Associations of diet quality and food consumption with serum biomarkers for lipid and amino acid metabolism in Finnish children: the PANIC study.

PURPOSE: To investigate the associations of overall diet quality and dietary factors with serum biomarkers for lipid and amino acid metabolism in a general population of children. METHODS: We studied 194 girls and 209 boys aged 6-8 years participating in the Physical Activity and Nutrition in Children study. Food consumption was assessed by 4-day food records and diet quality was quantified by the Finnish Children Healthy Eating Index (FCHEI). Fasting serum fatty acids, amino acids, apolipoproteins, as well as lipoprotein particle sizes were analyzed with high-throughput nuclear magnetic resonance spectroscopy. Data were analyzed using linear regression adjusted for age, sex, and body fat percentage. RESULTS: FCHEI was directly associated with the ratio of polyunsaturated (PUFA) to saturated fatty acids (SFA) (PUFA/SFA), the ratio of PUFA to monounsaturated fatty acids (MUFA) (PUFA/MUFA), the ratio of PUFA to total fatty acids (FA) (PUFA%), the ratio of omega-3-fatty acids to total FA (omega-3 FA%), and inversely associated with the ratio of MUFA to total FA (MUFA%), alanine, glycine, histidine and very-low density lipoprotein (VLDL) particle size. Consumption of vegetable oils and vegetable-oil-based margarine (≥ 60% fat) was directly associated with PUFA/SFA, PUFA/MUFA, PUFA%, the ratio of omega-6 FA to total FA (omega-6 FA%), and inversely associated with SFA, MUFA, SFA to total FA (SFA%), MUFA%, alanine and VLDL particle size. Consumption of high-fiber grain products directly associated with PUFA/SFA, PUFA/MUFA, omega-3 FA%, omega-6 FA%, PUFA% and inversely associated with SFA and SFA%. Fish consumption directly related to omega-3 FA and omega-3 FA%. Consumption of sugary products was directly associated with histidine and VLDL particle size. Vegetable, fruit, and berry consumption had direct associations with VLDL particle size and the ratio of apolipoprotein B to apolipoprotein A1. Consumption of low fat (< 1%) milk was directly associated with phenylalanine. A higher consumption of high-fat (≥ 1%) milk was associated with lower serum MUFA/SFA and higher SFA%. Sausage consumption was directly related to SFA% and histidine. Red meat consumption was inversely associated with glycine. CONCLUSIONS: Better diet quality, higher in intake of dietary sources of unsaturated fat and fiber, and lower in sugary product intake were associated with more favorable levels of serum biomarkers for lipid and amino acid metabolism independent of adiposity. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01803776, registered March 3, 2013.

Associations between physical fitness and cerebellar gray matter volume in adolescents.

Despite the importance of the developing cerebellum on cognition, the associations between physical fitness and cerebellar volume in adolescents remain unclear. We explored the associations of physical fitness with gray matter (GM) volume of VI, VIIb and Crus I & II, which are cerebellar lobules related to cognition, in 40 (22 females; 17.9 ± 0.8 year-old) adolescents, and whether the associations were sex-specific. Peak oxygen uptake (V̇O2peak ) and power were assessed by maximal ramp test on a cycle ergometer, muscular strength with standing long jump (SLJ), speed-agility with the shuttle-run test (SRT), coordination with the Box and Block Test (BBT) and neuromuscular performance index (NPI) as the sum of SLJ, BBT and SRT z-scores. Body composition was measured using a dual-energy X-ray absorptiometry. Cerebellar volumes were assessed by magnetic resonance imaging. V̇O2peak relative to lean mass was inversely associated with the GM volume of the cerebellum (standardized regression coefficient (ß) = -0.038, 95% confidence interval (CI) -0.075 to 0.001, p = 0.044). Cumulative NPI was positively associated with the GM volume of Crus I (ß = 0.362, 95% CI 0.045 to 0.679, p = 0.027). In females, better performance in SRT was associated with a larger GM volume of Crus I (ß = -0.373, 95% CI -0.760 to -0.028, p = 0.036). In males, cumulative NPI was inversely associated with the GM volume of Crus II (ß = -0.793, 95% CI -1.579 to -0.008 p = 0.048). Other associations were nonsignificant. In conclusion, cardiorespiratory fitness, neuromuscular performance and speed-agility were associated with cerebellar GM volume, and the strength and direction of associations were sex-specific.

