Point-of-care β-hydroxybutyrate measurement predicts adequate glucose metabolism suppression in cardiac FDG-PET/CT

AIMS

The aims of our study were to evaluate whether point-of-care β-hydroxybutyrate (BHB) measurement can be used to identify patients with adequate cardiac glucose metabolism suppression for cardiac [18F]-fluoro-2-deoxy- d-glucose-positron emission tomography with computerized tomography (FDG-PET/CT) and to develop a pretest probability calculator of myocardial suppression using other metabolic factors attainable before imaging.

METHODS AND RESULTS

We recruited 193 patients with any clinical indication for whole body [18F]-FDG-PET/CT. BHB level was measured with a point-of-care device. Maximal myocardial standardized uptake value using lean body mass (SULmax) was measured from eight circular regions of interest with 1 cm circumference and background from left ventricular blood pool. Correlations SULmax and point-of-care measured BHB were analysed. The ability of BHB test to predict adequate suppression was evaluated with receiver operating characteristic analysis. Liver and spleen attenuation in computed tomography were measured to assess the presence of fatty liver. BHB level correlated with myocardial uptake and, using a cut-off value of 0.35 mmol/L to predict adequate myocardial suppression, we reached specificity of 90% and sensitivity of 56%. Other variables to predict adequate suppression were diabetes, obesity, ketogenic diet and fatty liver. Using information attainable before imaging, we created a pretest probability calculator of inadequate myocardial glucose metabolism suppression. The area under the curve for BHB test alone was 0.802 and was 0.857 for the pretest calculator (p = 0.319).

CONCLUSIONS

BHB level measured with a point-of-care device is useful in predicting adequate myocardial glucose metabolism suppression. More detailed assessment of other factors potentially contributing to cardiac metabolism is needed.

Cross-sectional associations between physical fitness and biomarkers of inflammation in children-The PANIC study

BACKGROUND

Systemic low-grade inflammation has been proposed as an underlying pathophysiological mechanism for cardiometabolic diseases. We investigated the associations of physical fitness with a systemic low-grade inflammatory state in a population sample of children.

METHODS

Altogether 391 children aged 6-9 years were examined. Cardiorespiratory fitness (maximal power output, W_max ) was assessed by a maximal cycle ergometer test and neuromuscular fitness by hand grip strength, sit-up, standing long jump, 50-meter shuttle run, static balance, sit-and-reach, and box and block tests. Body fat percentage (BF%) and lean mass (LM) were assessed by dual-energy X-ray absorptiometry (DXA). High sensitivity C-reactive protein (hs-CRP), leptin, leptin receptor, high molecular weight adiponectin (HMW-adiponectin), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and glycoprotein acetyls (GlycA) were assessed from fasting blood samples. The modified inflammatory score (IS) was calculated using the population-specific z-scores and formula (^z hs-CRP + ^z leptin + ^z IL-6 + ^z TNF-α + ^z GlycA)-^z leptin receptor-^z HMW-adiponectin. The data were analyzed using linear regression analyses.

RESULTS

Higher W_max /kg of body mass (β = -0.416, 95% CI = -0.514 to -0.318), higher number of completed sit-ups (β = -0.147, 95% CI = -0.244 to -0.049), a longer distance jumped in the standing long jump test (β = -0.270, 95% CI = -0.371 to -0.169), and a shorter time in the 50-meter shuttle run test (β = 0.123, 95% CI = 0.022 to 0.223) were associated with lower IS. None of these associations remained statistically significant after adjustment for BF%.

CONCLUSIONS

Higher physical fitness is associated with a more favorable inflammatory biomarker profile in children. However, the associations were explained by BF%.

Cross-sectional associations between cardiorespiratory fitness and NMR-derived metabolic biomarkers in children - the PANIC study

OBJECTIVE

Cardiorespiratory fitness has been inversely associated with cardiovascular risk across the lifespan. Some studies in adults suggest that higher cardiorespiratory fitness is associated with cardioprotective metabolite profile, but the evidence in children is lacking. Therefore, we investigated the cross-sectional association of cardiorespiratory fitness with serum nuclear magnetic resonance derived metabolic biomarkers in children.

