The social patterns of a biological risk factor for disease: race, gender, socioeconomic position, and C-reactive protein

Racial/Ethnic differences in inflammation levels among older adults 56+: an examination of sociodemographic differences across inflammation measure

OBJECTIVE

Chronic inflammation is a key biological risk factor for many widespread adult health conditions. This study examines racial/ethnic differences in inflammation across several inflammatory markers, including selected cytokines that are identified as important for aging and age-related health outcomes.

METHODS

Data came from the 2016 Venous Blood Collection Subsample of the Health and Retirement Study. Using logistic regression models, we compared high-risk categories of C-reactive protein and cytokine markers (IL-6, IL-10, IL-1RA, TNFR1, and TGF-Beta), across race/ethnicity and whether these differences persisted among men and women.

RESULTS

The findings provided evidence of significant race/ethnic differences in inflammatory measures, but the patterns differed across marker types.

CONCLUSIONS

These findings emphasize that race/ethnic differences are not consistently captured across markers of inflammation and that researchers should proceed with caution when using individual markers of inflammation in an effort to not overlook potential racial/ethnic differences in biological risk.

Racial/Ethnic Differences in Biological Aging and Their Life Course Socioeconomic Determinants: The 2016 Health and Retirement Study

Objectives: This study examined differences in accelerated biological aging among non-Hispanic Blacks, Hispanics, and non-Hispanic Whites in the United States and assessed whether including life course socioeconomic conditions attenuated observed racial/ethnic differences. Methods: Data came from the Venous Blood Collection Subsample of the Health and Retirement Study. We used a comprehensive summary measure of biological age (BA-22). We determined whether key lifetime socioeconomic conditions contributed to racial/ethnic differences in biological aging. Results: Findings indicated that non-Hispanic Blacks and Hispanics have accelerated aging, and non-Hispanic Whites have decelerated aging. Racial/ethnic differences were strongly tied to educational attainment. We also observed a significant difference by birthplace for Hispanics. US-born Hispanics had accelerated biological aging, whereas foreign-born Hispanics did not. In age-stratified analyses, these racial/ethnic differences were found for adults aged 56-74, but not for adults aged 75+. Conclusions: These findings provide insight into biological differences underlying racial/ethnic disparities in health.

Student Debt and Cardiovascular Disease Risk Among U.S. Adults in Early Mid-Life

INTRODUCTION

Student loan debt has become common for young adults in the U.S. and is correlated with poor physical and mental health. It is unclear how the accumulation or repayment of student debt is associated with longer-term cardiovascular risks and chronic inflammation.

METHODS

Nationally representative data collected between 1994 and 2018 from >4,000 participants of a U.S. cohort study were analyzed in 2021 to assess the associations among change in student debt between young adulthood and early mid-life, 30-year Framingham cardiovascular disease risk scores, and C-reactive protein levels.

RESULTS

Ordinary least squares regression revealed higher cardiovascular disease and C-reactive protein risks among those in households who became indebted or were consistently in debt between young adulthood and early mid-life than among those in households who were either never in debt or repaid their loans. This pattern persisted after adjustments for degree completion, socioeconomic measures, and other sources of debt.

CONCLUSIONS

These findings provide a benchmark for widening health inequalities among a cohort bearing more student debt than any other in U.S.

HISTORY

As student debt accumulates, within-cohort disparities in cardiovascular disease and related morbidities may undermine the health benefits of postsecondary education.

Individuals with both higher recent negative affect and physical pain have higher levels of C-reactive protein

Conceptualizing physical pain and negative affect as potentially interactive, we hypothesized that higher levels of peripheral inflammatory markers would be observed consistently only among individuals with both higher negative affect and pain symptomatology. Participants were generally healthy midlife adults from the Bronx, NY (N ​= ​212, M_age ​= ​46.77; 60.8% Black, 25.5% Hispanic/Latina/o) recruited as part of a larger study. Key measures were: reported pain intensity and pain interference at baseline, recent negative affect averaged from self-reports 5x/day for 7 days, and peripheral inflammatory markers (C-reactive protein [CRP] and a composite cytokine measure based on seven cytokines). Controlling for age, BMI, gender, and education, recent negative affect significantly interacted with both pain variables to explain variance in CRP, with higher CRP levels observed only in individuals with both higher negative affect and either higher pain intensity or pain interference. These findings contribute to an emerging literature suggesting that negative affect, pain, and inflammation are related in important and complex ways.

Spatial Dynamics and Multiscale Regression Modelling of Population Level Indicators for COVID-19 Spread in Malaysia

As COVID-19 dispersion occurs at different levels of gradients across geographies, the application of spatiotemporal science via computational methods can provide valuable insights to direct available resources and targeted interventions for transmission control. This ecological-correlation study evaluates the spatial dispersion of COVID-19 and its temporal relationships with crucial demographic and socioeconomic determinants in Malaysia, utilizing secondary data sources from public domains. By aggregating 51,476 real-time active COVID-19 case-data between 22 January 2021 and 4 February 2021 to district-level administrative units, the incidence, global and local Moran indexes were calculated. Spatial autoregressive models (SAR) complemented with geographical weighted regression (GWR) analyses were executed to determine potential demographic and socioeconomic indicators for COVID-19 spread in Malaysia. Highest active case counts were based in the Central, Southern and parts of East Malaysia regions of Malaysia. Countrywide global Moran index was 0.431 (p = 0.001), indicated a positive spatial autocorrelation of high standards within districts. The local Moran index identified spatial clusters of the main high–high patterns in the Central and Southern regions, and the main low–low clusters in the East Coast and East Malaysia regions. The GWR model, the best fit model, affirmed that COVID-19 spread in Malaysia was likely to be caused by population density (β coefficient weights = 0.269), followed by average household income per capita (β coefficient weights = 0.254) and GINI coefficient (β coefficient weights = 0.207). The current study concluded that the spread of COVID-19 was concentrated mostly in the Central and Southern regions of Malaysia. Population’s average household income per capita, GINI coefficient and population density were important indicators likely to cause the spread amongst communities.

