PURPOSE: Active travel to school provides an opportunity for daily physical activity. Previous studies have shown that walking and cycling to school are associated with higher physical activity levels. The purpose of this study was to investigate whether the way that children and adolescents travel to school is associated with level of cardiovascular fitness. METHODS: Participants were recruited via a proportional, two-stage cluster sample of schools (N = 25) in the region of Odense, Denmark as part of the European Youth Heart Study (EYHS). Nine hundred nineteen participants (529 children, age 9.7 +/- 0.5 yr; 390 adolescents, age 15.5 +/- 0.4 yr) completed a maximal cycle ergometer test to assess cardiorespiratory fitness (Wmax x kg(-1)). Mode of travel to school was investigated by questionnaire. Physical activity was measured in 531 participants using an accelerometer. Regression analyses with robust standard errors and adjustment for confounders (gender, age, body composition (skinfolds), pubertal status, and physical activity) and the cluster sampling procedure were used to compare fitness levels for different travel modes. Multinomial logistic regression was applied to assess the odds for belonging to quartiles of fitness. RESULTS: Children and adolescents who cycled to school were significantly more fit than those who walked or traveled by motorized transport and were nearly five times as likely (OR 4.8; 95% CI 2.8-8.4) to be in the top quartile of fitness. CONCLUSION: Cycling to school may contribute to higher cardiovascular fitness in young people.
BACKGROUND: Identifying leisure time activities performed before and after school that influence time in physical activity (PA) and/or time spent sedentary can provide useful information when designing interventions aimed to promote an active lifestyle in young people. The purpose of this study was to examine associations between mode of transportation to school, outdoor play after school, participation in exercise in clubs, and TV viewing with objectively assessed PA and sedentary behaviour in children. METHODS: A total of 1327 nine- and 15-year-old children from three European countries (Norway, Estonia, Portugal) participated as part of the European Youth Heart Study. PA was measured during two weekdays and two weekend days using the MTI accelerometer, and average percent of time in moderate-to-vigorous PA (MVPA) and time spent sedentary were derived. Potential correlates were assessed by self-report. Independent associations between self-reported correlates with percent time in MVPA and percent time sedentary were analysed by general linear models, adjusted by age, gender, country, measurement period, monitored days and parental socio-economic status. RESULTS: In 9-year-olds, playing outdoors after school was associated with higher percent time in MVPA (P
BACKGROUND: Levels of overweight have increased and fitness has decreased in children. Potentially, these changes may be a threat to future health. Numerous studies have measured changes in body mass index (BMI), but few have assessed the independent effects of low fitness, overweight and physical inactivity on cardiovascular (CVD) risk factors. METHODS: A cross-sectional multi-center study including 1 769 children from Denmark, Estonia and Portugal. The main outcome was clustering of CVD risk factors. Independent variables were waist circumference, skinfolds, physical activity and cardio-respiratory fitness. RESULTS: Both waist circumference and skinfolds were associated with clustered CVD risk. Odds ratios for clustered CVD risk for the upper quartiles compared with the lowest quartile were 9.13 (95% CI: 5.78-14.43) and 11.62 (95% CI: 7.11-18.99) when systolic blood pressure, triglyceride, insulin resistance homeostasis assessment model (HOMA) score, cholesterol:HDL, and fitness were included in the score. When fitness was removed from the clustered risk variable, the association for fatness attenuated and after further adjustment for fitness, only the highest quartiles of the fatness parameters were significant. Fitness showed the same strength of association with the clustered risk score including systolic blood pressure, triglyceride, HOMA score, and cholesterol:HDL with odds ratio for the upper quartile of 4.97 (95% CI: 3.20-7.73). Physical activity was associated with clustered risk even after adjustment for fitness and fatness with an odds ratio for the upper quartile of 1.81 (95% CI: 1.18-2.76). CONCLUSION: Physical activity, fitness, skinfold and waist circumference were all independently associated with clustered CVD risk.
BACKGROUND: Atherosclerosis develops from early childhood; physical activity could positively affect this process. This study's aim was to assess the associations of objectively measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis. METHODS: We did a cross-sectional study of 1732 randomly selected 9-year-old and 15-year-old school children from Denmark, Estonia, and Portugal. Risk factors included in the composite risk factor score (mean of Z scores) were systolic blood pressure, triglyceride, total cholesterol/HDL ratio, insulin resistance, sum of four skinfolds, and aerobic fitness. Individuals with a risk score above 1 SD of the composite variable were defined as being at risk. Physical activity was assessed by accelerometry. FINDINGS: Odds ratios for having clustered risk for ascending quintiles of physical activity (counts per min; cpm) were 3.29 (95% CI 1.96-5.52), 3.13 (1.87-5.25), 2.51 (1.47-4.26), and 2.03 (1.18-3.50), respectively, compared with the most active quintile. The first to the third quintile of physical activity had a raised risk in all analyses. The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children. INTERPRETATION: Physical activity levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors.