METHODS

A population sample of 450 children aged 6-8 years was examined. Cardiorespiratory fitness was assessed by a maximal exercise test on a cycle ergometer and quantified as maximal power output normalised for lean body mass assessed by dual-energy X-ray absorbtiometry. Serum metabolites were assessed using a high throughput nuclear magnetic resonance platform. The data were analysed using linear regression analyses adjusted for age and sex and subsequently for body fat percentage (BF%) assessed by DXA.

RESULTS

Cardiorespiratory fitness was directly associated with high density lipoprotein (HDL) cholesterol (β=0.138, 95% CI=0.042 to 0.135, p=0.005), average HDL particle diameter (β=0.102, 95% CI=0.004 to 0.199, p=0.041), and the concentrations of extra-large HDL particles (β=0.103, 95% CI=0.006 to 0.201, p=0.038), large HDL particles (β=0.122, 95% CI=0.025 to 0.220, p=0.014), and medium HDL particles (β=0.143, 95% CI=0.047 to 0.239, p=0.004) after adjustment for age and sex. Higher cardiorespiratory fitness was also associated with higher concentrations of ApoA1 (β=0.145, 95% CI=0.047 to 0.242, p=0.003), glutamine (β=0.161, 95% CI=0.064 to 0.257, p=0.001), and phenylalanine (β=0.187, 95% CI=0.091 to 0.283, p<0.001). However, only the direct associations of cardiorespiratory fitness with the concentrations of HDL cholesterol (β=0.114, 95% CI=0.018 to 0.210, p=0.021), medium HDL particles (β=0.126, 95% CI=0.030 to 0.223, p=0.010), ApoA1 (β=0.126, 95% CI=0.030 to 0.223, p=0.011), glutamine (β=0.147, 95% CI=0.050 to 0.224, p=0.003), and phenylalanine (β=0.217, 95% CI=0.122 to 0.311, p<0.001) remained statistically significant after further adjustment for BF%.

CONCLUSIONS

Higher cardiorespiratory fitness was associated with a cardioprotective biomarker profile in children. Most associations were independent of BF% suggesting that the differences in serum metabolites between children are driven by cardiorespiratory fitness and not adiposity.

Changes in body composition by age and obesity status in preschool-aged children: the STEPS study

BACKGROUND/OBJECTIVES

Obesity in early childhood is associated with increased risk of chronic diseases, but studies of body composition at preschool ages are sparse. Therefore, we examined differences in body composition by sex and obesity status in Finnish preschool-aged children and within-individual changes in body composition in normal and overweight children.

SUBJECT/METHODS

Body composition was measured using segmental multifrequency bioimpedance analysis (BIA) in 476 children and in 781 children at age 3 and 5 years, respectively. Of those, 308 had repeated BIA measurements at both ages. BMI-SDS was used for classification of normal weight and overweight children.

RESULTS

Sex difference in the amount of lean mass (LM) was already seen at 3 years of age (boys 11.7 kg, girls 11.3 kg; p < 0.001). At 5 years of age, boys had lower fat mass (FM; 3.6 kg vs. 3.9 kg, p < 0.001), lower percent fat mass (%FM; 17.2% vs. 19.1%; p < 0.001), and higher LM (16.0 kg vs. 15.2 kg; p < 0.001) than girls. Overweight children had higher values in FM, %FM, and LM compared with normal weight peers at both ages. Among normal weight children, the increase of LM by age was associated with only minor changes in FM, whereas children who were or became overweight both LM and FM was substantially increased between 3 and 5 years of age.

CONCLUSIONS

BIA-assessed body composition differs by sex and obesity status already at age of 3 years. For children who are or become overweight at very young age, the patterns for the changes in LM and FM by age are different than for normal weight children.

Cardiorespiratory Fitness, Physical Activity, and Insulin Resistance in Children

PURPOSE

Few studies have investigated the independent and joint associations of cardiorespiratory fitness (CRF) and body fat percentage (BF%) with insulin resistance in children. We investigated the independent and combined associations of CRF and BF% with fasting glycemia and insulin resistance and their interactions with physical activity (PA) and sedentary time among 452 children age 6 to 8 yr.

