When analysing physical activity (PA) levels using accelerometry, the epoch setting is critical to capture intensity-specific PA correctly. The aim of the present study was to investigate the PA intensity signatures related to metabolic health in children using different epoch settings. A sample of 841 Norwegian children (age 10.2 ± 0.3 years; BMI 18.0 ± 3.0; 50% boys) provided data on accelerometry (ActiGraph GT3X+) and several indices of metabolic health (aerobic fitness, abdominal fatness, insulin sensitivity, lipid metabolism, blood pressure) that were used to create a composite metabolic health score. We created intensity spectra from 0-99 to = 10000 counts per minute (cpm) for files aggregated using 1, 10, and 60-second epoch periods and used multivariate pattern analysis to analyse the data. The association patterns with metabolic health differed substantially between epoch settings. The intensity intervals most strongly associated with metabolic health were 7000-8000 cpm for data analysed using 1-second epoch, 5500-6500 cpm for data analysed using 10-second epoch, and 4000-5000 cpm analysed using 60-second epoch. Aggregation of data over different epoch periods has a clear impact on how PA intensities in the moderate and vigorous range are associated with childhood metabolic health.
The purpose of this study was to describe levels of inflammation markers in Norwegian children and to examine the associations of adiposity, aerobic fitness, and muscle fitness with markers of inflammation.
In 2005-2006, 1467 nine-year-olds were randomly selected from all regions in Norway. The participation rate was 89%. The inflammatory markers evaluated included C-reactive protein (CRP), leptin, adiponectin, plasminogen activator inhibitor-1, tumor necrosis factor-a, hepatocyte growth factor, resistin, and interleukin-6. We assessed muscular strength by measuring explosive, isometric, and endurance strength. Aerobic fitness was measured directly during a maximal cycle ergometer test. Adiposity was expressed as waist circumference (WC).
The girls had significantly higher levels of CRP, leptin, adiponectin, and resistin and lower levels of tumor necrosis factor-a compared with the boys. We observed a graded association of CRP and leptin levels across quintiles of WC, aerobic fitness, and muscle fitness (P = 0.001 for all participants). The regression analyses revealed that WC, aerobic fitness, and muscle fitness were independently associated with the CRP (WC ß = 0.158, P
Our objective was to examine the influence of adult and childhood socioeconomic status (SES) on attained adult food intake patterns. We used data from a 20- to 22-y follow-up study of 1904 Danish teenagers. The baseline survey was conducted partly in 1983 and partly in 1985 and the follow-up survey was conducted in 2005. Dietary data were collected at follow-up using a 195-item FFQ. Food patterns were derived from principal component analysis. Two food patterns labeled "traditional-western food pattern" and "green food pattern" were identified. In men, adult SES was inversely associated with adherence to the traditional-western food pattern. High adherence to the green food pattern was positively related to high adult SES in both sexes. Among women, those with high SES in childhood had higher green food pattern factor scores than those with low childhood SES, regardless of adult SES. Among men, those with high adult SES had higher green food pattern factor scores than those with low adult SES, regardless of childhood SES. In conclusion, socioeconomic position is important for the development of adult food intake patterns. However, childhood SES seems more important for adult female food intake patterns, whereas adult SES seems more important for adult male food intake patterns.
Aerobic fitness is an apparent candidate for screening children and youth for poor cardiometabolic health and future risk of cardiovascular disease (CVD). Yet, age- and sex-specific cut points for children and youth determined using a maximal protocol and directly measured peak oxygen consumption (VO2peak ) does not exist. We used a nationally representative sample of 1462 Norwegian children and youth (788 boys and 674 girls aged 8.7-10.4 years and 14.7-16.7 years) who in 2005-2006 performed a maximal cycle ergometer test with direct measurement of VO2peak , along with measurement of several other risk factors for CVD (systolic blood pressure, waist circumference:height ratio, total:high-density lipoprotein cholesterol ratio, triglycerides, Homeostasis Model Assessment for Insulin Resistance). Based on the proportion of children having clustering (least favorable quartile) of 6 (1.6%), =5 (5.2%), and =4 (10.6%) CVD risk factors, we established the 2nd, 5th, and 10th percentile cut points for VO2peak (mL/kg/min) for children and youth aged 8-18 years. Classification accuracy was determined using the Kappa coefficient (k), sensitivity, and specificity. For boys, the 2nd, 5th, and 10th percentile VO2peak cut points were 33.6-36.4, 36.3-39.8, and 38.7-43.0 mL/kg/min, respectively. For girls, the corresponding cut points were 29.7-29.1, 32.4-31.4, and 34.8-33.5 mL/kg/min Together with BMI, but without more invasive measures of traditional risk factors for CVD, these cut points can be used to screen schoolchildren for poor cardiometabolic health with moderate discriminating ability (k = 0.53).