Correlates of Elevated C-Reactive Protein Among Black Older Adults: Evidence From the Health and Retirement Study

OBJECTIVES

Substantial evidence documents gender and racial disparities in C-reactive protein (CRP), a measure of systemic inflammation, among older adults. Yet, the comparative approaches of these studies may obscure distinct risk and protective factors associated with elevated CRP among older Black Americans. To pinpoint opportunities for intervention, this study utilizes a "within-group approach" to identify the sociodemographic, psychosocial, behavioral, and health-related correlates of elevated CRP among older Black women and men.

METHOD

The sample consisted of 2,420 Black respondents aged 51 and older in the Health and Retirement Study (2006-2016). Gender-stratified, random effects logistic regression models were used to examine correlates of elevated CRP (>3.0 mg/L).

RESULTS

More than 50% of Black women had elevated CRP, and younger age, Medicaid, lower mastery, religiosity, overweight/obesity, physical inactivity, and activities of daily living (ADLs) contributed to elevated CRP among this group. In contrast, elevated CRP was reported among only 37.25% of Black men, for whom financial distress was associated with lower odds of elevated CRP; religiosity, less neighborhood cohesion, current smoking, overweight/obesity, ADLs, and more chronic conditions were associated with greater odds of elevated CRP among this group.

DISCUSSION

Sociodemographic factors had a limited association with elevated CRP among older Black Americans. Rather, a range of psychosocial, behavioral, and health-related factors were more influential determinants of elevated CRP among older Black Americans. Most notably, findings demonstrate distinct correlates of CRP among Black women and men, underscoring the critical need to further evaluate the risk and protective mechanisms undergirding disparities among this aging population.

The Association Between Loneliness and Inflammation: Findings From an Older Adult Sample

Loneliness has been linked to poor mental and physical health outcomes. Past research suggests that inflammation is a potential pathway linking loneliness and health, but little is known about how loneliness assessed in daily life links with inflammation, or about linkages between loneliness and inflammation among older adults specifically. As part of a larger investigation, we examined the cross-sectional associations between loneliness and a panel of both basal and LPS-stimulated inflammatory markers. Participants were 222 socioeconomically and racially diverse older adults (aged 70-90 years; 38% Black; 13% Hispanic) systematically recruited from the Bronx, NY. Loneliness was measured in two ways, with a retrospective trait measure (the UCLA Three Item Loneliness Scale) and an aggregated momentary measure assessed via ecological momentary assessment (EMA) across 14 days. Inflammatory markers included both basal levels of C-reactive protein (CRP) and cytokines (IL-1β, IL-4, IL-6, IL-8, IL-10, TNF-α) and LPS-stimulated levels of the same cytokines. Multiple regression analyses controlled for age, body-mass index, race, and depressive symptoms. Moderation by gender and race were also explored. Both higher trait loneliness and aggregated momentary measures of loneliness were associated with higher levels of CRP (β = 0.16, p = 0.02; β = 0.15, p = 0.03, respectively). There were no significant associations between loneliness and basal or stimulated cytokines and neither gender nor race were significant moderators. Results extend prior research linking loneliness with systemic inflammation in several ways, including by examining this connection among a sample of older adults and using a measure of aggregated momentary loneliness.

AST to Platelet Ratio Index (APRI) is an easy-to-use predictor score for cardiovascular risk in metabolic subjects

Visceral obesity is characterized by a low-grade inflammatory systemic state that contributes to the genesis of non-alcoholic fatty liver disease (NAFLD), frequently associated with liver fibrosis. Non-invasive serum markers have recently emerged as reliable, easy-to-use scores to predict liver fibrosis. NAFLD is often linked to metabolic and cardiovascular risk. Thus, in this cross-sectional study, we investigated in a population of 1225 subjects if AST to Platelet Ratio Index (APRI), one of the non-invasive liver fibrosis serum markers, can predict cardiovascular risk (CVR). APRI has been previously validated as an efficient score to predict liver fibrosis in viral hepatitis patients with a cut-off of 0.5 for fibrosis and 1.5 for cirrhosis. Our study showed that APRI significantly correlates with CVR and determines, when elevated, a significant increase in CVR for both genders, especially females. This spike in CVR, observed when APRI is elevated, is relatively high in patients in the age of 51–65 years, but it is significantly higher in younger and premenopausal women, approaching risk values usually typical of men at the same age. Taken together, our data highlighted the role of APRI as a reliable predictor easy-to-use score for CVR in metabolic patients.