METHODS

We assessed CRF with a maximal cycle ergometer exercise test and used allometrically scaled maximal power output (Wmax) for lean body mass (LM) and body mass (BM) as measures of CRF. The BF% and LM were measured by dual-energy X-ray absorptiometry, fasting glycemia by fasting plasma glucose, and insulin resistance by fasting serum insulin and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The PA energy expenditure, moderate-to-vigorous PA (MVPA), and sedentary time were assessed by combined movement and heart rate sensor.

RESULTS

Wmax/LM was not associated with glucose (β = 0.065, 95% confidence interval [CI] = -0.031 to 0.161), insulin (β = -0.079, 95% CI = -0.172 to 0.015), or HOMA-IR (β = -0.065, 95% CI = -0.161 to 0.030). Wmax/BM was inversely associated with insulin (β = -0.289, 95% CI = -0.377 to -0.200) and HOMA-IR (β = -0.269, 95% CI = -0.359 to -0.180). The BF% was directly associated with insulin (β = 0.409, 95% CI = 0.325 to 0.494) and HOMA-IR (β = 0.390, 95% CI = 0.304 to 0.475). Higher Wmax/BM, but not Wmax/LM, was associated with lower insulin and HOMA-IR in children with higher BF%. Children with higher BF% and who had lower levels of MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR.

CONCLUSIONS

Children with higher BF% together with less MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR. Cardiorespiratory fitness appropriately controlled for body size and composition using LM was not related to insulin resistance among children.

Longitudinal Associations of Fitness, Motor Competence, and Adiposity with Cognition

PURPOSE

The purpose of this study was to investigate the longitudinal associations of cardiorespiratory fitness (CRF), motor competence (MC), and body fat percentage (BF%) with cognition in children.

METHODS

Altogether, 371 children (188 boys and 183 girls) 6-9 yr of age at baseline participated in this 2-yr follow-up study. We assessed CRF by maximal cycle ergometer test, computed the MC score from the z-scores of the 50-m shuttle run, static balance, and box and block test results, measured BF% by dual-energy x-ray absorptiometry, and assessed cognition using the Raven's Coloured Progressive Matrices (RCPM) score. The associations were studied by linear regression analysis and repeated-measures ANCOVA.

RESULTS

In boys, a higher MC score (β = -0.161, 95% confidence interval [CI] = -0.314 to -0.009), a shorter 50-m shuttle run test duration (β = 0.152, 95% CI = 0.007-0.296), and a higher number of cubes moved in the Box and block test (β = -0.161, 95% CI = -0.309 to -0.013) at baseline were associated with a smaller increase in the RCPM score during follow-up. These associations were largely explained by the RCPM score at baseline. However, boys in the highest third (mean difference = 2.5, 95% CI for difference = 0.66-4.33) and the middle third (mean difference = 2.1, 95% CI for difference = 0.39-3.82) of the MC score at baseline had a higher RCPM score over the 2-yr follow-up than boys in the lowest third. CRF, MC, or adiposity was not associated with the RCPM score in girls. Changes in CRF, MC, or BF% were not associated with changes in cognition.

CONCLUSIONS

Higher MC at baseline predicted better cognition during the first two school years in boys but not in girls. CRF or adiposity was not associated with cognition in boys or girls.

Peak oxygen uptake cut-points to identify children at increased cardiometabolic risk - The PANIC Study

