Methodological issues related to longitudinal epidemiological assessment of developmental trajectories in children.

This supplement presents some of the methodological issues that arose during the early phases of protocol development for the National Children's Study (NCS), a probability sample of 100,000 children that will be followed prospectively from pregnancy through 21 years of age, and to share some of the challenges and solutions that were discussed. These papers on motor, social/emotional, psychiatric and neurocognitive/behavioural development do not define the protocol of the NCS, but reflect methodology related to the design of research and assessment of developmental trajectories in children that may be useful to other epidemiologists planning similar longitudinal studies.

Assessing social-emotional development in children from a longitudinal perspective.

This paper provides an overview of methodological challenges related to the epidemiological assessment of social-emotional development in children. Because population-based studies involve large cohorts and are usually multicentre in structure, they have cost, participant burden and other specific issues that affect the feasibility of the types of measures that can be administered. Despite these challenges, accurate in-depth assessment of social-emotional functioning is crucial, based on its importance to child outcomes like mental health, academic performance, delinquency and substance abuse. Five dimensions of social-emotional development in children are defined: (1) social competence; (2) attachment; (3) emotional competence; (4) self-perceived competence; and (5) temperament/personality. Their measurement in a longitudinal study and associated challenges are discussed. Means of making valid, reliable assessments while at the same time minimising the multiple challenges posed in the epidemiological assessment of social-emotional development in children are reviewed.

Assessment of neuropsychological trajectories in longitudinal population-based studies of children.

This paper provides a strategy for the assessment of brain function in longitudinal cohort studies of children. The proposed strategy invokes both domain-specific and omnibus intelligence test approaches. In order to minimise testing burden and practice effects, the cohort is divided into four groups with one-quarter tested at 6-monthly intervals in the 0-2-year age range (at ages 6 months, 1.0, 1.5 and 2.0 years) and at annual intervals from ages 3-20 (one-quarter of the children at age 3, another at age 4, etc). This strategy allows investigation of cognitive development and of the relationship between environmental influences and development at each age. It also allows introduction of new domains of function when age-appropriate. As far as possible, tests are used that will provide a rich source of both longitudinal and cross-sectional data. The testing strategy allows the introduction of novel tests and new domains as well as piloting of tests when the test burden is relatively light. In addition to the recommended tests for each age and domain, alternative tests are described. Assessment methodology and knowledge about child cognitive development will change over the next 20 years, and strategies are suggested for altering the proposed test schedule as appropriate.

Approaches to psychiatric assessment in epidemiological studies of children.

An assessment protocol for the longitudinal measurement of developmental psychopathology in a population-based study of children and adolescents is proposed. The protocol is designed for use in a large cohort of up to 100,000 individuals followed from early gestation to 21 years of age. Although the protocol was constrained by specified methodological parameters, the recommendations may apply to other psychiatric epidemiological research designs. The issues and challenges inherent with psychiatric assessments in longitudinal epidemiological studies of children and adolescents are discussed.

Proposed motor development assessment protocol for epidemiological studies in children.

This paper proposes an approach to the implementation of a large-scale epidemiological study of child development. It addresses specifically how one might assess gross motor development longitudinally in a large population-based study of children, and recommends a three-phase process. Phase I, applied at key ages with the entire population, involves the use of parent-report screening tools that ask about specific age-appropriate motor skills, as well as any parental concerns about "quantity" or "quality" of their child's motor function and about any loss of motor function. In phase II, children who "fail" the screening phase (at any stage) are evaluated with specified developmental motor assessments. Those who "pass" revert to the screening stream, while those who "fail" continue to phase III. In this third component of the study, children are referred to experts in child development formally engaged in the study (including developmental paediatricians, paediatric neurologists and developmental therapists). These experts will use protocol-based evaluations to ascertain whether a child has a problem in development, what the problem might be from a diagnostic perspective, how "severe" the problem is, and what management services are or should be provided. It is argued that this is an efficient approach to the study of a population that would enable investigators to detect specific relatively common developmental motor disorders (in particular, cerebral palsy and developmental coordination disorder).

Social support and health behavior in hostile black and white men and women in CARDIA. Coronary Artery Risk Development in Young Adults.

OBJECTIVE: These cross-sectional analyses of the Coronary Artery Risk Development in Young Adults (CARDIA) data were stimulated by previous CARDIA analyses that showed an adverse association between hostility and several health behaviors: physical activity, cigarette smoking, alcohol consumption, and caloric intake, in both black and white men and women, such that the higher the hostility, the worse the health behavior profile. The current study investigated whether high social support was associated with better health behavior than low social support in individuals with high hostility scores. METHODS: The subjects were 5115 healthy black and white men and women ranging in age from 18 to 30 years. The hypothesis was that the association between hostility and certain adverse health behaviors would be diminished in the presence of high social support. Race-gender specific median cutpoints of the Cook-Medley Hostility scale and an index of social support defined levels of high and low hostility and social support. RESULTS: After controlling for age and body mass index (BMI), support was positively associated with more exercise in all groups except black women, but when coupled with high hostility, this positive association between support and exercise remained only in men. White women with high support were less often smokers but this association did not hold when examined only in the high-hostile group. Black men and white women with high support in the presence of high hostility consumed more alcohol, but the amount was moderate. CONCLUSIONS: We conclude that social support in the presence of high hostility only sometimes reduces the association of hostility to adverse health behaviors and that these effects are complex. Additional research investigating types of social support on health behavior in different race-gender groups is advocated.