Which indices of cardiorespiratory fitness are more strongly associated with brain health in children with overweight/obesity?

PURPOSE: To compare the strength of associations between different indices of cardiorespiratory fitness (CRF) and brain health outcomes in children with overweight/obesity. METHODS: Participants were 100 children aged 8-11 years. CRF was assessed using treadmill exercise test (peak oxygen uptake [V̇O2peak ], treadmill time, and V̇O2 at ventilatory threshold) and 20-metre shuttle run test (20mSRT, laps, running speed, estimated V̇O2peak using the equations by Léger et al., Mahar et al., and Matsuzaka et al.). Intelligence, executive functions, and academic performance were assessed using validated methods. Total gray matter and hippocampal volumes were assessed using structural MRI. RESULTS: V̇O2peak /body mass (ß = 0.18, 95% CI = 0.01-0.35) and treadmill time (ß = 0.18-0.21, 95% CI = 0.01-0.39) were positively associated with gray matter volume. 20mSRT laps were positively associated with executive functions (ß = 0.255, 95% CI = 0.089-0.421) and academic performance (ß = 0.199-0.255, 95% CI = 0.006-0.421), and the running speed was positively associated with executive functions (ß = 0.203, 95% CI = 0.039-0.367). Estimated V̇O2peak/Léger et al. was positively associated with intelligence, executive functions, academic performance, and gray matter volume (ß = 0.205-0.282, 95% CI = 0.013-0.500). Estimated V̇O2peak/Mahar et al. and V̇O2peak/Matsuzaka et al. (speed) were positively associated with executive functions (ß = 0.204-0.256, 95% CI = 0.031-0.436). CONCLUSION: Although V̇O2peak is considered the gold standard indicator of CRF in children, peak performance (laps or running speed) and estimated V̇O2peak/Léger et al. derived from 20mSRT had stronger and more consistent associations with brain health outcomes than other indices of CRF in children with overweight/obesity.

Cross-sectional and longitudinal associations between the 24-hour movement behaviours, including muscle and bone strengthening activity, with bone and lean mass from childhood to adolescence.

BACKGROUND: This study aimed to assess whether moderate-to-vigorous physical activity (MVPA), sport and exercise as a proxy measure of muscle and bone strengthening activity, sedentary behaviour, and sleep were associated with total-body-less-head (TBLH) bone mineral content (BMC) and TBLH lean mass cross-sectionally and longitudinally from age 6 to 9 years and age 9 to 11 years to age 15 to 17 years. METHODS: We used longitudinal data from a population sample of Finnish children from the Physical Activity and Nutrition in Children study (age 6 to 9 years: n = 478, 229 females; age 9 to 11 years: n = 384, 197 females; age 15 to 17 years: n = 222, 103 females). Linear regression analysed the cross-sectional and longitudinal associations between accelerometer-assessed MVPA, sedentary time and sleep, and questionnaire-assessed sport and exercise participation and screen time with dual-energy X-ray absorptiometry-assessed TBLH BMC and lean mass. RESULTS: In females, MVPA at age 6 to 9 years was positively associated with TBLH BMC at age 15 to 17 years (ß = 0.008, p = 0.010). Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (ß = 0.020, p = 0.002) and lean mass (ß = 0.343, p = 0.040) at age 15 to 17 years. MVPA at age 9 to 11 years was positively associated with TBLH lean mass (ß = 0.272, p = 0.004) at age 15 to 17 years. In males, sleep at age 6 to 9 years was positively associated with TBLH lean mass (ß = 0.382, p = 0.003) at age 15 to 17 years. Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (ß = 0.027, p = 0.012) and lean mass (ß = 0.721, p < 0.001) at age 15 to 17 years. CONCLUSIONS: Promoting engagement in the 24-hour movement behaviours in childhood, particularly sport and exercise to strengthen muscle and bone, is important in supporting bone and lean mass development in adolescence. TRIAL REGISTRATION: NCT01803776; first trial registration date: 04/03/2013.

Relationships of BMI, muscle-to-fat ratio, and handgrip strength-to-BMI ratio to physical fitness in Spanish children and adolescents.