BACKGROUND: Until recently, there has been no unified definition of the metabolic syndrome (MetS) in the youth. Therefore, the prevalence of MetS and its association with potential correlates are largely unknown. OBJECTIVE: The objective was to quantify the prevalence, identify the correlates, and examine the independent associations between potential correlates with MetS. DESIGN: A population-based cohort study was conducted in 10- and 15-y-old youth from Estonia, Denmark, and Portugal (n = 3193). MetS was defined according to the International Diabetes Federation. Correlates included maternal socioeconomic status, body mass index (BMI), hypertension, and prevalent diabetes and maternally reported child's birth weight and duration of breastfeeding. Data on sexual maturity, objectively measured physical activity, cardiorespiratory fitness, self-reported sports participation, television viewing, and regular play were collected for the children. RESULTS: The prevalence of MetS was 0.2% and 1.4% in 10- and 15-y-olds, respectively. Cardiorespiratory fitness (standardized odds ratio: 0.33; 95% CI: 0.15, 0.75), physical activity (standardized odds ratio: 0.40; 95% CI: 0.18, 0.88), and maternal BMI (standardized odds ratio: 1.61; 95% CI: 1.11, 2.34) were all independently associated with MetS after adjustment for sex, age group, study location, birth weight, and sexual maturity. An increase in daily moderate-intensity physical activity by 10-20% was associated with a 33% lower risk of being categorized with MetS. CONCLUSIONS: High maternal BMI and low levels of cardiorespiratory fitness and physical activity independently contribute to the MetS and may be targets for future interventions. Relatively small increases in physical activity may significantly reduce the risk of MetS in healthy children.
The Danish Fitness and Nutrition Council has evaluated the basis for recommending strategies to prevent obesity among children and adolescents. There is limited evidence of a preventive effect from large population based interventions. It is possible, though, to change to a healthier lifestyle. Currently, many different Administrations conduct interventions against obesity, and it is suggested that an independent authority should be established whose primary aim is to reduce the prevalence of obesity and which will be responsible for the effort against obesity.
OBJECTIVE: Examine if home environmental factors are associated with screen-viewing. METHODS: Data are for 2670, 3rd and 9th grade participants in Denmark, Portugal, Estonia and Norway collected between 1997 and 2000. Outcomes were spending >2 h after-school watching television (TV) and >1 h per day playing computer games. Child Autonomy and the home TV Environment were exposures. RESULTS: Each unit increase in Child Autonomy was associated with 9% increase in risk of watching more than 2 h of TV per day after school and a 19% increase in risk of spending more than an hour per day playing computer games. TV Environment was associated with a 31% per unit increase in risk of watching >2 h of TV after school and 11% increase in risk of spending >1 h playing computer games. CONCLUSIONS: A family environment in which after-school TV viewing is part of the home culture and homes where children have more autonomy over their own behavior are associated with an increased risk of watching >2 h of TV per day after school and spending more >1 h per day playing computer games. The home screen-viewing environment and Child Autonomy may be malleable targets for changing screen-viewing.
BACKGROUND: There is a shortage of longitudinal data analyzing associations between physical activity and indicators of insulin resistance among children and adolescents after accounting for adiposity change. To guide future prevention efforts, data were used from the Danish arm of the European Youth Heart Study to examine these issues. METHODS: Participants were 384 students in Grade 9 (aged 15 years) from the municipality of Odense, Denmark, who participated in surveys in 1997 and 2003. Physical activity was monitored for at least 3 days by accelerometer, and mean counts per minute (CPM) and minutes >3000 CPM per day were obtained. Blood samples were collected, and levels of fasting insulin, fasting glucose, and homeostasis model of assessment of insulin resistance (HOMA-IR) were obtained. Data were analyzed in 2008. RESULTS: Physical activity declined from 45 minutes >3000 CPM in 1997 to 35 minutes >3000 CPM in 2003. Longitudinal regression analyses showed that a change in minutes >3000 CPM was negatively associated with fasting insulin levels (z=-2.47, p=0.014) and HOMA-IR (z=-2.31, p=0.021) in 2003. Similar findings were found when CPM was used as the physical activity variable. Results demonstrated that a 6-year decline in physical activity was associated with higher insulin and HOMA-IR levels. CONCLUSIONS: The 6-year change in the volume of physical activity engaged in by adolescents aged 15 years was negatively associated with fasting insulin and HOMA-IR. Preventing an age-related decline in physical activity may be an effective means of preventing youth insulin resistance.
Comment In: Am J Prev Med. 2008 Dec;35(6):604-519000850
BACKGROUND: TV viewing has been linked to metabolic-risk factors in youth. However, it is unclear whether this association is independent of physical activity (PA) and obesity. METHODS AND FINDINGS: We did a population-based, cross-sectional study in 9- to 10-y-old and 15- to 16-y-old boys and girls from three regions in Europe (n = 1,921). We examined the independent associations between TV viewing, PA measured by accelerometry, and metabolic-risk factors (body fatness, blood pressure, fasting triglycerides, inverted high-density lipoprotein (HDL) cholesterol, glucose, and insulin levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardized values of the six subcomponents. There was a positive association between TV viewing and adiposity (p = 0.021). However, after adjustment for PA, gender, age group, study location, sexual maturity, smoking status, birth weight, and parental socio-economic status, the association of TV viewing with clustered metabolic risk was no longer significant (p = 0.053). PA was independently and inversely associated with systolic and diastolic blood pressure, fasting glucose, insulin (all p