Lost Touch? Implications of Physical Touch for Physical Health

Objectives

Growing research on the impact of physical touch on health has revealed links to lower blood pressure, higher oxytocin levels, and better sleep, but links to inflammation have not been fully explored. Physical touch may also buffer stress, underscoring its importance during the stressful time of living in the COVID-19 global pandemic – a time that has substantially limited social interactions and during which physical touch has been specifically advised against.

Methods

We analyze nationally representative longitudinal data on older adults (N=1124) from the National Social Life, Health, and Aging Project using cross-lagged path models.

Results

More frequent physical touch is significantly related to a lower likelihood of subsequent elevated inflammation.

Discussion

These findings highlight the importance of finding safe ways to incorporate physical touch, even in the aftermath of the COVID-19 pandemic.

Race, Gender, and Socioeconomic Variations in C-Reactive Protein Using the Health and Retirement Study

OBJECTIVES

To clarify the relationships among race, gender, and socioeconomic status (SES) with C-reactive protein (CRP).

METHOD

The present study analyzed data from 6,521 Black and White respondents aged 51 and older in the Health and Retirement Study, a nationally representative sample of midlife and older adults, to address two aims. We sought to (i) assess the independent associations between race, gender, and SES with CRP concentrations and (ii) test whether race, gender, and SES interacted to produce unequal CRP concentrations cross-sectionally and over a 4-year follow-up.

RESULTS

The results demonstrated that race, gender, and SES were each independently associated with baseline CRP, but only SES was associated with CRP at follow-up. Furthermore, race, gender, and education interacted to produce differential CRP levels at baseline. There were incremental benefits for each additional level of education for White men and women, but the relationship between education and CRP was more complicated for Black men and women. Compared with other race/gender groups with less than high school, Black women had the highest and Black men had the lowest levels of CRP. There were no apparent benefits to CRP for Black women with college compared with Black women with high school, while Black men with less than high school and college had similar concentrations of CRP.

DISCUSSION

In clarifying the complexity inherent in CRP disparities, this work contributes to a greater understanding of the biological mechanisms underlying racial disparities in leading causes of morbidity and mortality in the United States.

Early Social Origins of Biological Risks for Men and Women in Later Life

We investigate whether childhood exposures influence adult chronic inflammation and mortality risk via adult health characteristics and socioeconomic status (SES) and whether gender moderates these relationships. Analyzing a longitudinal national sample of 9,310 men and women over age 50, we found that childhood SES, parental behaviors, and adolescent behaviors were associated with adult chronic inflammation via health characteristics and SES in adulthood. The process of disadvantage initiated by low childhood SES (i.e., adult health risk factors, socioeconomic disadvantage, and chronic inflammation) subsequently raised mortality risk. In addition, gender moderated the mediating influence of childhood SES via unhealthy behaviors and parental behaviors via adult SES. Demonstrating how social forces shape biological health through multiple mechanisms informs health policies by identifying multiple points of intervention in an effort to reduce the lasting consequences of childhood disadvantage.

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.

Volunteering, Subjective Sleep Quality, and Chronic Inflammation: A 5-Year Follow-Up of the National Social Life, Health, and Aging Project

Studies indicate that the benefits of volunteering may extend to biological risk factors in disease development including chronic inflammation, though the pathway through which volunteer activity predicts chronic inflammation remains unclear. The current project focuses on the link between volunteering and C-reactive protein (CRP) as a measure of chronic inflammation, while paying a particular attention to sleep quality as a pathway. Using panel data from the National Social Life, Health, and Aging Project (N = 1,124), the present study examined whether sleep quality operates indirectly linking volunteer activity and CRP (indirect pathway), compensates for the lack of volunteerism (moderation-compensation), or regulates the benefits of volunteering on CRP (moderation-regulation). The findings suggest sleep quality as a compensatory pathway, in that sufficient sleep buffers the inflammatory effect of lack of volunteerism. The findings show that helping others may be beneficial for the helpers in terms of chronic inflammation and sleep quality as interconnected health outcomes.

Racial Differences in Elevated C-Reactive Protein Among US Older Adults

OBJECTIVES

To investigate racial differences in elevated C-reactive protein (CRP) and the potential factors contributing to these differences in US older men and women.

DESIGN

Nationally representative cohort study.

SETTING

Health and Retirement Study, 2006 to 2014.

PARTICIPANTS

Noninstitutionalized non-Hispanic black and white older adults living in the United States (n = 13 517).

MEASUREMENTS

CRP was categorized as elevated (>3.0 mg/L) and nonelevated (≤3.0 mg/L) as the primary outcome. Measures for demographic background, socioeconomic status, psychosocial factors, health behaviors, and physiological health were examined as potential factors contributing to race differences in elevated CRP.

RESULTS

Median CRP levels (interquartile range) were 1.67 (3.03) mg/L in whites and 2.62 (4.95) mg/L in blacks. Results from random effects logistic regression models showed that blacks had significantly greater odds of elevated CRP than whites (odds ratio = 2.58; 95% confidence interval [CI] = 2.20-3.02). Results also showed that racial difference in elevated CRP varied significantly by sex (predicted probability [PP] [white men] = 0.28 [95% CI = 0.27-0.30]; PP [black men] = 0.38 [95% CI = 0.35-0.41]; PP [white women] = 0.35 [95% CI = 0.34-0.36]; PP [black women] = 0.49 [95% CI = 0.47-0.52]) and remained significant after risk adjustment. In men, the racial differences in elevated CRP were attributable to a combination of socioeconomic (12.3%) and behavioral (16.5%) factors. In women, the racial differences in elevated CRP were primarily attributable to physiological factors (40.0%).

