Socioeconomic status gradients in inflammation in adolescence

A dyadic longitudinal analysis of parent-adolescent inflammation trends and the role of shared socioeconomic characteristics on family inflammation

The objective of the present study was to evaluate the interdependency of parent-adolescent inflammation trends across time and to examine whether shared family socioeconomic characteristics explained between-family differences in parents' and adolescents' risk for inflammation. A total of N = 348 families, consisting of one parent and one adolescent child, were followed every two years in a three-wave longitudinal study. Sociodemographic questionnaires were used to determine parental educational attainment and family income-to-needs ratio (INR). At each time point, parents and adolescents collected dried blood spot (DBS) samples that were assayed for circulating CRP and log-transformed prior to analysis by longitudinal dyadic models. Models revealed significant differences in parents' and adolescents' inflammation trends over time (bint = - 0.13, p < 0.001). While parental CRP levels remained relatively stable across the study period, adolescent CRP increased by approximately 38% between study waves. Parents' average CRP levels were positively correlated with adolescents' average CRP (r = 0.32, p < 0.001), but parental change in CRP over time was not significantly related to change in adolescents' CRP over time. Family dyads with higher parental educational attainment had lower average CRP (b = -0.08, p = 0.01), but parental education did not predict change in dyads' inflammation over time. Study findings suggest that shared family socioeconomic characteristics contribute to baseline similarities in parents' and adolescents' inflammation and potentially point to adolescence as a period of inflammatory change where youth may diverge from parental inflammation trends.

C-reactive protein (CRP) in high altitude Bolivian peri-urban adolescents varies by adiposity, current illness, height, socioeconomic status, sex, and menarcheal status: The potential benefits and costs of adipose reserves in arduous environments

OBJECTIVES

In non-industrialized and low-income populations, adipose stores can serve as a valuable buffer against harsh conditions such as seasonal food scarcity. However, these reserves may incur costs due to adipocytes' production of pro-inflammatory cytokines; inflammation is associated with increased risk for cardiometabolic diseases later in life. Life history theory posits that, especially in populations with high juvenile mortality, higher adiposity may nonetheless be advantageous if its benefits in early life outweigh its later costs. Relatively little is known about adolescents' C-reactive protein concentration (CRP; an inflammation biomarker) in such environments. We investigated CRP and its associations with several hypothesized predictors in adolescents in an economically diverse peri-urban Andean community.

METHODS

We measured CRP in dried blood spots and collected data on anthropometrics, illnesses, socioeconomic status (SES), and menarcheal status in 59 female and 40 male adolescents ("Alteños", 11.0-14.9 years old) with normal vital signs in El Alto, Bolivia (~4150 m amsl). We used Cole's LMS method to standardize all anthropometrics for sex and age, and principal components analysis to construct a "fat-factor" variable loading on these standardized z-scores. We used multiple linear regression to assess the influence of fat-factor and other likely predictors on CRP rank.

RESULTS

Compared to a national Bolivian growth reference, Alteños were, on average, shorter and leaner; only 6% were classified as overweight and none were obese. Pre-menarche females were on average leaner than post-menarche females. The best-fitting model explained 24% of the variance in CRP rank. Significant predictors were fat-factor, SES, current illness for males and pre-menarche females, and z-height for females.

CONCLUSIONS

Our results are consistent with a tradeoff between investments in growth versus immune functioning, as might be expected in an environment with limited resources and high pathogen exposure (e.g., soil-transmitted helminths, poor sanitation). Thinner Alteños appear to maintain a minimum CRP concentration independent of fat-factor, while fatter (or less-thin) Alteños' CRP rises with fat-factor. Female Alteños appear to be trading off investment in immune response for investment in growth and maturation. Alteños' high rate of stunting and absence of obesity suggests chronic, presumably multifactorial, stress. Adipose stores likely buffer against some of these stressors and, in an environment such as this-in which many lack sufficient nutritious foods, potable water, adequate sewage, and health care-may confer a net lifetime benefit.

Respiratory Sinus Arrhythmia as a Physiological Resilience Marker for Children's Health

OBJECTIVE

The current study aimed to test parasympathetic nervous system activity, indexed through resting respiratory sinus arrhythmia (RSA) as a resilience factor that moderates the associations between socioeconomic status (SES), circulating cytokines, and somatic health in children.

