Findings

In the Beginning...

Kevin Lewis

March 17, 2010

The Effect of Maternal Stress on Birth Outcomes: Exploiting a Natural Experiment

Florencia Torche
NYU Working Paper, March 2010

Abstract:
A growing literature highlights that in-utero conditions are consequential for individual outcomes throughout the life cycle, but research assessing causal processes is scarce. This paper examines the effect of one such condition - prenatal maternal stress - on birthweight. Birthweight is an early outcome shown to affect cognitive, educational, and socioeconomic attainment later in life. Exploiting a major earthquake as a natural experiment and a difference-in-difference methodology, I show that maternal stress has a substantial detrimental effect on birthweight. This effect is focused on the first trimester of gestation, and it is mediated by reduced gestational age rather than intra-uterine growth restriction. Several robustness and sensitivity tests confirm the causal influence of prenatal maternal stress and reject the hypothesis that the association is driven by unobserved selectivity of mothers. The findings highlight the relevance of understanding the early emergence of unequal opportunity and of investing in maternal wellbeing since the onset of pregnancy.

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Causes and Consequences of Early Life Health

Anne Case & Christina Paxson
NBER Working Paper, January 2010

Abstract:
We examine the consequences of childhood health for economic and health outcomes in adulthood, using height as a marker of health in childhood. After reviewing previous evidence, we present a conceptual framework that highlights data limitations and methodological problems associated with the study of this topic. We present estimates of the associations between height and a range of outcomes, including schooling, employment, earnings, health and cognitive ability, using data collected from early to late adulthood on cohort members in five longitudinal data sets. We find height is uniformly associated with better economic, health and cognitive outcomes - a result only partially explained by the higher average educational attainment of taller individuals. We then turn to the NLSY79 Children and Young Adult Survey to better understand what specific aspects of early childhood are captured by height. We find, even among maternal siblings, taller siblings score better on cognitive tests and progress through school more quickly. Part of the differences found between siblings arises from differences in their birth weights and lengths attributable to mother's behaviors while pregnant. Taken together, these results support the hypothesis that childhood health influences health and economic status throughout the life course.

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The Timing of Prenatal Exposure to Maternal Cortisol and Psychosocial Stress Is Associated With Human Infant Cognitive Development

Elysia Davis & Curt Sandman
Child Development, January/February 2010, Pages 131-148

Abstract:
The consequences of prenatal maternal stress for development were examined in 125 full-term infants at 3, 6, and 12 months of age. Maternal cortisol and psychological state were evaluated 5 times during pregnancy. Exposure to elevated concentrations of cortisol early in gestation was associated with a slower rate of development over the 1st year and lower mental development scores at 12 months. Elevated levels of maternal cortisol late in gestation, however, were associated with accelerated cognitive development and higher scores at 12 months. Elevated levels of maternal pre gnancy-specific anxiety early in pregnancy were independently associated with lower 12-month mental development scores. These data suggest that maternal cortisol and pregnancy-specific anxiety have programming influences on the developing fetus.

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How Much Should We Invest In Preventing Childhood Obesity?

Leonardo Trasande
Health Affairs, March 2010, Pages 372-378

Abstract:
Policy makers generally agree that childhood obesity is a national problem. However, it is not always clear whether enough is being spent to combat it. This paper presents nine scenarios that assume three different degrees of reduction in obesity/overweight rates among children in three age groups. A mathematical model was then used to project lifetime health and economic gains. Spending $2 billion a year would be cost-effective if it reduced obesity among twelve-year-olds by one percentage point. The analysis also found that childhood obesity has more profound economic consequences than previously documented. Large investments to reduce this major contributor to adult disability may thus be cost-effective by widely accepted criteria.

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Childhood Socioeconomic Position and Disability in Later Life: Results of the Health and Retirement Study

Mary Elizabeth Bowen & Hector González
American Journal of Public Health, April 2010, Pages S197-S203

Objectives: We used a life course approach to assess the ways in which childhood socioeconomic position may be associated with disability in later life.