CONCLUSION

In the US older adult population, blacks were significantly more likely to have elevated CRP than whites; and the factors contributing to these differences varied in men and women. J Am Geriatr Soc 68:362-369, 2020.

Epigenetic Changes Associated with Early Life Experiences: Saliva, A Biospecimen for DNA Methylation Signatures

BACKGROUND

Adverse Childhood Experiences (ACEs), which include traumatic injury, are associated with poor health outcomes in later life, yet the biological mechanisms mediating this association are unknown. Neurocircuitry, immune system and hormone regulation differ from normal in adults reporting ACEs. These systems could be affected by epigenetic changes, including methylation of cytosine (5mC) in genomic DNA, activated by ACEs. Since 5mC levels influence gene expression and can be long-lasting, altered 5mC status at specific sites or throughout the genome is hypothesized to influence mental and physical outcomes after ACE(s). Human and animal studies support this, with animal models allowing experiments for attributing causality. Here we provide a lengthy introduction and background on 5mC and the impact of early life adversity.

OBJECTIVE

Next we address the issue of a mixture of cell types in saliva, the most accessible biospecimen for 5mC analysis. Typical human bio-specimens for 5mC analysis include saliva or buccal swabs, whole blood or types of blood cells, tumors and post-mortem brain. In children saliva is the most accessible biospecimen, but contains a mixture of keratinocytes and white blood cells, as do buccal swabs. Even in saliva from the same individual at different time points, cell composition may differ widely. Similar issues affect analysis in blood, where nucleated cells represent a wide array of white blood cell types. Unless variations in ratios of these cells between each sample are included in the analysis, results can be unreliable.

METHODS

Several different biochemical assays are available to test for site-specific methylation levels genome-wide, each producing different information, with high-density arrays being the easiest to use, and bisulfite whole genome sequencing the most comprehensive. We compare results from different assays and use high-throughput computational processing to deconvolve cell composition in saliva samples.

RESULTS

Here we present examples demonstrating the critical importance of determining the relative contribution of blood cells versus keratinocytes to the 5mC profile found in saliva. We further describe a strategy to perform a reference-based computational correction for cell composition, and therefore to identify differential methylation patterns due to experience, or for the diagnosis of phenotypes that correlate between traits, such as hormone levels, trauma status and various mental health outcomes.

CONCLUSION

Specific sites that respond to adversity with altered methylation levels in either blood cells, keratinocytes or both can be identified by this rigorous approach, which will then be useful as diagnostic biomarkers and therapeutic targets.

Negative and positive affect as predictors of inflammation: Timing matters

Very little research has assessed how measures of negative and positive affect (NA and PA) derived from assessments at multiple time points per day (e.g., via ecological momentary assessment [EMA]), as opposed to questionnaires that rely on recall over a longer period, are related to levels of peripheral inflammation. We examined how different indicators of NA and PA predicted concentrations of C-reactive protein (CRP) and seven peripheral inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-8, IL-4, IL-10, and IFN-γ) that were examined in the form of an inflammatory composite. A community-based sample of 220 adults (62% Black/African-American and 25% Hispanic/Latino; aged 25-65; 65% female) completed questionnaires at baseline (including recalled affect "over the past month") and then provided EMA reports 5x/day for 14 days. Blood was drawn from each participant after completion of EMA and used to determine plasma levels of CRP and cytokines. Analyses examined if indicators of affect predicted inflammation, controlling for age, gender, body mass index, education, health conditions, and statin use. Neither recalled NA or PA nor momentary NA or PA (aggregated across the 14 days of EMA) were significantly associated with the cytokine composite or CRP. Negative mood more proximal to the blood draw (i.e., aggregated momentary NA in week 2 of EMA) was associated with the cytokine composite but not CRP. Exploratory moderation analyses revealed that the cytokine composite was also associated with PA in week 2 for men only, and with recalled NA for those with lower education. Exploratory analyses around temporal dynamics suggested that the timing of NA measurement relative to the blood draw mattered: Specifically, there were stronger trends of association between momentary NA and inflammatory cytokines when NA was assessed closer in time to blood collection. Future investigation of the relevance of temporal proximity and other measurement details may improve understanding of how affect relates to inflammation.

Systemic Inflammation Is Associated With Longitudinal Changes in Cognitive Performance Among Urban Adults