METHODS

The sample included 181 parent-child dyads (mean [standard deviation] child age = 9.91 [0.57] years; 50.3% boys). Parents reported on family income, parental education, and subjective social status, to index SES. Children provided serum samples for assaying circulating inflammatory cytokines and had RSA measured during a 5-minute seated resting period. We used a composite measure of inflammation that combined standardized measures of interleukin 6, interleukin 10, and tumor necrosis factor α. Parents reported on their child's global health impairment and number of chronic health conditions.

RESULTS

Lower SES was associated with poorer global health, and higher levels of inflammation were associated with poorer global health, but these associations were not significant among children with high resting RSA. Specifically, resting RSA moderated the association between SES and global health impairment (B = 0.09, standard error [SE] = 0.02, p < .001). Preliminary evidence suggests that resting RSA may also moderate the association between inflammation and global health impairment (B = -0.12, SE = 0.03, p < .001), although this effect was no longer significant after Winsorizing an outlier value of a child with high global health impairment (B = -0.06, SE = 0.03, p = .04).

CONCLUSIONS

High resting RSA may represent a physiological profile of resilience in children, weakening the associations between low SES and poor somatic health, and between greater inflammation and poor somatic health.

Socioeconomic Status and Inflammation in Women with Early-stage Breast Cancer: Mediation by Body Mass Index

BACKGROUND

Breast cancer is the most common cancer among women in the US, and women of low socioeconomic status (SES) show markedly poorer outcomes than those of high SES. SES may influence health through inflammation, although links between SES and inflammatory biomarkers have not been investigated in women with breast cancer. This study tested the hypothesis that breast cancer patients of lower SES would show higher levels of inflammation than those of higher SES. BMI was examined as a mediator of this association.

METHODS

Women recently diagnosed with early-stage breast cancer (N = 194) were recruited before neoadjuvant or adjuvant therapy. Participants completed questionnaires and provided blood samples for immune assessment. SES was indexed by participants' self-reported education and annual household income, BMI was determined by height and weight measurements, and blood was assayed for inflammatory biomarkers linked with cancer outcomes: IL-6, CRP, TNF-α, and sTNF-RII. General linear models tested associations between SES and inflammation, and mediation models examined indirect effects through BMI.

RESULTS

Consistent with hypotheses, education status was associated with CRP, (F(2,185) = 4.72, p = 0.001), and sTNF-RII, (F(2,185) = 4.19, p = 0.02), such that lower education was associated with higher levels of both biomarkers. Further, BMI mediated the associations between education and CRP, (95% CIs [-0.62, -0.11; -0.76, -0.21]), sTNF-RII, (95% CIs [-0.09, -0.01; -0.10, -0.02]), and IL-6, (95% CIs [-0.32, -0.05; -0.38, -0.09]). Annual household income was not significantly associated with inflammation (ps > 0.25), and indirect effects on inflammation through BMI were not significant.

CONCLUSIONS

Lower education was associated with higher levels of inflammation in this sample, which may presage poor breast cancer-related and clinical outcomes. SES should inform the development of interventions targeting BMI and inflammation in breast cancer.

Systemic inflammation as a driver of health disparities among sexually-diverse and gender-diverse individuals

Sexually-diverse individuals (those who seek sexual or romantic relationships with the same and/or multiple genders) and gender-diverse individuals (those whose gender identity and/or expression differs from their birth-assigned sex/gender) have disproportionately high physical health problems, but the underlying biological causes for these health disparities remain unclear. Building on the minority stress model linking social stigmatization to health outcomes, we argue that systemic inflammation (the body's primary response to both physical and psychological threats, indicated by inflammatory markers such as C-reactive protein and proinflammatory cytokines) is a primary biobehavioral pathway linking sexual and gender stigma to physical health outcomes. Expectations and experiences of social threat (i.e., rejection, shame, and isolation) are widespread and chronic among sexually-diverse and gender-diverse individuals, and social threats are particularly potent drivers of inflammation. We review research suggesting that framing "minority stress" in terms of social safety versus threat, and attending specifically to the inflammatory consequences of these experiences, can advance our understanding of the biobehavioral consequences of sexual and gender stigma and can promote the development of health promoting interventions for this population.

