Longitudinal associations of physical activity, sedentary time, and cardiorespiratory fitness with arterial health in children - the PANIC study.

We investigated the longitudinal associations of physical activity (PA), sedentary time (ST), and cardiorespiratory fitness (CRF) with arterial health among children. In our primary analyses, we investigated 245 children (girls 51.8%) aged 6-9 years participating in the baseline examinations who had data on arterial health at 2-year follow-up. We also utilized a subsample of 90 children who had a complete arterial health data at baseline and 2-year follow-up. ST (≤1.5 METs), light PA (>1.5-4 METs), moderate PA (>4-7 METs), vigorous PA (>7METs), and moderate-to-vigorous PA (MVPA, >4 METs) were assessed by combined movement and heart rate monitoring and CRF by maximal exercise testing on a cycle ergometer at baseline and 2-year follow-up. Stiffness index (SI) as a measure of arterial stiffness and change in reflection index during exercise test (DRI) as a measure of arterial dilation capacity were assessed by pulse contour analysis. Two-year change in vigorous PA was associated with DRI in boys but not in girls (p=0.021 for interaction). In a subsample analyses, 2-year changes in MPA, VPA, and MVPA were inversely associated with 2-year change in SI. In conclusion, promoting PA at higher intensities may confer larger benefits on arterial health than reducing ST and increasing LPA.

Associations of cardiometabolic risk factors with heart rate variability in 6- to 8-year-old children: The PANIC Study.

BACKGROUND: Associations of cardiometabolic risk factors with heart rate variability (HRV) in children are unclear. We examined associations of cardiometabolic risk score (CRS) and individual cardiometabolic risk factors with HRV variables in 6- to 8-year-olds. METHODS: The participants were a population-based sample of 443 children participating in baseline measurements of the Physical Activity and Nutrition in Children trial. Cardiometabolic risk factors included waist circumference (WC), insulin, glucose, triglycerides, HDL cholesterol, systolic blood pressure (SBP), and diastolic blood pressure (DBP). CRS was calculated as WC + insulin + glucose + triglycerides - HDL cholesterol + the mean of SBP and DBP. HRV variables (SDNN, RMSSD, HF, LF, LF/HF, Mean RR) were measured using 5-minute electrocardiography at rest and analyzed using the Kubios HRV software. In this cross-sectional study, associations of CRS and individual cardiometabolic risk factors with HRV were investigated using linear regression analyses adjusted for sex and peak height velocity. RESULTS: CRS was negatively associated with RMSSD, HF, Mean RR (P value < .05) and positively with LF/HF (P value = .005). Insulin was negatively associated with SDNN, RMSSD, HF, LF, and Mean RR (P value < .05) and positively with LF/HF (P value = .008). SBP was negatively associated with SDNN, RMSSD, HF, LF, and Mean RR (P value < .05). DBP was negatively associated with SDNN, RMSSD, and Mean RR (P value < .05). WC, glucose, triglycerides, or HDL cholesterol were not associated with HRV variables. CONCLUSIONS: Higher CRS, insulin, and blood pressure were associated with smaller HRV, mainly indicating lower parasympathetic activity, in young children. This knowledge may help improving the clinical management of metabolic syndrome and cardiovascular diseases since childhood.

Associations of physical activity, sedentary time, and cardiorespiratory fitness with heart rate variability in 6- to 9-year-old children: the PANIC study.