Objectives/Background: Systemic inflammation can affect cognitive performance over time. The current study examined associations between systemic inflammation and cognitive performance among African Americans and Whites urban adults, stratifying by sex, and age group and by race. Patients/Methods: Among 1,555-1,719 White and African-American urban adults [Age_base: 30-64y, 2004-2013, mean±SD follow-up time(y): 4.64 ± 0.93y], conducted linear mixed-effects regression models were conducted to test associations of inflammatory markers [C-reactive protein, Erythrocyte Sedimentation Rate (ESR), albumin, iron, and an inflammation composite score (ICS)] with longitudinal cognitive performance. Results: Among key findings, CRP was linked to poorer baseline mental status among younger women (≤50y, γ₀₁ = -0.03 ± 0.01, p = 0.002) and poorer attention in older women (>50y, γ₀₁ = -0.024 ± 0.007, p < 0.004) and African-Americans (γ₀₁ = -0.029 ± 0.008, p < 0.001). ESR was related to faster decline on verbal memory among older men (>50y, γ₁₁ = -0.008 ± 0.003, P = 0.009); with poorer performance on attention tests overall (γ₀₁ = -0.010 ± 0.003, P = 0.003) and among African-Americans (γ₀₁ = -0.013 ± 0.004, P = 0.002); on verbal fluency among older women (>50y,γ₀₁ = -0.037 ± 0.013, P = 0.004) and on executive function: overall (γ₀₁ = +0.62 ± 0.21, P = 0.004), older men (>50y, γ₀₁ = +1.69 ± 0.53, P = 0.001) and African-Americans (γ₀₁ = +0.84 ± 0.28, P = 0.002). Albumin was linked to slower attention decline among older men (>50y, γ₁₁ = +0.329 ± 0.103, P = 0.009), over-time improvement in executive function overall (γ₁₁ = -6.00 ± 2.26, P = 0.008), and better baseline psychomotor speed among African-Americans (γ₀₁ = +0.56 ± 0.19, P = 0.003). Finally, ICS predicted faster decline on visual memory/visuo-constructive abilities among older men (>50y, γ₁₁ = +0.17 ± 0.06, p = 0.003). Conclusion: In sum, strong associations between systemic inflammation and longitudinal cognitive performance were detected, largely among older individuals (>50y) and African-Americans. Randomized trials targeting inflammation are warranted.

The Relationship Between Religious and Psychospiritual Measures and an Inflammation Marker (CRP) in Older Adults Experiencing Life Event Stress

Inflammation, often measured by C-reactive protein (CRP), is thought to be related to a number of debilitating illnesses as we age, including cardiovascular disease, cancer and diabetes. Stress has also been implicated in these processes. This study examines potential protective effects of spirituality and religion in older adults who have experienced stressful life events. As part of the nationwide Landmark Study of Spirituality and Health, a subsample of 643 middle-aged and older adults (age ≥ 50) who were at or above the median in number of life stressors (≥ 2) was included in this analysis. Psychospiritual and religious (PS/R) variables included: religious service attendance, prayer, religious meaning, religious hope, general meaning, general hope and sense of peace. Control variables included: age, gender, education, BMI, smoking, alcohol use, social support. Only church attendance predicted significantly lower CRP after controlling for covariates, even above the other PS/R variables (standardized β = - 0.14, t = - 3.23 p = 0.001). Those with frequent religious service attendance were 38% less likely to have clinically elevated CRP than those who attend rarely or never. Religious service attendance may confer protection in older adults experiencing stressful events as it was significantly associated with lower CRP, an inflammatory marker associated with illness.

Socioeconomic Status Interacts with Conscientiousness and Neuroticism to Predict Circulating Concentrations of Inflammatory Markers

BACKGROUND

Socioeconomic health disparities research may benefit from further consideration of dispositional factors potentially modifying risk associated with low socioeconomic status, including that indexed by systemic inflammation.

PURPOSE

This study was conducted to investigate interactions of SES and the Five-Factor Model (FFM) personality traits in predicting circulating concentrations of the inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP).

METHOD

Using a sample of middle-aged and older adults from the Midlife in the United States Survey (MIDUS) biomarker project (N = 978), linear regression models tested interactions of each FFM trait with a composite measure of SES in predicting IL-6 and CRP, as well as the explanatory role of medical morbidity, measures of adiposity, and health behaviors.

RESULTS

SES interacted with conscientiousness to predict levels of IL-6 (interaction b = .03, p = .002) and CRP (interaction b = .04, p = .014) and with neuroticism to predict IL-6 (interaction b = -.03, p = .004). Socioeconomic gradients in both markers were smaller at higher levels of conscientiousness. Conversely, the socioeconomic gradient in IL-6 was larger at higher levels of neuroticism. Viewed from the perspective of SES as the moderator, neuroticism was positively related to IL-6 at low levels of SES but negatively related at high SES. Interactions of SES with both conscientiousness and neuroticism were attenuated upon adjustment for measures of adiposity.

CONCLUSIONS

Conscientiousness may buffer, and neuroticism amplify, excess inflammatory risk associated with low SES, in part through relationships with adiposity. Neuroticism may be associated with lower levels of inflammation at high levels of SES.

The Influence of Social Conditions Across the Life Course on the Human Gut Microbiota: A Pilot Project With the Wisconsin Longitudinal Study

Objective

To test the feasibility of collecting and integrating data on the gut microbiome into one of the most comprehensive longitudinal studies of aging and health, the Wisconsin Longitudinal Study (WLS). The long-term goal of this integration is to clarify the contribution of social conditions in shaping the composition of the gut microbiota late in life. Research on the microbiome, which is considered to be of parallel importance to human health as the human genome, has been hindered by human studies with nonrandomly selected samples and with limited data on social conditions over the life course.

Methods

No existing population-based longitudinal study had collected fecal specimens. Consequently, we created an in-person protocol to collect stool specimens from a subgroup of WLS participants.

Results

We collected 429 stool specimens, yielding a 74% response rate and one of the largest human samples to date.

