The risk of an incident hospital contact with a musculoskeletal disorder in Danish occupational fishers: a register-based study.

BACKGROUND: The prevalence of musculoskeletal disorders (MSDs) among occupational fishers is high, yet knowledge of the risk factors is scarce and inconsistent. The aim of this study was to investigate the risk from various work-related characteristics on incident hospital contact due to a musculoskeletal disorders and other pain disorders among Danish occupational fishers. METHODS: This register-based study comprised data from the Danish Occupational Cohort with eXposure (DOC*X) for all persons registered as occupational fishers between 1994 and 2017. Time-to-event analysis with Cox regression model was used with age as the time scale. RESULTS: Among the 15,739 fishers, 40% (n = 5,669 cases) had an incident hospital contact with an MSD during follow-up. Back disorders were the dominant complaint. Male fishers working less than 5 years or more than 15 years had higher risks of MSD (HR 2.40 (95% CI: 2.06, 2.80), HR: 2.04 (95% CI: 1.76, 2.35), respectively, than those working for over 20 years. Period effects confounded and reduced the risk from occupational seniority. CONCLUSION: Fishers occupational seniority vary in risk of MSDs across working life. Results showed a nonlinear relationship between the highest risk for fishers working less than 5 years and the lowest risk working more than 20 years as occupational fisher. More years in the workforce, a captain education, and primarily working part time significantly reduced the risk of experiencing a first MSDs for men. Healthy worker effect was documented.

Same, Same but Different: Comparing Program Fidelity at Early Versus Late Adopters of a Successful Long-Term School-Based Physical Activity Intervention.

Schools have been identified as a promising setting for promoting physical activity (PA). Yet, to realize changes at the population level, successful school-based PA programs need to go to scale. The Svendborgproject is an effective school-based program promoting additional physical education (PE) lessons. The aim of this study is to determine program fidelity across different school groups, representing early and late adopters of the Svendborgproject, and how these are adapting the intervention. Three different school groups were identified, covering the original intervention schools and two groups of late adopters consisting of four former control schools, and five normal schools without any previous connection to the program. A PE teacher questionnaire (n = 122) was used to determine school fidelity. The results show that, while the original intervention schools have implemented the program with the highest fidelity, all schools have implemented the program with medium to high fidelity. It is suggested that having front-runner schools achieving early success with the program both strengthens political project support and provides strategies to back late adopters' implementation of the program. Furthermore, results from the current study suggest that continual promotion of the program by school heads is less important if support is established at the structural and organizational macro level. Finally, we highlight the importance of scaling up organizational capacity when scaling up program reach to assure a workable balance between fidelity and improving the fit to specific contexts.

Recreational screen media use in Danish school-aged children and the role of parental education, family structures, and household screen media rules.

Screen media use is part of most children's everyday lives, but organisations have advised that use should be limited. The aims of this study were to describe 6-11-year-old Danish children's screen device ownership and screen media use (weekdays and weekends), including the role of parental education, family structure and household screen media rules. We conducted a cross-sectional study including 5274 Danish children aged 6-11-years sampled from ten Danish municipalities from May 2019 to November 2020. Characteristics of the sample and source population were obtained from the Danish Health Data Authority. Parent's completed the SCREENS questionnaire, which was developed to assess children's screen media habits. We used inverse probability weighted logistic and linear regression models. Smartphone and laptop ownership was higher with increasing age, and use of screen media varied across day type, age and gender. The proportion of children using screen media more than 4 h/day was 13% (95% CI 12%;14%) for weekdays and 28% (95% CI 27%;29%) for weekend days. Children of parents with medium-length or long educations had statistically significant lower odds of using screen media more than 4 h/day. We found a statistically significant graded relationship between household screen media rules and children's screen media use; the less parents reported presence of rules, the more time their children spent on screen media engagements. Our results suggest that parental educational level and family structure are related to unfavourable screen media habits, and household screen media rules may play an important role for parents to limit children's screen use.

