Age and Sex Differences in the Associations Among Socioeconomic Status, Affective Reactivity to Daily Stressors, and Physical Health in the MIDUS Study.

Background: Low socioeconomic status (SES) is robustly associated with increased risks of morbidity and mortality. Affective reactivity to daily stressors has been proposed to be a mediator for this association. However, few longitudinal studies have empirically tested the indirect effect of SES on health through affective reactivity to daily stressors.

Purpose: This study aimed to test the indirect effect of SES on physical health via affective reactivity to daily stressors over a 10-year period and to explore age and sex differences in such indirect effect.

Methods: Data were drawn from a subsample of 1,522 middle-aged and older adults (34-83 years of age, 57.2% female, 83.5% White) from the Midlife in the United States study. SES (i.e., education, household income, indicators of financial distress) was assessed in 2004-2006. Affective reactivity to daily stressors was computed using data collected during the 8-day daily stress assessment in 2004-2009. Self-reported physical health conditions were assessed in 2004-2006 and 2013-2014.

Results: There was a significant indirect effect of lower SES on more physical health conditions via elevated negative affective reactivity to daily stressors among women but not men. The indirect effect of SES on physical health conditions via negative affective reactivity to daily stressors was consistent across the middle and older adulthood.

Conclusions: Our findings suggest that negative affective reactivity to daily stressors might be a key intermediate process contributing to persistent SES disparities in physical health, particularly among women.