Discussion

The addition of data on the gut microbiome to the WLS-and to other population based longitudinal studies of aging-is feasible, under the right conditions, and can generate innovative research on the relationship between social conditions and the gut microbiome.

Elevated inflammation in association with alcohol abuse among Blacks but not Whites: results from the MIDUS biomarker study

Some studies document racial disparities in self-reported health associated with alcohol use and abuse. However, few studies examined biomarkers that underlie the onset of alcohol-related chronic diseases. We investigated whether the association between alcohol abuse and five biomarkers of inflammation (CRP, IL-6, fibrinogen, E-selectin, sICAM-1) vary between Black and White Americans aged 35 to 84 (n = 1173) from the Midlife in the United States Biomarker Study. Multivariable Ordinary Least Squares regressions were used to assess Black-White differences in the association between alcohol abuse and the biomarkers. Race moderated the association between alcohol abuse and CRP (b = 0.56, SE = 0.28, p = 0.048), IL-6 (b = 0.65, SE = 0.22, p = 0.004), and a composite inflammation score (b = 0.014, SE = 0.07, p = 0.041). These findings potentially shed light for why alcohol has a stronger negative association with poorer health for Blacks compared to Whites. Analysis should be replicated in larger prospective cohorts.

Childhood Socioeconomic Status and Stress in Late Adulthood: A Longitudinal Approach to Measuring Allostatic Load

Objectives: This study examines how the effects of childhood socioeconomic status (SES) may carry on into late adulthood. Methods: We examine how childhood SES affects both perceived stress and allostatic load, which is a cumulative measure of the body’s biologic response to chronic stress. We use the National Social Life, Health, and Aging Project, Waves 1 and 2, and suggest a novel method of incorporating a longitudinal allostatic load measure. Results: Individuals who grew up in low SES households have higher allostatic load scores in late adulthood, and this association is mediated mostly by educational attainment. Discussion: The longitudinal allostatic load measure shows similar results to the singular measures and allows us to include 2 time points into one outcome measure. Incorporating 2 separate time points into one measure is important because allostatic load is a measure of cumulative physiological dysregulation, and longitudinal data provide a more comprehensive measure.

Concurrent Social Disadvantages and Chronic Inflammation: The Intersection of Race and Ethnicity, Gender, and Socioeconomic Status

Disadvantaged social statuses, such as being female, poor, or a minority, are associated with increased psychosocial stress and elevated circulating concentrations of C-reactive protein, a biomarker of chronic inflammation and indicator of cardiovascular health. Individuals' experience of embodying psychosocial stress revolves around the multiplicative effects of concurrent gender, socioeconomic, and racial and ethnic identities. This study expands on prior research by examining chronic inflammation at the intersection of race and ethnicity, gender, socioeconomic status, and age group to understand which demographic subgroups in society are most vulnerable to the cumulative effects of social disadvantage. Using data from the National Health and Nutrition Examination Survey 2007-2010, the findings reveal inflammation disparities between non-poor whites and the following demographic subgroups, net of sociodemographic and biological factors: young poor Hispanic women, young poor white men, young poor and non-poor Hispanic men, middle-aged poor and non-poor black women, middle-aged poor and non-poor black men, and middle-aged poor Hispanic men. Disparities in inflammation on account of social disadvantage are most evident among those aged 45-64 years and diminish for those 65 and older in both men and women.

Social Inequalities in Inflammation: Age Variations in Older Persons

OBJECTIVE

Systemic inflammation is an important risk factor for cardiovascular diseases and inequalities by race/ethnicity, gender, and education have been documented. However, there is incomplete knowledge as to how these disparities present across age, especially in late life. This study assesses whether differences in C-reactive protein (CRP), a marker of inflammation, are contingent on age among older persons.

METHOD

Data are from the 2006/2008 Health and Retirement Study ( n = 10,974) biomarker assessment. CRP was regressed on interactions between age and other status characteristics.

RESULTS

Racial/ethnic differences in inflammation do not vary significantly by age. However, gender and education differences are greatest at younger ages and then narrow steadily with increasing age.

DISCUSSION

There is considerable heterogeneity in how disparities in inflammation present across age and characteristics such as race/ethnicity, gender, and education. Understanding status differences in the influence of age on factors affecting late-life health is useful for health disparities research.

Direct and Indirect Pathways From Social Support to Health?

Objectives

We aimed to investigate potential direct and indirect pathways linking social support and health, while considering mental health and chronic inflammation as inter-related outcomes. The study also contributes to the literature through testing potential bidirectional relationships between social support, mental health, and chronic inflammation.

Methods

This study uses Structural Equation Modeling and two waves of the National Social Life, Health, and Aging Project (NSHAP), including 1,124 community-living older adults aged 57–85 years at Wave 1 (2005).

Results

Analyses show that social support influenced mental health indirectly through better self-esteem. Moreover, social support was associated with lower levels of chronic inflammation but chronic inflammation did not influence social support.

Discussion

The growing number of older adults with an aging population urgently calls for a greater understanding of factors influencing their physical and mental health. The results of this study demonstrate the importance of social support in older adults’ health, while specifically focusing on understudied indirect pathways from social support to health.