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.

The development of a questionnaire to assess leisure time screen-based media use and its proximal correlates in children (SCREENS-Q).

BACKGROUND: The screen-media landscape has changed drastically during the last decade with wide-scale ownership and use of new portable touchscreen-based devices plausibly causing changes in the volume of screen media use and the way children and young people entertain themselves and communicate with friends and family members. This rapid development is not sufficiently mirrored in available tools for measuring children's screen media use. The aim of this study was to develop and evaluate a parent-reported standardized questionnaire to assess 6-10-year old children's multiple screen media use and habits, their screen media environment, and its plausible proximal correlates based on a suggested socio-ecological model. METHODS: An iterative process was conducted developing the SCREENS questionnaire. Informed by the literature, media experts and end-users, a conceptual framework was made to guide the development of the questionnaire. Parents and media experts evaluated face and content validity. Pilot and field testing in the target group was conducted to assess test-retest reliability using Kappa statistics and intraclass correlation coefficients (ICC). Construct validity of relevant items was assessed using pairwise non-parametric correlations (Spearman's). The SCREENS questionnaire is based on a multidimensional and formative model. RESULTS: The SCREENS questionnaire covers six domains validated to be important factors of screen media use in children and comprises 19 questions and 92 items. Test-retest reliability (n = 37 parents) for continuous variables was moderate to substantial with ICC's ranging from 0.67 to 0.90. For relevant nominal and ordinal data, kappa values were all above 0.50 with more than 80% of the values above 0.61 indicating good test-retest reliability. Internal consistency between two different time use variables (from n = 243) showed good correlations with rho ranging from 0.59 to 0.66. Response-time was within 15 min for all participants. CONCLUSIONS: SCREENS-Q is a comprehensive tool to assess children's screen media habits, the screen media environment and possible related correlates. It is a feasible questionnaire with multiple validated constructs and moderate to substantial test-retest reliability of all evaluated items. The SCREENS-Q is a promising tool to investigate children screen media use.

Short-term efficacy of reducing screen media use on physical activity, sleep, and physiological stress in families with children aged 4-14: study protocol for the SCREENS randomized controlled trial.

BACKGROUND: During the recent decade presence of digital media, especially handheld devices, in everyday life, has been increasing. Survey data suggests that children and adults spend much of their leisure on screen media, including use of social media and video services. Despite much public debate on possible harmful effects of such behavioral shifts, evidence from rigorously conducted randomized controlled trials in free-living settings, investigating the efficacy of reducing screen media use on physical activity, sleep, and physiological stress, is still lacking. Therefore, a family and home-based randomized controlled trial - the SCREENS trial - is being conducted. Here we describe in detail the rationale and protocol of this study. METHODS: The SCREENS pilot trial was conducted during the fall of 2018 and spring of 2019. Based on experiences from the pilot study, we developed a protocol for a parallel group randomized controlled trial. The trial is being conducted from May 2019 to ultimo 2020 in 95 families with children 4-14 years recruited from a population-based survey. As part of the intervention family members must handover most portable devices for a 2-week time frame, in exchange for classic mobile phones (not smartphones). Also, entertainment-based screen media use during leisure must be limited to no more than 3 hours/week/person. At baseline and follow-up, 7-day 24-h physical activity will be assessed using two triaxial accelerometers; one at the right hip and one the middle of the right thigh. Sleep duration will be assessed using a single channel EEG-based sleep monitor system. Also, to assess physiological stress (only assessed in adults), parameters of 24-h heart rate variability, the cortisol awakening response and diurnal cortisol slope will be quantified using data sampled over three consecutive days. During the study we will objectively monitor the families' screen media use via different software and hardware monitoring systems. DISCUSSION: Using a rigorous study design with state-of-the-art methodology to assess outcomes and intervention compliance, analyses of data from the SCREENS trial will help answer important causal questions of leisure screen media habits and its short-term influence on physical activity, sleep, and other health related outcomes among children and adults. TRIAL REGISTRATION: NCT04098913 at https://clinicaltrials.gov [20-09-2019, retrospectively registered].

