Social Relationships and Inflammatory Markers in the MIDUS Cohort: The Role of Age and Gender Differences.

OBJECTIVE: To better understand age and gender differences in associations of social relationships with chronic inflammation. METHOD: Using a sample of middle-aged and older adults ( N = 963) from the Midlife Development in the United States (MIDUS) biomarker project, we examined interactions of age and gender with structural and functional social network measures in predicting interleukin-6 (IL-6) and C-reactive protein (CRP). RESULTS: Significant interactions involving age and gender showed that social support was associated with lower IL-6 in older women, whereas perceived positive relationships and social integration were related to lower IL-6 in both men and women of advanced age. Functional measures were associated with higher CRP in both men and women after adjustment for health conditions and behaviors, with some further variation by age. DISCUSSION: Greater social support may be related to lower IL-6 in older women. Further research is needed to understand observed associations of social support with higher CRP.

Associations of Lifetime Trauma and Chronic Stress With C-reactive Protein in Adults Ages 50 Years and Older: Examining the Moderating Role of Perceived Control.

OBJECTIVE: The aim of the study was to investigate whether high perceived control mitigates systemic inflammatory risk associated with traumatic and chronic stress exposures in older adults. METHODS: A sample of community-dwelling adults ages 50 years and older (N = 4779) was drawn from the Health and Retirement Study. Structural equation models tested interactions of lifetime trauma and chronic stress with mastery and perceived constraints predicting baseline levels and 4-year change in C-reactive protein (CRP). RESULTS: There were significant interactions of lifetime trauma (ß = -.058, p = .012) and chronic stress (ß = -.069, p = .010) with mastery as related to baseline CRP levels. Both measures were associated with higher CRP at low (ß = .102, p = .003; ß = .088, p = .015) but not high levels of mastery. In addition, chronic stress interacted with baseline mastery (ß = .056, p = .011) and change in mastery (ß = -.056, p = .016) to predict 4-year change in CRP. Chronic stress was associated with an increase in CRP at high baseline mastery (ß = .071, p = .022) and when mastery decreased during follow-up (ß = .088, p = .011). There were no main effects of stress or control variables other than an association of constraints with a larger increase in CRP (ß = .062, p = .017). Interactions were minimally attenuated (<15%) upon further adjustment for negative affect, body mass index, smoking, and physical activity. CONCLUSIONS: High mastery may protect against elevated systemic inflammation associated with substantial lifetime trauma exposure. Individuals who experience declines in mastery may be most susceptible to increases in inflammation associated with chronic stress.

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.

Socioeconomic status, psychological resources, and inflammatory markers: Results from the MIDUS study.

OBJECTIVE: Our objective was to investigate interactions of psychological resources and socioeconomic status (SES)-as well as potential gender differences and the explanatory role of childhood and adult stress exposures, health behaviors, and negative and positive affect-in predicting markers of systemic inflammation. METHOD: We utilized a sample of adults from the Midlife Development in the U.S. (MIDUS) study who provided biomarker data (N = 1,152). SES was operationalized as a composite of education, income, and occupational prestige, and the psychological resources construct was operationalized as a latent factor measured with optimism, perceived control, and self-esteem. Linear regression models examined these 2 factors and their interaction in predicting interleukin-6 (IL-6) and C-reactive protein (CRP) measured on average 2 years later, as well as 3-way interactions involving gender and the impact of covariate adjustment. RESULTS: Psychological resources interacted with SES in men (for IL-6: p < .001; for CRP: p = .04) but not in women. In men, greater psychological resources was associated with lower concentrations of IL-6 at lower levels of SES but higher concentrations of both markers at higher levels of SES. The inverse association between resources and IL-6 at low SES was moderately attenuated upon adjustment for negative affect. CONCLUSION: Socioeconomic status might modulate the linkage between psychological resources and systemic inflammation in men. At lower levels of SES, resources may be related to lower inflammation in part through lower negative affect. Associations with higher inflammation at higher SES add to growing evidence suggesting that adaptive psychological characteristics may be associated with markers of poorer physiological function under certain conditions. (PsycINFO Database Record