Exploring Black-White Differences in the Relationship Between Inflammation and Timing of Menopause

Understanding the biosocial context of menopausal timing offers insight into social and health inequalities. Prior research on inflammatory chronic conditions suggests that inflammation may predict how early women experience menopause. We explore the ability of black race to moderate the overall relationship between chronic inflammation and timing of menopause. We use data from the National Social Life, Health, and Aging Project on inflammation, age of last menstruation, and race as well as relevant social and medical covariates. We conduct event history modeling to predict age at menopause by inflammatory biomarker levels. Using interaction analysis, we investigate whether being black may shape the overall relationship between inflammation status and menopause timing. Our analyses find no significant statistical interactions between black race and inflammation in predicting menopausal onset. However, we do identify independent correlational relationships between inflammation and black race (r = 0.136) and between menopausal timing and black race (r = -0.129) as well as inflammation (r = -0.138) that emerge as significant in corresponding regression models. We conclude that race probably does not moderate associations between inflammation and menopause. Yet, we also note that the original parameter estimate for black race's impact on menopausal onset (HR = 1.29, p < 0.05) becomes non-significant in a model that includes inflammation (HR = 1.06, p < 0.01). To translate our findings into policy and practice implications, we present alternate conceptualizations of black-white disparity in the inflammation-menopause relationship and recommend future research using mediation modeling.

The Impact of Educational Attainment on Observed Race/Ethnic Disparities in Inflammatory Risk in the 2001-2008 National Health and Nutrition Examination Survey

Inflammation has shown to be an independent predictor of cardiovascular disease (CVD) and growing evidence suggests Non-Hispanic Blacks (NHBs) and certain Hispanic subgroups have higher inflammation burden compared to Non-Hispanic Whites (NHWs). Socioeconomic status (SES) is a hypothesized pathway that may account for the higher inflammation burden for race/ethnic groups yet little is known about the biological processes by which SES “gets under the skin” to affect health and whether income and education have similar or distinct influences on elevated inflammation levels. The current study examines SES (income and education) associations with multiple levels of C-Reactive Protein (CRP), an important biomarker of inflammation, in a sample of 13,362 NHWs, 7696 NHBs and 4545 Mexican Americans (MAs) in the United States from the 2001 to 2008 National Health and Nutrition Examination Survey. After adjusting for age, sex, and statin use, NHBs and MAs had higher intermediate and high CRP levels compared to NHWs. Income lessened the magnitude of the association for both race/ethnic groups. The greater intermediate and high CRP burden for NHBs and MAs was strongly explained by educational attainment. MAs were more vulnerable to high CRP levels for the lowest (i.e., less than nine years) and post high school (i.e., associates degree) educational levels. After additional adjustment for smoking, heavy drinking, high waist circumference, high blood pressure, diabetes and statin use, the strength of the association between race/ethnicity and inflammation was reduced for NHBs with elevated intermediate (RR = 1.31; p ≤ 0.001) and high CRP levels (RR = 1.14; p ≤ 0.001) compared to NHWs but the effect attenuated for MAs for both intermediate (RR = 0.74; p ≤ 0.001) and high CRP levels (RR = 0.38; p ≤ 0.001). These findings suggest educational attainment is a powerful predictor of elevated CRP levels in race/ethnic populations and challenges studies to move beyond examining income as a better predictor in the SES-inflammation pathway.

Genetics of Plasma Soluble Receptor for Advanced Glycation End-Products and Cardiovascular Outcomes in a Community-based Population: Results from the Atherosclerosis Risk in Communities Study

Plasma soluble Receptor for Advanced Glycation End-products (sRAGE) is a strong marker of vascular outcomes although evidence on the direction of association is mixed. Compared to whites, blacks have lower levels of sRAGE. We hypothesized that genetic determinants of sRAGE would help clarify the causal role of sRAGE and the black-white difference in sRAGE levels. We conducted a genome-wide analysis of sRAGE in whites and blacks from the Atherosclerosis Risk in Communities Study. Median plasma sRAGE levels were lower in blacks than whites (728 vs. 1067 pg/ml; P<0.0001). The T (vs. C) allele of rs2070600, a missense variant in AGER, the gene encoding RAGE, was associated with approximately 50% lower sRAGE levels in both whites (N = 1,737; P = 7.26x10^-16; minor allele frequency (MAF) = 0.04) and blacks (N = 581; P = 0.02; MAF = 0.01). In blacks, the T (vs. C) allele of rs2071288, intronic to AGER, was associated with 43% lower sRAGE levels (P = 2.22x10^-8; MAF = 0.10) and was nearly absent in whites. These AGER SNPs explained 21.5% and 26% of the variation in sRAGE in blacks and whites, respectively, but did not explain the black-white difference in sRAGE. These SNPs were not significantly associated with incident death, coronary heart disease, diabetes, heart failure, or chronic kidney disease in whites (N = 8,130–9,017) or blacks (N = 2,293–2,871) (median follow up ~20 years). We identified strong genetic determinants of sRAGE that did not explain the large black-white difference in sRAGE levels or clearly influence risk of clinical outcomes, suggesting that sRAGE may not be a causal factor in development of these outcomes.