Association of Inflammatory Activity With Larger Neural Responses to Threat and Reward Among Children Living in Poverty

OBJECTIVE

Children exposed to severe, chronic stress are vulnerable to mental and physical health problems across the lifespan. To explain how these problems develop, the neuroimmune network hypothesis suggests that early-life stress initiates a positive feedback loop between peripheral inflammatory cells and networked brain regions involved in threat and reward processing. The authors sought to test this hypothesis by studying a sample of urban children from diverse socioeconomic backgrounds.

METHODS

The authors examined the basic predictions of the neuroimmune network hypothesis in 207 children (mean age=13.9 years, 63% female; 33% Black; 30% Hispanic), focusing on poverty as a stressor. The children had fasting blood drawn to quantify five inflammatory biomarkers-C-reactive protein, tumor necrosis factor-α, and interleukins-6, -8, and -10-which were averaged to form a composite score. Children also completed two functional MRI tasks, which measured amygdala responsivity to angry facial expressions and ventral striatum responsivity to monetary rewards.

RESULTS

Poverty status and neural responsivity interacted statistically to predict inflammation. Among children living in poverty, amygdala threat responsivity was positively associated with inflammation, and the same was true for ventral striatum responsivity to reward. As children's socioeconomic conditions improved, these brain-immune associations became weaker. In sensitivity analyses, these patterns were robust to alternative measures of socioeconomic status and were independent of age, sex, racial and ethnic identity, and pubertal status. The associations were also condition specific; no interactions were apparent for amygdala responsivity to neutral faces, or striatal responsivity to monetary losses.

CONCLUSIONS

These findings suggest that childhood poverty is associated with accentuated neural-immune signaling, consistent with the neuroimmune network hypothesis.

Socioeconomic status and inflammation: a meta-analysis

Socioeconomic status (SES), often conceptualized as income, education, or occupation, is associated with risk for disease morbidity and psychopathology. Recent research has focused on the potential biological mechanisms linking lower SES and poor outcomes; much of this work has examined the relationship between SES and markers of systemic inflammation. The strength of the estimated association between SES and inflammatory markers varies widely across individual studies. Thus, we used meta-analytic techniques to quantify the magnitude of this relationship. To accomplish this, PubMed and PsycINFO were searched for papers that reported on SES and two commonly measured systemic inflammatory markers, C-reactive protein (CRP) and interleukin-6 (IL-6). Peer-reviewed, empirical papers conducted in non-patient populations were included. Data from 43 papers (N = 111,156) reporting a total of 63 relevant effect sizes were included in analyses. SES, broadly defined, was significantly associated with both levels of CRP (Z = 0.12; 95% CI, 0.09-0.16) and IL-6 (Z = 0.15; 95% CI, 0.12-0.18); individuals with lower SES showed higher levels of systemic inflammation. Subanalyses demonstrated that studies operationalizing SES as either levels of income or educational attainment also found significant associations with both CRP and IL-6. Moderator analyses revealed that effect sizes varied based on sample characteristics and analysis approaches. Lower SES is associated with significantly elevated levels of inflammatory markers of disease risk. Thus, pro-inflammatory pathways are likely an important mechanism translating socioeconomic inequalities into mental and physical health disparities.

Childhood socioeconomic conditions are associated with increased chronic low-grade inflammation over adolescence: findings from the EPITeen cohort study

OBJECTIVE

Early life adversity has been associated with increased risk of inflammation and inflammation-related diseases in adulthood. This study aimed to examine the association of childhood socioeconomic conditions with chronic low-grade inflammation over adolescence.

METHODS

We used information on 2942 members (1507 girls and 1435 boys) of the EPITeen (Epidemiological Health Investigation of Teenagers in Porto) cohort that was established in 2003 in Porto, Portugal, and included 13-year-old adolescents were further evaluated at 17 and 21 years. Mother' and father's education and occupation were used as indicators of childhood socioeconomic conditions. High-sensitivity C reactive protein (hs-CRP) was measured at three points in time (13, 17 and 21 years). hs-CRP levels were categorised in tertiles separately for each wave; chronic low-grade inflammation in adolescence was defined as having hs-CRP levels in the highest tertile in at least two waves and never in the lowest tertile.

