Abbey Alkon

Psychobiologic reactivity to stress and childhood respiratory illnesses: results of two prospective studies.

Psychological stress is thought to undermine host resistance to infection through neuroendocrine-mediated changes in immune competence. Associations between stress and infection have been modest in magnitude, however, suggesting individual variability in stress response. We therefore studied environmental stressors, psychobiologic reactivity to stress, and respiratory illness incidence in two studies of 236 preschool children. In Study 1, 137 3- to 5-year-old children from four childcare centers underwent a laboratory-based assessment of cardiovascular reactivity (changes in heart rate and mean arterial pressure) during a series of developmentally challenging tasks. Environmental stress was evaluated with two measures of stressors in the childcare setting. The incidence of respiratory illnesses was ascertained over 6 months using weekly respiratory tract examinations by a nurse. In Study 2, 99 5-year-old children were assessed for immune reactivity (changes in CD4+, CD8+, and CD19+ cell numbers, lymphocyte mitogenesis, and antibody response to pneumococcal vaccine) during the normative stressor of entering school. Blood for immune measures was sampled 1 week before and after kindergarten entry. Environmental stress was indexed with parent reports of family stressors, and a 12-week respiratory illness incidence was measured with biweekly, parent-completed symptom checklists. The two studies produced remarkably similar findings. Although environmental stress was not independently associated with respiratory illnesses in either study, the incidence of illness was related to an interaction between childcare stress and mean arterial pressure reactivity (beta =.35, p <.05) in Study 1 and to an interaction between stressful life events and CD19+ reactivity (beta =.51, p <.05) in Study 2. In both studies, reactive children sustained higher illness rates under high-stress conditions, but lower rates in low-stress conditions, compared with less reactive peers. Stress was associated with increased rates of illnesses, but only among psychobiologically reactive children. Less reactive children experienced no escalation in illness incidence under stressful conditions, suggesting that only a subset of individuals may be susceptible to the health-altering effects of stressors and adversity.

Resilience and vulnerability among preschool children: family functioning, temperament, and behavior problems.

OBJECTIVE To examine the effects of child temperament and stressful family functioning on child behavior problems among preschool children. METHOD One hundred forty-five preschool children, aged 2 to 5 years, were evaluated by teachers, mothers, and independent observers. Teachers reported on child temperament; from these ratings, two dimensions of temperament were derived: difficult/easy and approachability. Mothers reported on two dimensions of family functioning: conflict and expressiveness. Both teachers and independent observers rated child behavior problems. RESULTS Children with more difficult temperaments who were in high-conflict families had the most internalizing and externalizing behavior problems, while children with easy temperaments had fewer such problems, regardless of levels of family conflict. Difficult children whose families were highly expressive engaged in the most observed aggression. CONCLUSIONS Results suggest that temperament is involved in both protective and vulnerability processes. A difficult temperament operates as a vulnerability factor for internalizing and externalizing behavior problems and observed aggression, while an easy temperament functions as a protective mechanism for these outcomes.

Principles and Practices of Neurodevelopmental Assessment in Children: Lessons Learned from the Centers for Children's Environmental Health and Disease Prevention Research

Principles and practices of pediatric neurotoxicology are reviewed here with the purpose of guiding the design and execution of the planned National Children’s Study. The developing human central nervous system is the target organ most vulnerable to environmental chemicals. An investigation of the effects of environmental exposures on child development is a complex endeavor that requires consideration of numerous critical factors pertinent to a study’s concept, design, and execution. These include the timing of neurodevelopmental assessment, matters of biologic plausibility, site, child and population factors, data quality assurance and control, the selection of appropriate domains and measures of neurobehavior, and data safety and monitoring. Here we summarize instruments for the assessment of the neonate, infant, and child that are being employed in the Centers for Children’s Environmental Health and Disease Prevention Research, sponsored by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency, discuss neural and neurobiologic measures of development, and consider the promises of gene–environment studies. The vulnerability of the human central nervous system to environmental chemicals has been well established, but the contribution these exposures may make to problems such as attention deficit disorder, conduct problems, pervasive developmental disorder, or autism spectrum disorder remain uncertain. Large-scale studies such as the National Children’s Study may provide some important clues. The human neurodevelopmental phenotype will be most clearly represented in models that include environmental chemical exposures, the social milieu, and complex human genetic characteristics that we are just beginning to understand.