How old do you feel? The role of age discrimination and biological aging in subjective age

Subjective age, or how young or old individuals experience themselves to be relative to their chronological age, is a crucial construct in gerontology. Subjective age is a significant predictor of important health outcomes, but little is known about the criteria by which individuals' subjectively evaluate their age. To identify psychosocial and biomedical factors linked to the subjective evaluation of age, this study examined whether perceived age discrimination and markers of biological aging are associated with subjective age. Participants were 4776 adults (M_age = 68) from the 2008 and 2010 waves of the Health and Retirement Study (HRS) who completed measures of subjective age, age discrimination, demographic variables, self-rated health and depression, and had physical health measures, including peak expiratory flow, grip strength, waist circumference, systolic and diastolic blood pressure. Telomere length was available for a subset of participants in the 2008 wave (n = 2214). Regression analysis indicated that perceived age discrimination, lower peak expiratory flow, lower grip strength, and higher waist circumference were associated with an older subjective age, controlling for sociodemographic factors, self-rated health, and depression. In contrast, blood pressure and telomere length were not related to subjective age. These findings are consistent with the hypothesis that how old a person feels depends in part on psychosocial and biomedical factors, including the experiences of ageism and perceptible indices of fitness and biological age.

Health benefits of religion among Black and White older adults? Race, religiosity, and C-reactive protein

The study investigates potential health benefits of religiosity to protect against chronic inflammation associated with the risk of cardiovascular diseases. The study uses longitudinal data from a representative survey of adults 57-85 years old at the beginning of the National Social Life, Health, and Aging Project. Linear regression models were used to analyze the association between religiosity, as measured by affiliation, attendance, and having a clergy confidant, and logged values of C-reactive protein (CRP) concentration (mg/L). Although religious attendance was not related to CRP among the White respondents, attendance was associated with lower CRP-and change in CRP over time-among the Black respondents. There was no evidence that religious affiliation alone had any health benefit. The study provides evidence of the salutary effects of religious engagement on chronic inflammation among older adults, especially for Black Americans, which may be useful in reducing the prevalence of hypertension and cardiovascular disease.

Do productive activities reduce inflammation in later life? Multiple roles, frequency of activities, and C-reactive protein

PURPOSE OF THE STUDY

The study investigates whether productive activities by older adults reduce bodily inflammation, as indicated by C-reactive protein (CRP), a biomeasure associated with the risk of cardiovascular diseases.

DESIGN AND METHODS

The study uses a representative survey of adults aged 57-85 from the National Social Life, Health, and Aging Project (N = 1,790). Linear regression models were used to analyze the effects of multiple roles (employment, volunteering, attending meetings, and caregiving) and the frequency of activity within each role on log values of CRP concentration (mg/L) drawn from assayed blood samples.

RESULTS

Number of roles for productive activities was associated with lower levels of CRP net of chronic conditions, lifestyle factors, and socioeconomic resources. When specific types of activity were examined, volunteering manifested the strongest association with lower levels of inflammation, particularly in the 70+ group. There was no evidence that frequent engagement in volunteer activity was associated with heightened inflammation.

IMPLICATIONS

Productive activities-and frequent volunteering in particular-may protect individuals from inflammation that is associated with increased risk of hypertension and cardiovascular disease.

Decreased levels of proapoptotic factors and increased key regulators of mitochondrial biogenesis constitute new potential beneficial features of long-lived growth hormone receptor gene-disrupted mice

Decreased somatotrophic signaling is among the most important mechanisms associated with extended longevity. Mice homozygous for the targeted disruption of the growth hormone (GH) receptor gene (GH receptor knockout; GHRKO) are obese and dwarf, are characterized by a reduced weight and body size, undetectable levels of GH receptor, high concentration of serum GH, and greatly reduced plasma levels of insulin and insulin-like growth factor-I, and are remarkably long lived. Recent results suggest new features of GHRKO mice that may positively affect longevity-decreased levels of proapoptotic factors and increased levels of key regulators of mitochondrial biogenesis. The alterations in levels of the proapoptotic factors and key regulators of mitochondrial biogenesis were not further improved by two other potential life-extending interventions-calorie restriction and visceral fat removal. This may attribute the primary role to GH resistance in the regulation of apoptosis and mitochondrial biogenesis in GHRKO mice in terms of increased life span.

Insulin-like growth factor-1 bioactivity plays a prosurvival role in older participants

The aim of this study was to address the intriguing issue of the role of the insulin-like growth factor (IGF)-1 system in longevity looking at the role of different components of IGF system. Vital status was ascertained in 1,197 men and women aged greater than or equal to 65 years from the InCHIANTI study. Hormonal levels were categorized into quartiles, and ratio of IGF-1 to IGF-binding protein (IGFBP)-1 was calculated. The relationship between hormones and mortality was tested by Cox proportional hazard models adjusted for age, sex, and confounders. During the 8-year follow-up period, 240 died and 957 survived. Lowest quartiles of IGF-1 and IGFBP-1 were considered as reference. Compared with the lowest quartiles, IGF-1 in upper quartiles was a negative predictor of mortality independent of age and sex (p = .01) but not independent of IGFBP-1 and other confounders. IGFBP-1 in second-third quartiles was negatively associated and that in the fourth quartiles was positively associated with risk of death. IGF-1/IGFBP-1 ratio in the lowest quartiles was a strong positive predictor of mortality, in age- and sex-adjusted model (p = .005), and independent of additional confounders (p = .037). High IGFBP-1 and low IGF-1/IGFBP-1 ratio are associated with all-cause mortality in older population.