Anna Bugge

Tracking of clustered cardiovascular disease risk factors from childhood to adolescence

Background:Clustering of cardiovascular disease (CVD) risk factors has been found in children as young as 9 y of age. However, the stability of this clustering over the course of childhood has yet to be determined. The purpose of this study was to determine the tracking of clustered CVD risk from young school age through adolescence and to examine differences in tracking between levels of overweight/obesity and cardiorespiratory fitness (VO2peak).Methods:Beginning at 6 y, children (n = 434) were measured three times in 7 y. Anthropometrics, blood pressure, and VO2peak were measured. Fasting blood samples were analyzed for CVD risk factors. A clustered risk score (z-score) was constructed by adding sex-specific z-scores for blood pressure, homeostatic model assessment (HOMA-IR), triglyceride (TG), skinfolds, and negative values of high-density lipoprotein cholesterol (HDLc) and VO2peak.Results:Significant tracking coefficients were found between clustered z-score at all time intervals (r = 0.514, 0.559, and 0.381 between ages 6–9, 9–13, and 6–13 y, respectively, all P < 0.0001). Tracking was higher for low-fit children, whereas no clear pattern was found for different levels of body fat.Conclusion:We found that clustered z-score is a fairly stable characteristic through childhood. Implementation of preventive strategies could therefore start at early school age.

The association between physical activity, physical fitness and development of metabolic disorders

BACKGROUND Cardiovascular (CVD) risk factors have been shown to cluster in some children. This has been shown in children from the age of nine years, but recently we found no clustering in six-year old children. It is uncertain when clustering develops and which parameters are related to the development of clustered CVD risk. METHODS A longitudinal study including 484 children aged six years. Three years later, 434 children participated in a follow-up. The main outcome was clustering of five CVD risk factors: homeostasis assessment insulin resistance (HOMA), total cholesterol:HDL ratio, triglyceride (TG), systolic blood pressure and sum of four skinfolds. Independent variables were physical activity and cardiorespiratory fitness. RESULTS CVD risk factors were independently distributed in the six-year-olds, and there was no association between composite risk factor score and physical fitness or activity even if there were obese and unfit children in the population. Clustering of CVD risk factors was found at the age of nine years, and the observed number with three or more CVD risk factors was 3.33 (95% CI: 1.41-7.87) times higher than expected if risk factors had been independently distributed. At the age of nine years, the lowest quartile of fitness had 34.9 (95% CI: 8.0-152.5) times higher risk of having clustered risk than the most fit quartile. CONCLUSION Clustering of CVD risk factors developed between the age of six and nine years. At nine years of age clustered CVD risk was highly associated with low fitness level.

Objectively measured daily physical activity related to aerobic fitness in young children

Abstract The purpose of this study was to investigate by direct measurement the cross-sectional relationship between accelerometer-measured physical activity and peak oxygen uptake ([Vdot]O2peak: ml · min−1 · kg−1), in a population-based cohort of young children, since such data are scarce. The study included 468 children (246 boys, 222 girls) aged 6.7 ± 0.4 years, recruited from a population-based cohort. Peak oxygen uptake was measured by indirect calorimetry during a maximal treadmill exercise test. Physical activity was assessed by accelerometers over a 4-day period. Minutes of sedentary, light, moderate, moderate-to-vigorous, and vigorous activity per day were calculated. Mean counts per minute were considered to reflect total physical activity. Pearson correlation coefficients indicated a weak relationship between daily physical activity variables and [Vdot]O2peak in boys (r = 0.15–0.28, P < 0.05), with the exception of time in sedentary and light activity, which was not related to [Vdot]O2peak. None of the daily physical activity variables were related to [Vdot]O2peak in girls, with the exception of a very weak relationship for moderate activity (r = 0.14, P < 0.05). Multiple regression analyses indicated that the various physical activity variables explained between 2 and 8% of the variance in [Vdot]O2peak in boys. In this population-based cohort, most daily activity variables were positively related to aerobic fitness in boys, whereas less clear relationships were observed in girls. Our finding that physical activity was only uniformly related to aerobic fitness in boys partly contradicts previous studies in older children and adolescents.