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.

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.

Spinal pain is prospectively associated with cardiovascular risk factors in girls but not boys (CHAMPS study-DK).

PURPOSE: To examine the prospective associations between spinal pain exposures and risk factors for cardiovascular disease in children and explore the mediating role of health-related physical activity. METHODS: Students were recruited from ten public primary schools. Each week from November 2008 to October 2010, parents reported spinal pain occurrences in their children via text messaging. Clustered cardiovascular risk was estimated with a composite score comprising fasting serum triglycerides, homeostasis assessment model-estimated insulin resistance (HOMA-IR), total to high-density lipoprotein cholesterol ratio, and systolic blood pressure. Additional outcomes were fasting serum insulin and glucose concentrations and body mass index categories. Associations were explored with multilevel mixed regression models and reported with beta coefficients (ß) and percent difference scores. All models were adjusted for potential confounders. RESULTS: Data from 1022 children (53% female) with mean ± SD age of 8.4 ± 1.4 years were included. Girls with spinal pain had greater clustered cardiovascular risk (ß [95% CI]; percent difference [95% CI] = .41 [.02-.80]; 3.3% [.2-6.4%]) than those without spinal pain. Similar outcomes were observed for log insulin (percent difference [95% CI] = 3.4% [.6-6.2%]) and log HOMA-IR = (percent difference [95% CI] = 3.8% [.4-7.3%]). Remaining associations between spinal pain and cardiovascular risk in girls were nonsignificant. There were no associations between spinal pain and cardiovascular risk in boys. Moderate-to-vigorous-intensity physical activity did not appear to mediate this relationship. CONCLUSION: These findings suggest a potentially important link between spinal pain and cardiovascular risk in girls that may be independent of health-related physical activity. These slides can be retrieved under Electronic Supplementary Material.

Insulin sensitivity is reduced in children with high body-fat regardless of BMI.

PURPOSE: To examine the association between insulin sensitivity and adiposity in children stratified according to their body mass index (BMI: normal weight, NW; overweight or obese, OW/OB) and body-fat percentage (BF%: adipose or NonAdipose), and determine whether cardiorespiratory fitness (CRF) ameliorates any deleterious associations. METHODS: This prospective cohort study comprises a cross-sectional and longitudinal analyses of data collected at baseline and 2 years later on children (7.7-13.4 years) attending public school in Denmark. Levels of CRF were measured using the Andersen test, whereas BF% was measured by dual-energy X-ray absorptiometry (DXA). Fasting plasma glucose and insulin concentrations were measured and the homoeostatic model assessment of insulin resistance (HOMA-IR) used to assess insulin sensitivity. RESULTS: Approximately 8% of children classified as normal weight by BMI had high BF% (NW + Adipose). Children with high BF% had significantly higher insulin (NW + adipose: 32.3%; OW/OB + Adipose: 52.2%) and HOMA-IR scores (NW + Adipose: 32.3%; OW/OB + Adipose: 55.3%) than children classified as NW without high BF% (reference group; NW + NonAdipose). Adjusting for CRF reduced this difference, but did not completely ameliorate these associations. Longitudinally, children with high BF% (OW/OB + Adipose or NW + Adipose) had significantly worse insulin sensitivity 2 years later than NW + NonAdipose children (All p < 0.001). The few children (n = 14) who improved their BMI or BF% during the 2 years follow-up, no longer had significantly worse insulin sensitivity than children with NW + NonAdipose. CONCLUSION: High BF% in children is associated with significantly lower insulin sensitivity even when BMI is considered NW. Longitudinally, insulin sensitivity is lower in children with high BF% with or without high BMI. The CRF was a significant covariate in these models, but CRF did not completely ameliorate the effects of high BF% on insulin sensitivity.