RESULTS

Prevalence of chronic low-grade inflammation during adolescence was significantly higher among participants with low parental socioeconomic position. Low parental socioeconomic position was associated with chronic low-grade inflammation in adolescence, after adjustment for sex, perinatal and physical environment factors, health-related behaviours and health status in adolescence OR=1.6; 95% CI: 1.1 to 2.4 for lowest versus highest mother's education and OR=1.6; 95% CI: 1.1 to 2.3 for lowest versus highest father's occupation.

CONCLUSION

Low childhood socioeconomic conditions are associated with chronic low-grade inflammation during adolescence. Our results suggest that the early life socioeconomic environment has an impact on inflammatory processes over adolescence.

The Unique Nature of Depression and Anxiety among College Students with Adverse Childhood Experiences

It is well established that adverse childhood experiences (ACEs) contribute to the development of mental disorders in adulthood. However, less is known about how childhood trauma impacts the mind and the body, whether the resulting mental disorders have different characteristics than those occurring without these antecedent conditions, and if treatment modalities need to reflect the unique nature of mental disorders rooted in trauma. Survey and biomarker data were gathered from a sample of college students (n = 93) to explore the relationship between childhood trauma and mental health. We examine how neuroimmune systems (inflammation and neuroplasticity) relate to depression and anxiety and whether these associations vary for those with and without a history of childhood trauma. Findings reveal that students with 4 or more ACEs are more likely to have depression and anxiety than students without these experiences. In addition, we find that inflammation (CRP) and neuronal health (BDNF) are associated with mental health disorders among students with four or more ACEs, but not for students without this history. These findings suggest that mental disorders associated with four or more ACEs may be uniquely tied to physiological processes, and consequently, warrant tailored treatments. The implications for mental health intervention include, 1) screening for childhood trauma, inflammation, and neuronal health and 2) referral to treatments which are theoretically and empirically tied to the root causes of mental disorders rather than those designed merely to suppress their symptoms.

Early childhood risk exposures and inflammation in early adolescence

There is now reliable evidence that early psychosocial stress exposures are associated with behavioral health in children; the degree to which these same kinds of stress exposures predict physical health outcomes is not yet clear. We investigated the links between economic adversity, family and caregiving stress in early childhood and several markers of immune function in early adolescence. The sample is derived from the Family Life Project, a prospective longitudinal study of at-risk families. Socio-demographic and psychosocial risks have been assessed at regular intervals since the children were first assessed at 2 months of age. When the children were early adolescents, we conducted an in-depth health assessment of a subsample of families; blood samples were collected from venipuncture for interleukin(IL)-6, Tumor Necrosis Factor (TNF)-alpha, and C-reactive protein (CRP), as well as glucocorticoid resistance. Results indicated limited but reliable evidence of an association between early risk exposure and inflammation in adolescence. Specifically, caregiver depressive symptoms in early childhood predicted elevated CRP almost a decade later, and the prediction was significant after accounting for multiple covariates such as socio-economic adversity, health behaviors and body mass index. Our findings provide strong but limited evidence that early stress exposures may be associated with inflammation, suggesting one mechanism linking early stress exposure to compromised behavioral and somatic health.

Do upsetting life events explain the relationship between low socioeconomic status and systemic inflammation in childhood? Results from a longitudinal study

BACKGROUND

Children from families of low socioeconomic status (SES) are more likely to be exposed to upsetting situations and stressors. Such exposures have, in turn, been linked to inflammation in some studies. In this study we explore if low SES is related to inflammation in children via such stressful life events.

METHODS

Data on 4525 children of the Avon Longitudinal Study of Parents and Children, a general population birth cohort, were used to explore associations between SES at ages 0-3 years, upsetting life events at ages 3-9 years and inflammatory markers [interleukin 6 (IL-6) and C-reactive protein (CRP)] at age 9 years. Confounders included body mass index, gender, financial problems, and upsetting life events at ages 0-3 years.

RESULTS

Using Structural Equation Modelling, we found that early socioeconomic disadvantage predicted higher levels of IL-6 (β = 0.034, 95% CI = 0.005, 0.063) even after adjusting for confounders. This association was partially mediated by upsetting life events (β = 0.003, 95% CI = 0.001, 0.006).

CONCLUSIONS

In the general child population, low SES is associated with increased exposure to stressful life events, in turn associated with later inflammation. These findings highlight the role of stressors associated with poverty and disadvantage in the development of inflammation among children in the general population.

