Lipid levels in a cohort of healthy Danish schoolchildren ages 5 to 17 years.

It is internationally recognized to use clinical decision limits (CDL) when interpreting the lipid levels in both adults and children, even though the evidence for children is scarce. The purpose of this study is to describe how lipid levels progress in healthy Danish children ages 5 to 17 years. This study is based on the Childhood Health, Activity, and Motor Performance School Study Denmark (CHAMPS-study DK) consisting of 1456 observations of schoolchildren aged 5 to 17 years. Participants have been tested for blood levels of total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, and remnant cholesterol levels are calculated. Finally, sex-specific percentile reference curves are presented. Percentile reference curves stratified by sex were generated for all cholesterols and showed that the total cholesterol level peaks at 4.32 mmol/l in 10-year-old boys and 4.46 mmol/l in nine-year-old girls. HDL levels in boys peak at 1.72 mmol/l in nine-year-old boys. HDL levels in girls and LDL levels in both sexes are nearly constant. Triglycerides kept rising to the age of 17 years in both sexes and remnant cholesterol decreased from age 5 to 17 years in both sexes. BMI z-score adjustment revealed no significant association with total cholesterol in both sexes but a significant association between HDL, LDL, triglycerides, and remnant cholesterol. This study is the first to generate percentile reference curves for blood levels of total cholesterol, LDL, HDL, triglycerides, and remnant cholesterol in a cohort of healthy Danish children aged 5 to 17 years.

Recreational screen time trajectories during early childhood and imaging-measured body composition at age 7 in the Odense child cohort.

BACKGROUND: Children spend increasing amounts of time on recreational screen media, which may lead to an obesogenic environment. OBJECTIVES: We investigated the association of trajectories of screen time across ages 3, 5 and 7 years with body composition at age 7 in the Odense Child Cohort. METHODS: Data were collected in the Municipality of Odense, Denmark, between 2010 and 2019. Group-based trajectory modelling was applied to group participants into four trajectories of prospective parent-reported screen time. Body composition was assessed using dual-energy x-ray absorptiometry with calculated fat-mass index (FMI) as the primary outcome. Primary models were linear multivariable regression models adjusted for participants' sex, age, birthweight, maternal origin, maternal education, maternal body-mass-index, and maternal age. Further models were adjusted for additional possible confounders. Selection bias was addressed by inverse probability weighting. RESULTS: In total, 803 children (48.2% female) were included in the primary analysis. Participants with screen time at all time points were assigned to four trajectory groups [constant low screen time (12.7%), low increase (36.3%), high increase between ages 3 and 5 (33.5%) and high increase in screen time (17.5%)]. Sample characteristics differed across missing data status and trajectories. Mean FMI (kg/m2 ) and standard deviation (SD) were 3.7 (SD 1.3) and 3.9 (SD 1.6) for the constant low versus high screen time, respectively. No differences in FMI were found between screen time trajectory groups at age 7 (adjusted mean difference 0.1 kg/m2 , 95% confidence interval -0.3, 0.5 for constant low versus high screen time). No consistent associations between screen time groups and secondary body composition outcomes were found. CONCLUSIONS: Results from this study do not suggest that recreational screen time from age 3 to 7 years is associated with adiposity or other measures of body composition.

Predicting Injury Risk Over Changes in Physical Activity in Children Using the Acute:Chronic Workload Ratio.

