State level income inequality affects cardiovascular stress responses: Evidence from the Midlife in the United States (MIDUS) study.

Rationale: The slow and insidious effects of income inequality on health means that their effects can be difficult to reveal, taking many years to become apparent. These effects can also be experienced differently according to subjective status and ethnicity making the relation between income inequality and health difficult to understand. Cardiovascular reactions to acute stress are indicative of future health outcomes.

Objective: To examine whether short to medium term income inequality affected cardiovascular responses to acute stress whilst accounting for ethnic groups and subjective status.

Method: Participants state of residence was available for 1155 people who participated in the MIDUS biomarker data project. This detail was used to merge the relevant US state level inequality data 1, 5, 10 and 15 years prior to the MIDUS biomarker data project which assessed cardiovascular responses to acute stress.

Results: Our analysis demonstrated an association between inequality 5, 10 and 15 year prior and cardiovascular reactions to acute stress. Subjective community status and Black and minority ethnic group membership interacted to affect the association between inequality and cardiovascular reactions.

Conclusions: In states where income inequality was high, less healthy cardiovascular responses were evident. However lower subjective community status and Black and Ethnic minority group members interacted with income inequality such that their impact was variable contingent on state level inequality. These findings extend the literature on income inequality and health and particularly highlights a psychophysiology pathway linking income inequality and health.