Total volume versus bouts: prospective relationship of physical activity and sedentary time with cardiometabolic risk in children.

BACKGROUND/OBJECTIVES: Examine the prospective relationship of total volume versus bouts of sedentary behaviour (SB) and moderate-to-vigorous physical activity (MVPA) with cardiometabolic risk in children. In addition, the moderating effects of weight status and MVPA were explored. SUBJECTS/METHODS: Longitudinal study including 454 primary school children (mean age 10.3 years). Total volume and bouts (i.e. ≥10 min consecutive minutes) of MVPA and SB were assessed by accelerometry in Nov 2009/Jan 2010 (T1) and Aug/Oct 2010 (T2). Triglycerides, total cholesterol/HDL cholesterol ratio (TC:HDLC ratio), homoeostatic model assessment of insulin resistance, systolic blood pressure and waist circumference were assessed at T2 (Sept/Oct 2010) and combined in a composite cardiometabolic risk score. Associations of total time and uninterrupted MVPA and SB were examined using multilevel mixed linear models, with or without mutual adjustments between MVPA and SB. The moderating effects of weight status and MVPA (for SB only) were examined by adding interaction terms. RESULTS: Children engaged daily in about 60 min of total MVPA and 0-15 min/week in MVPA bouts. Mean total sedentary time was around 7 h/day with over 3 h/day accumulated in bouts. Higher mean levels of MVPA were significantly associated with a lower waist circumference, triglycerides, insulin resistance, TC:HDLC ratio and composite cardiometabolic risk, with non-significant associations for uninterrupted MVPA. Associations with sedentary time were much smaller and inconsistent: higher total sedentary time was associated with higher insulin resistance; after adjusting for MVPA, higher mean total and bouts of sedentary time were associated with lower waist circumference, and sedentary bouts with lower composite cardiometabolic risk. CONCLUSIONS: Children accumulated MVPA intermittently and rarely in bouts, and about half their total sedentary time in bouts. Total MVPA is important for lowering cardiometabolic risk in children, whereas both total and uninterrupted sedentary time seem of less importance.

Influence of a 2- to 6-year physical education intervention on scholastic performance: The CHAMPS study-DK.

The aim of this study was to investigate the influence of a school-based intervention with a tripling of physical education (PE) lessons from two (90 minutes) to six lessons per week (270 minutes) on scholastic performance. This study is part of the CHAMPS study-DK, a quasi-experimental study that began in 2008. The intervention group consisted of six schools, and the control group consisted of four matched schools (mean age at baseline=8.4 years, kindergarten class fourth grade). Academic performance was extracted from the national test system from 2010 to 2014 (Math and Danish were measured at third and sixth, and second, fourth and sixth grades, respectively). Participants included 1888 students participating in at least one scholastic performance test. Linear mixed models were applied to test for differences between groups and adjusted for known confounders. No significant differences were observed between groups in the academic performance tests (control group reference); Danish second grade ß=-1.34 (95% CI -9.90, 7.22), fourth grade ß=0.22 (95% CI -6.12, 6.56), sixth grade ß=1.03 (95% CI -5.02, 7.08), and all grades combined ß=0.28 (95% CI -5.74, 6.31) and Math third grade ß=-2.87 (95% CI -9.65, 3.90), sixth grade ß=0.99 (95% CI -7.36, 9.34) and combined ß=-1.20 (95% CI -8.10, 5.71). In conclusion, no significant differences were observed between intervention and control schools for scholastic performance. Importantly, there were no negative effects of additional PE on scholastic outcomes, despite more PE and longer school days for intervention children.

Long-term follow-up on biological risk factors, adiposity, and cardiorespiratory fitness development in a physical education intervention: a natural experiment (CHAMPS-study DK).