We aimed to develop cut-points for directly measured peak oxygen uptake ( V ˙ O 2 peak ) to identify boys and girls at increased cardiometabolic risk using different scaling methods to control for body size and composition. Altogether 352 children (186 boys, 166 girls) aged 9-11 years were included in the analyses. We measured V̇O_2peak directly during a maximal cycle ergometer exercise test and lean body mass (LM) by bioelectrical impedance. We computed a sex- and age-specific cardiometabolic risk score (CRS) by summing important cardiometabolic risk factors and defined increased cardiometabolic risk as >1 standard deviation above the mean of CRS. Receiver operating characteristics curves were used to detect V̇O_2peak cut-points for increased cardiometabolic risk. Boys with V̇O_2peak <45.8 mL kg body mass (BM)^-1  min^-1 (95% confidence interval [CI] = 45.1 to 54.6, area under the curve [AUC] = 0.86, P < 0.001) and <63.2 mL kg LM^-1  min^-1 (95% CI =52.4 to 67.5, AUC = 0.65, P = 0.006) had an increased CRS. Girls with V̇O_2peak <44.1 mL kg BM^-1  min^-1 (95% CI = 44.0 to 58.6, AUC = 0.67, P = 0.013) had an increased CRS. V̇O_2peak scaled by BM^-0.49 and LM^-0.77 derived from log-linear allometric modeling poorly predicted increased cardiometabolic risk in boys and girls. In conclusion, directly measured V ˙ O 2 peak <45.8 mL kg BM^-1  min^-1 among boys and <44.1 mL kg BM^-1  min^-1 among girls were cut-points to identify those at increased cardiometabolic risk. Appropriately controlling for body size and composition reduced the ability of cardiorespiratory fitness to identify children at increased cardiometabolic risk.

Relation of oxygen uptake to work rate in prepubertal healthy children - reference for VO2 /W-slope and effect on cardiorespiratory fitness assessment

PURPOSE

Exercise testing by cycle ergometer allows to observe the interaction between oxygen uptake (VO₂ ) and workload (W), and VO₂ /W-slope can be used as a diagnostic tool. Respectively, peak oxygen uptake (VO_2PEAK ) can be estimated by maximal workload. We aim to determine reference for VO₂ /W-slope among prepubertal children and define agreement between estimated and measured VO_2PEAK .

METHODS

A total of 38 prepubertal children (20 girls) performed a maximal cycle ergometer test with respiratory gas analysis. VO₂ /W-slopes were computed using linear regression. Agreement analysis by Bland and Altman for estimated and measured VO_2PEAK was carried out including limits of agreement (LA). Determinants for VO₂ /W-slopes and estimation bias were defined.

RESULTS

VO2/W-slope was in both girls and boys ≥9·4 and did not change with exercise level, but the oxygen cost of exercise was higher among physically more active children. Estimated VO_2PEAK had 6·4% coefficient of variation, and LA varied from 13% underestimation to 13% overestimation. Bias had a trend towards underestimation along lean mass proportional VO_2PEAK . The primary determinant for estimation bias was VO2/W-slope (β = -0·65; P<0·001).

CONCLUSION

The reference values for VO₂ /W-slope among healthy prepubertal children were similar to those published for adults and among adolescents. Estimated and measured VO_2PEAK should not be considered to be interchangeable because of the variation in the relationship between VO₂ and W. On other hand, variation in the relationship between VO₂ and W enables that VO₂ /W-slope can be used as a diagnostic tool.

Adiposity, physical activity and neuromuscular performance in children

We investigated the associations of body fat percentage (BF%), objectively assessed moderate-to-vigorous physical activity (MVPA) and different types of physical activity assessed by a questionnaire with neuromuscular performance. The participants were 404 children aged 6-8 years. BF% was assessed using dual-energy x-ray absorptiometry and physical activity by combined heart rate and movement sensing and a questionnaire. The results of 50-m shuttle run, 15-m sprint run, hand grip strength, standing long jump, sit-up, modified flamingo balance, box-and-block and sit-and-reach tests were used as measures of neuromuscular performance. Children who had a combination of higher BF% and lower levels of physical activity had the poorest performance in 50-m shuttle run, 15-m sprint run and standing long jump tests. Higher BF% was associated with slower 50-m shuttle run and 15-m sprint times, shorter distance jumped in standing long jump test, fewer sit-ups, more errors in balance test and less cubes moved in box-and-block test. Higher levels of physical activity and particularly MVPA assessed objectively by combined accelerometer and heart rate monitor were related to shorter 50-m shuttle run and 15-m sprint times. In conclusion, higher BF% and lower levels of physical activity and particularly the combination of these two factors were associated with worse neuromuscular performance.