Limited research exists on the relationship between changes in physical activity levels and injury in children. In this study, we investigated the prognostic relationship between changes in activity, measured by the acute:chronic workload ratio (ACWR), and injury in children. We used data from the Childhood Health, Activity, and Motor Performance School Study Denmark (2008-2014), a prospective cohort study of 1,660 children aged 6-17 years. We modeled the relationship between the uncoupled 5-week ACWR and injury, defined as patient-reported musculoskeletal pain, using generalized additive mixed models. These methods accounted for repeated measures, and they improved model fit and precision compared with previous studies that used logistic models. The prognostic model predicted an injury risk of approximately 3% between decreases in activity level of up to 60% and increases of up to 30%. Predicted risk was lower when activity decreased by more than 60% (minimum of 0.5% with no recreational activity). Predicted risk was higher when activity increased by more than 30% (4.5% with a 3-fold increase in activity). Girls were at significantly higher risk of injury than boys. We observed similar patterns but lower absolute risks when we restricted the outcome to clinician-diagnosed injury. Predicted increases in injury risk with increasing activity were much lower than those of previous studies carried out in adults.

The metabolic syndrome is frequent in children and adolescents with type 1 diabetes compared to healthy controls.

OBJECTIVE: There is a rise in overweight and obesity among children and adolescents with type 1 diabetes (T1D) in parallel with the rise in the metabolic syndrome (MetS) among children and adolescents. The aim of the study was to describe the prevalence and characteristics of MetS in children and adolescents with T1D compared to their healthy counterparts. RESEARCH DESIGN AND METHODS: The study includes two Danish cohorts; (i) the Copenhagen cross sectional cohort 2016 of 277 children and adolescents with T1D that attend the pediatric outpatient clinic at a large hospital in greater Copenhagen and (ii) the CHAMPS-study DK which is a population-based cohort study of Danish children and adolescents (control cohort). Participants were categorized to have MetS if at least two of the following criteria were met: (i) systolic and/or diastolic blood pressure ≥ 90th percentile, (ii) waist circumference ≥90th percentile, and (iii) triglyceride ≥90th percentile and/or HDL ≤10th percentile. RESULTS: The prevalence of children with Mets in the T1D cohort was higher than in the control cohort (p = 0.002). Moreover, participants with T1D had MetS at a lower level of BMI (p < 0.001) and waist circumference (p < 0.001) than participants with MetS from the control cohort (z-scores = 0.90 and 1.51). Participants with MetS were younger than the other T1D participants (median 12.8 [9.9,14.8] vs. median 14.6 [11.2,16.9] years, p = 0.006). CONCLUSIONS: Children and adolescents with T1D have an increased risk of MetS compared to healthy controls and clinicians and caretakers should consider early prevention and health promotion strategies.

Spinal pain in childhood: prevalence, trajectories, and diagnoses in children 6 to 17 years of age.

This study aimed to investigate the trajectories of spinal pain frequency from 6 to 17 years of age and describe the prevalence and frequency of spinal pain and related diagnoses in children following different pain trajectories. First through fifth-grade students from 13 primary schools were followed for 5.5 years. Occurrences of spinal pain were reported weekly via text messages. Children reporting spinal pain were physically evaluated and classified using International Classification of Disease criteria. Trajectories of spinal pain frequency were modeled from age 6 to 17 years with latent class growth analysis. We included data from 1556 children (52.4% female, mean (SD) baseline age = 9.1 (1.9) years) and identified 10,554 weeks of spinal pain in 329,756 weeks of observation. Sixty-three percent of children reported one or more occurrences of spinal pain. We identified five trajectories of spinal pain frequency. Half the children (49.8%) were classified as members of a "no pain" trajectory. The remaining children followed "rare" (27.9%), "rare, increasing" (14.5%), "moderate, increasing" (6.5%), or "early-onset, decreasing" (1.3%) spinal pain trajectories. The most common diagnoses in all trajectory groups were non-specific (e.g., "back pain"). Tissue-specific diagnoses (e.g., muscle strain) were less common and pathologies (e.g., fracture) were rare.  Conclusion: From childhood through adolescence, spinal pain was common and followed heterogeneous courses comprising stable, increasing, and early-onset trajectories. These findings accord with recommendations from adult back pain guidelines that most children with spinal pain can be reassured that they do not have a serious disease and encouraged to stay active. What is Known: • Spinal pain imposes a large burden on individuals and society. • Although many people first experience the condition in childhood, little is known about the developmental trajectories of spinal pain from childhood to adolescence. What is New: • Data from 1556 children and 329,756 participant weeks showed five unique spinal pain trajectories from 6 to 17 years: most children rarely reported spinal pain, while one in five followed increasing or early-onset trajectories. • Most pain occurrences were non-specific; pathological diagnoses were rare.

