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.

Low Occurrence of Musculoskeletal Symptoms in Swimming? Musculoskeletal Symptoms and Sports Participation in Adolescents: Cross Sectional Study (ABCD-Growth Study).

The purpose of this paper was to identify the association between the occurrence of musculoskeletal symptoms (MS) and sports participation in adolescents. The sample included 193 adolescents (11 to 17 years of age; 131 boys and 62 girls). For this cross-sectional study, participants were categorized into four groups: "no-sports", "repetitive non-impact sports", "high-impact sports", and "odd-impact sports". A questionnaire was used, which defined MS as pain or any musculoskeletal complaint that led to restriction of current normal activities. In the entire sample, 112 adolescents reported at least one episode of MS during the recording, representing 58% of the sample. Our findings highlight that adolescents regularly engaged in odd-impact sports, such as martial arts, report a higher occurrence of MS than swimmers and adolescents who do not participate in any physical activity.

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.

More than Sports Participation: The Role of Ground Reaction Force, Osteocalcin and Lean Soft Tissue on Bone Density Accrual in Adolescents: ABCD Growth Study.

The objective of this study was to identify predictors of 12-mo areal bone density accrual in different body segments, lean soft tissue, and osteogenic characteristics attributed to sports participation among adolescent girls and boys. Adolescents (Girls [n = 64], [aged = 14.7]); Boys [n = 129], [aged = 14.6]) were stratified into three groups according to their engagement in different sports (Control [n = 68], Swimming [n = 25], and Weight-bearing sports [n = 100]). Areal bone density (aBMD [g/cm²]) and lean soft tissue (LST) [kg] were measured by dual-energy x-ray absorptiometry (DXA; Lunar DPX-NT; General Electric Healthcare, Little Chalfont, Buckinghamshire, United Kingdom). The ground reaction force (GRF) index attributed to sports participation (Sport-GRF) was created considering the GRF attributed to each sport, body weight of the adolescent, and the amount of time spent in sports participation. Osteocalcin levels (ng/mL) were estimated from a venous blood sample. Multiple regression analysis showed that after adjusting for covariates, the models involving sport-GRF, LST (Δ), and osteocalcin explained 15.8% to 76.2% of the aBMD gains. Specifically in girls, OC was only associated with lower limb aBMD accrual. In boys, however, sport ground reaction forces were positively associated with total spine aBMD accrual. Furthermore, the LST (Δ) was positively associated with aBMD accrual in all body sites (ß = 0.003 to 0.011) in both sexes. Increases in LST contributed significantly to gains in aBMD accrual in both sexes, being a more important predictor of changes in bone outcomes than ground reaction forces and osteocalcin.

The Mediating Role of Lean Soft Tissue in the Relationship between Somatic Maturation and Bone Density in Adolescent Practitioners and Non-Practitioners of Sports.

This study aimed to identify the mediating effect of lean soft tissue (LST) in the association between somatic maturation and areal bone mineral density (aBMD) in adolescents by sex and sport participation. The sample included 558 adolescents (401 males, mean age of 14.0 years) that were practitioners of sports (11 sport modalities, n = 402) and a non-sport group (n = 157). Somatic maturation was assessed by using a validated peak height velocity prediction equation. Dual-energy X-ray absorptiometry (DXA) was used to assess aBMD (upper and lower limbs, spine and total body less head-TBLH) and LST. For both sexes, LST mediated the association between somatic maturation and aBMD at all skeletal sites (mediation percentage ranging from 36.3% to 75.4%). For sport and non-sport groups, the LST also mediated the association between somatic maturation and aBMD at all skeletal sites (mediation percentage ranging from 51.6% to 85.6%). The direct effect was observed in all groups, except for lower limbs and TBLH in the non-sport group. The association between somatic maturation and aBMD was mediated by LST in adolescents of both sexes and regardless of involvement in organized sports. Our findings highlighted the role of improving LST to mitigate the association of somatic maturation with aBMD.