BACKGROUND: Schools are a key setting for large-scale primordial non-communicable disease prevention in young people, but little data on sustainability of impacts on cardiometabolic risk markers is available. METHODS: Six and a half year follow-up of a natural experiment. In 2008, six public schools in the municipality of Svendborg (Denmark) augmented their curricular physical education (intervention) and four matched schools served as controls. At long term follow up in 2015 n = 312 participants aged 5-11 years had complete data (33% of children providing necessary baseline data). The intervention, that consisted of a trebling of weekly physical education lessons and courses provided to physical education teachers, was provided at intervention schools up until 6th grade. Participants attended 6th to 10th grade at follow-up. Differences in the homeostasis model assessment of insulin resistance, blood pressure, triglycerides, cholesterol ratios, cardiorespiratory fitness, waist-circumference, and a composite score of these, between participants attending intervention and control schools were analysed by mixed linear regression models. Differences in physical activity at follow-up was analysed cross-sectionally (no baseline available) in n = 495. RESULTS: Compared to controls, children at intervention schools had a non-significant - 0.07 (- 0.32 to 0.18) standard deviations lower composite risk score 6.5 years after project initiation. Likewise, no statistically significant differences between intervention and control schools were found for any of the other outcomes (p-values ≥ 0.41). However, six of seven outcomes were in a direction favouring intervention schools. No statistically significant differences between intervention and control schools were observed for physical activity outcomes (p-values ≥ 0.13). CONCLUSIONS: An augmented physical activity program including 270 min of weekly physical education provided for three to seven years did not materialize in statistically significant differences in established risk markers in children from intervention compared to control schools. As the intervention was discontinued after 6th grade, the post-intervention effect of augmented physical education throughout adolescence is unknown. School-based physical activity programs may benefit from incorporating instruments for behaviour translation to leisure time in their intervention models to increase the probability of achieving public health relevance. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03510494 .

The influence of anthropometry and body composition on children's bone health: the childhood health, activity and motor performance school (the CHAMPS) study, Denmark.

Overweight, physical inactivity and sedentary behaviour have become increasing problems during the past decade. Increased sedentary behaviour may change the body composition (BC) by increasing the fat mass relative to the lean mass (LM). These changes may influence bone health to describe how anthropometry and BC predict the development of the bone accruement. The longitudinal study is a part of The CHAMPS study-DK. Children were DXA scanned at baseline and at 2-year follow-up. BC (LM, BF %) and BMC, BMD and BA were measured. The relationship between bone traits, anthropometry and BC was analysed by multilevel regression analyses. Of the invited children, 742/800 (93%) accepted to participate. Of these, 682/742 (92%) participated at follow-up. Mean (range) of age at baseline was 9.5 years (7.7-12.1). Height, BMI, LM and BF % predicted bone mineral accrual and bone size positively and independently. Height and BMI are both positive predictors of bone accruement. LM is a more precise predictor of bone traits than BF % in both genders. The effects of height and BMI and LM on bone accruement are nearly identical in the two genders, while changes in BF % have different but positive effects on bone accretion in both boys and girls.

Do extra compulsory physical education lessons mean more physically active children--findings from the childhood health, activity, and motor performance school study Denmark (The CHAMPS-study DK).