Reference serum percentile values of adiponectin, leptin, and adiponectin/leptin ratio in healthy Danish children and adolescents.

The adipokines adiponectin and leptin play key roles in human metabolic regulation and have gained great attention as biomarkers for various metabolic pathologies. Though, pediatric reference values are few and needed. This study aims to establish age- and sex-specific adipokine reference percentiles based on healthy Danish school children. Further, it elucidates sex-specific differences in associations between z-scores of examined adipokines and metabolic variables. Serum adiponectin and serum leptin from 853 observations of healthy Danish schoolchildren aged 8-17 years (median 10.0) were quantified by immunoassays. Age- and sex-specific adipokine reference percentiles were calculated cross-sectionally using the LMS method, and adipokine z-scores were calculated from the fitted model. Multiple linear regression models were used to examine sex-specific differences in associations between adipokine z-scores and various metabolic variables. Girls had a higher median value of adiponectin (11.31 vs. 10.65 µg/mL, p < .001) and leptin (2.30 vs. 1.00 ng/mL, p < .001) and a lower median value of adiponectin/leptin ratio (4.64 vs. 10.76, p < .001) compared to boys. Sex-specific differences were found in associations between adiponectin z-score and HDL (p = .010), between leptin z-score and waist circumference z-score (p = .027) and LDL (p = .048), and between adiponectin/leptin ratio z-scores and waist circumference z-score (p = .044) and LDL (p = .040). Reference percentiles of adiponectin, leptin, and adiponectin/leptin ratio are presented in this paper. To our knowledge, this study is the first to demonstrate sex-specific differences in associations between adipokine z-scores and waist circumference z-score and lipids, respectively in healthy children and adolescents.

Association of change in the school travel mode with changes in different physical activity intensities and sedentary time: A International Children's Accelerometry Database Study.

Our aim was to assess the association between changes in active travel to school and changes in different intensities of physical activity (i.e. moderate - MPA and vigorous - VPA) and time spent sedentary (SED) among adolescents and assess the moderating effect of children's sex, age and weight status. Data from six cohort studies in the International Children's Accelerometry Database were used (4108 adolescents aged 10-13y at baseline, with 1.9±0.7y of follow-up). Participants self-reported travel mode to school at baseline and follow-up. Mutually exclusive categories of change were created using passive (e.g. by car) or active (cycling or walking) forms of transport (active/active, passive/active, active/passive, passive/passive). Multilevel linear regression analyses assessed associations with change in accelerometer-assessed time spent MPA, VPA and SED, adjusting for potential confounders. The moderation of sex, age and weight status was tested though the inclusion of interaction terms in the regression models. Relative to those remaining in active travel (active/active), participants classified as passive/active increased VPA (B: 2.23 min/d; 95%CI: 0.97-3.48), while active/passive (MPA: -5.38min/d; -6.77 to -3.98; VPA: -2.92min/d; -4.06 to -1.78) and passive/passive (MPA: -4.53min/d; -5.55 to -3.50; VPA: -2.84min/d; -3.68 to -2.01) decreased MPA and VPA. There were no associations with SED. An interaction was observed, age group moderated the association with change in VPA: among 12-13y-olds a greater increase in VPA was observed for the passive/active group compared to active/active. Promoting active travel to school can be a strategy to attenuate the decline in physical activity through adolescence.

Effectiveness of Conservative Nonpharmacologic Therapies for Pain, Disability, Physical Capacity, and Physical Activity Behavior in Patients With Degenerative Lumbar Spinal Stenosis: A Systematic Review and Meta-Analysis.