Influential role of lean soft tissue in the association between training volume and bone mineral density among male adolescent practitioners of impact-loading sports: ABCD Growth study.

BACKGROUND: Training volume is associated with direct and indirect pathways of bone adaptations. In addition, training volume is a training variable associated with lean soft tissue (LST), which has been shown to be an important predictor of areal bone mineral density (aBMD). Thus, the aim of this study is to investigate the influential role of lean soft tissue (LST) in the association between training volume and aBMD in male adolescent athletes. METHODS: This cross-sectional study was composed of 299 male adolescent athletes, mean age 14.1 (1.8) years, from 9 different weight-bearing modalities. The Ethical Board approved the investigation. The adolescents reported the number of days per week they trained and the time spent training and, from this, the training volume (h/wk) was estimated. The LST and aBMD were assessed by dual-energy x-ray absorptiometry. Somatic maturation was estimated by the peak of height velocity. Mediation analysis was performed to investigate the role of LST in the association between training volume and aBMD. Level of significance was set at p < 0.05. RESULTS: LST partially explained the association between training volume and aBMD in all body segments: upper limbs (58.37%; ß = 0.00142), lower limbs (28.35%; ß = 0.00156), spine (33.80%; ß = 0.00124), and whole body (41.82%, ß = 0.00131). There was no direct effect of training volume on aBMD in upper limbs (CI -0.00085 to 0.00287). CONCLUSION: The association between training volume and aBMD is influenced by LST in different body segments, mainly upper limbs, demonstrating that interventions aiming to enhance aBMD should also consider LST as an important variable to be managed.

Categorizing 10 Sports According to Bone and Soft Tissue Profiles in Adolescents.

PURPOSE: Considering the different loading and training characteristics of the sports practiced during growth, it is important to specify and categorize the bone and soft tissue adaptations in adolescent athletes. This study aimed to categorize 10 different loading sports and a nonsport group and identify the differences in bone density and soft tissues. METHODS: The sample included 625 adolescents (10 to 17 yr of age) of 10 sports (soccer, basketball, volleyball, track and field, judo, karate, kung fu, gymnastics, baseball, and swimming) and a nonsport group. Dual-energy x-ray absorptiometry assessed areal bone mineral density (aBMD), bone mineral apparent density (BMAD), and soft tissues (lean soft tissue and fat mass). The results were adjusted for sex, peak height velocity status, lean soft tissue, fat mass, and weekly training volume. RESULTS: The comparisons among groups showed that soccer had the highest whole-body aBMD (mean ± SEM: 1.082 ± 0.007 g·cm) and lower limb aBMD (1.302 ± 0.010 g·cm). Gymnastics presented the highest upper limb aBMD (0.868 ± 0.012 g·cm) and whole-body BMAD (0.094 ± 0.001 g·cm). Swimming presented the lowest aBMD values in all skeletal sites (except at the upper limbs) and whole-body BMAD. The soft tissue comparisons showed that soccer players had the highest lean soft tissue (43.8 ± 0.7 kg). The lowest fat mass was found in gymnasts (8.04 ± 1.0 kg). CONCLUSION: The present study investigated and categorized for the first time 10 different sports according to bone density and soft tissue profiles. Soccer and gymnastics sport groups were found to have the highest bone density in most body segments, and both sports were among the groups with the lowest fat mass.

Bone accrual over 18 months of participation in different loading sports during adolescence.