Methods: We used longitudinal data from the nationally representative Health and Retirement Study (1998-2006) to examine associations between parental education, paternal occupation, and disabilities relating to activities of daily living (ADLs) and instrumental activities of daily living (IADLs).

Results: Respondents whose fathers had low levels of education and those whose fathers were absent or had died while they were growing up were at increased risk of disability in later life, net of social, behavioral, and pathological health risks in adulthood. Social mobility and health behaviors were also important factors in the association between low childhood socioeconomic position and ADL and IADL disabilities.

Conclusions: Our findings highlight the need for policies and programs aimed at improving the well-being of both children and families. A renewed commitment to such initiatives may help reduce health care costs and the need for people to use health and social services in later life.

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Childrens' learning and behaviour and the association with cheek cell polyunsaturated fatty acid levels

A. Kirby, A. Woodward, S. Jackson, Y. Wang & M.A. Crawford
Research in Developmental Disabilities, forthcoming

Abstract:
Increasing interest in the role of omega-3 fatty acids in relation to neurodevelopmental disorders (e.g. ADHD, dyslexia, autism) has occurred as a consequence of some international studies highlighting this link. In particular, some studies have shown that children with ADHD may have lower concentrations of polyunsaturated fatty acids (PUFAs), particularly omega-3, in their red blood cells and plasma, and that supplementation with omega-3 fatty acids may alleviate behavioural symptoms in this population. However, in order to compare levels it seems appropriate to establish fatty acid levels in a mainstream school aged population and if levels relate to learning and behaviour. To date no study has established this. For this study, cheek cell samples from 411 typically developing school children were collected and analysed for PUFA content, in order to establish the range in this population. In addition, measures of general classroom attention and behaviour were assessed in these children by teachers and parents. Cognitive performance tests were also administered in order to explore whether an association between behaviour and/or cognitive performance and PUFA levels exists. Relationships between PUFA levels and socio-economic status were also explored. Measures of reading, spelling and intelligence did not show any association with PUFA levels, but some associations were noted with the level of omega-3 fatty acids and teacher and parental reports of behaviour, with some evidence that higher omega-3 levels were associated with decreased levels of inattention, hyperactivity, emotional and conduct difficulties and increased levels of prosocial behaviour. These findings are discussed in relation to previous findings from omega-3 supplementation studies with children.

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The scaffolded mind: Higher mental processes are grounded in early experience of the physical world

Lawrence Williams, Julie Huang & John Bargh
European Journal of Social Psychology, December 2009, Pages 1257-1267

Abstract:
It has long been a staple of psychological theory that early life experiences significantly shape the adult's understanding of and reactions to the social world. Here we consider how early concept development along with evolved motives operating early in life can come to exert a passive, unconscious influence on the human adult's higher-order goal pursuits, judgments, and actions. In particular, we focus on concepts and goal structures specialized for interacting with the physical environment (e.g., distance cues, temperature, cleanliness, and self-protection), which emerge early and automatically as a natural part of human development and evolution. It is proposed that via the process of scaffolding, these early sensorimotor experiences serve as the foundation for the later development of more abstract concepts and goals. Experiments using priming methodologies reveal the extent to which these early concepts serve as the analogical basis for more abstract psychological concepts, such that we come easily and naturally to speak of close relationships, warm personalities, moral purity, and psychological pain. Taken together, this research demonstrates the extent to which such foundational concepts are capable of influencing people's information processing, affective judgments, and goal pursuit, oftentimes outside of their intention or awareness.