OBJECTIVE: To investigate the effectiveness of conservative nonpharmacologic therapies on pain, disability, physical capacity, and physical activity outcomes in patients with degenerative lumbar spinal stenosis (LSS). DATA SOURCES: Systematic search of MEDLINE, EMBASE, CENTRAL, and PsycINFO from inception to November 4, 2019, without language restrictions. STUDY SELECTION: Pairs of review authors independently identified randomized controlled trials published in peer-reviewed scientific journals reporting on the effects of rehabilitation interventions on pain intensity (back or leg), disability, symptom severity, physical capacity, physical activity behavior, or adverse events (secondary outcome) in adults with LSS. The search identified 1718 records; data from 21 reports of 19 trials (1432 patients) were included. DATA EXTRACTION: Review author pairs independently extracted data and assessed included studies. We assessed risk of bias with the Cochrane tool, and overall study quality with the Grading of Recommendations Assessment, Development and Evaluation classification. DATA SYNTHESIS: We pooled data using random-effects meta-analyses; treatment effects were reported as mean differences (MD) and 95% confidence intervals (CI). Directed exercise and manual therapy was superior to self-directed or group exercise for improving short-term walking capacity (MD, 293.3 m; 95% CI, 61.7-524.9 m; low-quality evidence), back pain (MD, -1.1; 95% CI, -1.8 to -0.4; moderate quality evidence), leg pain (MD, -.9; 95% CI, -0.2 to -1.5; moderate-quality evidence), and symptom severity (MD, -0.3; 95% CI, -0.4 to -0.2; low quality evidence). There is very low quality evidence that rehabilitation is no better than surgery at improving intermediate- or long-term disability. Single trials provided conflicting evidence of effectiveness for a variety of therapies. CONCLUSIONS: For patients with LSS, there is low- to moderate-quality evidence that manual therapy with supervised exercises improves short-term walking capacity and results in small improvements in pain and symptom severity compared with self-directed or group exercise. The choice between rehabilitation and surgery for LSS is very uncertain owing to the very low quality of available evidence.

Cryoneurolysis for the management of chronic pain in patients with knee osteoarthritis; a double-blinded randomized controlled sham trial.

OBJECTIVE: Pain is the principal symptom in knee osteoarthritis (OA). Current non-operative treatment options have only moderate effects and often patients experience persistent pain or side-effects. Novel advances in the field of cryoneurolysis applies low temperatures to disrupt nerve signaling at the painful area, providing pain relief. The primary aim of this randomized controlled trial (RCT) is to investigate if cryoneurolysis is superior to sham at decreasing pain intensity 2 weeks after the intervention in patients with knee OA. Secondary aims are to explore effects on pain, quality of life and functional performance over 24 months. METHODS: This two-arm, parallel-group RCT, approved by the Regional Ethics Committee, will randomly allocate patients (n = 94) to a cryoneurolysis intervention group + standardized education and exercise (CRYO) or a sham group + standardized education and exercise (SHAM) (1:1 ratio). Both groups will be assessed at baseline, 2 weeks post intervention, post education and exercise and at 6, 12 and 24 months after cryoneurolysis. The primary outcome is the NRS knee pain intensity score assessed 2 weeks post the intervention. Secondary outcome measures include functional performance (chair-stand test, 40 m walk, stair test and maximum voluntary contraction of the knee), patient reported outcomes (quality of life (EQ5D), Knee and osteoarthritis outcome scores (KOOS), among others), use of analgesics, and adverse events over 24 months. IMPACT STATEMENT: Cryoneurolysis could potentially provide an effective, safe and non-pharmacological therapeutic option to treat pain in OA patients. The potential benefits include increased functional capacity and quality of life as a result of significant pain relief and improved benefits of physical exercise. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03774121 , registered 3 March 2018, http://www.clinicaltrials.gov.