Hostility, social support, and carotid artery atherosclerosis in the National Heart, Lung, and Blood Institute Family Heart Study.

This cross-sectional study investigates the association of hostility and social support (measured by standardized instruments) to carotid artery atherosclerosis in men and women with a high familial risk for coronary heart disease (CHD) and those with low to medium risk. The hypothesis was that high hostility and low social support would have a stronger association in subjects with a familial predisposition to CHD. There were 535 low- to medium-risk women, 491 low- to medium-risk men, 1,950 high-risk women, and 1,667 high-risk men in the study. The extent of carotid artery atherosclerosis was assessed by B-mode ultrasound imaging. A lesion was defined as an intimal-medial far wall thickness of 1 mm in the common, internal, or carotid bifurcation, or identification of plaque at any site. Odds ratios and their 95% confidence intervals were calculated using generalized estimating equations (GEE) for logistic regression. Family was specified as the clustering variable, and robust SEEs were obtained that account for dependence of the data within families. After controlling for age, education, body mass index, ever having smoked, ever drinking > 5 drinks a day, and metabolic index, hostility was significantly associated with increased odds of carotid lesions in only high-risk women. High-risk women showed a significantly reduced odds of carotid lesions with high social support, but the extent of this protection was reduced when age and education were included in the equation. A combination of high hostility and low social support was associated with higher odds than hostility alone in both high-risk men and women. These results suggest that women with a high familial predisposition for CHD may be more vulnerable to cardiovascular influences from hostility and social support than high-risk men or men and women with low to medium risk.

Familial resemblance for hostility: the National Heart, Lung, and Blood Institute Family Heart Study.

OBJECTIVE: The purpose of this study was to examine whether several aspects of hostility as measured by the Cook-Medley Hostility Scale (ie, aggressive responding, hostile affect, cynicism, and overall hostility score) were determined in part by family factors (ie, genes and/or familial environments). METHODS: Analyses were based on 680 European-American families (2525 individuals) from the NHLBI Family Heart Study (FHS), a population-based study of genetic and nongenetic determinants of CHD, atherosclerosis, and cardiovascular risk factors. The influence of family relationships, age, and education on the variation in each of the four hostility scores were estimated. RESULTS: Significant familial resemblance in all hostility scores was found, accounting for 42% of the variance in total hostility, 30% in cynicism, 38% in aggressive responding, and 18% in hostile affect. Very little of this resemblance could be explained by similarities in education. Familial resemblance for cynicism was solely due to significant parent-offspring and sibling correlations (ie, no spouse resemblance), suggesting the possibility of genetic influences. Gender and generation differences were also evident in the familial correlations. CONCLUSIONS: Hostility aggregates in families. Both family environmental and genetic sources of resemblance are suggested for hostility.

Hostility, social support, and coronary heart disease in the National Heart, Lung, and Blood Institute Family Heart Study.

This cross-sectional study investigated the association of hostility and social support to coronary heart disease (CHD) in 2 groups of men and women: those with a familial predisposition for CHD (high-risk sample) and a randomly selected group. The hypothesis was that hostility and low social support would be associated with CHD, and would have a greater effect in the high-risk group. The random sample contained 2,447 individuals (47.1% male) from 576 families, and the high-risk sample consisted of 2,300 people (45.5% male) from 542 families. Odds ratios (OR) and their 95% confidence intervals were calculated using generalized estimating equations (GEE) for logistic regression. Family was specified as the clustering variable, and robust SEEs were obtained to account for dependence of the data within families. After controlling for age, education, body mass index, exercise, smoking history, drinking history, and drinking >5 drinks a day, hostility was associated with a history of coronary bypass surgery or coronary angioplasty in high-risk men (OR 1.21) and a history of myocardial infarction in high-risk women (OR 1.39). High-risk women with high social support had reduced odds of a previous myocardial infarction (OR 0.76), whereas women with high network adequacy in the random sample had reduced risk of myocardial infarction (OR 0.41) and angina (OR 0.49). A ratio of high hostility to low social support was associated with past myocardial infarction in high-risk women (OR 2.47) and a history of angina (OR 2.02) in the random sample men. These results suggest that high hostility and low social support are associated with some manifestations of CHD after controlling for adverse health behaviors.

Social isolation and cardiovascular disease: an atherosclerotic pathway?

This paper outlines two pathways through which social support can influence the prevention or progression of cardiovascular disease: health behaviors and neuroendocrine mechanisms. Its primary focus is on neuroendocrine pathways, reviewing data which suggest that lack of social support is etiologically related to coronary artery lesion development through two mechanisms: sympathetic-adrenomedullary influences on platelet function, heart rate and blood pressure in the initial endothelial injury; and pituitary-adrenal cortical factors involved in smooth muscle cell proliferation during progression of the lesion after injury has taken place. It hypothesizes that the buffering effect of social support on the cardiovascular system is mediated primarily through mechanisms associated with the release of oxytocin.