This study investigated the impact and non-impact sports on bone mineral density accrual in adolescents over 18 months. The impact sports were beneficial for bone health (accrual of bone density). In contrast, swimmers had similar or lower bone mineral density compared with the control group depending on the skeletal site. PURPOSE: To investigate the impact and non-impact sports on bone mineral density (BMD) accrual in adolescents over a period of 18 months METHODS: The sample was composed of 71 adolescents, avarage age of 12.7 (± 1.7) years old at baseline. Bone outcomes were compared according to the loading of the sports practiced (impact sports, n = 33 [basketball, karate, and judo], non-impact sport, n = 18 [swimming], and control group, n = 20). Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) and bone mineral apparent density (BMAD) estimated through equation. The results were compared between the groups using analysis of variance and analysis of covariance. RESULTS: Adjusted aBMD at lower limbs, whole body less head (WBLH), and adjusted WBLH BMAD were significantly greater in the impact sport group than the non-impact sport group at all time points. Adjusted upper limbs aBMD was significantly higher at the impact sports group compared to the non-impact sport group at 9 months and 18 months, besides compared to the control group at baseline and 18 months. Non-impact sport group presented a significant lower adjusted aBMD compared with control group at lower limbs and WBLH at 9 months, and at 9 months and 18 months in WBLH BMAD. There was a significant interaction (time × sport group) at upper limbs (p = 0.042) and WBLH aBMD (p = 0.006), and WBLH BMAD (p < 0.001). CONCLUSION: Impact sports were more beneficial on accumulating aBMD and BMAD over a period of 18 months, while non-impact group (swimmers) had similar and lower aBMD and BMAD compared with the control group.

Impact of changes in fat mass and lean soft tissue on bone mineral density accrual in adolescents engaged in different sports: ABCD Growth Study.

Body composition can have a significant impact on bone mineral density (BMD) in pediatric patients and may cause bone disease. This study demonstrated that lean soft tissue (LST) seems to have a greater impact on BMD gain in the lower limbs of adolescents. PURPOSE: To analyze the impact of changes in lean soft tissue (LST) and fat mass on areal bone mineral density (BMD) accrual in the lower limbs among adolescents engaged in sports with different weight-bearing levels. METHODS: Longitudinal (12 months: measurements at two time points). Adolescents of both sexes (n = 191; 62 girls [32.5%] and 129 boys [67.5%]) were divided into three groups: control group (n = 65), swimming group (n = 25), and weight-bearing sports group (n = 100). Absolute changes in LST (kg) and fat mass (kg) were the independent variables, while BMD accrual (left and right legs) was the dependent variable. Linear regression was used to assess the relationship between dependent and independent variables in a multivariate model adjusted by sex, body weight, somatic maturation, serum osteocalcin, and baseline values of BMD of the lower limbs. RESULTS: For the left leg, LST was positively related to areal BMD accrual in the control (ß = 0.021 [95%CI: 0.001 to 0.042]) and weight-bearing sport groups (ß = 0.051 [95%CI: 0.037 to 0.065]), but not among swimmers (ß = 0.029 [95%CI: - 0.004 to 0.062]). For the right leg, LST was positively related to areal BMD accrual in the swimming group (ß = 0.065 [95%CI: 0.031 to 0.100]) and weight-bearing sport groups (ß = 0.048 [95%CI: 0.034 to 0.062]), but not in the control group (ß = 0.014 [95%CI: - 0.002 to 0.030]). Fat mass was not significantly related to areal BMD in either leg. CONCLUSIONS: Changes in LST were the most relevant determinant of BMD accrual in the lower limbs, mainly among adolescents engaged in sports.

Bone Mineral Density and Sports Participation.

The objective of our study was to identify differences in bone mineral density (BMD) according to different sports among adolescents, as well as to identify assessments of relevant mediators. The sample consisted of 429 adolescents with a mean age of 13.3 ± 1.7 yr. The sports modalities that we evaluated were judo, karate, kung fu, swimming, basketball, and soccer. Nonsports group was composed of 111 adolescents. Bone density was assessed using dual-energy X-ray absorptiometry. Regarding BMD values, female engaged in karate had higher BMD values than girls from the no sports group (p = 0.01). Boys engaged in soccer and karate presented the highest BMD values than all the other groups (p = 0.01). The most relevant mediators were the body mass index and lean soft tissue for boys and girls. Different sports presented different results regarding BMD gains, which were influenced by body mass index and whole-body lean soft tissue.

Impact of Artistic Gymnastics on Bone Formation Marker, Density and Geometry in Female Adolescents: ABCD-Growth Study.

