Einat A. Schmutz

Correlates of preschool children’s objectively measured physical activity and sedentary behavior: a cross-sectional analysis of the SPLASHY study

BackgroundIdentifying ways to promote physical activity and decrease sedentary time during childhood is a key public health issue. Research on the putative influences on preschool children’s physical activity (PA) and sedentary behavior (SB) is limited and has yielded inconsistent results. Our aim was to identify correlates of PA and SB in preschool children.MethodsCross-sectional data were drawn from the Swiss Preschoolers’ Health Study (SPLASHY), a Swiss population-based cohort study. Of 476 two to six year old children, 394 (54% boys) had valid PA data assessed by accelerometry. Information on exposure data was directly measured or extracted from parental questionnaires. Multilevel linear regression modeling was used to separately assess associations between 35 potential correlates and total PA (TPA), moderate-to-vigorous PA (MVPA) and SB.ResultsIn total, 12 correlates from different domains were identified. TPA and MVPA were greater in boys than girls, increased with age and were positively associated with gross motor skills. Children from single parent families had a higher level of TPA and spent less time sedentary than those living with two parents. Time spent outdoors was positively associated with TPA and negatively with SB. The child’s activity temperament was related all three outcomes, whereas parental sports club membership, living area per person and neighborhood safety were associated with SB only. Fixed and random factors in the final models accounted for 28%, 32% and 22% of the total variance in TPA, MVPA and SB, respectively. Variance decomposition revealed that age, sex and activity temperament were the most influential correlates of both, TPA and MVPA, whereas the child’s activity temperament, time outdoors and neighborhood safety were identified as the most important correlates of SB.ConclusionsA multidimensional set of correlates of young children’s activity behavior has been identified. Personal factors had the greatest influence on PA, whereas environmental-level factors had the greatest influence on SB. Moreover, we identified a number of previously unreported, potentially modifiable correlates of young children’s PA and SB. These factors could serve to define target groups or become valuable targets for change in future interventions.Trial registrationCurrent Controlled Trials ISRCTN41045021 (date of registration: 21.03.14).

Relation of Heart Rate and its Variability during Sleep with Age, Physical Activity, and Body Composition in Young Children

Background: Recent studies have claimed a positive effect of physical activity and body composition on vagal tone. In pediatric populations, there is a pronounced decrease in heart rate with age. While this decrease is often interpreted as an age-related increase in vagal tone, there is some evidence that it may be related to a decrease in intrinsic heart rate. This factor has not been taken into account in most previous studies. The aim of the present study was to assess the association between physical activity and/or body composition and heart rate variability (HRV) independently of the decline in heart rate in young children. Methods: Anthropometric measurements were taken in 309 children aged 2–6 years. Ambulatory electrocardiograms were collected over 14–18 h comprising a full night and accelerometry over 7 days. HRV was determined of three different night segments: (1) over 5 min during deep sleep identified automatically based on HRV characteristics; (2) during a 20 min segment starting 15 min after sleep onset; (3) over a 4-h segment between midnight and 4 a.m. Linear models were computed for HRV parameters with anthropometric and physical activity variables adjusted for heart rate and other confounding variables (e.g., age for physical activity models). Results: We found a decline in heart rate with increasing physical activity and decreasing skinfold thickness. HRV parameters decreased with increasing age, height, and weight in HR-adjusted regression models. These relationships were only found in segments of deep sleep detected automatically based on HRV or manually 15 min after sleep onset, but not in the 4-h segment with random sleep phases. Conclusions: Contrary to most previous studies, we found no increase of standard HRV parameters with age, however, when adjusted for heart rate, there was a significant decrease of HRV parameters with increasing age. Without knowing intrinsic heart rate correct interpretation of HRV in growing children is impossible.

Impact of age, sex, socioeconomic status, and physical activity on associated movements and motor speed in preschool children

ABSTRACT Introduction: Young children generally show contralateral associated movements (CAMs) when they are making an effort to perform a unimanual task. CAM and motor speed are two relevant aspects of motor proficiency in young children. These CAMs decrease over age, while motor speed increases. As both CAM and motor speed are associated with age, we were interested in whether these two parameters are also linked with each other. Method: In this study, three manual dexterity tasks with the dominant and nondominant hands (pegboard, repetitive hand, and repetitive finger tasks) were used to investigate the effect of covariates (age, sex, socioeconomic status, total physical activity) on both motor speed and CAMs in preschool children. Results: There was a significant age effect for both motor speed and CAMs in all tasks when the dominant hand was used. When the nondominant hand was used, the decrease in the intensity of CAMs over age was not consistently significant. The influence of physical activity and socioeconomic status on motor proficiency was small. Furthermore, the correlation between motor speed and CAMs, although significant, was low. Conclusions: Motor speed improved with age over three fine motor tasks in preschool children. Decrease in CAMs was observed but it was not always significant when the nondominant hand was working. Motor speed and CAMs were only weakly associated. We conclude that the excitatory pathways responsible for motor speed and inhibitory pathways responsible for reducing CAMs occupy two different domains in the brain and therefore mostly behave independently of each other.