This study aimed to determine the relationship of body mass index (BMI), muscle-to-fat ratio (MFR), and handgrip strength-to-BMI ratio to physical fitness parameters in an active young population according to sex across four different time points. A total of 2256 Spanish children and adolescents (aged 5-18) from rural areas participating in an extracurricular sport in different municipal sports schools participated in this study. Participants were divided into children (5-10 years) and adolescents (11-18 years), boys and girls, and across four different time points (2018, 2019, 2020, 2021). Data on anthropometric measures (BMI, MFR, appendicular skeletal muscle mass) and physical fitness (handgrip strength, cardiorespiratory fitness, and vertical jump) were collected. Boys who were overweight, but especially boys with obesity, had higher absolute handgrip strength in children and adolescents than their normal weight counterparts in 2020 and 2021. Boys and girls with normal weight presented higher cardiorespiratory fitness and vertical jump than their overweight and obese peers over the years. The MFR was directly correlated with the cardiorespiratory fitness and vertical jump variables, but not with handgrip strength, in boys and girls. The handgrip strength-to-BMI ratio in both sexes was positively correlated to the different physical fitness parameters.  Conclusion: BMI, MFR, and handgrip strength-to-BMI can be used as health and physical fitness indicators in this population. What is Known: • BMI is the main indicator commonly used as a proxy for obesity for many years. Nevertheless, it cannot differentiate between fat mass and fat-free mass. • There are other indicators such as MFR and handgrip strength-to-BMI that might be more accurate and can serve to monitor the health and fitness of children and adolescents. What is New: • MFR showed a positive and significant correlation with cardiorespiratory fitness and vertical jump in both sexes. On the other hand, the handgrip strength-to-BMI presented a positive correlation with cardiorespiratory fitness, vertical jump, and handgrip strength. • The use of these indicators obtained through different parameters of body composition and physical fitness can serve as a tool to identify the relationships of the paediatric population with physical fitness.

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, Wmax ) 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 Wmax /kg of body mass (ß = -0.416, 95% CI = -0.514 to -0.318), higher number of completed sit-ups (ß = -0.147, 95% CI = -0.244 to -0.049), a longer distance jumped in the standing long jump test (ß = -0.270, 95% CI = -0.371 to -0.169), and a shorter time in the 50-meter shuttle run test (ß = 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%.

Effects of 2-year dietary and physical activity intervention on cognition in children-a nonrandomized controlled trial.

BACKGROUND AND OBJECTIVE: We investigated the effects of a combined dietary and PA intervention on cognition in children and whether changes in diet quality, PA, sedentary behavior (SB), and sedentary time (ST) are associated with changes in cognition. METHODS: We conducted a 2-year nonrandomized controlled trial in 504 children aged 6-9 years at baseline. The children were allocated to a combined dietary and PA intervention group (n = 237) or a control group (n = 160) without blinding. INTERVENTIONS: The children and their parents allocated to the intervention group had six dietary counseling sessions of 30-45 min and six PA counseling sessions of 30-45 min during the 2-year intervention period. The children were also encouraged to participate in after-school exercise clubs. Cognition was assessed by the Raven's Colored Progressive Matrices. We assessed dietary factors by 4 days food records and computed the Baltic Sea Diet Score (BSDS) as a measure of diet quality. PA and ST were assessed by a combined heart rate and body movement monitor, types of PA and SB by a questionnaire. RESULTS: The intervention had no effect on cognition. Increased BSDS and consumption of low-fat milk and decreased consumption of red meat and sausages were associated with improved cognition over 2 years. Increased organized sports, ST, and reading were positively, while unsupervised PA, computer use, and writing were negatively associated with cognition. CONCLUSION: Combined dietary and PA intervention had no effect on cognition. Improved diet quality and increased organized sports and reading were associated with improved cognition.

Physical activity volume and intensity distribution in relation to bone, lean and fat mass in children.

Considering physical activity (PA) volume and intensity may provide novel insights into the relationships of PA with bone, lean, and fat mass. This study aimed to assess the associations of PA volume, PA intensity distribution, including moderate-to-vigorous PA (MVPA) with total-body-less-head bone mineral content (BMC), lean, and fat mass in children. A population sample of 290 Finnish children (158 females) aged 9-11 years from the Physical Activity and Nutrition in Children (PANIC) Study was studied. PA, including MVPA, was assessed with a combined heart rate and movement sensor, and the uniaxial acceleration was used to calculate average-acceleration (a proxy metric for PA volume) and intensity-gradient (reflective of PA intensity distribution). Linear regression analyzed the associations of PA volume, PA intensity and MVPA with BMC, lean mass, and fat mass assessed by dual-energy X-ray absorptiometry. PA volume was positively associated with BMC in females (unstandardised regression coefficient [ß] = 0.26) and males (ß = 0.47), and positively associated with lean (ß = 7.33) and negatively associated with fat mass in males (ß = -20.62). PA intensity was negatively associated with BMC in males (ß = -0.13). MVPA was positively associated with lean mass in females and males (ß = 0.007 to 0.012), and negatively associated with fat mass in females and males (ß = -0.030 to -0.029). PA volume may be important for improving BMC in females and males, and increasing lean and reducing fat mass in males, whereas MVPA may be important for favorable lean and fat outcomes in both sexes.

Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial.

Regular exercise and sauna bathing have each been shown to improve cardiovascular function in clinical populations. However, experimental data on the cardiovascular adaptations to regular exercise in conjunction with sauna bathing in the general population are lacking. Therefore, we compared the effects of exercise and sauna bathing to regular exercise using a multi-arm randomized controlled trial. Participants (n = 47) aged 49 ± 9 with low physical activity levels and at least one traditional cardiovascular disease (CVD) risk factor were randomly assigned (1:1:1) to guideline-based regular exercise and 15-min postexercise sauna (EXS), guideline-based regular exercise (EXE), or control (CON) for 8 wk. The primary outcomes were blood pressure (BP) and cardiorespiratory fitness (CRF). Secondary outcomes included fat mass, total cholesterol levels, and arterial stiffness. EXE had a greater change in CRF (+6.2 mL/kg/min; 95% CI, +4.2 to +8.3 mL/kg/min) and fat mass but no differences in BP when compared with CON. EXS displayed greater change in CRF (+2.7 mL/kg/min; 95% CI, +0.2 to +5.3 mL/kg/min), lower systolic BP (-8.0 mmHg; 95% CI, -14.6 to -1.4 mmHg), and lower total cholesterol levels compared with EXE. Regular exercise improved CRF and body composition in sedentary adults with CVD risk factors. However, when combined with exercise, sauna bathing demonstrated a substantially supplementary effect on CRF, systolic BP, and total cholesterol levels. Sauna bathing is a valuable lifestyle tool that complements exercise for improving CRF and decreasing systolic BP. Future research should focus on the duration and frequency of exposure to ascertain the dose-response relationship.

Associations of resting and peak fat oxidation with sex hormone profile and blood glucose control in middle-aged women.

BACKGROUND AND AIMS: Menopause may reduce fat oxidation. We investigated whether sex hormone profile explains resting fat oxidation (RFO) or peak fat oxidation (PFO) during incremental cycling in middle-aged women. Secondarily, we studied associations of RFO and PFO with glucose regulation. METHOD AND RESULTS: We measured RFO and PFO of 42 women (age 52-58 years) with indirect calorimetry. Seven participants were pre- or perimenopausal, 26 were postmenopausal, and nine were postmenopausal hormone therapy users. Serum estradiol (E2), follicle-stimulating hormone, progesterone, and testosterone levels were quantified with immunoassays. Insulin sensitivity (Matsuda index) and glucose tolerance (area under the curve) were determined by glucose tolerance testing. Body composition was assessed with dual-energy X-ray absorptiometry; physical activity with self-report and accelerometry; and diet, with food diaries. Menopausal status or sex hormone levels were not associated with the fat oxidation outcomes. RFO determinants were fat mass (ß = 0.44, P = 0.006) and preceding energy intake (ß = -0.40, P = 0.019). Cardiorespiratory fitness (ß = 0.59, P = 0.002), lean mass (ß = 0.49, P = 0.002) and physical activity (self-reported ß = 0.37, P = 0.020; accelerometer-measured ß = 0.35, P = 0.024) explained PFO. RFO and PFO were not related to insulin sensitivity. Higher RFO was associated with poorer glucose tolerance (ß = 0.52, P = 0.002). CONCLUSION: Among studied middle-aged women, sex hormone profile did not explain RFO or PFO, and higher fat oxidation capacity did not indicate better glucose control.

Accelerometer-based osteogenic indices, moderate-to-vigorous and vigorous physical activity, and bone traits in adolescents.