School-based interventions modestly increase physical activity and cardiorespiratory fitness but are least effective for youth who need them most: an individual participant pooled analysis of 20 controlled trials.

OBJECTIVES: To determine if subpopulations of students benefit equally from school-based physical activity interventions in terms of cardiorespiratory fitness and physical activity. To examine if physical activity intensity mediates improvements in cardiorespiratory fitness. DESIGN: Pooled analysis of individual participant data from controlled trials that assessed the impact of school-based physical activity interventions on cardiorespiratory fitness and device-measured physical activity. PARTICIPANTS: Data for 6621 children and adolescents aged 4-18 years from 20 trials were included. MAIN OUTCOME MEASURES: Peak oxygen consumption (VO2Peak mL/kg/min) and minutes of moderate and vigorous physical activity. RESULTS: Interventions modestly improved students' cardiorespiratory fitness by 0.47 mL/kg/min (95% CI 0.33 to 0.61), but the effects were not distributed equally across subpopulations. Girls and older students benefited less than boys and younger students, respectively. Students with lower levels of initial fitness, and those with higher levels of baseline physical activity benefitted more than those who were initially fitter and less active, respectively. Interventions had a modest positive effect on physical activity with approximately one additional minute per day of both moderate and vigorous physical activity. Changes in vigorous, but not moderate intensity, physical activity explained a small amount (~5%) of the intervention effect on cardiorespiratory fitness. CONCLUSIONS: Future interventions should include targeted strategies to address the needs of girls and older students. Interventions may also be improved by promoting more vigorous intensity physical activity. Interventions could mitigate declining youth cardiorespiratory fitness, increase physical activity and promote cardiovascular health if they can be delivered equitably and their effects sustained at the population level.

Changes in Physical Activity and Sedentary Patterns on Cardiometabolic Outcomes in the Transition to Adolescence: International Children's Accelerometry Database 2.0.

OBJECTIVE: To examine the associations of changes in physical activity and sedentary patterns with changes in cardiometabolic outcomes from childhood to adolescence. STUDY DESIGN: Youth from the International Children's Accelerometry Database (n = 1088; 55% girls), aged 8-13 years and followed for ∼4 years, were used in this analysis. Hip-mounted accelerometers were used and all physical activity intensities were expressed as the % of total wear-time. Sedentary time was separated into time spent in bouts <10 minutes and ≥10 minutes. A composite z score for cardiometabolic risk (CMR score) was computed by summing the standardized values for systolic and diastolic blood pressure, triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), and the inverse high-density lipoprotein cholesterol. Multivariate analyses were performed using adjusted linear regression models. RESULTS: Increase in sedentary time was unfavorably associated with changes in CMR score (ß = 0.021; CI 0.004-0.037), TG (ß = 0.003; CI 0.001-0.005), and diastolic blood pressure (ß = 0.068; CI 0.009-0.128). Decrease in moderate-to-vigorous physical activity was unfavorably associated with changes in LDL-c (ß = -0.009; CI -0.017 to -0.001) and TG (ß = -0.007; CI -0.013 to -0.001). Increase in ≥10 minutes sedentary time was unfavorably associated with changes in CMR score (ß = 0.017; CI 0.004-0.030), LDL-c (ß = 0.003; CI 0.000-0.005), and TG (ß = 0.003; CI 0.000-0.004). Decrease in light-intensity physical activity was unfavorably associated with changes in CMR score (ß = -0.020; CI = -0.040 to 0.000). CONCLUSIONS: More physical activity and less prolonged sedentary time are beneficial for cardiometabolic health in youth transitioning to adolescence.

Variations in accelerometry measured physical activity and sedentary time across Europe - harmonized analyses of 47,497 children and adolescents.

