Early life adversity and inflammation in African Americans and whites in the midlife in the United States survey

Childhood misfortune as a threat to successful aging: avoiding disease

PURPOSE

The purpose of this study was to examine whether childhood misfortune reduces the likelihood of being disease free in adulthood.

DESIGN AND METHODS

This article used a sample of 3,000+ American adults, aged 25-74, who were first interviewed in 1995 and reinterviewed in 2005. Logistic regression was used to estimate the odds of avoiding disease at the first wave and remaining disease free a decade later.

RESULTS

Consistent with a life course view of successful aging, higher levels of childhood misfortune (e.g., abuse, financial strain) are associated with a lower probability of disease avoidance. This pattern was observed across a large set of chronic conditions and in multivariate analyses spanning both waves of the study.

IMPLICATIONS

Childhood misfortune has approximately equal consequences for adult disease avoidance as does the combined effect of moderate lifetime smoking and obesity. Efforts to alleviate adverse experiences for children may have long-term benefits for successful aging.

Childhood adversity and immune and inflammatory biomarkers associated with cardiovascular risk in youth: a systematic review

BACKGROUND

Research suggests that adverse experiences in childhood affect the development of cardiovascular disease (CVD), and immune and inflammation dysregulation has been postulated to play role. However, it is unclear whether the effects of social adversity on immune-related biomarkers are evident in early life, and if these biomarkers may provide an early risk marker for targeting prevention and intervention. The purpose of this review is to evaluate research on the relationship between adversity and CVD-relevant immune biomarkers in youth, assess the consistency of the findings, and consider what additional research is needed.

METHODS

PubMed and PsycINFO searches were conducted through September 2011. Studies were selected using criteria related to the childhood exposure, biomarker outcome, age range, and sample selection. Twenty articles were identified, examining associations between childhood adversity and immune biomarkers (assessed during childhood) that are potential risk markers for CVD later in life.

RESULTS

Although childhood adversity was not consistently related to youth levels of inflammatory and other immune markers relevant to CVD, a trend toward positive findings was observed. No detectable patterns were evident based on measure of adversity, biomarker, study design, or sample size.

CONCLUSIONS

Overall, our findings suggest this avenue of research is worth continued investigation. We offer recommendations for future research related to (1) study design and sample, (2) definition and measurement of adversity, (3) statistical analysis, and (4) outcomes that will help distinguish whether there are immunologic alterations related to adversity and subsequent CVD risk that can be reliably detected in childhood.

The social context of cardiovascular disease: challenges and opportunities for the Jackson Heart Study

African Americans have higher rates of cardiovascular disease (CVD) than Whites and the racial gap in heart disease is widening over time. There are especially striking patterns of the earlier onset of disease, greater severity of illness and large racial differences in CVD even when Blacks and Whites are compared at the same level of economic status. This paper outlines critical research opportunities for the Jackson Heart Study to advance the science base for understanding and effectively addressing racial disparities in CVD. These include: 1) the study of CVD by using a life course perspective; 2) comprehensively characterizing social stressors; 3) expanding our analysis of how racism affects health; 4) explicating variation in the levels and impact of risk factors; 5) advancing our understanding of the contribution of genetics to CVD; 6) understanding resilience and its effects on CVD; and 7) identifying how economic crises can shape CVD risk.

Psychological stress in childhood and susceptibility to the chronic diseases of aging: moving toward a model of behavioral and biological mechanisms

Among people exposed to major psychological stressors in early life, there are elevated rates of morbidity and mortality from chronic diseases of aging. The most compelling data come from studies of children raised in poverty or maltreated by their parents, who show heightened vulnerability to vascular disease, autoimmune disorders, and premature mortality. These findings raise challenging theoretical questions. How does childhood stress get under the skin, at the molecular level, to affect risk for later diseases? And how does it incubate there, giving rise to diseases several decades later? Here we present a biological embedding model, which attempts to address these questions by synthesizing knowledge across several behavioral and biomedical literatures. This model maintains that childhood stress gets "programmed" into macrophages through epigenetic markings, posttranslational modifications, and tissue remodeling. As a consequence these cells are endowed with proinflammatory tendencies, manifest in exaggerated cytokine responses to challenge and decreased sensitivity to inhibitory hormonal signals. The model goes on to propose that over the life course, these proinflammatory tendencies are exacerbated by behavioral proclivities and hormonal dysregulation, themselves the products of exposure to early stress. Behaviorally, the model posits that childhood stress gives rise to excessive threat vigilance, mistrust of others, poor social relationships, impaired self-regulation, and unhealthy lifestyle choices. Hormonally, early stress confers altered patterns of endocrine and autonomic discharge. This milieu amplifies the proinflammatory environment already instantiated by macrophages. Acting in concert with other exposures and genetic liabilities, the resulting inflammation drives forward pathogenic mechanisms that ultimately foster chronic disease.