BACKGROUND: Primarily, this study aims to examine whether children attending sports schools are more active than their counterpart attending normal schools. Secondary, the study aims to examine if physical activity (PA) levels in specific domains differ across school types. Finally, potential modifications by status of overweight/obesity and poor cardio-respiratory fitness are examined. METHODS: Participants were from the first part of the CHAMPS-study DK, which included approximately 1200 children attending the 0th - 6th grade. At the sports schools, the mandatory physical education (PE) program was increased from 2 to 6 weekly lessons over a 3-year period. Children attending normal schools were offered the standard 2 PE lessons. PA was assessed at two different occasions with the GT3X ActiGraph accelerometer, once during winter in 2009/10 and once during summer/fall in 2010. Leisure time organized sports participation was quantified by SMS track. Based on baseline values in 2008, we generated a high-BMI and a low-cardio-respiratory fitness for age and sex group variable. RESULTS: There were no significant differences in PA levels during total time, PE, or recess between children attending sports schools and normal schools, respectively. However, children, especially boys, attending sports schools were more active during school time than children attending normal schools (girls: ß=51, p=0.065; boys: ß=113, p<0.001). However, in the leisure time during weekdays children who attended sports schools were less active (girls: ß=-41, p=0.004; boys: ß=-72, p<0.001) and less involved in leisure time organized sports participation (girls: ß=-0.4, p=0.016; boys: ß=-0.2, p=0.236) than children who attended normal schools. Examination of modification by baseline status of overweight/obesity and low cardio-respiratory fitness indicated that during PE low fit girls in particular were more active at sports schools. CONCLUSION: No differences were revealed in overall PA levels between children attending sports schools and normal schools. Sports schools children were more active than normal schools children during school time, but less active during leisure time. In girls, less organized sports participation at least partly explained the observed differences in PA levels during leisure time across school types. Baseline status of cardio-respiratory fitness modified school type differences in PA levels during PE in girls.

Six physical education lessons a week can reduce cardiovascular risk in school children aged 6-13 years: a longitudinal study.

AIMS: Cardiovascular disease (CVD) originates during childhood and adolescence. Schools are potentially effective settings for early public health prevention strategies. The aim of this study was to evaluate the effect of six physical education (PE) lessons on children's CVD risk. METHODS: This longitudinal study in 10 public schools (1218 children, aged 6-13 years), 6 intervention and 4 control schools evaluates a natural experiment, where intervention schools tripled PE to six lessons per week compared to the mandatory two PE lessons in the control schools. Baseline (2008) and 2-year follow-up measures were anthropometrics, cardiorespiratory fitness, blood pressure and blood samples providing lipids and measures for insulin resistance. Based on these variables, a composite risk score was calculated and used for further analysis. Multivariate multilevel mixed effect regression models were used to estimate effect of intervention taking the hierarchical structure of data into account. Individual, class and school were considered random effects. Intra class correlation (ICC) was calculated. RESULTS: Intervention significantly lowered mean of composite risk score with 0.17 SD (95% CI: -0.34 to -0.01). Six PE lessons per week had a beneficial effect on triglycerides (TG) levels (-0.18 SD, 95% CI: -0.36 to 0.00), systolic blood pressure (SBP) (-0.22 SD, 95% CI: -0.42 to -0.02) and insulin resistance (HOMA-IR) (-0.17 SD, 95% CI: -0.34 to 0.01). CONCLUSIONS: Six PE lessons at school can reduce children's CVD risk measured as a composite risk score. The changes in risk score are considered substantial in the perspective of public health strategy for preventing CVD in later life.

Total body fat percentage and body mass index and the association with lower extremity injuries in children: a 2.5-year longitudinal study.

BACKGROUND: Overweight youths are generally recognised as being at increased risk of sustaining lower extremity injuries in sports. However, previous studies are inconclusive and choices for measuring overweight are manifold. OBJECTIVE: To examine two different measures of overweight, body mass index (BMI) and total body fat percentage (TBF%), as risk factors for lower limb injuries in a school-based cohort. STUDY DESIGN: A longitudinal cohort study. METHODS: A total of 632 school children, baseline age 7.7-12.0 years, were investigated. Whole body dual energy x-ray absorptiometry scans provided measures of TBF%. Measures of BMI were obtained by standard anthropometric methods. Musculoskeletal complaints were reported by parents answering weekly mobile phone text messages during 2.5 years. Injuries were diagnosed by clinicians. Leisure time sports participation was reported weekly using text messaging. RESULTS: During 2.5 years of follow-up, 673 lower extremity injuries were diagnosed. Children being overweight by both BMI and TBF% showed the highest risk of sustaining lower extremity injuries (IRR 1.38 (95% CI 1.05 to 1.81)). Children who were overweight using BMI and TBF% showed the highest risk of sustaining lower extremity injuries (IRR 1.38 (95% CI 1.05 to 1.81)). CONCLUSIONS: The risk of lower extremity injuries appeared to be increased for overweight children. When comparing two different measures of overweight, overweight by TBF% is a higher risk factor than overweight by BMI. This suggests that a high proportion of adiposity is more predictive of lower extremity injuries, possibly due to a lower proportion of lean muscle mass.