Associations of cardiorespiratory fitness, physical activity, and adiposity with arterial stiffness in children

Associations of cardiorespiratory fitness (CRF), physical activity (PA), sedentary behavior, and body fat percentage (BF%) with arterial stiffness and dilation capacity were investigated in 160 prepubertal children (83 girls) 6-8 years of age. We assessed CRF (watts/lean mass) by maximal cycle ergometer exercise test, total PA, structured exercise, unstructured PA, commuting to and from school, recess PA and total and screen-based sedentary behavior by questionnaire, BF% using dual-energy X-ray absorptiometry, and arterial stiffness and dilation capacity using pulse contour analysis. Data were adjusted for sex and age. Poorer CRF (standardized regression coefficient β = -0.297, P < 0.001), lower unstructured PA (β = -0.162, P = 0.042), and higher BF% (β = 0.176, P = 0.044) were related to higher arterial stiffness. When CRF, unstructured PA, and BF% were in the same model, only CRF was associated with arterial stiffness (β = -0.246, P = 0.006). Poorer CRF was also related to lower arterial dilation capacity (β = 0.316, P < 0.001). Children with low CRF (< median) and high BF% (≥ median; P = 0.002), low CRF and low unstructured PA (< median; P = 0.006) or children with low unstructured PA and high BF% (P = 0.005) had higher arterial stiffness than children in the opposite halves of these variables. Poor CRF was independently associated with increased arterial stiffness and impaired arterial dilation capacity among children.

Associations of motor and cardiovascular performance with academic skills in children

PURPOSE

We investigated the associations of cardiovascular and motor performance in grade 1 with academic skills in grades 1-3.

METHODS

The participants were 6- to 8-yr-old children with complete data in grades 1-2 for 174 children and in grade 3 for 167 children. Maximal workload during exercise test was used as a measure of cardiovascular performance. The shuttle run test (SRT) time, the errors in balance test, and the number of cubes moved in box and block test (BBT) were measures of motor performance. Academic skills were assessed using reading fluency, reading comprehension, and arithmetic skill tests.

RESULTS

Among boys, longer SRT time was associated with poorer reading fluency in grades 1-3 (β = -0.29 to -0.39, P < 0.01), reading comprehension in grades 1-2 (β = -0.25 to -0.29, P < 0.05), and arithmetic skills in grades 1-3 (β = -0.33 to -0.40, P < 0.003). Poorer balance was related to poorer reading comprehension (β = -0.20, P = 0.042). The smaller number of cubes moved in BBT was related to poorer reading fluency in grades 1-2 (β = 0.23-0.28, P < 0.03), reading comprehension in grade 3 (β = 0.23, P = 0.037), and arithmetic skills in grades 1-2 (β = 0.21-0.23, P < 0.043). Among girls, longer SRT time was related to poorer reading fluency in grade 3 (β = -0.27, P = 0.027) and arithmetic skills in grade 2 (β = -0.25, P = 0.040). The smaller number of cubes moved in BBT was associated with worse reading fluency in grade 2 (β = 0.26, P = 0.030). Cardiovascular performance was not related to academic skills.

CONCLUSIONS

Poorer motor performance was associated with worse academic skills in children, especially among boys. These findings emphasize early identification of children with poor motor performance and actions to improve these children's motor performance and academic skills during the first school years.

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.

The presentation of adrenarche is sexually dimorphic and modified by body adiposity

CONTEXT

Adrenarche refers to the onset of increased production of adrenal androgens in childhood leading variably to clinical signs of androgen action. The prevalence and presentation of adrenarche in prepubertal girls and boys is not well known.

OBJECTIVE

Our objective was to examine the prevalence and clinical presentation of adrenarche in a population sample of prepubertal children aged less than 9 years.

DESIGN AND PARTICIPANTS

This cross-sectional study included prepubertal children (209 girls and 228 boys; median age 7.6 [range 6.8-8.9] years) taking part in The Physical Activity and Nutrition in Children (PANIC) Study.