Comparative insights into the regulation of inflammation: levels and predictors of interleukin 6 and interleukin 10 in young adults in the Philippines

Inflammation is a central part of innate immunity, but its role in anti-pathogen defenses has been overshadowed by recent interest in the contribution of inflammation to a wide range of chronic degenerative diseases. Current research on chronic inflammation is conducted primarily in affluent populations with low levels of infectious disease; comparative research in different ecological settings is needed to advance understandings of the causes and consequences of variation in the regulation of inflammation. This article investigates the levels and predictors of interleukin-6 (IL-6) and interleukin-10 (IL-10)-two cytokines important to the regulation of inflammation-in a large, population-based study in the Philippines. Concentrations of IL-6 and IL-10 were determined in N = 1,569 healthy young adults (20-22 years) in Metro Cebu, Philippines. IL-6 and IL-10 concentrations were positively correlated, and body mass index and symptoms of infectious disease were both associated with higher concentrations of IL-6 and IL-10. Median concentrations of IL-6 (1.0 pg/mL) and IL-10 (7.56 pg/mL) were substantially lower and higher, respectively, than levels reported for other populations based on a systematic review of prior research. This study contributes to a growing body of research in human ecological immunology, and suggests that there may be substantial population differences in the regulation of inflammation that has implications for the association between inflammation and disease.

The effect of HIV infection and HAART on inflammatory biomarkers in a population-based cohort of women

OBJECTIVE

HIV causes inflammation that can be at least partially corrected by HAART. To determine the qualitative and quantitative nature of cytokine perturbation, we compared cytokine patterns in three HIV clinical groups, including HAART responders (HAART), untreated HIV noncontrollers, and HIV-uninfected (NEG).

METHODS

Multiplex assays were used to measure 32 cytokines in a cross-sectional study of participants in the Women's Interagency HIV Study. Participants from three groups were included: HAART (n = 17), noncontrollers (n = 14), and HIV NEG (n = 17).

RESULTS

Several cytokines and chemokines showed significant differences between noncontrollers and NEG participants, including elevated interferon gamma-induced 10 (IP-10) and tumor necrosis factor-α (TNF-α) and decreased interleukin-12(p40) [IL-12(p40)], IL-15, and fibroblast growth factor-2 (FGF-2) in noncontroller participants. Biomarker levels among HAART women more closely resembled the NEG, with the exception of TNF-α and FGF-2. Secondary analyses of the combined HAART and noncontroller groups revealed that IP-10 showed a strong, positive correlation with viral load and negative correlation with CD4(+) T-cell counts. The growth factors vascular endothelial growth factor, epidermal growth factor, and FGF-2 all showed a positive correlation with increased CD4(+) T-cell counts.

CONCLUSION

Untreated, progressive HIV infection was associated with decreased serum levels of cytokines important in T-cell homeostasis (IL-15) and T-cell phenotype determination (IL-12), and increased levels of innate inflammatory mediators such as IP-10 and TNF-α. HAART was associated with cytokine profiles that more closely resembled those of HIV-uninfected women. The distinctive pattern of cytokine levels in the three study groups may provide insights into HIV pathogenesis, and responses to therapy.

