Child Physiology Research Articles

Socioeconomic status inequalities in low-grade inflammation during childhood

BackgroundFamily socioeconomic status (SES) is an important source of child health disparities in the USA. Chronic stress is one way SES may impact children's physiology with implications for later health...

Consequences of 'tiger' parenting: a cross-cultural study of maternal psychological control and children's cortisol stress response.

Parenting strategies involving psychological control are associated with increased adjustment problems in children. However, no research has examined the extent to which culture and psychological control predict children's stress physiology. We examine cultural differences in maternal psychological control and its associations with children's cortisol. Chinese (N=59) and American (N=45) mother-child dyads participated in the study. Mothers reported on psychological control. Children's cortisol was collected during a stressor and two indices of Area Under the Curve (AUC) were computed: AUCg which accounts for total output, and AUCi, which captures reactivity. Results indicate that Chinese mothers reported higher levels of psychological control and Chinese children had higher levels of AUCg than their American counterparts. Across both cultures, psychological control was significantly associated with increased cortisol levels as indexed by AUCg. There were no associations for AUCi. Finally, mediation analyses demonstrated that psychological control fully explained cultural differences in children's cortisol stress response as indexed by AUCg.

Socioeconomic Status, Subjective Social Status, and Perceived Stress: Associations with Stress Physiology and Executive Functioning

Several studies have investigated associations between socioeconomic status (SES) and indicators of children's physiological and cognitive self-regulation. Although objective measures of family SES may be good proxies for families' experiences of disadvantage, less is known about subjective aspects of families' experiences. We hypothesize that subjective social status (SSS) and perceived stress may be important independent predictors of children's stress physiology and executive functioning (EF). Eighty-two children from diverse SES backgrounds were administered EF measures and provided saliva samples for cortisol assay. Caregivers reported on objective SES, SSS, and perceived stress. Results suggest that SES and SSS are both independently and positively related to EF. In models predicting stress physiology, higher perceived stress was associated with lower baseline cortisol. Moreover, SES and age interacted to predict cortisol levels such that among younger children, lower SES was associated with higher cortisol, whereas among older children, lower SES was associated with lower cortisol. Results highlight the importance of considering both objective and subjective indicators of families' SES and stressful experiences in relation to multiple aspects of children's self-regulation.

Cranioplasty for Large-Sized Calvarial Defects in the Pediatric Population: A Review

Large-sized calvarial defects in pediatric patients pose a reconstructive challenge because of children's unique physiology, developing anatomy, and dynamic growth. We review the current literature and outcomes with autologous and alloplastic cranioplasty in the pediatric population.

Sleep physiology and its relevance for the management of behavioral sleep disorders in children

Sleep problems are among the most frequent behavioural issues during childhood. This article highlights some of the most important aspects of children's sleep physiology and presents a clinical approach for the management of behavioural sleep disorders in children. Our concept is based on developmental aspects of sleep physiology and also uses behavioural strategies for the parents and their child to handle maladaptive sleep behaviour.

Dissonance Between Parent‐Selected Bedtimes and Young Children's Circadian Physiology Influences Nighttime Settling Difficulties

Nighttime settling difficulties (i.e., bedtime resistance, sleep-onset delay) occur in about 25% of young children and are associated with attentional, behavioral, and emotional problems. We examined whether the timing of internal (endogenous) circadian melatonin phase (i.e., dim light melatonin onset; DLMO) and its relationship with parent-selected bedtimes were related to nighttime settling behaviors. Fourteen regularly napping preschoolers (8 females; 30-36 months) participated in a 6-day protocol (parent-report of nighttime settling, actigraphic assessment of sleep onset latency, evening salivary DLMO). Average DLMO clock time was 07:40 p.m. ± 00:48 minutes, occurring 29 minutes ± 32 minutes prior to bedtime (lights-out). Children with later DLMOs had longer sleep-onset latencies (r = .62) and poorer success in falling asleep (r = -.59). Children whose bedtimes were closer to their DLMO had longer sleep-onset latencies (r = .72) and increased bedtime resistance (r = -.54). We conclude that dissonance between parent-selected bedtimes and children's circadian physiology may contribute to the development of nighttime settling difficulties in early childhood.

