models, adjusted for sexual maturation, included free-fat mass (girls - ß= 0.419, p< 0.001; boys - ß= 0.455; p< 0.001) and handgrip strength (girls - ß= 0.358, p< 0.05; boys - ß= 0.325; p< 0.05) and these variables together explained 51.8% and 62.9% of the variation of bone mineral density, in girls and boys, respectively. Handgrip strength and free-fat mass were positively associated with bone mineral density. A sex-specific difference indicated that higher levels of free-fat mass are of paramount importance for both sexes.