Rationale and methodological options for assessing infectious disease and related measures in social science surveys

Chronic Ongoing Stressors and C-Reactive Protein: A Within-Person Study

Objectives: Literature suggests C-reactive protein (CRP)-as a marker of low-grade systemic inflammation-may mediate the linkage between chronic stressors and cardiometabolic conditions. Previous population-based reports are based on weak methodologies and may have yielded incorrect inferences. The current study examined linkages of within-person CRP variation with corresponding variation in stressor burdens. Method: Data were from the 2006, 2010, and 2014 waves of the U.S. Health and Retirement Study. Analysis was through unit fixed effects and first-difference estimators. Both gender-combined and gender-specific models were run. Results: In none of the analyses was CRP positively associated with chronic stressors. This was true among both genders, and in models of linear as well as nonlinear change. Results held in a series of separate robustness checks. Discussion: CRP may not mediate the social etiology of degenerative diseases. Population representative evidence of inflammation's role in these processes remains absent.

Depression, Inflammation, and Physiological Risk in Late Life: A National Longitudinal Study

This nationally representative study queried effects of community dwelling older adults' depression and inflammation at baseline on over-time changes in surrogate markers of their cardiometabolic risk. Data were from the 2005-2006 and 2010-2011 waves of the U.S. National Social Life, Health, and Aging Project. Inflammation was indicated by C-reactive protein and depression by the CES-D scale. Cardiometabolic markers included hemoglobin A1c and systolic BP. Lagged dependent variable models were used to examine effects. In none of the models did Wave 1 depression predict residual change in cardiometabolic states (i.e., Wave 2 values net of Wave 1). In contrast, men's baseline C-reactive protein predicted their Wave 2 hemoglobin A1c (Coeff. = 0.02, p < .05) as well as their systolic BP (Coeff. = 3.22, p < .05). No such effects were found among women. Contrary to a growing clinical literature, depression may not increase cardiometabolic risk among older adults on average. Moderators that may interact with depression to yield such effects in delimited samples remain to be identified. Inflammation, in contrast, does seem linked to increase in physiological risk-but only among men, not women. Clinical research is needed to identify biological factors responsible for this sex difference.

Psychosocial distress and inflammation: Which way does causality flow?

OBJECTIVES

This study queried causal direction in linkages of inflammation with psychosocial distress.

METHODS

Data were from the 2005-2006 and 2010-2011 waves of the U.S. National Social Life, Health, and Aging Project. Inflammation was indicated by C-reactive protein, and distress by depression, anxiety, as well as stress. Autoregressive cross-lagged panel models were used to examine causal direction.

RESULTS

Rather than being an outcome of psychosocial distress, inflammation was a predictor of it. Linkages were gender differentiated, with inflammation seeming to induce depression among men but stress among women.

DISCUSSION

Contrary to previous literature, inflammation may not be a mechanism through which psychosocial distress gets "under the skin" to cause cardiovascular and metabolic issues. Rather, it may be a node through which social pathologies and life events influence both mental health and physiological problems.

Dimensions of Socioeconomic Status and Childhood Asthma Outcomes: Evidence for Distinct Behavioral and Biological Associations

OBJECTIVES

The objective of this study was to investigate 2 key dimensions of socioeconomic status (SES)-prestige and resources-and their associations with immune, behavioral, and clinical outcomes in childhood asthma.

METHODS

Children ages 9 to 17 years with a physician's diagnosis of asthma (N = 150), and one of their parents participated in this study. Children and parents completed interviews and questionnaires about SES (prestige = parent education; resources = family assets), environmental exposures, and clinical asthma measures. Spirometry was conducted to assess children's pulmonary function, and blood was collected to measure cytokine production in response to nonspecific stimulation, allergen-specific stimulation, and microbial stimulation.