BACKGROUND: To compare bone density accrual and markers of bone geometry and formation between female adolescents engaged and not engaged in artistic gymnastics (AGs). METHODS: This was a 12-month longitudinal study involving 20 female adolescents, including 10 controls and 10 gymnasts (AGs) aged 11 to 16 years. At baseline, the gymnasts had a minimum of 12 months of practice, and the controls reported no participation in any organized sport. Bone mineral density (BMD) was measured in the lower limbs, upper limbs, spine, and whole body. In addition, BMD and geometrical properties of the femur were assessed. As a bone formation marker, osteocalcin level was measured. RESULTS: Femoral aspects were increased in the gymnasts by 19% (P=0.009), 14% (P=0.047), and 10% (P=0.046) in the Ward's triangle, trochanter, and the overall bone, respectively, than in the control girls. Geometrical parameters, bone accrual, and osteocalcin levels were similar in both groups. The weekly training load explained 30.8% of all bone gains on the lower limbs and affected the density on parts of the femur. CONCLUSIONS: The gymnasts, after a 12-month follow-up, demonstrated a higher BMD in the Ward's triangle and whole femur than the controls, as well as an improvement in femur density. These changes were mainly due to the weekly training load. Lastly, the gymnasts had significant bone accrual (after 12 months) in the upper limbs, lower limbs, and whole body.

Sports participation and muscle mass affect sex-related differences in bone mineral density between male and female adolescents: A longitudinal study.

BACKGROUND: Sports participation plays an important role in bone gain during childhood and adolescence. The aim here was to identify sex-related determinants of bone mineral density (BMD) differences between male and female adolescents, with emphasis on the role of sports participation. DESIGN AND SETTING: Longitudinal study conducted in a public university in Presidente Prudente, Brazil. METHODS: The sample comprised 48 adolescents aged 11-17 years, of both sexes, who were matched according to sex, age and sports participation. BMD was the main outcome, while muscle mass, sports participation, calendar age and biological maturation were treated as covariates. Participants were followed up after nine months. RESULTS: At baseline, BMD values were similar between the sexes. However, adjustment for covariates showed that BMD was higher among girls at all sites, with a contribution from lean soft tissue (LST) in the model (partial eta-squared, ES-r = 0.619 in upper limbs; 0.643 in lower limbs; 0.699 in spine; and 0.599 in whole body). Sports participation only explained the upper-limb variance (ES-r = 0.99). At the follow-up, the results resembled the baseline except in the lower limbs (P = 0.109), in which BMD was similar between the groups. BMD gain over time was similar between girls and boys in all segments, and baseline LST affected upper-limb and whole-body BMD accrual (ES-r = 0.396 and 0.107, respectively). CONCLUSION: Whole-body and specific-site BMD differed between baseline and follow-up. However,BMD accrual was similar between the sexes, given that muscle mass constituted the most relevant determinant of the difference between them.

Prevalence of sports participation among Brazilian adolescents: a systematic review / Prevalência da participação esportiva entre adolescentes brasileiros: uma revisão sistemática

Abstract The objective of this study was to describe the prevalence of sports participation in Brazilian children and adolescents using a systematic review approach. This review follows the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement and the protocol was previously registered on PROSPERO (95441), the searches were performed in the following electronic databases: PubMed, ScIELO, Bireme, and EMBASE. The search strategy included a combination of keywords: Children and adolescents, prevalence and sports participation. Four papers included 7104 adolescents aged from 10 to 18 years old, living in four different cities located at Southeast (n= 1) and South (n= 3) of Brazil data collections were carried out between 2004 and 2012. Most of the studies had cross-sectional design and the findings of all surveys were published in international journals. The definition of "sports participation" was not the same in all papers. The overall prevalence of sports participation among adolescents was 58.1%, higher among boys (65.9%) than in girls (51.5%). The systematic review identified that the prevalence of sports participation among Brazilian adolescents is low and significantly affected by gender.