Adverse childhood experiences and neuroinflammatory biomarkers-The role of sex

Despite the growing interest in adverse childhood experiences and biomarkers, less attention has been paid to multiple biomarkers as representing interrelated systems among college students. Guided by the neuroinflammatory pathway hypothesis, the current project takes the initial step in examining the link between three types of childhood adversity and biomarkers of neuroplasticity (brain-derived neurotropic factor [BDNF]) and low-grade inflammation (C-reactive protein [CRP]) in an overarching model and whether this link may differ in men and women. Undergraduate students (n = 85) were recruited through multiple departments from a state university. The participants responded to the detailed online survey questionnaire on childhood adversity and provided one blood sample via venous blood draw. Given that CRP and BDNF represent two interrelated systems, structural equation models were considered the most suitable for the analyses. The findings partially support neural and inflammatory pathways, such that childhood adversity and particularly family dysfunction have a significant positive effect on BDNF (b = 30.41, p < .01). The link between family dysfunction and CRP was stronger in female students (b = 0.57, p < .05). Results suggest that interventions for college students with family dysfunctions may need to target different physiological and behavioral outcomes for male and female students.

Childhood socioeconomic status and inflammation: A systematic review and meta-analysis

Recent research suggests that risk for chronic diseases of aging including cardiovascular disease, diabetes, and even cancer can be programmed early in the lifespan as a result of exposure to chronic stressors like low socioeconomic status (SES) that are hypothesized to promote a pro-inflammatory response in immune cells that results in chronic, systemic inflammation. The present paper conducted a meta-analysis to establish whether exposure to low (versus higher) SES in childhood and adolescence is associated with higher levels of inflammation (as measured by C-reactive protein, IL-6, and fibrinogen) concurrently and in adulthood. We conducted meta-analyses with both unadjusted bivariate associations between SES and inflammation and with adjusted associations that controlled for a range of covariates including demographic factors, body mass index, smoking, physical activity and current SES. A systematic review of Pubmed and PsycINFO identified a total 35 studies (26 with unadjusted and 31 adjusted effect sizes) to be included in the meta-analysis. Random-effects meta-analysis showed that individuals who were exposed to low SES in childhood and adolescence had significantly higher levels of inflammatory markers (r = -0.07, p < .001, 95% CI = -0.09, -0.05). This association remained significant in adjusted analyses (r = -0.06, p < .001, 95% CI = -0.09, -0.03). However, the relationship between childhood SES and inflammation was non-significant in a meta-analysis with longitudinal studies that all controlled for adulthood SES (r = -0.03, p = .356, 95% CI = -0.08, 0.03). Future longitudinal research should utilize measurement of inflammatory markers at multiple time points to further examine the complex relationships between SES and health both in childhood and adulthood.

Future Directions in the Study of Early-Life Stress and Physical and Emotional Health: Implications of the Neuroimmune Network Hypothesis

Early-life stress is associated with increased vulnerability to physical and emotional health problems across the lifespan. The recently developed neuroimmune network hypothesis proposes that one of the underlying mechanisms for these associations is that early-life stress amplifies bidirectional crosstalk between the brain and the immune system, contributing to several mental and physical health conditions that have inflammatory underpinnings, such as depression and coronary heart disease. Neuroimmune crosstalk is thought to perpetuate inflammation and neural alterations linked to early-life stress exposure, and also foster behaviors that can further compromise health, such as smoking, drug abuse and consumption of high-fat diets. The goal of the present review is to briefly summarize the neuroimmune network hypothesis and use it as a starting point for generating new questions about the role of early-life stress in establishing a dysregulated relationship between neural and immune signaling, with consequences for lifespan physical and emotional health. Specifically, we aim to discuss implications and future directions for theory and empirical research on early-life stress, as well as for interventions that may improve the health and well-being of children and adolescents living in adverse conditions.

Socioeconomic status inequalities in low-grade inflammation during childhood

BACKGROUND

Family socioeconomic status (SES) is an important source of child health disparities in the USA. Chronic stress is one way SES may impact children's physiology with implications for later health inequalities. These processes may work differently across childhood due to differences in exposure and susceptibility to stressors at different ages. We assess associations between family SES and one biomarker of chronic stress exposure-low-grade inflammation detected by elevated C reactive protein (CRP)-and evaluate differences in the associations by child age.