OBJECTIVES: We investigated the associations of accelerometry-derived osteogenic indices (OIs), moderate-to-vigorous (MVPA), and vigorous intensity physical activity (VPA) with peripheral quantitative computed tomography (pCQT) parameters in 99 adolescents aged 10-13 years. METHODS: Bone parameters were assessed at the distal (4%) and shaft (66%) of the tibia using pQCT. Accelerometers were worn on the right hip for 7 consecutive days. OIs were calculated based on acceleration peak histograms either using all of the peaks (OI) or peaks with acceleration ≥5.2 g (HOI). MVPA and VPA were defined using previously published cut-points. RESULTS: HOI was positively associated with total area (Partial correlation= 0.22, 95% CI=0.01 to 0.41), cortical area (CoA) (0.33, 95% CI=0.13 to 0.50), and stress strain index (SSI) (0.29, 95% CI=0.09 to 0.47) of tibial shaft and with total density at the distal tibia (0.23, 95% CI=0.02 to 0.42). OI was positively associated with CoA (0.31, 95% CI=0.11 to 0.49) and SSI (0.26, 95% CI=0.05 to 0.44) of tibial shaft. MVPA was positively associated with CoA (0.28, 95% CI=0.07 to 0.46) of the tibial shaft. CONCLUSIONS: OI and HOI were positively associated with pQCT parameters while MVPA and VPA demonstrated less consistent associations with them.

Longitudinal and cross-sectional associations of adherence to 24-hour movement guidelines with cardiometabolic risk.

This study aimed to examine (1) adherence to 24 h movement guidelines over a 2 years follow-up in children aged 6-8 years and (2) association of this adherence with cardiometabolic risk factors. Physical activity and sleep were assessed by a monitor combining heart rate and accelerometry measurements. Screen time was reported by the parents. Body fat percentage, waist circumference, blood glucose, serum insulin, plasma lipids, and blood pressure were assessed, and a cardiometabolic risk score was calculated using z-scores. Children were classified as meeting the guidelines if they had on average ≥60 min/day of moderate-to-vigorous physical activity during the valid days; ≤120 min/day of screen time; and 9-11 h/day of sleep. In total, 485 children had valid data at baseline or at 2 years follow-up. Analyses were conducted using adjusted logistic and linear regression models. Most children adhered to the 24 h movement guidelines at baseline, but the adherence decreased over the 2 years follow-up. Meeting physical activity guidelines individually, or in combination with screen time and/or sleep, was longitudinally associated with a lower cardiometabolic risk score, insulin and waist circumference, and cross-sectionally additionally with lower diastolic blood pressure and higher high-density lipoprotein cholesterol. However, these associations became statistically non-significant after adjustment for body fat. In conclusion, meeting 24 h movement guidelines at baseline increases the odds of meeting them at 2 years follow-up in school-aged children. Furthermore, meeting 24 h movement guidelines is associated with lower levels of cardiometabolic risk factors, but these associations are partly explained by lower body fat. Thus, promoting movement behaviors, especially physical activity, and healthy weight in early childhood is important in supporting cardiometabolic health in children.

The effects of a 2-year physical activity and dietary intervention on plasma lipid concentrations in children: the PANIC Study.

PURPOSE: We studied the effects of a physical activity and dietary intervention on plasma lipids in a general population of children. We also investigated how lifestyle changes contributed to the intervention effects. METHODS: We carried out a 2-year controlled, non-randomized lifestyle intervention study among 504 mainly prepubertal children aged 6-9 years at baseline. We assigned 306 children to the intervention group and 198 children to the control group. We assessed plasma concentrations of total, LDL, HDL, and VLDL cholesterol, triglycerides, HDL triglycerides, and VLDL triglycerides. We evaluated the consumption of foods using 4-day food records and physical activity using a movement and heart rate sensor. We analyzed data using linear mixed-effect models adjusted for age at baseline, sex, and pubertal stage at both time points. Furthermore, specific lifestyle variables were entered in these models. RESULTS: Plasma LDL cholesterol decreased in the intervention group but did not change in the control group ( - 0.05 vs. 0.00 mmol/L, regression coefficient (ß) = - 0.0385, p = 0.040 for group*time interaction). This effect was mainly explained by the changes in the consumption of high-fat vegetable oil-based spreads (ß = - 0.0203, + 47% change in ß) and butter-based spreads (ß = - 0.0294, + 30% change in ß), moderate-to-vigorous physical activity (ß = - 0.0268, + 30% change in ß), light physical activity (ß = - 0.0274, + 29% change in ß) and sedentary time (ß = - 0.0270, + 30% change in ß). The intervention had no effect on other plasma lipids. CONCLUSION: Lifestyle intervention resulted a small decrease in plasma LDL cholesterol concentration in children. The effect was explained by changes in quality and quantity of dietary fat and physical activity. CLINICAL TRIAL REGISTRY NUMBER: NCT01803776, ClinicalTrials.gov.