Racial differences in tumor necrosis factor-α-induced endothelial microparticles and interleukin-6 production

African Americans (AA) tend to have heightened systemic inflammation and endothelial dysfunction. Endothelial microparticles (EMP) are released from activated/apoptotic endothelial cells (EC) when stimulated by inflammation. The purpose of our study was to assess EMP responses to inflammatory cytokine (TNF-α) and antioxidant (superoxide dismutase, SOD) conditions in human umbilical vein ECs (HUVECs) obtained from AA and Caucasians. EMPs were measured under four conditions: control (basal), TNF-α, SOD, and TNF-α + SOD. Culture supernatant was collected for EMP analysis by flow cytometry and IL-6 assay by ELISA. IL-6 protein expression was assessed by Western blot. AA HUVECs had greater EMP levels under the TNF-α condition compared to the Caucasian HUVECs (6.8 ± 1.1 vs 4.7% ± 0.4%, P = 0.04). The EMP level increased by 89% from basal levels in the AA HUVECs under the TNF-α condition (P = 0.01) compared to an 8% increase in the Caucasian HUVECs (P = 0.70). Compared to the EMP level under the TNF-α condition, the EMP level in the AA HUVECs was lower under the SOD only condition (2.9% ± 0.3%, P = 0.005) and under the TNF-α + SOD condition (2.1% ± 0.4%, P = 0.001). Basal IL-6 concentrations were 56.1 ± 8.8 pg/mL/μg in the AA and 30.9 ± 14.9 pg/mL/μg in the Caucasian HUVECs (P = 0.17), while basal IL-6 protein expression was significantly greater (P < 0.05) in the AA HUVECs. These preliminary observational results suggest that AA HUVECs may be more susceptible to the injurious effects of the proinflammatory cytokine, TNF-α.

Emotional functioning at age 7 years is associated with C-reactive protein in middle adulthood

OBJECTIVE

Few have considered whether and how child emotional functioning is associated with inflammation later in life. Therefore, we evaluated whether child emotional functioning at age 7 years is associated with C-reactive protein (CRP), an indicator of systemic inflammation, in middle adulthood.

METHODS

We studied adult offspring (mean age 42.2 years) of participants in the National Collaborative Perinatal Project, a national cohort of pregnant women enrolled between 1959 and 1966. Three measures of child emotional functioning were derived from psychologist ratings of child behavior at age 7 years: inappropriate self-regulation (ISR), distress proneness, and behavioral inhibition. Multiple linear regression models were fit to investigate the association between childhood emotional functioning and adulthood CRP and also to evaluate potential mediators of this association. Model n's were from 400 for Model 1 to 379 for Model 4 depending on covariates included and missing data on those covariates.

RESULTS

Children with high ISR and distress proneness at age 7 years had significantly higher CRP as adults (ISR: β = 0.86; standard error [SE] = 0.28; p = .002; distress proneness: β = 1.23; SE = 0.57; p = .03). In contrast, children with high levels of behavioral inhibition had lower CRP as adults (β = -0.58; SE = 0.38; p = .04). Furthermore, there was evidence that associations of ISR and distress proneness with CRP may be mediated in part by adulthood body mass index (Sobel significance tests of mediation: ISR: p = .003; distress proneness: p = .07).

CONCLUSIONS

Findings suggest that poor childhood emotional functioning is associated with inflammation in adulthood. These results suggest a potential childhood origin of adult inflammatory risk.

Population differences in proinflammatory biology: Japanese have healthier profiles than Americans

The pleiotropic cytokine, interleukin-6 (IL-6), has emerged as a key factor in the biology of aging and the physiology of inflammation. Yet much of what we know about the normal functioning of IL-6 has been generated primarily from research on European populations and Americans of European descent. Our analyses compared IL-6 levels in 382 middle-aged and older Japanese to the values found in 1209 Caucasian- and African-Americans from the Midlife in the United States survey (MIDUS). Across the life span from 30 to 80 years of age, mean IL-6 levels were strikingly lower in Japanese individuals. Significantly lower levels of C-reactive protein (CRP) and fibrinogen (FBG) provided confirmatory evidence for a population difference in proinflammatory activity. Because IL-6 release has been associated with obesity, differences in body mass index (BMI) were taken into consideration. Japanese had the lowest, and African-Americans had the highest overall BMIs, but significant group differences in IL-6 persisted even after BMI was included as a covariate in the analyses. Additional support for distinct variation in IL-6 biology was generated when systemic levels of the soluble receptor for IL-6 (sIL-6r) were evaluated. Serum sIL-6r was higher in Japanese than Americans, but was most notably low in African-Americans. Our cytokine data concur with national differences in the prevalence of age-related illnesses linked to inflammatory physiology, including cardiovascular disease. The findings also highlight the importance of broadening the diversity of people included in population studies of health and aging, especially given the relative paucity of information for some Asian countries and on individuals of Asian heritage living in the US.