Resumo O objetivo deste estudo foi descrever a prevalência da participação esportiva em crianças e adolescentes brasileiros por meio de uma revisão sistemática. Esta revisão segue os itens Preferred Reporting for Systematic reviews e Meta-Analysis (PRISMA) e o protocolo foi previamente cadastrado no PROSPERO (95441), as buscas foram realizadas nas seguintes bases de dados eletrônicas: PubMed, ScIELO, Bireme e EMBASE . A estratégia de busca incluiu uma combinação de palavras-chave: crianças e adolescentes, prevalência e participação esportiva. Quatro artigos incluíram 7104 adolescentes com idades entre 10 e 18 anos, residentes em quatro cidades diferentes localizadas no Sudeste (n = 1) e Sul (n = 3) do Brasil, foram realizadas coletas de dados entre 2004 e 2012. As maiorias dos estudos tiveram desenho transversal e os achados de todas as pesquisas foram publicados em revistas internacionais. A definição de "participação esportiva" não foi a mesma em todos os artigos. A prevalência geral de participação esportiva entre adolescentes foi de 58,1%, maior entre os meninos (65,9%) do que nas meninas (51,5%). A revisão sistemática identificou que a prevalência de participação esportiva entre adolescentes brasileiros é baixa e significativamente afetada por gênero.

Track and Field Practice and Bone Outcomes among Adolescents: A Pilot Study (ABCD-Growth Study).

BACKGROUND: Osteoporosis is considered a public health problem with high worldwide prevalence. One approach to prevention is through the promotion of physical activity, especially exercise, during adolescence. METHODS: This study compared bone variables in different body segments in adolescents according to participation in track and field. The study included 34 adolescents (22 boys), of whom 17 were track and field athletes and 17 were control subjects. Bone mineral density (BMD, g/cm2) and bone mineral content (BMC, g) were analyzed using dual energy X-ray absorptiometry (total body stratified by body segments). Peak height velocity was used to estimate somatic maturation. RESULTS: Athletes had higher BMD (P=0.003) and BMC (P=0.011) values in the lower limbs and higher whole body BMD (P=0.025) than the control group. However, when adjusted for confounding factors, the difference was not maintained. The groups had similar lean soft tissue values (P=0.094). Training overload was positively correlated with BMD in the upper limbs (r=0.504; 95% confidence interval, 0.031-0.793). Although track and field athletes had higher BMD and BMC values in the lower limbs, these differences were not significant when adjusted for confounding factors. CONCLUSIONS: Track and field participation in adolescence appears to influence BMD and BMC in lower limbs, and fat-free mass seems to mediate this effect. Also, higher training loads were found to be positive for bone health in upper limbs.

The Impact of Training Load on Bone Mineral Density of Adolescent Swimmers: A Structural Equation Modeling Approach.

PURPOSE: To investigate the mediating effect of muscle mass on the relationship between training load and bone density in adolescent swimmers. METHODS: A cross-sectional study involving 87 control and 22 swimmers aged 10-19 years (overall sample: n = 109). Swimmers had a minimum of 1 year of competition in regional and national championships, and control adolescents reported 1 year without any organized sport. Bone density was the main outcome (dual-energy X-ray absorptiometry), which was measured in upper limbs, lower limbs, spine, and whole body. Monthly training load was the independent variable, while the mediation effect of lean soft tissue was assessed. Maturity offset, age, inflammation, and vitamin D intake were treated as covariates. RESULTS: Swimmers had lower bone density than controls; there was a significant and positive relationship between training load and muscle mass. In boys, training load presented a negative correlation with bone density in lower limbs [r = -.293; 95% confidence interval (CI), -.553 to -.034]. In girls, training load was negatively related to bone mineral density in lower limbs (r = .563; 95% CI, -.770 to -.356) and whole body (r = -.409; 95% CI, -.609 to -.209). CONCLUSION: Training load had a negative relationship on bone density of swimmers of both sexes, independently of the positive effect of lean soft tissue on bone density.