A new approach to define and diagnose cardiometabolic disorder in children

The aim of the study was to test the performance of a new definition of metabolic syndrome (MetS), which better describes metabolic dysfunction in children. Methods. 15,794 youths aged 6–18 years participated. Mean z-score for CVD risk factors was calculated. Sensitivity analyses were performed to evaluate which parameters best described the metabolic dysfunction by analysing the score against independent variables not included in the score. Results. More youth had clustering of CVD risk factors (>6.2%) compared to the number selected by existing MetS definitions (International Diabetes Federation (IDF) < 1%). Waist circumference and BMI were interchangeable, but using insulin resistance homeostasis model assessment (HOMA) instead of fasting glucose increased the score. The continuous MetS score was increased when cardiorespiratory fitness (CRF) and leptin were included. A mean z-score of 0.40–0.85 indicated borderline and above 0.85 indicated clustering of risk factors. A noninvasive risk score based on adiposity and CRF showed sensitivity and specificity of 0.85 and an area under the curve of 0.92 against IDF definition of MetS. Conclusions. Diagnosis for MetS in youth can be improved by using continuous variables for risk factors and by including CRF and leptin.

Effects of a three-year intervention: the Copenhagen School Child Intervention Study.

INTRODUCTION This study assessed short-term and long-term effects of a 3-yr controlled school-based physical activity (PA) intervention on fatness, cardiorespiratory fitness (VO(2peak)) and CVD risk factors in children. METHODS The study involved 18 schools (10 intervention and 8 controls) and included a follow-up 4 yr after the end of intervention. The analyses included 696, 6- to 7-yr-old children at baseline, 612 postintervention (age 9.5 yr) and 441 at follow-up (age 13.4 yr). The intervention consisted of a doubling of the amount of physical education (PE; from 90 to 180 min·wk(-1)), training of PE teachers, and upgrading of PE and playing facilities. Anthropometrics and systolic blood pressure (SBP) were measured. VO(2peak) was directly measured, and PA was assessed using accelerometry. Fasting blood samples were analyzed for CVD risk factors. A composite risk score was computed from z-scores of SBP, triglycerides, total cholesterol-to-HDL cholesterol ratio, homeostatic model assessment (HOMA score), skinfolds, and inverse VO(2peak). RESULTS The HOMA score of the intervention group boys had a smaller increase from baseline to postintervention compared with control boys (P = 0.004). From baseline to follow-up intervention group boys had a smaller increase in SBP compared with control boys (P = 0.010). There were no other significant differences between groups. CONCLUSIONS This 3-yr school-based PA intervention caused positive changes in SBP and HOMA score in boys but not in girls, and no effects were seen in PA, VO(2peak), fatness, and the other measured CVD risk factors. Our results indicate that a doubling of PE and providing training and equipment may not be sufficient to induce major improvements in CVD risk factors in a normal population.

Cytokines and clustered cardiovascular risk factors in children

The aim was to evaluate the possible role of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), C-reactive protein (CRP), low fitness, and fatness in the early development of clustering of cardiovascular disease (CVD) risk factors and insulin resistance. Subjects for this cross-sectional study were obtained from 18 schools near Copenhagen, Denmark. Two hundred ten 9-year-old children were selected for cytokine analysis from 434 third-grade children with complete CVD risk profiles. The subgroup was selected according to the CVD risk factor profile (upper and lower quartile of a composite CVD risk score). All the CVD risk factors and CRP differed between the high- and low-risk groups; but plasma glucose, TNF-alpha, and IL-6 had small and inconsistent differences. Strong associations were found between CVD risk scores and fitness (VO(2peak)) or fatness. No associations were found between CVD risk scores and TNF-alpha and IL-6. C-reactive protein was associated with fitness, fatness, and CVD risk score. This study does not support an association between plasma IL-6 or TNF-alpha and low insulin sensitivity or clustering of CVD risk factors in a young cohort. Inflammation was more pronounced in fat and unfit children based on the association with CRP levels. The association between fitness and fatness variables, insulin resistance, and clustered risk could be caused by other mechanisms related to these exposures. The role of IL-6 remains unclear.