BACKGROUND: Levels of physical activity and variation in physical activity and sedentary time by place and person in European children and adolescents are largely unknown. The objective of the study was to assess the variations in objectively measured physical activity and sedentary time in children and adolescents across Europe. METHODS: Six databases were systematically searched to identify pan-European and national data sets on physical activity and sedentary time assessed by the same accelerometer in children (2 to 9.9 years) and adolescents (≥10 to 18 years). We harmonized individual-level data by reprocessing hip-worn raw accelerometer data files from 30 different studies conducted between 1997 and 2014, representing 47,497 individuals (2-18 years) from 18 different European countries. RESULTS: Overall, a maximum of 29% (95% CI: 25, 33) of children and 29% (95% CI: 25, 32) of adolescents were categorized as sufficiently physically active. We observed substantial country- and region-specific differences in physical activity and sedentary time, with lower physical activity levels and prevalence estimates in Southern European countries. Boys were more active and less sedentary in all age-categories. The onset of age-related lowering or leveling-off of physical activity and increase in sedentary time seems to become apparent at around 6 to 7 years of age. CONCLUSIONS: Two third of European children and adolescents are not sufficiently active. Our findings suggest substantial gender-, country- and region-specific differences in physical activity. These results should encourage policymakers, governments, and local and national stakeholders to take action to facilitate an increase in the physical activity levels of young people across Europe.

The multivariate physical activity signature associated with metabolic health in children and youth: An International Children's Accelerometry Database (ICAD) analysis.

There is solid evidence for an association between physical activity and metabolic health outcomes in children and youth, but for methodological reasons most studies describe the intensity spectrum using only a few summary measures. We aimed to determine the multivariate physical activity intensity signature associated with metabolic health in a large and diverse sample of children and youth, by investigating the association pattern for the entire physical intensity spectrum. We used pooled data from 11 studies and 11,853 participants aged 5.8-18.4 years included in the International Children's Accelerometry Database. We derived 14 accelerometry-derived (ActiGraph) physical activity variables covering the intensity spectrum (from 0-99 to ≥8000 counts per minute). To handle the multicollinearity among these variables, we used multivariate pattern analysis to establish the associations with indices of metabolic health (abdominal fatness, insulin sensitivity, lipid metabolism, blood pressure). A composite metabolic health score was used as the main outcome variable. Associations with the composite metabolic health score were weak for sedentary time and light physical activity, but gradually strengthened with increasing time spent in moderate and vigorous intensities (up to 4000-5000 counts per minute). Association patterns were fairly consistent across sex and age groups, but varied across different metabolic health outcomes. This novel analytic approach suggests that vigorous intensity, rather than less intense activities or sedentary behavior, are related to metabolic health in children and youth.

Weekly variation in markers of cardiometabolic health - the possible effect of weekend behavior - a cross-sectional study.

BACKGROUND: Adolescents' health-related behavior varies from weekday to weekend. Only few studies, however, have examined to which degree such variation will affect markers of cardiometabolic health. Therefore, the primary aim of this study is to examine if markers of cardiometabolic health differ between different days of the week in adolescents. METHODS: This cross-sectional school-based study included up to 581 participants, 11-17 years old. Markers of metabolic health were insulin, glucose, triglyceride, HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C) and blood pressure. Linear mixed regression modelling was used to examine the cardiometabolic profile across weekdays. RESULTS: Significant declining trends were observed across the week in adolescents' levels of cardiometabolic health markers. Lower levels of insulin (16.1%), glucose (2.6%) and triglyceride (24.7%) were observed on Fridays compared to Mondays (p ≤ 0.006). Gradual improvement in measurement profiles across weekdays was less apparent for HDL-C, LDL-C, systolic blood pressure and diastolic blood pressure (P ≥ 0.06). Analyses stratified by sex suggested a more noticeable pattern of gradual improvement across weekdays in boys than in girls. CONCLUSION: Significantly lower levels of insulin, glucose and triglyceride were observed in adolescents on Fridays compared to Mondays. However, when sex specific analyses were performed significant profile variations were only observed across the week in boys. More research is needed to better understand which behavioral factors in particular seem to influence weekly variation in markers of cardiometabolic health - especially since such variation potentially will have an impact on how assessments of markers of cardiometabolic health optimally should be planned, standardized and carried out, both in research and in medical practice.