RESULTS

Higher scores on both dimensions of childhood SES were associated with better clinical outcomes in children (β's from |.18 to .27|, p values < .05). Higher prestige, but not resources, was associated with better home environment control behaviors and less exposure to smoke (β's from |.21 to .22|, p values < .05). Higher resources, but not prestige, was associated with more favorable immune regulation, as manifest in smaller peripheral blood mononuclear cell (PBMC) TH1 and TH2 cytokine responses (β's from -.18 to -.19; p values < .05), and smaller proinflammatory cytokine responses (β = -.19; p < .05) after ex vivo stimulation. Higher resources also were associated with more sensitivity to glucocorticoid inhibition of TH1 and TH2 cytokine production (β's from -.18 to -.22; p values < .05).

CONCLUSIONS

These results suggest that prestige and resources in childhood family environments have different implications for behavioral and immunological processes relevant to childhood asthma. They also suggest that childhood SES relates to multiple aspects of immunologic regulation of relevance to the pathophysiology of asthma.

Childhood adversity and cell-mediated immunity in young adulthood: does type and timing matter?

Childhood adversity can have powerful effects on health over the life course. Persistent changes in cell-mediated immune function may be one pathway linking adverse childhood experiences with later disease risk. However, limited research has examined childhood adversity in relation to cell-mediated immune function, and in particular, immune response to latent viruses in adulthood. The present study investigated the association of two types of childhood adversity, socioeconomic disadvantage during adolescence and abuse prior to age 18, with Epstein-Barr Virus (EBV) antibody titers in a large nationally representative sample of young adults aged 24-32years. Data were drawn from the National Longitudinal Study on Adolescent Health, Wave 4 (n=13,162). We examined the associations of three indicators of adolescent SES (parental education, household income, and occupational status) and frequency and timing of physical and sexual abuse with EBV antibodies, controlling for age, sex, race/ethnicity, and presence of a smoker in the household during adolescence. Lower parental occupational status and some categories of lower education were associated with elevated EBV antibodies (p<.05), and individuals who reported sexual abuse that occurred more than 10times had elevated EBV antibodies relative to individuals who were not sexually abused (p=0.03). Among individuals exposed to physical abuse, those who were first abused at age 3-5years had heightened EBV antibodies relative to those first abused during adolescence (p=0.004). This study extends prior research linking early adversity and immune function, and provides initial evidence that childhood adversity has a persistent influence on immune responses to latent infection in adulthood.

Effects of prenatal care on child health at age 5

The broad goal of contemporary prenatal care is to promote the health of the mother, child, and family through the pregnancy, delivery, and the child's development. Although the vast majority of mothers giving birth in developed countries receive prenatal care, past research has not found compelling evidence that early or adequate prenatal care has favorable effects on birth outcomes. It is possible that prenatal care confers health benefits to the child that do not become apparent until after the perinatal period. Using data from a national urban birth cohort study in the US, we estimate the effects of prenatal care on four markers of child health at age 5-maternal-reported health status, asthma diagnosis, overweight, and height. Prenatal care, defined a number of different ways, does not appear to have any effect on the outcomes examined. The findings are robust and suggest that routine health care encounters during the prenatal period could potentially be used more effectively to enhance children's health trajectories. However, future research is needed to explore the effects of prenatal care on additional child health and developmental outcomes as well as the effects of preconceptional and maternal lifetime healthcare on child health.

How does race get "under the skin"?: inflammation, weathering, and metabolic problems in late life

Using nationally representative data from the 2005-2006 U.S. National Social Life, Health, and Aging Project, this study queries the mechanisms underlying worse metabolic outcomes--blood-sugar control and cardiovascular health--among black than white men ages 57-85. Results indicate that contrary to much of the academic literature as well as media accounts-implicitly rooted in a "culture of irresponsibility" model--older black men's social isolation, poor health behaviors, or obesity may not play a major role in their worse metabolic problems. Instead, these outcomes seem to derive more consistently from a factor almost unexamined in the literature--chronic inflammation, arguably a biological "weathering" mechanism induced by these men's cumulative and multi-dimensional stress. These findings highlight the necessity of focusing attention not simply on proximal behavioral interventions, but on broader stress-inducing social inequalities, to reduce men's race disparities in health.