METHODS

We used nationally representative data from the National Health and Nutrition Examination Survey and Tobit regression models to estimate SES associations with CRP and the moderating effects of age for children age 2-18 years. Our sample was limited to CRP ≤10 mg/l to focus on low-grade inflammation (N=13 165).

RESULTS

Children whose parent had less than a high school degree had 35% higher CRP than those with a college graduate parent; and, poor children had 24% higher CRP than those with high family income, net of controls. When children's body mass index was accounted for, low education and poverty associations were reduced to 19% and 15%, respectively. Child age interactions were negative and significant for both parental education and family income.

CONCLUSIONS

This study provides new evidence that SES is associated with low-grade inflammation in children, and that these associations may be particularly strong during early and mid-childhood. Future research should further our understanding of stressors related to low family SES that may lead to immune system dysregulation during childhood.

Income and Markers of Immunological Cellular Aging

OBJECTIVE

Socioeconomic disadvantage may contribute to poor health through immune-related biological mechanisms. We examined the associations between socioeconomic status, as measured by annual household income, and T-cell markers of aging, including the ratios of CD4 and CD8 effector cells to naïve cells (E/N ratio) and the CD4/CD8 T-cell ratio. We hypothesized that participants with a lower income would have higher E/N ratios and lower CD4/CD8 ratios compared with participants with a higher income, and that these associations would be partially mediated by elevated cytomegalovirus (CMV) IgG antibody levels, a virus implicated in aging and clonal expansion of T cells.

METHODS

Data were from 79 individuals who participated in the population-based Detroit Neighborhood Health Study. We used linear regression to quantify the association between a $10,000 decrease in income and each ratio outcome.

RESULTS

After adjustment for age, sex, race, smoking, medication use, and lifetime history of mental health conditions, lower income was associated with a 0.41 (95% confidence interval = 0.09-0.72) log-unit increase in the CD4 E/N ratio and a 0.20 (95% confidence interval = 0.02-0.39) log-unit increase in the CD8 E/N ratio. CMV immunoglobulin G antibody level partially mediated these associations.

CONCLUSIONS

Our study suggests that low socioeconomic status is associated with immunological aging as measured by the E/N ratio and that impaired immune control of CMV may partially mediate these associations.

Sex Differences in Associations Between Subjective Social Status and C-Reactive Protein in Young Adults

OBJECTIVE

In middle-aged and older samples, perceived subjective socioeconomic status (SSS) is a marker of social rank that is associated with elevated inflammation and cardiovascular disease risk independent of objective indicators of SES (oSES). Whether SSS is uniquely associated with elevated inflammation during young adulthood and whether these linkages differ by sex have not been studied using a nationally representative sample of young adults.

METHODS

Data came from the National Longitudinal Study of Adolescent to Adult Health. At Wave IV, young adults aged mostly 24 to 32 years reported their SSS, oSES, and a range of covariates of both SES and elevated inflammation. Trained fieldworkers assessed medication use, body mass index, and waist circumference, and also collected bloodspots from which high-sensitivity C-reactive protein (hs-CRP) was assayed. The sample size for the present analyses was n = 13,236.

RESULTS

Descriptive and bivariate analyses revealed a graded association between SSS and hs-CRP (b = -0.072, standard error [SE] = 0.011, p < .001): as SSS declined, mean levels of hs-CRP increased. When oSES indicators were taken into account, this association was no longer significant in women (b = -0.013, SE = 0.019, p = .514). In men, a small but significant SSS-hs-CRP association remained after adjusting for oSES indicators and additional potential confounders of this association in the final models (b = -0.034, SE = 0.011 p = .003; p < .001 for the sex by SSS interaction).

CONCLUSIONS

SSS is independently associated with elevated inflammation in young adults. The associations were stronger in men than in women. These data suggest that subjective, global assessments of social rank might play a role in developing adverse health outcomes.

An 8-Year Prospective Study of Depressive Symptoms and Change in Insulin From Adolescence to Young Adulthood

OBJECTIVE

To evaluate whether depressive symptoms predict change in fasting insulin among adolescents followed into young adulthood. We hypothesized that higher depressive symptoms would predict increased insulin and that puberty and race/ethnicity would moderate this relationship.