A Cross-Sectional Study of the Prevalence and Factors Associated With Tinnitus and/or Hyperacusis in Children.

OBJECTIVES: The aim of this study was to determine the prevalence of tinnitus and/or hyperacusis in Danish children aged 10 to 16 years, and to assess associations between tinnitus or hyperacusis and other relevant factors. DESIGN: A cross-sectional study based on a previously established child cohort. A total of 501 children were enrolled in the project. The study was performed in eight mainstream schools and data were collected during an 8-week period from October 27, 2014 to December 16, 2014. RESULTS: Using broad tinnitus research questions, the prevalence of any tinnitus was 66.9%; of noise-induced tinnitus (NIT) was 35.7%; and of spontaneous tinnitus (ST) was 53.7%. Bothersome tinnitus was reported by 34.6% of the children with any tinnitus, 23.2% of the whole population. Few children were severely bothered (2.4%, 1.6%, respectively). It was significantly more common for children with NIT to report tinnitus episodes lasting for minutes or longer than for children with ST (p = 0.01). Girls were more likely than boys to be bothered by tinnitus [Odds ratio (OR) = 2.96; 95% confidence interval (CI) 1.34 to 6.51; p = 0.01]. 14.6% of the children reported hyperacusis, and 72.6% of those reporting hyperacusis were bothered by it, 10.6% of the whole population. The odds of having hyperacusis were 4.73 (1.57, 14.21) times higher among those with ST compared with those without ST. Furthermore, hyperacusis was associated with sound avoidance behaviors such as experience of sound-induced pain in the ear (OR = 2.95, 95% CI 1.65 to 5.27; p < 0.001), withdrawal from places or activities (OR = 3.33; 95% CI 1.44 to 7.69; p = 0.01), or concerns about sound could damage the hearing (OR = 1.85, 95% CI 1.06 to 3.31; p = 0.03). CONCLUSIONS: Tinnitus and hyperacusis are common in children but prevalence is dependent on tinnitus definitions. Only a few children are severely bothered by tinnitus. In the case of hyperacusis, children may exhibit sound avoidance behavior.

Exposure to perfluoroalkylated substances (PFAS) in relation to fitness, physical activity, and adipokine levels in childhood: The european youth heart study.

BACKGROUND: perfluoroalkylated substances (PFAS) are highly persistent chemicals that are able to alter the human metabolism - potentially via disruption of cell signaling pathways mediated by adipokines. Both adiponectin and leptin are influenced by and exert influence on energy storage and energy expenditure, wherefore associations between PFAS and adipokines may be mediated by fitness and fat mass. OBJECTIVES: the aim of this cross-sectional study was to investigate the association between childhood exposure to PFAS and adipokines (adiponectin and leptin), while considering associations between PFAS and children's level of fitness, physical activity and fat mass to elucidate potential mediation by fitness, physical activity and fat mass. METHODS: 9-year old children from Danish public schools were recruited in the European Youth Heart Study in 1997. For this study only children with valid measures on PFAS (PFOS, PFOA, PFNA, PFDA and PFHxS), adipokines (adiponectin and leptin), fitness, fat mass and co-variates (parity and maternal income) were included (N = 242). Multiple linear regression models with and without conditioning and causal mediation analysis were applied. RESULTS: this study found inverse associations between PFOA, PFDA and PFHxS and leptin. PFOA was positively associated with adiponectin, whereas PFHxS was inversely associated with adiponectin in boys. Latter association seemed to be mediated by fat mass. Associations with leptin showed indirect effects of fitness and fat mass but were unable to demonstrate significant mediation. Neither PFOS nor PFNA were associated with the outcome. DISCUSSION: these results may indicate a favorable leptin profile with increasing PFAS, although the results could be driven by residual negative confounding from socio-economic factors and mediation by fitness and fat mass.