Physical activity accumulation along the intensity spectrum differs between children and adults.

PURPOSE: Detailed exploration of physical activity accumulation with fine grading along the intensity spectrum has indicated the potential pragmatic utility of such an approach. However, it is currently unclear what sorts of accumulation patterns along particular intensity bands are found in the children and adult populations. Therefore, we conducted a comparison of activity accumulation in specific intensity bands between four distinct populations: children, adults with sedentary lifestyles, habitual joggers, habitual marathon runners. METHODS: Free-living waist-worn accelerometry records from 28 children aged 7 to 11, and 61 adults aged 25 to 35 were analysed. Activity intensity was evaluated in 5 s non-overlapping epochs as mean amplitude deviation (MAD) and normalised to acceleration intensities corresponding to walking at 3 metabolic equivalents of a task (METs). Adult data were normalised to 0.091 g MAD based on literature, and data from children to 0.170 g MAD based on laboratory experimentation. The normalised epoch values were divided into 100 intensity gradations. RESULTS: Children accumulated more activity in 0.74 to 1.58 normalised acceleration intensities (all p < 0.005) compared to adults. Adult joggers/runners accumulated more activity in normalised acceleration intensities from 7.1 to 11.1 compared to the other groups (p < 0.008). CONCLUSION: The primary bulk of children's free-living activities are of relatively low intensity not likely to provoke cardiometabolic improvement. These sorts of explorations could be used in informing intervention development aiming at optimising healthy development. Evidence is mounting to justify randomised controlled trials based on intervention targets identified based on exploring the intensity spectrum.

Associations of age, body size, and maturation with physical activity intensity in different laboratory tasks in children.

We investigated the associations of age, sex, body size, body composition, and maturity with measures of physical activity (PA) intensity in children. PA intensity was assessed using VO2 as % of VO2reserve or VO2 at ventilatory threshold (VT), muscle activity measured by textile electromyography, mean amplitude deviation (MAD) measured by accelerometry, and metabolic equivalent of task (MET) during laboratory activities.Age, stature, and muscle mass were inversely associated with VO2 as % of VO2reserve and % of VT, during walking or running on a treadmill for 4, 6, and 8 km/h (Spearman r = -0.645 to -0.358). Age was inversely associated with MAD during walking on treadmill for 4 km/h (r = -0.541) and positively associated with MAD during running on a treadmill for 8 km/h, playing hopscotch, and during self-paced running (r = 0.368 to 0.478). Fat mass was positively associated with VO2 as % of VO2reserve and VO2 as % of VO2 at VT and waist circumference was positively associated with VO2 as a % of VO2reserve and muscle activity during stair climbing (r = 0.416 to 0.519).Fixed accelerometry cut-offs used to define PA intensities should be adjusted for age, sex, body size, and body composition.

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.

A 2 year physical activity and dietary intervention attenuates the increase in insulin resistance in a general population of children: the PANIC study.