MAIN OUTCOME MEASURE

The prevalence of adrenarche was assessed.

RESULTS

The prevalence of any clinical sign of androgen action was higher in girls than in boys (26.1% vs 10.0%; P < .001) and biochemical adrenarche without any clinical sign was less common in girls than in boys (8.1% vs 16.7%; P = .007). When premature adrenarche was defined by serum dehydroepiandrosterone sulfate concentration ≥1 μmol/L (≥37 μg/dL) and any clinical sign before the age of 8 years in girls and 9 years in boys, its total prevalence was 8.6% in girls and 1.8% in boys. The risk of having any clinical sign increased with higher body fat percentage in boys and with higher serum dehydroepiandrosterone sulfate concentration in girls.

CONCLUSIONS

Clinical signs of androgen action are more common, but biochemical adrenarche without any clinical sign is less common in prepubertal girls than boys. This sexual dimorphism of adrenarche might be explained by sex-dependent differences in peripheral androgen metabolism or action that are modified by body fat.

Measures of cardiorespiratory fitness in relation to measures of body size and composition among children

BACKGROUND

In the exercise testing measures of cardiorespiratory fitness need to be scaled by body size or composition to enable comparison between individuals. Traditionally used weight-proportional measures are potentially confounded by body adiposity that hampers their interpretation and applicability in the clinical assessment of cardiorespiratory fitness.

OBJECTIVE

We aimed to find the most appropriate measure of body size or composition for scaling of measures of cardiorespiratory fitness among children.

METHODS

We assessed body weight and height, maximal workload (W MAX ) and maximal oxygen uptake (VO2 MAX ) using cycle ergometer exercise test with respiratory gas analysis and body lean mass (LM) and fat mass (FM) by dual-energy X-ray absorptiometry and by bioimpedance analysis among 38 children. The data were analysed using Pearson's coefficients for correlation and stepwise linear regression models.

RESULTS

Lean mass (r > 0.54) and height (r > 0.51) had stronger positive correlations with absolute W MAX and VO2 MAX than weight (r > 0.30) in girls and boys. None of the measures of body size or composition correlated with LM-proportional W MAX or VO2 MAX in girls or boys. Only LM correlated positively with height-proportional W MAX (r = 0.65) and VO2 MAX (r = 0.71) in boys. FM correlated negatively with weight-proportional W MAX (r < -0.58) and VO2 MAX (r < -0.64) in girls and boys. FM was even stronger determinant of weight-proportional W MAX (β = -0.68) and VO2 MAX (β = -0.61) than exercise performance in multivariate linear regression models.

CONCLUSIONS

While assessing cardiorespiratory fitness, LM is the most appropriate measure of body size or composition for scaling of W MAX and VO2 MAX, because scaling by body weight introduces confounding by body adiposity.

Validation of metabolic syndrome score by confirmatory factor analysis in children and adults and prediction of cardiometabolic outcomes in adults

AIMS/HYPOTHESIS

We validated the metabolic syndrome (MetS) score by confirmatory factor analysis (CFA) in children, middle-aged men, and older women and men and by investigating the relationships of the MetS score to incident type 2 diabetes, myocardial infarction, and cardiovascular and overall death in middle-aged men.

METHODS

We assessed the core features of MetS, calculated the MetS score using z scores for waist circumference, insulin, glucose, triacylglycerols, HDL-cholesterol and blood pressure, and carried out CFA to investigate whether MetS represents a single entity in population samples of 491 children, 1,900 middle-aged men, 614 older women and 555 older men from Finland. We also followed-up incident type 2 diabetes for 11 years and other outcomes for 17-18 years in middle-aged men.

RESULTS

We carried out second-order CFAs in which the MetS was represented by a second-order latent variable underlying four latent variables characterised by abdominal obesity, insulin resistance, dyslipidaemia and raised blood pressure in different age groups. These second-order factors and factors derived from first-order CFA using previously proposed models were strongly associated with a composite MetS score in all age groups (r = 0.84-0.94) and similarly predicted type 2 diabetes, cardiovascular outcomes and mortality in middle-aged men. The risk of type 2 diabetes, myocardial infarction, cardiovascular death and overall death increased 3.67-, 1.38-, 1.56- and 1.44-fold, respectively, for a 1 SD increase in the MetS score.