PURPOSE: To study the associations of physical activity (PA), sedentary time (ST), and cardiorespiratory fitness (CRF) with heart rate variability (HRV) in children. METHODS: The participants were a population sample of 377 children aged 6-9 years (49% boys). ST, light PA (LPA), moderate PA (MPA), vigorous PA (VPA), and moderate-to-vigorous PA (MVPA), and PA energy expenditure (PAEE) were assessed using a combined heart rate and movement sensor, maximal power output per kilograms of lean body mass as a measure of CRF by maximal cycle ergometer exercise test, and HRV variables (SDNN, RMSSD, LF, and HF) using 5 min resting electrocardiography. Data were analysed by linear regression adjusted for years from peak height velocity. RESULTS: In boys, ST was inversely associated (ß = - 0.185 to - 0.146, p ≤ 0.049) and MVPA, VPA, PAEE, and CRF were directly associated (ß = 0.147 to 0.320, p ≤ 0.048) with HRV variables. CRF was directly associated with all HRV variables and PAEE was directly associated with RMSSD after mutual adjustment for ST, PAEE, and CRF (ß = 0.169 to 0.270, p ≤ 0.046). In girls, ST was inversely associated (ß = - 0.382 to - 0.294, p < 0.001) and LPA, MPA, VPA, MVPA, and PAEE were directly associated with HRV variables (ß = 0.144 to 0.348, p ≤ 0.049). After mutual adjustment for ST, PAEE, and CRF, only the inverse associations of ST with HRV variables remained statistically significant. CONCLUSIONS: Higher ST and lower PA and CRF were associated with poorer cardiac autonomic nervous system function in children. Lower CRF in boys and higher ST in girls were the strongest correlates of poorer cardiac autonomic function.

Associations of Cardiorespiratory Fitness and Adiposity With Arterial Stiffness and Arterial Dilatation Capacity in Response to a Bout of Exercise in Children.

Purpose: To investigate the associations of directly measured peak oxygen uptake ( V˙O2peak ) and body fat percentage (BF%) with arterial stiffness and arterial dilatation capacity in children. Methods: Findings are based on 329 children (177 boys and 152 girls) aged 8-11 years. V˙O2peak was assessed by a maximal cardiopulmonary exercise test on a cycle ergometer and scaled by lean body mass (LM). BF% and LM were measured by bioelectrical impedance. Stiffness index (measure of arterial stiffness) and change in reflection index (ΔRI, measure of arterial dilatation capacity) were assessed by pulse contour analysis. Data were analyzed by linear regression models. Results:V˙O2peak/LM was positively associated with ΔRI in boys adjusted for age and BF% (ß = 0.169, P = .03). Further adjustments for systolic blood pressure, heart rate, and the study group had no effect on this association, but additional adjustment for clinical puberty attenuated it (ß = 0.171, P = .07). BF% was inversely related to ΔRI in boys adjusted for age and V˙O2peak/LM (ß = -0.171, P = .03). V˙O2peak or BF% was not associated with ΔRI in girls or with stiffness index in either boys or girls. Conclusion: Increasing cardiorespiratory fitness and decreasing adiposity may improve arterial health in childhood, especially among boys.

Associations of Objectively Measured Physical Activity and Sedentary Time With Arterial Stiffness in Pre-Pubertal Children.

PURPOSE: To investigate the relationships of objectively measured physical activity (PA) and sedentary time (ST) to arterial stiffness in prepubertal children. METHOD: Altogether 136 children (57 boys, 79 girls) aged 6-8-years participated in the study. Stiffness index (SI) was assessed by pulse contour analysis based on photoplethysmography. ST, light PA, moderate PA, and vigorous PA were assessed using combined acceleration and heart rate monitoring. We investigated the associations of ST (<1.5METs) and time spent in intensity level of PA above 2-7METs in min/d with SI using linear regression analysis. We studied the optimal duration and intensity of PA to identify children being in the highest quarter of SI using Receiver Operating Characteristics curves. RESULTS: Moderate PA, vigorous PA, and cumulative time spent in PA above 3 (ß=-0.279, p = .002), 4 (ß =-0.341, P<0.001), 5 (ß =-0.349, P<0.001), 6 (ß =-0.312, P<0.001), and 7 (ß =-0.254, p = .005) METs were inversely associated with SI after adjustment for age, sex, and monitor wear time. The cutoffs for identifying children being in the highest quarter of SI <68 min/d for PA exceeding 5 METs and <26 min/d for PA exceeding 6 METs. CONCLUSION: Lower levels of PA exceeding 3-6 METs were related to higher arterial stiffness in children.

Finger skin temperatures in 8- to 11-year-old children: determinants including physical characteristics and seasonal variation. The Physical Activity and Nutrition in Children (PANIC) Study.