AIMS/HYPOTHESIS: We studied for the first time the long-term effects of a combined physical activity and dietary intervention on insulin resistance and fasting plasma glucose in a general population of predominantly normal-weight children. METHODS: We carried out a 2 year non-randomised controlled trial in a population sample of 504 children aged 6-9 years at baseline. The children were allocated to a combined physical activity and dietary intervention group (306 children at baseline, 261 children at 2-year follow-up) or a control group (198 children, 177 children) without blinding. We measured fasting insulin and fasting glucose, calculated HOMA-IR, assessed physical activity and sedentary time by combined heart rate and body movement monitoring, assessed dietary factors by a 4 day food record, used the Finnish Children Healthy Eating Index (FCHEI) as a measure of overall diet quality, and measured body fat percentage (BF%) and lean body mass by dual-energy x-ray absorptiometry. The intervention effects on insulin, glucose and HOMA-IR were analysed using the intention-to-treat principle and linear mixed-effects models after adjustment for sex, age at baseline, and pubertal status at baseline and 2 year follow-up. The measures of physical activity, sedentary time, diet and body composition at baseline and 2 year follow-up were entered one-by-one as covariates into the models to study whether changes in these variables might partly explain the observed intervention effects. RESULTS: Compared with the control group, fasting insulin increased 4.65 pmol/l less (absolute change +8.96 vs +13.61 pmol/l) and HOMA-IR increased 0.18 units less (+0.31 vs +0.49 units) over 2 years in the combined physical activity and dietary intervention group. The intervention effects on fasting insulin (regression coefficient ß for intervention effect -0.33 [95% CI -0.62, -0.04], p = 0.026) and HOMA-IR (ß for intervention effect -0.084 [95% CI -0.156, -0.012], p = 0.023) were statistically significant after adjustment for sex, age at baseline, and pubertal status at baseline and 2 year follow-up. The intervention had no effect on fasting glucose, BF% or lean body mass. Changes in total physical activity energy expenditure, light physical activity, moderate-to-vigorous physical activity, total sedentary time, the reported consumption of high-fat (≥60%) vegetable oil-based spreads, and FCHEI, but not a change in BF% or lean body mass, partly explained the intervention effects on fasting insulin and HOMA-IR. CONCLUSIONS/INTERPRETATION: The combined physical activity and dietary intervention attenuated the increase in insulin resistance over 2 years in a general population of predominantly normal-weight children. This beneficial effect was partly mediated by changes in physical activity, sedentary time and diet but not changes in body composition. TRIAL REGISTRATION: ClinicalTrials.gov NCT01803776 Graphical abstract.

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 dietary carbohydrate and fatty acid intakes with cognition among children.

OBJECTIVE: To investigate the cross-sectional associations of dietary carbohydrate and fatty acid intakes with cognition in mid-childhood. DESIGN: Dietary carbohydrate and fatty acid intakes were assessed using 4-d food records, and cognition was evaluated using the Raven's Coloured Progressive Matrices (RCPM) score. The cross-sectional associations of dietary carbohydrate and fatty acid intakes with cognition were investigated using linear regression analyses adjusted for age, sex, body fat percentage, household income, parental education and daily energy intake. SETTING: The baseline examinations of the Physical Activity and Nutrition in Children study. PARTICIPANTS: A population-based sample of 487 children (250 boys, 237 girls) aged 6-8 years living in the city of Kuopio, Finland. RESULTS: A higher dietary intake of fructose (standardised regression coefficient, ß = 0·24, P < 0·001), total fibre (ß = 0·16, P = 0·02) and soluble fibre (ß = 0·15, P = 0·02) was associated with a higher RCPM score in boys. Other dietary carbohydrates and fatty acids, including total carbohydrates, glucose, sucrose, starch, insoluble fibre, total fat, SFAs, MUFAs, PUFAs, palmitic acid (C16), stearic acid (C18), linoleic acid (C18:2), α-linoleic acid (C18:3), arachidonic acid (C20:4), EPA (C20:5n-3) and DHA (C22:6n-6), were not associated with the RCPM score in boys. Dietary carbohydrates or fatty acids were not associated with the RCPM score in girls. CONCLUSIONS: Higher dietary fructose and fibre intakes were associated with better cognition in boys, but not in girls. Dietary fatty acids were not related to cognition in boys or in girls.

Maturation changes the excitability and effective connectivity of the frontal lobe: A developmental TMS-EEG study.

The combination of transcranial magnetic stimulation with simultaneous electroencephalography (TMS-EEG) offers direct neurophysiological insight into excitability and connectivity within neural circuits. However, there have been few developmental TMS-EEG studies to date, and they all have focused on primary motor cortex stimulation. In the present study, we used navigated high-density TMS-EEG to investigate the maturation of the superior frontal cortex (dorsal premotor cortex [PMd]), which is involved in a broad range of motor and cognitive functions known to develop with age. We demonstrated that reactivity to frontal cortex TMS decreases with development. We also showed that although frontal cortex TMS elicits an equally complex TEP waveform in all age groups, the statistically significant between-group differences in the topography of the TMS-evoked peaks and differences in current density maps suggest changes in effective connectivity of the right PMd with maturation. More generally, our results indicate that direct study of the brain's excitability and effective connectivity via TMS-EEG co-registration can also be applied to pediatric populations outside the primary motor cortex, and may provide useful information for developmental studies and studies on developmental neuropsychiatric disorders.