The link between aerobic fitness and physical activity in children has been studied in a number of earlier studies and the results have generally shown weak to moderate correlations. This overall finding has been widely questioned partly because of the difficulty in obtaining valid estimates of physical activity. This study investigated the cross-sectional and longitudinal relationship between aerobic fitness and physical activity in a representative sample of 9 and 15-year-old children (n = 1260 cross-sectional, n = 153 longitudinal). The specific goal was to improve past studies using an objective method of activity assessment and taking into account a number of major sources of error. Data came from the Danish part of the European youth heart study, 1997-2003. The cross-sectional results generally showed a weak to moderate association between aerobic fitness and physical activity with standardized regression coefficients ranging from 0.14 to 0.33. The longitudinal results revealed a tendency towards an interaction effect of baseline physical activity on the relationship between changes in physical activity and aerobic fitness. Moderate to moderately strong regression effect sizes were observed in the lower quadrant of baseline physical activity compared to weak effect sizes in the remaining quadrants. In conclusion, the present study confirms earlier findings of a weak to moderate association between aerobic fitness and physical activity in total population of children. However, the study also indicates that inactive children can achieve notable increase in aerobic fitness by increasing their habitual physical activity level. A potential physiological explanation for these results is highlighted.
BACKGROUND: The aim of this study was to analyze the association of fitness and fatness with blood pressure (BP) and hypertension.This was a cross-sectional study of 13,557 boys and girls 15-20 years of age. Fitness was estimated from a shuttle run test, fatness from body mass index (BMI), and BP was measured sitting after 5 min of rest. Other lifestyle variables were self-reported. RESULTS: Boys had a higher systolic BP (SBP) than girls. A low physical fitness level and high BMI were independently associated with a high BP and risk of having hypertension in both girls and boys. Interaction was found between BMI and fitness. In a stratified analysis an odds ratio (OR) of 3.99 was found for hypertension in girls with a BMI > 25 kg m(-2) compared to lean girls if all had a low fitness level, and an OR of 2.14 for a high BMI in girls with a high fitness level. In boys, OR for high versus low BMI were 3.23 in the low fit and 2.34 and 2.50 in the middle and upper tertile of fitness, respectively. CONCLUSIONS: Fitness and BMI were independently associated to BP. BMI was a stronger predictor of hypertension in those with a low fitness level, especially in girls.
In this study we examined the association between leptin and blood pressure in a population-based study of Danish and Norwegian children and adolescents. Because of the putative bidirectional relationship between leptin and adiposity we formally tested (i) the mediating effect of body mass index in the association between leptin and blood pressure, and (ii) the mediating effect of leptin in the association between body mass index and blood pressure.
To examine these aims we used a cross-sectional random sample of children and adolescents from Denmark and Norway (n = 1993) who had measures of leptin, anthropometry, blood pressure and other personal and biological risk factors for raised blood pressure available.