PURPOSE: The fingertip skin temperature (FST) reflects skin blood flow, and FST measurement has been suggested for the investigation of vascular responses. As a limitation, the multifactorial nature and the seasonal variation in measured values have been earlier described in adults but not in children. In the present study, we identify the modifiers of FST in a population sample of Finnish children. METHODS: FST was measured in children (age range 8-11 years, n = 432) with infrared thermometer, and its possible determinants including the subjects' physical characteristics and seasonal variables, such as daylight time and outdoor temperature, were identified. RESULTS: In univariate regression models, FST was dependent on the sex, age and anthropometric characteristics of the children with the higher body fat content-related variables and a lower surface area-to-mass ratio as strongest single modifiers of FST. There was interaction between sex and puberty with FST. In addition, FST was directly related to daylight time and outdoor temperature although the children had stayed inside for at least 2 h before the measurements. The FST values were lowest in the winter and highest in the summer. In multivariate regression model, main determinants of FST were a higher body fat percentage (standardized regression coefficient ß = 0.472; p < 0.001), male sex (ß = 0.291; p < 0.001) and longer daylight time (0.226; p < 0.001). CONCLUSIONS: Altogether, complex effects of body composition and sex with the confounding effect of seasonal variation may complicate the use of FST as a tool to study the vascular function in children.

Cardiorespiratory fitness, respiratory function and hemodynamic responses to maximal cycle ergometer exercise test in girls and boys aged 9-11 years: the PANIC Study.

PURPOSE: We aimed to provide comprehensive data on and reference values for cardiorespiratory fitness, respiratory function and hemodynamic responses during and after maximal cycle ergometer test in children. METHODS: The participants were a population sample of 140 children (69 girls) aged 9-11 years. Heart rate (HR) and systolic blood pressure (SBP) were measured from pre-exercise rest to the end of recovery. Respiratory gases were measured directly by the breath-by-breath method. Peak workload, HR changes, peak oxygen uptake (VO2), peak oxygen pulse (O2 pulse), peak respiratory exchange ratio (RER) and the lowest ratio of ventilation and carbon dioxide output (VE/VCO2) during the exercise test in girls and boys were presented according to their distributions in 5 categories. RESULTS: HR decreased more during 4-min recovery in boys than in girls (76 vs. 67 beats/min, p < 0.001), whereas SBP decrease was similar in boys and girls (30 vs. 22 mmHg, p = 0.66). Boys had a higher peak VO2 per weight [51.9 vs. 47.6 ml/kg/min, p < 0.001] and per lean mass [67.3 vs. 63.0 ml/kg/min, p < 0.001] than girls. Peak O2 pulse per lean mass was higher in boys than in girls (0.34 vs. 0.31 ml/kg/beat, p < 0.001). There was no difference in the lowest VE/VCO2 during the test between boys and girls (28 vs. 29, p = 0.18). CONCLUSIONS: The indicators of cardiorespiratory fitness were better in boys than in girls. These data enable the evaluation of cardiorespiratory function during and after maximal exercise test and the detection of children with abnormal values.

Metabolic risk factors are associated with stiffness index, reflection index and finger skin temperature in children--Physical Activity and Nutrition in Children (PANIC) study.

BACKGROUND: Childhood metabolic syndrome (MetS) has been found to predict adulthood MetS, type 2 diabetes and cardiovascular disease, emphasizing the early identification of children at increased risk of these diseases. Children with clustering of metabolic risk factors have been reported to have a mild arterial stiffness and endothelial dysfunction, but limited evidence is available from population-based samples of children. METHODS AND RESULTS: The associations of metabolic risk factors with arterial stiffness, tone and endothelial function were studied in 173 prepubertal children (90 girls) 6-8 years of age. MetS was assessed both by continuous MetScore and dichotomously. Stiffness index (SI), reflection index (RI) and finger skin temperature (FST) were measured before and after maximum exercise test, and percent change was calculated for RI (RI%Δ) and FST (FST%Δ). MetScore (r=0.26, P=0.001), fasting insulin (r=0.24, P=0.002), fasting triglycerides (r=0.20, P=0.009), systolic (SBP; r=0.24, P=0.002) and diastolic blood pressure (DBP; r=0.19, P=0.013) correlated with SI. MetScore (r=-0.17, P=0.024, r=0.21, P=0.006), waist circumference (r=-0.19, P=0.012, r=0.23, P=0.003) and SBP (r=-0.16, P=0.035, r=0.21, P=0.005) correlated with RI and FST. High-density lipoprotein cholesterol correlated with FST (r=-0.22, P=0.004) and FST%Δ (r=-0.24, P=0.002). RI decreased and FST increased with exercise (P<0.001). Waist circumference correlated inversely with RI%Δ in boys (r=-0.22, P=0.046) and directly with RI%Δ in girls (r=0.27, P=0.011). CONCLUSIONS: Metabolic risk factors are associated with arterial stiffness, tone and endothelial function in prepubertal children.