METHODS

Data came from the Princeton School District Study, a school-based longitudinal cohort of non-Hispanic black and white adolescents (2001-2011). Depressive symptoms, fasting insulin, and body mass index were measured at baseline (adolescence) and 8 years later (young adulthood) in 685 participants. Puberty was assessed using a validated protocol measuring sex steroids and physical changes. The primary outcome was change in fasting insulin. Analyses accounted for age, sex, race, parental education, baseline insulin, body mass index z score, puberty, and time to follow-up.

RESULTS

At baseline, depressive symptoms were correlated with insulin (ρ = 0.13, p = .001). High baseline insulin predicted insulin change (B = -11.50, standard error [SE] = 2.30, p < .001). Depressive symptoms also predicted insulin change, but only for pubertal adolescents (B = -0.23, SE = 0.11, p = .038). This relationship was moderated by race (p = .047); depressive symptoms predicted insulin change only among pubertal black adolescents (p = .030), not white (p = .49), and in the direction opposite that hypothesized (Bblacks = -0.51, SE = 0.23). Post hoc analyses revealed that pubertal black adolescents with high depressive symptoms had the highest baseline insulin, which stayed high across the follow-up period.

CONCLUSIONS

Among pubertal black adolescents, elevated depressive symptoms are associated with increased risk for sustained hyperinsulinemia from adolescence into adulthood. These youths may be particularly vulnerable for Type 2 diabetes.

Educational level and chronic inflammation in the elderly--the role of obesity: results from the population-based CARLA study

This study aimed to assess the mediating role of anthropometric parameters in the relation of education and inflammation in the elderly. Cross-sectional data from the population-based CARdio-vascular Disease, Living and Ageing in Halle study were used after excluding subjects with a plasma level of high-sensitive C-reactive protein (hsCRP) above 10 mg L(-1) (916 men/760 women remaining). Education was categorized in accordance with International Standard Classification of Education. As inflammation parameters, the soluble tumour necrosis factor type 1 (sTNF-R1), hsCRP and interleukin 6 (IL-6) were taken into account. Anthropometric parameters were the body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHeR). We used covariate adjusted mixed models to assess associations. Effect measures were the natural indirect effect (NIE), controlled direct effect and total effect (TE). Education was associated with sTNF-R1, hsCRP and IL-6 in men, and sTNF-R1 and hsCRP in women. Anthropometric parameters correlated with all inflammation parameters after covariate adjustment. BMI and WHeR were strong mediators of educational differences in sTNF-R1 (percentage of NIE of TE: 28% in men; 33% in women) and hsCRP (percentage of NIE of TE: 35% in men; 52% in women), while WHR was the weakest mediator. General obesity mediates roughly one-third of the association of education with chronic inflammation in the elderly.

Developmental Trajectories of Subjective Social Status

BACKGROUND AND OBJECTIVE

Subjective social status (SSS), a person's sense of their (or for youth, abstract their family's) position in the socioeconomic hierarchy, is strongly related to health in adults but not health in adolescence. Understanding this developmental discrepancy requires first understanding the developmental trajectory of SSS. The objective of this study was to identify the number and shape of SSS trajectories as adolescents transition to adulthood and explore if trajectory membership affects health.

METHODS

Using data from 7436 assessments from the Princeton School District Study, a decade long cohort study of non-Hispanic black and white youth, latent class growth models with 3 to 7 SSS trajectories were developed. Model fit, trajectory structure, and shape were used to guide optimal model selection. Using this optimal model, the associations of trajectory membership with BMI and depressive symptoms in young adulthood were explored.

RESULTS

The 5-class model was optimal. In this model, trajectories were persistent high (7.8%),mid–high (32.2%), middle (43.4%), low–lower (7.4%), and high–low (9.1%). Non-Hispanic black race/ethnicity, lower household income, and low parent education were associated with membership in this high–low trajectory. High–low trajectory membership was associated with higher BMI and depressive symptoms in non-Hispanic white subjects but was not associated with depressive symptoms. It was associated with lower BMI only after adjustment for BMI in adolescence in non-Hispanic black subjects.

CONCLUSIONS

SSS is relatively stable in adolescence and the transition to adulthood, and it generally reflects objective markers of social advantage. However, socially disadvantaged youth with high SSS in early adolescence may be at increased health risk.