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How Low Socioeconomic Status Affects 2-Year Hormonal Trajectories in Children

Edith Chen, Sheldon Cohen & Gregory Miller
Psychological Science, January 2010, Pages 31-37

Abstract:
Disparities by socioeconomic status (SES) are seen for numerous mental and physical illnesses, and yet understanding of the pathways to health disparities is limited. We tested whether SES alters longitudinal trajectories of cortisol output and what types of psychosocial factors could account for these links. Fifty healthy children collected saliva samples (four times per day for 2 days) at 6-month intervals for 2 years. At baseline, families were interviewed about SES and psychosocial factors. Lower-SES children displayed greater 2-year increases in daily cortisol output compared with higher-SES children. These effects were partially mediated by children's perceptions of threat and by family chaos. These findings may help explain, and provide some first steps toward ameliorating, low-SES children's vulnerability to health problems later in life by identifying the tendency to perceive threat in ambiguous situations and experiences of chaos as factors that link low SES to 2-year hormonal trajectories.

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Early-Childhood Poverty and Adult Attainment, Behavior, and Health

Greg Duncan, Kathleen Ziol-Guest & Ariel Kalil
Child Development, January/February 2010, Pages 306-325

Abstract:
This article assesses the consequences of poverty between a child's prenatal year and 5th birthday for several adult achievement, health, and behavior outcomes, measured as late as age 37. Using data from the Panel Study of Income Dynamics (1,589) and controlling for economic conditions in middle childhood and adolescence, as well as demographic conditions at the time of the birth, findings indicate statistically significant and, in some cases, quantitatively large detrimental effects of early poverty on a number of attainment-related outcomes (adult earnings and work hours). Early-childhood poverty was not associated with such behavioral measures as out-of-wedlock childbearing and arrests. Most of the adult earnings effects appear to operate through early poverty's association with adult work hours.

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The Long Reach of Childhood Health and Circumstance: Evidence from the Whitehall II Study

Anne Case & Christina Paxson
NBER Working Paper, January 2010

Abstract:
We use data from the Whitehall II study to examine the potential role played by early-life health and circumstances in determining health and employment status in middle and older ages. The population from which the Whitehall II cohort was drawn consisted almost exclusively of white collar civil servants. We demonstrate that estimates of the impact of early-life conditions based on the Whitehall II cohort provide a lower bound on the effect of early-life circumstances on adult health and economic status for the population as a whole. That said, using the Whitehall II cohort data, we find early life circumstances are all predictive of entry grade and promotion to higher grade in Whitehall. Even with controls for entry grade or current grade, we find that childhood circumstances predict cohort members' current health status. Using fixed effect and first-difference models of self-assessed health status and civil service employment grade, we find no evidence of civil service grade affecting future self-assessed health. However, we find self-assessed health has a significant effect on future civil service grade.

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Do social disadvantage and early family adversity affect the diurnal cortisol rhythm in infants? The Generation R Study

N.S. Saridjan, A.C. Huizink, J.A. Koetsier, V.W.V. Jaddoe, J.P. Mackenbach, A. Hofman, C. Kirschbaum, F.C. Verhulst & H. Tiemeier
Hormones and Behavior, February 2010, Pages 247-254

Abstract:
Dysregulation of diurnal cortisol secretion patterns may explain the link between adversities early in life and later mental health problems. However, few studies have investigated the influence of social disadvantage and family adversity on the hypothalamic-pituitary-adrenal (HPA) axis early in life. In 366 infants aged 12-20 months from the Generation R Study, a population-based cohort from fetal life onwards, parents collected saliva samples from their infant at 5 moments during one day. The area under the curve (AUC), the cortisol awakening response (CAR) and the diurnal cortisol slope were calculated as different composite measures of the diurnal cortisol rhythm. Information about social disadvantage and early adversity was collected using prenatal and postnatal questionnaires. We found that older infants showed lower AUC levels; moreover, infants with a positive CAR were significantly older. Both the AUC and the CAR were related to indicators of social disadvantage and early adversity. Infants of low income families, in comparison to high income families, showed higher AUC levels and a positive CAR. Infants of mothers who smoked during pregnancy were also significantly more likely to show a positive CAR. Furthermore, infants of mothers experiencing parenting stress showed higher AUC levels. The results of our study show that effects of social disadvantage and early adversity on the diurnal cortisol rhythm are already observable in infants. This may reflect the influence of early negative life events on early maturation of the HPA axis.


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