Associations of physical activity, sedentary time, and diet quality with biomarkers of inflammation in children.

We investigated the associations of physical activity (PA), sedentary time (ST), and diet quality with biomarkers of inflammation in 390 children (192 girls, 198 boys) aged 6-8 years. PA energy expenditure (PAEE), light PA, moderate PA (MPA), vigorous PA (VPA), moderate-to-vigorous PA (MVPA), and ST were assessed by combined movement and heart rate sensor. Finnish Children Healthy Eating Index was calculated using data from 4 d food records. Body fat percentage (BF%) was measured by dual-energy X-ray absorptiometry. High-sensitivity C-reactive protein (Hs-CRP), leptin, interleukin-6 (IL-6), adiponectin, tumour necrosis factor-α, and glycoprotein acetyls were measured from fasting blood samples. PAEE, MPA, VPA, and MVPA were inversely associated with hs-CRP (ß=-191 to -139, 95% CI=-0.294 to -0.024), leptin (ß=-0.409 to -0.301, 95% CI=-0.499 to -0.107), IL-6 (ß=-0.136 to -0.104, 95% CI=-0.240 to -0.001) and PAEE, MPA, and MVPA were inversely associated with glycoprotein acetyls (ß=-0.117 to -0.103, 95% CI=-0.213 to -0.001). ST was directly associated with hs-CRP (ß=0.170, 95% CI=0.070-0.269), leptin (ß=0.355, 95% CI=0.265-0.445), and IL-6 (ß=0.105, 95% CI=0.005-0.205). VPA was inversely associated with hs-CRP, leptin, and IL-6 in children with higher BF% (ß=-0.344 to -0.181, 95% CI=-0.477 to -0.033) but not among children with lower BF% (ß=-0.007-0.033, 95% CI=-0.183-0.184). In conclusion, PA was inversely and ST directly associated with circulating levels of biomarkers of inflammation among children. Furthermore, we observed that PA was inversely associated with these biomarkers for inflammation in children with a higher BF%. HighlightsSystemic inflammation, as indicated by increased circulating concentrations of biomarkers for inflammation, may be important in causal pathways leading to insulin resistance, sub-clinical atherosclerosis, and eventually clinical manifestations of cardiovascular diseases.Higher levels of physical activity and lower levels of sedentary time were associated with more favourable inflammatory profile.Body fat percentage modified these associations and especially vigorous intensity physical activity was inversely associated with biomarkers of inflammation on children with higher body fat percentage but not in children with lower body fat percentage.

Reproducibility of pulse wave velocity and augmentation index derived from non-invasive occlusive oscillometric tonometry analysis in adolescents.