Both body mass index and leptin were positively associated with blood pressure (P
OBJECTIVES: To examine the association between socioeconomic position and insulin resistance in children from three countries in northern Europe (Denmark), eastern Europe (Estonia), and southern Europe (Portugal) that have different physical, economic, and cultural environments. DESIGN: Cross sectional study. PARTICIPANTS: 3189 randomly selected schoolchildren aged 9 and 15 years from Denmark (n = 933), Estonia (n = 1103), and Portugal (n = 1153). MAIN OUTCOME MEASURE: Insulin resistance (homoeostasis model assessment). RESULTS: Family income and parental education were inversely associated with insulin resistance in Danish children but were positively associated with insulin resistance in Estonian and Portuguese children. Among Danish children, insulin resistance was 24% lower (95% confidence interval -38% to -10%) in those whose fathers had the most education compared with those with the least education. The equivalent results were 15% (2% to 28%) higher for Estonia and 19% (2% to 36%) higher for Portugal. These associations remained after adjustment for a range of covariates: -20% (-36% to -5%) for Denmark, 10% (-4% to 24%) for Estonia, and 18% (-1% to 31%) for Portugal. Strong statistical evidence supported differences between the associations in Denmark and those in the other two countries in both unadjusted and adjusted models (all P
Associations between objectively assessed physical activity and indicators of body fatness in 9- to 10-y-old European children: a population-based study from 4 distinct regions in Europe (the European Youth Heart Study).
BACKGROUND: The rising prevalence of obesity in children may be due to a reduction in physical activity (PA). OBJECTIVE: Our aim was to study the associations of objectively measured PA volume and its subcomponents with indicators of body fatness. DESIGN: A cross-sectional study of 1292 children aged 9-10 y from 4 distinct regions in Europe (Odense, Denmark; the island of Madeira, Portugal; Oslo; and Tartu, Estonia) was conducted. PA was measured by accelerometry, and indicators of body fatness were the sum of 5 skinfold thicknesses and body mass index (BMI; in kg/m(2)). We examined the associations between PA and body fatness by using general linear models adjusted for potential confounding variables. RESULTS: After adjustment for sex, study location, sexual maturity, birth weight, and parental BMI, time (min/d) spent at moderate and vigorous PA (P = 0.032) and time (min/d) spent at vigorous PA were significantly (P = 0.015) and independently associated with body fatness. Sex, study location, sexual maturity, birth weight, and parental BMI explained 29% (adjusted R(2) = 0.29) of the variation in body fatness. Time spent at vigorous PA explained an additional 0.5%. Children who accumulated 2 h/d. CONCLUSIONS: The accumulated amount of time spent at moderate and vigorous PA is related to body fatness in children, but this relation is weak; the explained variance was
Associations between objectively measured physical activity intensity in childhood and measures of subclinical cardiovascular disease in adolescence: prospective observations from the European Youth Heart Study.
No prospective studies have investigated the association between physical activity (PA) and carotid subclinical cardiovascular disease across childhood. Therefore, the primary aim was to investigate the association between PA intensity across childhood and carotid intima media thickness (cIMT) and stiffness in adolescence. Second, we included a clustered cardiovascular disease risk score as outcome.
This was a prospective study of a sample of 254 children (baseline age 8-10 years) with a 6-year follow-up. The mean exposure and the change in minutes of moderate-and-vigorous and vigorous PA intensity were measured using the Actigraph activity monitor. Subclinical cardiovascular disease was expressed as cIMT, carotid arterial stiffness and secondarily as a metabolic risk z-score including the homoeostasis model assessment score of insulin resistance, triglycerides, total cholesterol to high-density lipoprotein ratio, inverse of cardiorespiratory fitness, systolic blood pressure and the sum of four skinfolds.
No associations were observed between PA intensity variables and cIMT or carotid arterial stiffness (p>0.05). Neither change in PA intensity (moderate-and-vigorous nor vigorous) nor mean minutes of moderate-and-vigorous PA intensity was associated to the metabolic risk z-score in adolescence (p>0.05). However, a significant inverse association was observed between mean minutes of vigorous PA and the metabolic risk z-score in adolescence independent of gender and biological maturity (standard ß=-0.19 p=0.007).
A high mean exposure to, or changes in, minutes spent at higher PA intensities across childhood was not associated to cIMT or stiffness in the carotid arteries in adolescence. Our observations suggest that a high volume of vigorous PA across childhood independently associated with lower metabolic cardio vascular disease risk in adolescence.