Psychosocial factors and plasma lipids in black and white young adults: the Coronary Artery Risk Development in Young Adults Study data.

These analyses examined the relationship between fasting plasma lipids and several psychosocial factors in a healthy cohort of 5115 black and white men and women between the ages of 18 and 30. Primary analyses were performed within race/gender subgroups and were supplemented with analyses examining consistency of associations across these groups. After controlling for age, high density lipoprotein (HDL) decreased, triglycerides increased, low density lipoprotein (LDL) increased, and the total cholesterol/HDL cholesterol ratio increased with increasing level of education in black men. This pattern is, in general, opposite to that found in other groups, particularly white women, whose lipid profile was found to be less atherogenic the higher the education. These associations were strongly confounded with health behaviors. There was also a positive association between hostility and triglycerides in women but not in men. No significant association with any plasma lipid for either race or gender was found for Type A behavior, social support, or life events. Despite a narrow plasma lipid range in these young adults, these data support the conclusion that increasing education is associated with a less atherogenic plasma lipid profile, except in black men, for whom education is associated with a less favorable plasma lipid profile. Among other psychosocial factors, the only consistent finding was an inverse association between hostility and triglycerides in women.

Genetic and environmental influences on perceptions of organizational climate.

Genetic and environmental influences on perceptions of organizational climate were assessed by using a 4-group twin design. Data were obtained as part of the Swedish Adoption/Twin Study of Aging. The Work Environment Scale (WES) was used to evaluate perceptions of organizational climate. A measure of job satisfaction was also used to evaluate the effects of genes and environments on job attitudes. Maximum likelihood estimates of genetic and environmental influence suggested significant genetic effects for Supportive Climate--1 factor resulting from a factor analysis of the WES--but not for a second factor, Time Pressure. Significant environmental effects were found for both Supportive Climate and Time Pressure. Genetic effects were not significant for job satisfaction. The relevance of findings to organizational climate research and personnel selection are discussed.

Gender differences in the psychosocial variance of Framingham and Bortner Type A measures.

The object of the present study was to determine whether the non-genetic variance of a Type A scale composed of Framingham and Bortner items had gender specific psychosocial components. The study was performed on a group of Swedish twins so that variance explained by heritability for Type A could first be removed from the equation. The overall Type A score had been found to relate to self-reported CHD in this population. The dependent variable was the standardized score residual remaining after removing the genetic variance (i.e., that explained by co-twin score and zygosity). Multiple regression analyses revealed that there were differences in the psychosocial components of the Type A residual in men and women. These results are discussed in terms of culturally accepted gender roles and their possible implications for health endpoints.

Perception of social support and blood pressure in young men.

This study investigated the association between perceived social support, blood pressure, and heart rate during rest and stress. 29 men were selected from 184 students on the basis of having high and low perceived social support. During rest and two of the laboratory stressors, the low-support group had higher diastolic pressure than the high-support group. Systolic blood pressure and heart rate did not differ between the two groups during either rest or stress. The low-support group was slightly older (24.8 yr.) than the high-support group (22.4 yr.), but the groups did not differ with respect to parental history of hypertension, body mass index, smoking, anxiety, anger inhibition, or environmental stress.

The relation of social support and working environment to medical variables associated with elevated blood pressure in young males: a structural model.

The object of the present study was to examine the interaction of working environment factors and the individual social support network with medical variables related to blood pressure elevations in young (mean age = 28 years) hypertensives. The results of path analyses reveal that the medical variables which explained a significant amount of the variation in systolic blood pressure were blood hemoglobin, plasma adrenaline and relative weight. High relative weight was associated with a low level of employment security and high plasma adrenaline with a poor self-reported social network as well as a job providing few possibilities for learning new things. High levels of diastolic pressure were associated with elevated hemoglobin levels, increased heart rate and low plasma renin activity. Increased heart rate was influenced by a lack of 'anger' coping in conflict situations at work and a low number of contacts with acquaintances. Working environment and social support are hypothesized to assert their influence through increased sympathetic stimulation mediated by limbic-hypothalamic discharge.

Alpha enhancement, autonomic activation, and extraversion.

Autonomic activation as reflected by heart rate, skin conductance, muscle tension, and T-wave amplitude of the electrocardiogram were registered during biofeedback training of EEG alpha. The group of 25 subjects showed significant enhancement of alpha but no systematic change in autonomic activation. This result was interpreted as supporting Eysenck's theory of two feedback loops for mediating cortical arousal. According to this theory, autonomic changes would not be expected to accompany changes in cortical arousal during resting conditions lacking emotional content and, therefore, not involving the visceral brain. Although some of the subjects who succeeded in increasing alpha experienced it as positive and others as strenuous, alpha change did not correlate significantly either with the dimension of extraversion, or with those of locus of control and neuroticism.