Literacy promotion: An essential component of primary care pediatric practice

Reading regularly with young children stimulates optimal patterns of brain development and strengthens parent-child relationships at a critical time in child development, which, in turn, builds language, literacy, and social-emotional skills that last a lifetime. Pediatric providers have a unique opportunity to encourage parents to engage in this important and enjoyable activity with their children beginning in infancy. Research has revealed that parents listen and children learn as a result of literacy promotion by pediatricians, which provides a practical and evidence-based opportunity to support early brain development in primary care practice. The American Academy of Pediatrics (AAP) recommends that pediatric providers promote early literacy development for children beginning in infancy and continuing at least until the age of kindergarten entry by (1) advising all parents that reading aloud with young children can enhance parent-child relationships and prepare young minds to learn language and early literacy skills; (2) counseling all parents about developmentally appropriate shared-reading activities that are enjoyable for children and their parents and offer language-rich exposure to books, pictures, and the written word; (3) providing developmentally appropriate books given at health supervision visits for all high-risk, low-income young children; (4) using a robust spectrum of options to support and promote these efforts; and (5) partnering with other child advocates to influence national messaging and policies that support and promote these key early shared-reading experiences. The AAP supports federal and state funding for children’s books to be provided at pediatric health supervision visits to children at high risk living at or near the poverty threshold and the integration of literacy promotion, an essential component of pediatric primary care, into pediatric resident education. This policy statement is supported by the AAP technical report “School Readiness” and supports the AAP policy statement “Early Childhood Adversity, Toxic Stress, and the Role of the Pediatrician: Translating Developmental Science Into Lifelong Health.”

Nutrition and physical activity randomized control trial in child care centers improves knowledge, policies, and children’s body mass index

BackgroundTo address the public health crisis of overweight and obese preschool-age children, the Nutrition And Physical Activity Self Assessment for Child Care (NAP SACC) intervention was delivered by nurse child care health consultants with the objective of improving child care provider and parent nutrition and physical activity knowledge, center-level nutrition and physical activity policies and practices, and children’s body mass index (BMI).MethodsA seven-month randomized control trial was conducted in 17 licensed child care centers serving predominantly low income families in California, Connecticut, and North Carolina, including 137 child care providers and 552 families with racially and ethnically diverse children three to five years old. The NAP SACC intervention included educational workshops for child care providers and parents on nutrition and physical activity and consultation visits provided by trained nurse child care health consultants. Demographic characteristics and pre - and post-workshop knowledge surveys were completed by providers and parents. Blinded research assistants reviewed each center’s written health and safety policies, observed nutrition and physical activity practices, and measured randomly selected children’s nutritional intake, physical activity, and height and weight pre- and post-intervention.ResultsHierarchical linear models and multiple regression models assessed individual- and center-level changes in knowledge, policies, practices and age- and sex-specific standardized body mass index (zBMI), controlling for state, parent education, and poverty level. Results showed significant increases in providers’ and parents’ knowledge of nutrition and physical activity, center-level improvements in policies, and child-level changes in children’s zBMI based on 209 children in the intervention and control centers at both pre- and post-intervention time points.ConclusionsThe NAP SACC intervention, as delivered by trained child health professionals such as child care health consultants, increases provider knowledge, improves center policies, and lowers BMI for children in child care centers. More health professionals specifically trained in a nutrition and physical activity intervention in child care are needed to help reverse the obesity epidemic.Trial registrationNational Clinical Trials Number NCT01921842

Developmental changes in autonomic nervous system resting and reactivity measures in Latino children from 6 to 60 months of age.

Objective: This study describes the developmental changes and individual stability in autonomic nervous system (ANS) resting and challenge responses for a cohort of primarily Latino, low-income children during the first 5 years of life. Methods: ANS measures of the parasympathetic nervous system (respiratory sinus arrhythmia [RSA]) and sympathetic nervous system (preejection period [PEP]) were collected on a representative sample of the full cohort at 6, 12, 42, and 60 months of age (N = 378). The children participated in a standardized protocol to elicit ANS responses during resting and challenging states. Reactivity profiles were created to summarize each childs combined RSA and PEP reactivity (i.e., change in response to challenges compared to a resting state). Results: Results showed developmental changes in ANS measures from 6 to 60 months: heart rate decreased, RSA increased, PEP increased, and frequency of classic reactivity profiles of reciprocal sympathetic activation and parasympathetic withdrawal increased. Correlations showed moderate stability for resting and challenging conditions but not reactivity. Conclusions: These findings suggest that low-income Latino children, from 6 to 60 months of age, showed ANS developmental changes and moderate individual stability for resting and challenge responses but not for reactivity. There was a significant shift in the frequency of children with the classic reactivity profile from 6 by 60 months of age. This is the first cohort study to show the developmental changes in ANS and young childrens increase in their biologic sensitivity to the environment during the first 5 years of life.