Early Exposure to Parental Depression and Parenting: Associations with Young Offspring’s Stress Physiology and Oppositional Behavior

Hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress is posited to play a role in the intergenerational transmission of risk for psychopathology and other negative outcomes in the offspring of depressed parents. We tested the hypothesis that the joint, interactive effects of exposure to parental depression during early childhood and parental hostility impact the development of young children's stress physiology and early emerging behavior problems. A sample of 165 preschool-age children (81 boys, 84 girls), of whom 103 had a parent with a history of depression, was exposed to a stress-inducing laboratory task, and five salivary cortisol samples were obtained. Parents completed clinical interviews and an observational parent-child interaction task. We found that the offspring exposed to maternal depression during early childhood and whose parents displayed hostile parenting behaviors during an observational task evidenced high and increasing cortisol levels in response to a laboratory stressor. In addition, the total amount of exposure to maternal depression over the child's life exerted a dose-response effect on the positive relation between parental hostility and child observed oppositional behavior. This study underscores the importance of the early rearing environment on young children's stress physiology and early emerging behavior problems.

Asthma Vital Signs at Triage

Commonly used acute asthma scoring systems assess severity of symptoms, whereas other clinical models aim to predict hospitalization; all rely on a measure of response to treatment and use the same criteria across age ranges. This may not reflect a child's changing physiology and response to illness as he or she grows older.This study aimed to find age-specific objective predictors of hospitalization readily known at triage. The goal is to identify rapidly those who will likely need admission regardless of treatment administered or response to aggressive treatment in the emergency department (ED). Children between 1 and 18 years of age with a final primary ED International Classification of Diseases, Ninth Revision, diagnosis of asthma or asthma-related spectrum of disease were studied using data from the National Hospital Ambulatory Medical Care Survey. The primary outcome was hospital admission (observation unit, ward, monitored, or pediatric intensive care unit).Triage vital signs, mode of arrival, recent visits, emergency severity index score, as well as demographic and socioeconomic factors were incorporated into age-specific forward-selection multiple logistic regression models. In 2,454,983 ED visits for asthma or reactive airway disease among children 1 to 18 years of age, patterns of vital sign predictors for admission varied by age group. Across all ages, diastolic hypotension at triage was an early, consistent, independent predictor of admission, especially in 1- to 3-year-olds (odds ratio, 6.27; 95% confidence interval, 6.01-6.54) and 3- to 6-year-olds (odds ratio, 17.95; 95% confidence interval, 16.80-19.17). Age-specific assessment is important in the evaluation of acute asthma or reactive airway exacerbation. Diastolic hypotension may serve as an early warning indicator of severity of disease and need for hospitalization. Variability by age group in vital sign predictor for admission calls for further development or refinement of age-specific asthma assessment tools.

Mapping cardiac physiology and parenting processes in maltreating mother–child dyads.

Child maltreatment (CM) lies on an extreme end of the continuum of parenting-at-risk, and while CM has been linked with a variety of behavioral indicators of dysregulation in children, less is known about how physiological markers of regulatory capacity contribute to this association. The present study examined patterns of mother and child physiological regulation and their relations with observed differences in parenting processes during a structured interaction. Abusing, neglecting, and non-CM mothers and their 3- to 5-year-old children completed a resting baseline and moderately challenging joint task. The structural analysis of social behavior was used to code mother-child interactions while simultaneous measures of respiratory sinus arrhythmia were obtained. Results indicated that physically abusive mothers were more likely to react to children's positive bids for autonomy with strict and hostile control, than either neglecting or non-CM mothers. CM exposure and quality of maternal responding to children's autonomous bids were uniquely associated with lower parasympathetic tone in children. Results provide evidence of neurodevelopmental associations between early CM exposure, the immediate interactive context of parenting, and children's autonomic physiology.

To the 30th anniversary of the Children's Physiology and Pathology problem committee work

«Children physiology and pathology» problem committee has summed up the results of 30 years of work. The results of postgraduate and doctorate training program for the given period are presented. The modern scientific research trends were emphasized.

Contributions of child's physiology and maternal behavior to children's trajectories of temperamental reactivity.

Trajectories of children's temperamental reactivity (negative affectivity and surgency) were examined in a community sample of 370 children across the ages of 4 to 7 with hierarchical linear modeling. Children's physiological reactivity (respiratory sinus arrhythmia [RSA]), physiological regulation (Delta RSA), and maternal parenting behavior were included as predictors of children's trajectories of temperamental reactivity. Results indicated that negative affectivity and surgency decreased from 4 to 7 years of age; however, within-person changes in negative affectivity were dependent on levels of baseline RSA and not age. Increases in negative affectivity were also predicted by higher levels of earlier maternal controlling behavior. Decreases in surgency were predicted by higher levels of Delta RSA during mother-child interaction tasks and positive parenting behavior. Baseline RSA and maternal controlling parenting also accounted for interindividual differences in children's negative affectivity at age 7, and gender and children's baseline RSA accounted for interindividual differences in children's surgency at age 7. Overall, these results provide further evidence that parenting behavior and children's RSA influence the changes that occur in children's temperamental reactivity.