Socioeconomic status, daily affective and social experiences, and inflammation during adolescence

OBJECTIVE

To assess the relation between socioeconomic status (SES) and inflammation during adolescence and determine whether daily affective and social experiences across a 15-day period mediate this relation.

METHODS

Adolescents (n = 316) completed daily diary reports of positive affect, negative affect, and negative social interactions for 15 days and provided whole blood spot samples for the assessment of C-reactive protein (CRP). Parents provided information on SES, including the highest level of education they and their spouses completed and household income.

RESULTS

Lower parent education was associated with higher levels of adolescent CRP, controlling for age, sex, ethnicity, and body mass index (β = -.12, p = .031). Mean daily positive affect, negative affect, and negative social interactions were examined as potential mediators of this association. In these models, parent education was no longer associated with adolescent CRP (β = -.09, p = .12), and only positive affect was related to CRP (β = -.12, p = .025). Bootstrapping confirmed the mediating role of positive affect (indirect effect = -0.015, 95% confidence interval = -0.038 to -0.002).

CONCLUSIONS

Adolescents with less educated parents tended to have higher levels of CRP, which may be explained by their lower levels of positive affect. Findings suggest that a lack of positive affect may be a pathway by which SES confers early risk for poor health in adulthood. It is possible that adolescents who display positive affect during daily life in circumstances of relatively adverse socioeconomic circumstances may have better health outcomes related to lower inflammatory factors.

Modeling the association between lifecourse socioeconomic disadvantage and systemic inflammation in healthy adults: The role of self-control

OBJECTIVE

We sought to identify pathways connecting lifecourse socioeconomic status (SES) with chronic, low-grade inflammation, focusing on the explanatory roles of self-control, abdominal adiposity, and health practices.

METHODS

Participants were 360 adults aged 15-55 who were free of chronic medical conditions. They were roughly equally divided between low and high current SES, with each group further divided between low and high early-life SES. Structural equation modeling (SEM) was used to identify direct and indirect pathways linking early-life and current SES with low-grade, chronic inflammation in adulthood, as manifest by serum interleukin-6 and C-reactive protein. Low SES was hypothesized to relate to inflammation by reducing self-control, which in turn was hypothesized to facilitate lifestyle factors that potentiate inflammation (smoking, alcohol use, sedentary behavior, and weight gain).

RESULTS

Analyses revealed that self-control was pivotal in linking both early-life and current SES to inflammation. Low early-life SES was related to a harsher family climate, and in turn lower adult self-control, over and above the effects of current SES. Controlling for early-life SES, low current SES was associated with perceived stress and, in turn, diminished self-control. Results showed that lower self-control primarily operated through higher abdominal adiposity to associate with greater inflammation.

CONCLUSIONS

The findings suggest a mechanistic scenario wherein low SES in early life or adulthood depletes self-control and, in turn, fosters adiposity and inflammation. These pathways should be studied longitudinally to elucidate and potentially ameliorate socioeconomic disparities in health.

Family chaos and adolescent inflammatory profiles: the moderating role of socioeconomic status

OBJECTIVE

To test whether family chaos influences adolescents' inflammatory profiles and whether adolescents from low socioeconomic status (SES) environments are at higher risk for experiencing adverse inflammatory profiles from living in chaotic family environments.

METHODS

A total of 244 families with an adolescent aged 13 to 16 years participated. Parents completed measures of family SES and family chaos. Both systemic inflammation and stimulated proinflammatory cytokine production in response to bacterial challenge were assessed in adolescents.

RESULTS

Our results suggest that SES moderates the detrimental effect of family chaos on systemic inflammation and interleukin-6 (B = -0.010, standard error [SE] = 0.004, p = .026), but not C-reactive protein (B = 0.009, SE = 0.006, p = .11), and on stimulated proinflammatory cytokine production (B = -0.098, SE = 0.044, p = .026) in adolescents, such that a chaotic family environment is positively associated with greater systemic inflammation and greater stimulated proinflammatory cytokine production in adolescents as family SES declines.

CONCLUSIONS

These findings indicate that living in chaotic family environments places youth who may be vulnerable based on socioeconomic factors at a potentially higher risk for inflammation-related diseases.