Relationship between carotid intima-media thickness, physical activity, sleep quality, metabolic/inflamatory profile, body fatness, smoking and alcohol consumption in young adults

AIM: The aim of this longitudinal study was to analyze the relationship between sleep disorder and intima-media thickness. METHOD: Baseline measurements included carotid intima-media thickness, assessed by an ultrasound device; questionnaires about sleep and other behavioral variables; physical activity was measured by pedometer; body fatness was estimated by Dual-Energy X-ray Absorptiometry; fasting glucose, lipid profile and C-reactive protein were collected. RESULTS: The occurrence rate of sleep-related disorders was 47% (95%CI= 37.2%-56.7%). Carotid intima-media thickness was related to symptoms of insomnia (r= 0.328 [0.141 to 0.493]) and, after adjustments for potential confounders, the relationship between carotid intima-media thickness and insomnia remained statistically significant (ß #946;= 0.121 [95%CI= 0.017; 0.225]). CONCLUSIONS: In young adults, sleep disorder was significantly related to premature increase in carotid intima-media thickness.(AU)

Can participation in sports during childhood influence physical activity in adulthood?

Abstract Aims: The promotion of sports participation during the early years of life is important not only because it promotes health during childhood and adolescence, but also because it has benefits in adulthood. This study was developed to identify the association between sports participation during the early years of life and adulthood, to analyze the non-participation in sports throughout life and to identify the correlates of non-participation in sports. DESIGN: Cross-sectional study. Methods: The sample was composed of 743 adults randomly selected in a medium-size Brazilian city. Non-participation in sports during childhood and adolescence was assessed through specific questions, and non-participation in sports in adulthood was assessed using the second section of Baecke questionnaire. Answering "no" in the three periods assessed (childhood, adolescence and adulthood) was characterized as non-participation in sports throughout life. Chronological age, sex, formal education, BMI, current job and ethnicity were considered covariates. Categorical data were expressed as rates and compared using chi-square test and binary logistic regression. Results: The prevalence of adults not engaged in sports throughout life was 58.5% (95% CI= 55.1 - 62.1). Females (OR = 2.41 [1.71 - 3.38]), those more advanced in age (OR = 3.29 [1.82-5.94]) and/or possessing a lower level of education (OR = 4.47 [2.45 - 8.17]) were associated with the non-engagement in sports. Conclusion: Non-participation in sports during childhood can influence non-participation in sports during adulthood, which is significantly affected by sex, age and education level.

Prolonged Practice of Swimming Is Negatively Related to Bone Mineral Density Gains in Adolescents.

BACKGROUND: The practice of swimming in "hypogravity" conditions has potential to decrease bone formation because it decreases the time engaged in weight-bearing activities usually observed in the daily activities of adolescents. Therefore, adolescents competing in national levels would be more exposed to these deleterious effects, because they are engaged in long routines of training during most part of the year. To analyze the effect of swimming on bone mineral density (BMD) gain among adolescents engaged in national level competitions during a 9-month period. METHODS: Fifty-five adolescents; the control group contained 29 adolescents and the swimming group was composed of 26 athletes. During the cohort study, BMD, body fat (BF) and fat free mass (FFM) were assessed using a dual-energy x-ray absorptiometry scanner. Body weight was measured with an electronic scale, and height was assessed using a stadiometer. RESULTS: During the follow-up, swimmers presented higher gains in FFM (Control 2.35 kg vs. Swimming 5.14 kg; large effect size [eta-squared (ES-r)=0.168]) and BMD-Spine (Swimming 0.087 g/cm(2) vs. Control 0.049 g/cm(2); large effect size [ES-r=0.167]) compared to control group. Male swimmers gained more FFM (Male 10.63% vs. Female 3.39%) and BMD-Spine (Male 8.47% vs. Female 4.32%) than females. Longer participation in swimming negatively affected gains in upper limbs among males (r=-0.438 [-0.693 to -0.085]), and in spine among females (r=-0.651 [-0.908 to -0.036]). CONCLUSIONS: Over a 9-month follow-up, BMD and FFM gains were more evident in male swimmers, while longer engagement in swimming negatively affected BMD gains, independently of sex.