Challenges in Pediatric Drug Development

A paradigm change is taking place from protecting children against clinical research to protecting them through research. It is based on a better scientific understanding of the child's physiology, on the increasing potential of biomedical interventions, and on an evolving conviction of children's right to benefit from scientific and pharmaceutical progress. The WHO campaign 'Make medicines child size' is contributing to expand this to a global vision of the health of all children. Research-based pharmaceutical industry develops innovative new medicines for serious and life-threatening diseases. It has built up competency in pediatric drug development and has welcomed US and EU pediatric legislation as well as the WHO campaign. More diseases without effective therapy in the past will become treatable conditions. Eventually these advances will also be reflected in the medical care in developing countries. Research-based pharmaceutical industry can support specific pediatric aspects of drug development in neglected diseases by sharing its learning. The way forward will be a constructive dialog among the key stakeholders to ensure continuing improvement in worldwide child healthcare.

Modeling Approaches for Estimating the Dosimetry of Inhaled Toxicants in Children

Risk assessment of inhaled toxicants has typically focused upon adults, with modeling used to extrapolate dosimetry and risks from lab animals to humans. However, behavioral factors such as time spent playing outdoors may lead to more exposure to inhaled toxicants in children. Depending on the inhaled agent and the age and size of the child, children may receive a greater internal dose than adults because of greater ventilation rate per body weight or lung surface area, or metabolic differences may result in different tissue burdens. Thus, modeling techniques need to be adapted to children in order to estimate inhaled dose and risk in this potentially susceptible life stage. This paper summarizes a series of inhalation dosimetry presentations from the U.S. EPA's Workshop on Inhalation Risk Assessment in Children held on June 8–9, 2006 in Washington, DC. These presentations demonstrate how existing default models for particles and gases may be adapted for children, and how more advanced modeling of toxicant deposition and interaction in respiratory airways takes into account children's anatomy and physiology. These modeling efforts identify child-adult dosimetry differences in respiratory tract regions that may have implications for children's vulnerability to inhaled toxicants. A decision framework is discussed that considers these different approaches and modeling structures including assessment of parameter values, supporting data, reliability, and selection of dose metrics.

Approaches to Acrylamide Physiologically Based Toxicokinetic Modeling for Exploring Child–adult Dosimetry Differences

Dietary exposure to acrylamide is common as a result of its formation during the cooking of carbohydrate foods. This leads to widespread human exposure in adults and children alike. Acrylamide is neurotoxic and is metabolized by cytochrome P-450 (CYP) 2E1 to a mutagenic epoxide, glycidamide. This article describes a modeling framework for assessing acrylamide and glycidamide dosimetry in rats and human adults and children. The challenges in building a physiologically based toxicokinetic (PBTK) model that is compatible with existing rat and human data are described, with an emphasis on calibration against the hemoglobin adduct database. This exploratory PBTK model was adapted to children by incorporating life-stage-specific parameters consistent with children's changing physiology and metabolic capacity for processes involved in acrylamide disposition in terms of CYP2E1, glutathione conjugation, and epoxide hydrolase. Monte Carlo analysis was used to simulate the distribution of internal doses to gain an initial understanding of the range of child/adult differences possible. This analysis suggests modest dosimetry differences between children and adults, with area-under-the-curve (AUC) doses for the 99th percentile child up to fivefold greater than the median adult for both acrylamide and glycidamide. Early life immaturities tended to exert a greater effect on acrylamide than glycidamide dosimetry because immaturities in CYP2E1 and glutathione counteract one another for glycidamide AUC, but both lead to greater acrylamide dose. The analysis points toward glutathione conjugation parameters as being particularly influential and uncertain in early life, making this a key area for future research.

Children's nurses and nurse prescribing: a case study identifying issues for developing training programmes in the UK

(1) To develop an insight into the opportunities and barriers to nurse prescribing for a case study of children's nurses. (2) To consider the implications of independent nurse prescribing for children's nurses and the potential for nurse prescribing to be developed in acute children's care settings. (3) To use research data to develop a training strategy. Nurse prescribing in the UK is evolving and current initiatives aim to extend the range and scope of prescribing. Children's nursing presents interesting challenges because of off-license drugs. Successful nurse prescribing lies in practice area preparation, local policy and practice development and identifying precourse training needs. Case study. (1) What opportunities do children's nurses identify as being appropriate for nurse prescribing? (2) Can children's nurses identify the benefits of patient group directives and the different levels of nurse prescribing? (3) What preparation do children's nurses need for nurse prescribing? Focus group of health visitors/district nurses to inform a survey of 500 nurses working in acute and specialist care settings in a large Children's Hospital. Results. Focus group main themes - training, supervision and the development of confidence, record keeping, benefits of nurse prescribing, autonomous practice, the formulary and its use in practice. Response rate was 27%. Senior nurses and specialists identified potential benefits for their practice. Course content needed to focus on children, i.e. children's physiology and pharmokinetics. Children's nurses frequently advise junior medical colleagues on prescribing issues. Patient group directives are a useful alternative to prescribing. The results provide an insight into the training needs of children's nurses and specialist nurses which may be used to develop nurse prescribing training and practice. Training may need to be targeted at senior nurses/specialist nurses initially to develop a critical mass to change organizational culture. Pertinent for senior nurses responsible for developing children's nursing practice and services for children in acute settings.