CONCLUSIONS

The MetS can be described as a single entity in all age groups. The MetS score is a valid tool for research evaluating cardiometabolic risk in different age groups. Further research is needed to define cut-off points for risk estimation in clinical practice.

Physical activity and sedentary behaviour in relation to cardiometabolic risk in children: cross-sectional findings from the Physical Activity and Nutrition in Children (PANIC) Study

Background

Lower levels of physical activity (PA) and sedentary behaviour (SB) have been associated with increased cardiometabolic risk among children. However, little is known about the independent and combined associations of PA and SB as well as different types of these behaviours with cardiometabolic risk in children. We therefore investigated these relationships among children.

Methods

The subjects were a population sample of 468 children 6–8 years of age. PA and SB were assessed by a questionnaire administered by parents and validated by a monitor combining heart rate and accelerometry measurements. We assessed body fat percentage, waist circumference, blood glucose, serum insulin, plasma lipids and lipoproteins and blood pressure and calculated a cardiometabolic risk score using population-specific Z-scores and a formula waist circumference + insulin + glucose + triglycerides - HDL cholesterol + mean of systolic and diastolic blood pressure. We analysed data using multivariate linear regression models.

Results

Total PA was inversely associated with the cardiometabolic risk score (β = -0.135, p = 0.004), body fat percentage (β = -0.155, p < 0.001), insulin (β = -0.099, p = 0.034), triglycerides (β = -0.166, p < 0.001), VLDL triglycerides (β = -0.230, p < 0.001), VLDL cholesterol (β = -0.168, p = 0.001), LDL cholesterol (β = -0.094, p = 0.046) and HDL triglycerides (β = -0.149, p = 0.004) and directly related to HDL cholesterol (β = 0.144, p = 0.002) adjusted for age and gender. Unstructured PA was inversely associated with the cardiometabolic risk score (β = -0.123, p = 0.010), body fat percentage (β = -0.099, p = 0.027), insulin (β = -0.108, p = 0.021), triglycerides (β = -0.144, p = 0.002), VLDL triglycerides (β = -0.233, p < 0.001) and VLDL cholesterol (β = -0.199, p < 0.001) and directly related to HDL cholesterol (β = 0.126, p = 0.008). Watching TV and videos was directly related to the cardiometabolic risk score (β = 0.135, p = 0.003), body fat percentage (β = 0.090, p = 0.039), waist circumference (β = 0.097, p = 0.033) and systolic blood pressure (β = 0.096, p = 0.039). Resting was directly associated with the cardiometabolic risk score (β = 0.092, p = 0.049), triglycerides (β = 0.131, p = 0.005), VLDL triglycerides (β = 0.134, p = 0.009), VLDL cholesterol (β = 0.147, p = 0.004) and LDL cholesterol (β = 0.105, p = 0.023). Other types of PA and SB had less consistent associations with cardiometabolic risk factors.

Conclusions

The results of our study emphasise increasing total and unstructured PA and decreasing watching TV and videos and other sedentary behaviours to reduce cardiometabolic risk among children.

Trial registration

ClinicalTrials.gov Identifier: NCT01803776.

Cardiovascular fitness and haemodynamic responses to maximal cycle ergometer exercise test in children 6-8 years of age

We investigated cardiovascular fitness and haemodynamic responses to maximal cycle ergometer exercise test in children. The participants were a population sample of 425 children (204 girls, 221 boys) aged 6-8 years. Heart rate (HR) and systolic blood pressure (SBP) were measured from the beginning of pre-exercise rest to the end of recovery period. We provided reference values for peak workload and changes in HR and SBP during and after maximal exercise test in girls and boys. Girls had a lower cardiovascular fitness, indicated by peak workload per body weight [mean (2 s) 2.7 (0.9) vs. 3.1 (1.0) W · kg(-1), P < 0.001] and lean mass [mean (2 s) 3.5 (0.9) vs. 3.8 (1.0) W · kg(-1), P < 0.001] than boys. Plateau or decline in SBP close to the end of the test was found in about third of children and was considered a normal SBP response. Girls had a slower HR decrease within 2 min after the test than boys [mean (2 s) 53 (18) vs. 59 (22) beats · min(-1), P < 0.001]. The results are useful for physicians and exercise physiologists to evaluate cardiovascular fitness and haemodynamic responses to exercise in children and to detect children with low exercise tolerance or abnormal haemodynamic responses to exercise.