Autonomic reactivity and clinical severity in children with sickle cell disease

Individual differences in autonomic nervous system reactivity have been studied in relation to physical and mental health outcomes, but rarely among children with chronic disease. The purpose of this study was to examine the associations among autonomic reactivity, clinical severity, family stressors, and mental health symptoms in children with homozygous sickle cell disease. Nineteen children with homozygous sickle cell disease participated in a cross-sectional study involving parent-completed measures, medical record reviews and laboratory-based measures of autonomic nervous system responses to social, cognitive, physical and emotional challenges. Autonomic reactivity was significantly associated with both clinical severity and externalizing behavior symptoms. Children with greater parasympathetic withdrawal during challenges compared to rest had significantly more severe disease (r=–0.45, p<0.05); greater sympathetic activation during challenges compared to rest was associated with more externalizing behavior symptoms (r=0.44, p<0.05). Children experiencing major family stressors had internalizing behavior symptoms but no difference in autonomic reactivity or clinical severity compared to children experiencing fewer family stressors. Individual differences in autonomic reactivity may offer a new, biologically plausible account for observed variation in painful episodes, other physical complications and behavioral symptoms among children with sickle cell disease.

Nocturnal Sleep and Daytime Nap Behaviors in Relation to Salivary Cortisol Levels and Temperament in Preschool-Age Children Attending Child Care

The purpose of this study was to describe nocturnal sleep and daytime nap duration in relation to salivary cortisol levels and child temperament in nonproblem nappers and problem nappers. Nighttime sleep and nap durations were obtained with continuous actigraph recordings for 3 days and nights (Tuesday, Wednesday, and Thursday) on 38 children aged 3 to 5 years who attended full-day child care centers. Nap times and disruptive behaviors were also observed and coded on each of the 3 days. Parents completed a temperament scale, sleep diaries, and the Childrens Sleep Habits Questionnaire. Salivary cortisol samples were collected midmorning and in the afternoon after a nap on 2 consecutive days (Wednesday and Thursday). Problem napping and disruptive behaviors were associated with more negative affect, higher afternoon cortisol levels, and a smaller decrement in cortisol from morning to afternoon. Problem napping and disruptive behaviors were also associated with longer nighttime sleep, shorter nap durations, and later rise times. These data provide some insight into the associations among nighttime sleep, napping behavior, and salivary cortisol.

Dimensions of psychobiologic reactivity: Cardiovascular responses to laboratory stressors in preschool children.

Individual differences in children’s physiologic responses to environmental stressors may be responsible for significant, but modest, associations found in past studies between stress and various morbidities. Because no standardized approach currently exists for eliciting and measuring cardiovascular reactivity (CVR) to laboratory stressors in preschool children, we developed a laboratory-based reactivity protocol that derives three dimensions of CVR-intensity, variability, and attenuation-and collected reliability data for each. A sample of 137 children between the ages of three and five years completed a series of seven devel-opmentally challenging tasks, comprising interpersonal, cognitive, and fine motor problems. Pulse rate (PR), diastolic blood pressure (DBP), systolic blood pressure (SBP), and mean arterial blood pressure (MAP) were measured at twelve standardized points using a Dinamap oscillometric blood pressure monitor. CVR scores were calculated for each of the four cardiovascular measures using: (a) a difference score; (b) a standardized residual score; and (c) three scores characterizing the dimensions of intensity, variability, and attenuation. Four to six weeks following initial testing, the protocol was readministered to ascertain temporal stability of reactivity measures.All four cardiovascular measures were responsive to the presented tasks (p>.001), and extensive variability was found in the character of cardiovascular responses. Subjects less than four years of age showed higher task PRs and lower DBPs, SBPs, and MAPs compared to older peers, but no gender differences were found. Difference scores were highly correlated with standardized residual scores (r’s=.94 and .79,p>.001 for PR and MAP, respectively), but the three reactivity dimension scores showed a lack of intercorrelation and were independent of both difference and residual scores. Only the intensity and variability dimension scores showed modest and significant test-retest reliability (r’s=.25 to .50,P>.01). Although previous CVR research has generally utilized difference or residual scores, dimensional scores reflecting the intensity and variability of CVR may achieve greater reliability in preschool childen.

A violence-prevention and evaluation project with ethnically diverse populations

The purpose of this paper is to describe some of the challenges encountered and lessons learned while providing and evaluating a violence-prevention program for and with ethnically diverse populations in child care settings. The paper discusses Safe Start, a violence prevention education program for child care staff and parents, and the evaluation of the program. Safe Start was designed to include culturally relevant content to increase cultural awareness for child care staff and parents from diverse ethnic backgrounds. The evaluation project enrolled child care centers with families representing the ethnically diverse communities in which they were located. Violence prevention research involving children from diverse ethnic backgrounds presents new methodologic challenges, but also provides new opportunities for creative, novel methods. This paper describes some of the challenges encountered with curriculum development, staff recruitment, instrument selection, and data collection procedures.