Reinforcing Value of Interval and Continuous Exercise Above and Below the Ventilatory Threshold

PURPOSE: Activities that children engage in at high rates are reinforcing to them. Observational studies show that during play children engage in ≥15 sec intermittent bouts of activity, much like interval training. These bouts comprise 95% of total physical activity whereas bouts >30 sec account for only 5%. Children may not be motivated to adhere to exercise prescriptions that are based on extended periods of continuous activity. Engaging in brief bouts may be driven by a child's physiology, which is ideally suited for performing short bouts of activity, especially when the intensity is above the ventilatory threshold (VT). However, the reinforcing value of continuous versus interval exercise at intensities above and below VT has not been determined. METHODS: Boys (n = 7 age 10±1.29) performed a progressive exercise test on a cycle ergometer to determine VO2 peak and VT. Children returned to the laboratory and sampled interval and continuous exercise on a cycle ergometer at an intensity that was either 20% <VT on one day and 5% >VT on another day. Sampling and intensity orders were counterbalanced. The exercise protocols were matched for energy expenditure. For the continuous protocol children pedaled at a fixed workload for 5 min and for the interval protocol they performed 20 sec of work followed by 20 sec of active recovery for 5 min. After sampling the exercise protocols children played a computer game to assess the reinforcing value of interval or continuous exercise by having the children work to earn access to either interval or continuous exercise in 2-min blocks for a total of 10 minutes. The amount of time children chose to perform interval or continuous exercise above and below VT was compared. RESULTS: One-way ANOVA showed children worked for a greater amount of interval exercise at intensities >VT (8.29±1.38 min) than interval exercise <VT (4.86±2.55 min) (p<0.04). Children also worked for a greater amount of interval time (8.29±1.38 min) than continuous time (1.31±1.38 min) when exercising >VT (P=0.001). However, there was no preference between interval (4.86±2.55 min) or continuous (5.14±2.55 min) exercise <VT (P=0.89). CONCLUSIONS: Children chose to be active in interval rather than continuous exercise >VT. Additionally, >VT children chose a greater amount of interval than continuous exercise. Below VT there was no preference for interval or continuous exercise. However, children broke the 10 min <VT period into a 5 min period and a series of 20 sec intervals demonstrating that 10 min of continuous physical activity is not reinforcing even at low intensities. Supported by NIH grant RO1 HD042766 to JNR and a Gatorade Sports Science Institute grant to JEB.

Children's Exercise Physiology, 2nd Edition

Children's Exercise Physiology, 2nd Edition

Ethical considerations in research involving children

Ethical concerns and medical advances unique to children and adolescents make pediatric research an evolving endeavor. The child's changing physiology from infancy to maturity requires understanding of the benefits and risks of medical therapies currently available, but often not tested in children, as well as the risks and benefits of inclusion of children in clinical research. Recent mandates from the US Food and Drug Administration (FDA) require that drugs be tested for safety and efficacy in children. Growing concern for the prevalence of chronic disorders and increasing understanding of distinct phenotypes of these disorders points to a likely need for unique interventions matched to specific phenotypes. All contribute to the increasing complexity of ethical considerations in pediatric research.

An overview of children as a special population—Relevance to predictive biomarkers

There has been an increasing focus on children as a special population in the fields of toxicology and epidemiology. At the same time, there has been considerable improvement in the technology for defining normal development and pathways of pathogenesis. Increased support of these areas has culminated in stronger research programs and greater professional involvement in addressing the specific challenges of applying new techniques and data to the improvement of children's health. Part of these challenges relates to the ever changing environment of the child. Not only does a child's anatomy, physiology, and metabolism change with time, but their lifestyle and awareness change as well. All of these can have a significant impact on a child's exposure and the potential of that exposure to have an effect on health and development. This paper will provide a brief overview of the susceptibility of the child relative to sensitive developmental life stages, the changing nature of exposure parameters during development, and how these factors can impact the relevance of predictive biomarkers of chemical toxicity in children.

The Child's Physiology of Taste

The Child's Physiology of Taste