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.

Craniofacial morphology but not excess body fat is associated with risk of having sleep-disordered breathing--the PANIC Study (a questionnaire-based inquiry in 6-8-year-olds)

We investigated the associations of dental occlusion, other craniofacial features and body fat with paediatric sleep-disordered breathing (SDB) in a representative population sample of 491 Finnish children 6-8 years of age. Overweight and obesity were defined using age- and sex-specific body mass index cutoffs by International Obesity Task Force (IOTF) criteria. Body fat percentage was assessed by dual-energy X-ray absorptiometry. Facial proportions, dental occlusion and soft tissue structures were evaluated by an orthodontist. Sleep was assessed by a sleep questionnaire administered by the parents. SDB was defined as apnoeas, frequent or loud snoring or nocturnal mouth breathing observed by the parents. The prevalence of SDB was 9.9 % with no difference between boys and girls. The median (interquartile range) of body fat percentage was 20.6 (17.4-27.1) in girls and 15.0 (11.4-21.6) in boys. Altogether 11.4 % of boys and 15.6 % of girls were classified as having overweight or obesity according to the IOTF criteria. There was no difference in the prevalence of overweight, obesity or body fat percentage between children with SDB and those without it. Children with tonsillar hypertrophy had a 3.7 times higher risk of suffering SDB than those with normal size tonsils after adjustment for age, sex and body fat percentage. Furthermore, children with cross bite had a 3.3 times higher risk of having SDB than those without cross bite, and children with a convex facial profile had a 2.6 times higher risk of having SDB than those with a normal facial profile.

CONCLUSION

Abnormal craniofacial morphology, but not excess body fat, is associated with an increased risk of having SDB in 6-8-year-old children. A simple model of necessary clinical examinations (i.e. facial profile, dental occlusion and tonsils) is recommended to recognize children with an increased risk of SDB.

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.

The effect of probiotic fermented milk and inulin on the functions and microecology of the intestine

We investigated the effects of a probiotic fermented milk and inulin on gastrointestinal function and microecology. The study was double-blinded and comprised 66 healthy adults (22 male, 44 female), mean age 40 years (range, 22-60 years). After a 12-d baseline period the subjects were randomized to consume, for 3 weeks, 3x200 ml daily of either (1) a fermented milk with probiotics (Bifidobacterium longum BB536, Bifidobacterium spp. 420 and Lactobacillus acidophilus 145), (2) a fermented milk with the same probiotics plus 4 g inulin, or (3) a control fermented milk. During the last 7 d of the baseline and the intervention periods, the subjects kept a record of their defaecation frequency and gastrointestinal symptoms, and collected all their faeces. Intestinal transit time, stool weight and faecal enzyme activities were measured. Thirty-nine subjects were randomized to give faecal samples for analysis of pH and microbes, including lactobacilli, bifidobacteria, coliforms, Escherichia coli, Bacteroides and Clostridium perfringens. Consumption of fermented milk with probiotics or with probiotics and inulin increased the faecal number of lactobacilli (P=0.009, P=0.003) and bifidobacteria (P=0.046, P=0.038) compared with the baseline. Compared with the control fermented milk, both active products increased lactobacilli (P=0.005, ANCOVA). Subjects consuming fermented milk with probiotics and inulin suffered from gastrointestinal symptoms, especially flatulence, more than the others (P<0.001). In conclusion, the probiotic fermented milk product had a positive effect by increasing the number of lactobacilli and bifidobacteria in the colon. Inulin did not alter this effect but it increased gastrointestinal symptoms.