Regional sociocultural differences as important correlate of physical activity and sedentary behaviour in Swiss preschool children

QUESTION Regional differences in physical activity in school-aged children and adults even within one country with the same political and health care system have been observed and could not be explained by sociodemographic or individual variables. We analysed whether such differences were already present in preschool children. METHODS Swiss children from 84 childcare centres in five cantons (Aargau, Bern, Fribourg, Vaud, Zurich) comprising about 50% of the population of the country participated. Physical activity was quantified with accelerometers (ActiGraph, wGT3X-BT) and potential correlates were assessed with measurements at the childcare centre or questionnaires. Mixed regression models were used to test associations between potential correlates of total physical activity (TPA), moderate-to-vigorous physical activity (MVPA), light physical activity (LPA) or sedentary behaviour with a special focus on regional differences. RESULTS 394 of 476 children (83%) provided valid physical activity data (at least 2 weekdays and 1 weekend day with 10 h recording; mean age 3.9 ± 0.7 years, 54% boys) with 26% and 74% living in the French- and German-speaking parts of Switzerland, respectively. Days consisted of (mean ± standard deviation) 1.5 ± 0.5 h MVPA, 5.0 ± 0.6 h LPA, and 6.3 ± 0.8 h sedentary behaviour with an average of 624 ± 150 counts/min TPA. TPA and MVPA (but not sedentary behaviour or LPA) increased with age, were higher in boys and children with better motor skills. Despite controlling for individual characteristics, familial factors and childcare exposure, children from the French-speaking part of Switzerland showed 13% less TPA, 14% less MVPA, 6% less LPA and 8% more sedentary behaviour than German-speaking children. CONCLUSION Beside motor skills and non-modifiable individual factors, the regional sociocultural difference was the most important correlate of phyical activity and sedentary behaviour. Therefore, regionally adapted public health strategies may be needed.

Age-Adapted Stress Task in Preschoolers Does not Lead to Uniform Stress Responses

Acute stress response measures serve as an indicator of physiological functioning, but have previously led to contradictory results in young children due to age-related cortisol hypo-responsivity and methodological inconsistencies in assessment. The aim of this study was to investigate stress responses during a validated age-adapted socio-evaluative stress task in children aged 2-6 years in a child care environment and to detect socio-demographic, task- and child-related characteristics of stress responses. Stress responses were assessed in 323 children for salivary cortisol and salivary alpha amylase (sAA), and in 328 children for changes in heart rate variability (HRV). These data were then associated with socio-demographic (e.g. SES), task-related (e.g. task length) and child-related characteristics (e.g. self-regulation) of stress responses using multilevel models. Analyses revealed elevated sympathetic reactivity (sAA: Coeff=0.053, p=0.004) and reduced HRV (Coeff=-0.465, p<0.001), but no hypothalamic-pituitary-adrenal (HPA) response (Coeff=0.017, p=0.08) during the stress task. Childs age (Coeff=-5.82, p<0.001) and movement during the task (Coeff=-0.17, p=0.015) were associated with acute cortisol release, while diurnal sAA was associated with acute sAA release (Coeff=0.24, p<0.001). Age (Coeff=-0.15, p=0.006) and duration of the task (Coeff=0.13, p=0.015) were further associated with change of HRV under acute stress condition. Children showed inconsistent stress responses which contradicts the assumption of a parallel activation of both stress systems in a valid stress task for young children and might be explained by a pre-arousal to the task of young children in a child care setting. Further results confirm that child- and task-related conditions need to be considered when assessing stress responses in these young children.

Prevalence and Predictors of Behavioral Problems in Healthy Swiss Preschool Children Over a One Year Period

Behavioral problems impair children’s health but prevalence rates are scarce and persistence rates vary due to divergence in age ranges, assessment methods and varying environmental factors. The aim of this study was to assess prevalence rates of behavioral problems, their persistence over a 1-year period, and the impact of child- and parent-related factors on behavioral problems. 555 2–6-year-old healthy preschool children were assessed at baseline and 382 of the initial sample at 1-year follow-up. Assessment included questionnaires concerning behavioral problems and their potential predictors (e.g. socio-economic status or parenting style). Altogether, nearly 7% of these children showed clinically relevant behavioral problems, and 3% showed persistent symptoms. Low SES, inconsistent parenting and corporal punishment were positively associated with behavioral problems. The prevalence rates of behavioral problems in Swiss preschoolers are similar to other European countries, but persistence is still rather low within preschool age. These findings need further confirmation in longitudinal studies.

Associated movements and inhibitory control in children between 2 and 6 years are related

Background: Motor development refers to the development of movement abilities and includes the ability of children to selectively activate certain muscles and inhibit those that are not supporting a specific movement. Up to 6 years, this inhibition is still limited and associated movements (AMs) are frequent in complex motor tasks. In parallel, evidence is accumulating that other inhibitory processes (i.e., inhibitory control) more related to psychological functioning are also still developing. It was the aim of this study to focus on the associations between the amount of AMs and inhibitory control in children below 6.

The relationship of physiological stress measures, behavioral problems and body composition in preschool children

Background: Findings on the relationship of physiological stress measures and weight or behavioral problems in older children are controversial and data of young children is missing. The aim of the study was to investigate this relationship in young children.

Associations between physical activity and psychological health in Swiss preschool children

Background: Findings on the relationship of physiological stress measures and weight or behavioral problems in older children are controversial and data of young children is missing. The aim of the study was to investigate this relationship in young children.

Contralateral Associated Movements Correlate with Poorer Inhibitory Control, Attention and Visual Perception in Preschool Children

Contralateral associated movements (CAMs) frequently occur in complex motor tasks. We investigated whether and to what extent CAMs are associated with inhibitory control among preschool children in the Swiss Preschoolers’ Health Study. Participants were 476 healthy, typically developing children (mean age = 3.88 years; 251 boys) evaluated on two consecutive afternoons. The children performed the Zurich Neuromotor Assessment, the statue subtest of the Neuropsychological Assessment for Children (NEPSY), and cognitive tests of the Intelligence and Development Scales-Preschool (IDS-P). CAMs were associated with poor inhibitory control on the statue test and poor selective attention and visual perception on the IDS-P. We attributed these findings to preschoolers’ general immaturity of the central nervous system.