Effect of four additional physical education lessons on body composition in children aged 8-13 years--a prospective study during two school years.

BACKGROUND: Strategies for combating increasing childhood obesity is called for. School settings have been pointed out as potentially effective settings for prevention. The objective of this paper was to evaluate the effect of four additional Physical Education (PE) lessons/week in primary schools on body composition and weight status in children aged 8-13. METHODS: Children attending 2nd to 4th grade (n = 632) in 10 public schools, 6 intervention and 4 control schools, participated in this longitudinal study during 2 school years. OUTCOME MEASURES: Primary: Body Mass Index (BMI) and Total Body Fat percentage (TBF%) derived from Dual Energy X ray Absorptiometry (DXA). Secondary: the moderating effect of overweight/obesity (OW/OB) and adiposity based on TBF% cut offs for gender. RESULTS: Intervention effect on BMI and TBF% (BMI: ß -0.14, 95% CI: -0.33; 0.04, TBF%: ß -0.08, 95% CI:-0.65;0.49) was shown insignificant. However, we found significant beneficial intervention effect on prevalence of OW/OB based on BMI (OR 0.29, 95% CI: 0.11;0.72). The intervention effect on adiposity based on TBF% cut offs was borderline significant (OR 0.64, 95% CI:0. 39; 1.05). CONCLUSION: Four additional PE lessons/week at school can significantly improve the prevalence of OW/OB in primary schoolchildren. Mean BMI and TBF% improved in intervention schools, but the difference with controls was not significant. The intervention had a larger effect in children who were OW/OB or adipose at baseline.

The intensity of physical activity influences bone mineral accrual in childhood: the childhood health, activity and motor performance school (the CHAMPS) study, Denmark.

BACKGROUND: Studies indicate genetic and lifestyle factors can contribute to optimal bone development. In particular, the intensity level of physical activity may have an impact on bone health. This study aims to assess the relationship between physical activity at different intensities and Bone Mineral Content (BMC), Bone Mineral Density (BMD) and Bone Area (BA) accretion. METHODS: This longitudinal study is a part of The CHAMPS study-DK. Whole-body DXA scans were performed at baseline and after two years follows up. BMC, BMD, and BA were measured. The total body less head (TBLH) values were used. Physical activity (PA) was recorded by accelerometers (ActiGraph, model GT3X). Percentages of different PA intensity levels were calculated and log odds of two intensity levels of activity relative to the third level were calculated. Multilevel regression analyses were used to assess the relationship between the categories of physical activity and bone traits. RESULTS: Of 800 invited children, 742 (93%) accepted to participate. Of these, 682/742 (92%) participated at follow up. Complete datasets were obtained in 602/742 (81%) children. Mean (range) of age was 11.5 years (9.7-13.9). PA at different intensity levels was for boys and girls respectively, sedentary 62% and 64%, low 29% for both genders and moderate to high 9% and 7% of the total time. Mean (range) BMC, BMD, and BA was 1179 g (563-2326), 0.84 g/cm2 (0.64-1.15) and 1393 cm2 (851-2164), respectively. Valid accelerometer data were obtained for a mean of 6.1 days, 13 hours per day. CONCLUSIONS: There 7was a positive relationship between the log odds of moderate to high-level PA versus low level activity and BMC, BMD and BA. Children with an increased proportion of time in moderate to high-level activity as opposed to sedentary and low-level activity achieved positive effects on BMC, BMD and BA.