The aim of this study was to investigate the short-term reproducibility of aortic pulse wave velocity (PWVao) and augmentation index (AIx%) assessed by the non-invasive oscillometric device. Altogether of 55 (19 boys, 36 girls) adolescents 16-19-years-of-age participated in the study. PWVao and AIx% were measured during the same laboratory visit at 2 min intervals using the Arteriograph™ device. Peak oxygen uptake (V̇O2peak ) was assessed by the maximal exercise test on a cycle ergometer and body fat percentage by bioelectrical impedance analysis. We studied reproducibility using intraclass correlation coefficients (ICC), coefficient variation with the root-means-square method expressed as percentages (CV%), and 95% limit of agreement (95% LA) and coefficient repeatability of the Bland-Altman plot. ICC for PWVao was 0·90, CV% 3·7 and the limits of agreement were -0·70 and 0·58 with a coefficient repeatability of 0·65. ICC for AIx% was 0·88, CV% 29·1%, and the limits of agreement were -6·8 and 7·1 with a coefficient repeatability of 6·9. No relevant differences in ICC, CV%, and coefficient repeatability for PWVao between adolescents with higher or lower V̇O2peak or body fat percentage were observed. For AIx%, ICC was lower, CV% higher and coefficient repeatability higher in adolescents with higher V̇O2peak or lower body fat percentage than in adolescents with lower V̇O2peak or higher body fat percentage. Short-term reproducibility of Arteriograph™-derived PWVao was relatively good and was not affected by V̇O2peak or adiposity. However, the reproducibility of AIx% was modest especially among adolescents with higher V̇O2peak and lower body fat percentage.

Normal values for heart rate variability parameters in children 6-8 years of age: the PANIC Study.

BACKGROUND: Measurement of heart rate variability (HRV) is a useful method for examining cardiac autonomic control. HRV has been measured in many studies among adults, but research on this topic among children is limited. We therefore defined reference values for a large number of HRV parameters among children. METHODS: The subjects were a population sample of 465 mainly prepubertal children 6-8 years of age. Electrocardiogram (ECG) was recorded at rest, and 1- and 5-min ECG samples were selected for HRV analyses. HRV data were analysed in boys and girls separately to study possible gender differences in HRV parameters. Pearson's coefficients for correlation of age, maturity stage, height, weight and body mass index - standard deviation score (BMI-SDS) with HRV parameters were computed to study whether these factors confounded the definition of the reference values for HRV parameters. RESULTS: We found no statistically significant differences in HRV parameters between genders. Therefore, we defined the reference values for all HRV parameters as 5th, 25th, 50th, 75th and 95th percentiles from the ECG samples in all children, but not in boys and girls separately. Age, maturity stage, height, weight and BMI-SDS had weak, if any, associations with HRV parameters, suggesting that they did not confound the definition of the reference values. CONCLUSION: Same reference values for HRV parameters can be used in boys and girls. Although 5-min ECG recordings are preferable for measuring HRV, also 1-min recordings provide reliable data on most HRV parameters, especially those that mainly describe cardiac parasympathetic regulation.

Reproducibility of pulse contour analysis in children before and after maximal exercise stress test: the Physical Activity and Nutrition in Children (PANIC) study.

OBJECTIVE: Arterial stiffness index (SI) and reflection index (RI) from digital pulse contour analysis have been shown to be good measures of arterial stiffness and may be useful in the evaluation of endothelial function. Finger skin temperature (FST) is also considered to reflect peripheral circulatory functions. We evaluated the reproducibility of SI, RI and FST before and after the exercise stress test. METHODS: The subjects were 36 children (16 boys, 20 girls) 6-8 years of age. We measured SI, RI and FST at rest both before and after the exercise stress test on a cycle ergometer and repeated these measurements within 5-14 days. The reproducibility of SI, RI and FST was evaluated by calculating intraclass correlation coefficients (ICC), coefficients of variation (CV%) and 95% limits of agreements. RESULTS: SI had a greater reproducibility after the exercise stress test than before it (CV% 4·8 versus 6·3%, ICC 0·548 versus 0·438). RI had a better ICC (0·689 versus 0·416) but a higher CV% (28·6 versus 18·7%) after the exercise stress test than before it. Relative change in response to the exercise stress test in SI (-1·5% at first visit and 0·4% at second visit) was not as dramatic as in RI (-49·3% at first visit and -46·5% at second visit). The reproducibility of FST was also better after the exercise test than before it (CV% 5·7 versus 10·0%, ICC 0·509 versus 0·503). CONCLUSION: In healthy children, the reproducibility of SI, RI and FST was relatively good, especially after the exercise stress test.