Association between sweet drink intake and adiposity in Danish children participating in a long‐term intervention study

In several studies direct associations between intake of sugar‐sweetened beverages and adiposity have been reported. However, most previous studies were conducted among Americans and assessed the intake in the sub‐categories of soft drinks and sugar‐sweetened beverages, only, rather than the total intake of sweet drinks.

Associations of Adiposity and Aerobic Fitness with Executive Function and Math Performance in Danish Adolescents

OBJECTIVE To examine the associations of adiposity and aerobic fitness with executive function and math performance in Danish adolescents. STUDY DESIGN Cross-sectional analyses were conducted with data on 525 adolescents attending sixth and seventh grades from 14 schools in the 5 main regions of Denmark. A modified Eriksen flanker task was used to assess inhibitory control, a key aspect of executive function. Academic performance was assessed by a customized math test. Aerobic fitness was assessed by an intermittent shuttle-run test (Andersen test). RESULTS Body mass index (BMI) was negatively associated with accuracy on incongruent trials during the flanker task (P = .005). A higher BMI was associated with a larger accuracy interference score (P = .01). Similarly, waist circumference (WC) was negatively associated with accuracy on incongruent trials (P = .008). A higher WC was associated with a larger reaction time (RT) interference score (P = .02) and accuracy interference score (P = .009). Higher aerobic fitness was associated with a faster RT on congruent trials (P = .009) and incongruent trials (P = .003). Higher aerobic fitness was associated with a smaller RT interference score (P = .04). Aerobic fitness was positively associated with math score (P < .001). BMI and WC were not associated with math score (P > .05). CONCLUSIONS These results suggest that aerobic fitness is positively associated with both inhibitory control and math performance in adolescents. Adiposity is negatively associated with inhibitory control in adolescents. Adiposity is not associated with math performance.

Importance of proper scaling of aerobic power when relating to cardiometabolic risk factors in children

Background: The relationship between cardiometabolic risk factors (CMRF) and aerobic power (VO2max) scaled as mL O2 per kilogram body mass is controversial because mass includes both fat and fat-free mass, and fat mass is independently associated with the CMRF. Aim: To examine common units used to scale VO2max and their relationships to mean blood pressure (MBP), total cholesterol (TC), HDL cholesterol, triglycerides (TG), insulin resistance (HOMA-IR) and cumulative risk score (z-score). Subjects: 1784, 8–18 year-old youths, 938 girls and 886 boys. Methods: Fasting blood samples were obtained. VO2max was estimated in mL/min from cycle ergometry and scaled to body mass (kg), fat free mass (kgFFM), body surface area (m2), height (cm) and allometric (mL/kg0.67/min). Results: Unadjusted correlations between CMRF and many of the scaled VO2max units were significant (p < 0.0001), especially for MBP, HOMA-IR, HDL and z-score, with lower correlations for TC and TG. After adjusting for ancestry, sex, height and body fat associations were greatly weakened (r < 0.09), except for MBP. Conclusions: On a population basis, the physical characteristics of the child, especially body fat, are more related to CMRF than any scaled units of VO2max; thus care is needed when relating fitness and health issues.

The Copenhagen Consensus Conference 2016 : children, youth, and physical activity in schools and during leisure time

From 4 to 7 April 2016, 24 researchers from 8 countries and from a variety of academic disciplines gathered in Snekkersten, Denmark, to reach evidence-based consensus about physical activity in children and youth, that is, individuals between 6 and 18 years. Physical activity is an overarching term that consists of many structured and unstructured forms within school and out-of-school-time contexts, including organised sport, physical education, outdoor recreation, motor skill development programmes, recess, and active transportation such as biking and walking. This consensus statement presents the accord on the effects of physical activity on childrens and youths fitness, health, cognitive functioning, engagement, motivation, psychological well-being and social inclusion, as well as presenting educational and physical activity implementation strategies. The consensus was obtained through an iterative process that began with presentation of the state-of-the art in each domain followed by plenary and group discussions. Ultimately, Consensus Conference participants reached agreement on the 21-item consensus statement.