Three times as much physical education reduced the risk of children being overweight or obese after 5 years.

AIM: We evaluated the effect that increasing physical education lessons from 1.5 to 4.5 hours per week for 5 years had on the body mass index (BMI) and waist circumferences of children aged 5-11 years at inclusion. METHODS: From 2008 to 2013, six intervention schools in Svendborg, Denmark, delivered 4.5 hours of physical education lessons per week to 750 children. Meanwhile, four matched control schools gave 549 children the standard 1.5 hours of physical education lessons per week. Measurements were taken at baseline and yearly for 5 years. Of the 1299 children, 81 joined the schools after 2008. RESULTS: At baseline, the percentage of overweight children was 12% in the intervention schools and 13% in the control schools, whereas 15% and 19% were abdominal obese, respectively. After 5 years, the respective risks of remaining abdominal obese or overweight were 43% and 51% in the intervention schools and 78% and 84% in the control schools. Mean BMI increased 0.450 kg/m2 more in the control group over the five-year period. The intervention was not effective in decreasing the average waist circumference. CONCLUSION: Three times as much physical education lessons per week, for 5 years, effectively decreased BMI and the likelihood of remaining overweight or obese.

Statement on methods in sport injury research from the 1st METHODS MATTER Meeting, Copenhagen, 2019.

High quality sports injury research can facilitate sports injury prevention and treatment. There is scope to improve how our field applies best practice methods-methods matter (greatly!). The 1st METHODS MATTER Meeting, held in January 2019 in Copenhagen, Denmark, was the forum for an international group of researchers with expertise in research methods to discuss sports injury methods. We discussed important epidemiological and statistical topics within the field of sports injury research. With this opinion document, we provide the main take-home messages that emerged from the meeting.

Physical education and leisure-time sport reduce overweight and obesity: a number needed to treat analysis.

BACKGROUND: School-based physical education (PE) and organised leisure-time sports participation (LTSP) represent important physical activity opportunities for children. We examined the preventive effect of increased PE as well as LTSP on overweight and obesity (OW/OB) in school children. METHODS: Longitudinal data from children attending 10 primary schools in the Danish municipality of Svendborg, comprising 6 intensive PE (270 min/week) and 4 control (90 min/week) schools were assessed. Age- and sex-specific cut-offs for body mass index (BMI) determined OW/OB status. Associations between OW/OB status and school type (intensive PE or control) or LTSP were investigated using mixed, multilevel logistic regression models. Significant parameter estimates were converted into number needed to treat statistics (NNT). RESULTS: In total, 1009 children (53.3% female; mean age 8.4 ± 1.4 years) were included in the analysis, with 892 children (52% female) being normal weight (NW) at baseline. Eighteen (NNT = 17.1; 95% CI [11.0, 226.1]) children attending an intensive PE school for 2 years, resulted in one fewer case of OW/OB compared with attendance at a normal PE school. For NW children, prevention of one case of OW/OB requires 36 (NNT = 35.8; 95% CI [25.1, 596.3]) children to participate in intensive PE for 2 years in comparison with normal PE. LTSP over 2 years may prevent OW/OB if 15 children participate in one LTSP session/week, 9 in two LTSP sessions/week and 8 in three LTSP sessions/week; for normal weight children, 25 children had to participate in one LTSP session/week, 16 in two LTSP sessions/week and 14 in three LTSP sessions/week. CONCLUSION: We provide the first NNT estimates of school-based PE and LTSP to prevent the onset of OW/OB. PE, and separately, LTSP seem to have both a protective and a treatment effect against OW/OB in children.

Correction to: Physical activity intensity, bout-duration, and cardiometabolic risk markers in children and adolescents.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.