Association between ambient air pollution and county-level cardiovascular mortality in the United States by social deprivation index.

BACKGROUND

Air pollution and socioeconomic status have both been strongly associated with cardiovascular (CV) outcomes. We sought to determine if socioeconomic status modifies the risk association between fine particulate matter air pollution (PM) and CV mortality.

METHODS

We linked county-level age-adjusted CV mortality data from Multiple Cause of Death files (2000-2016, ICD10: I00-I99) with 2015 Social Deprivation Index (SDI), a validated estimate of socioeconomic status, and modelled spatial and temporal mean annual PM exposures (2012-2018). Higher SDI suggests greater deprivation and lower socioeconomic status. Associations between PM and age adjusted CV mortality were estimated using linear models.

RESULTS

A total of 5,769,315 cardiovascular deaths from 2012-2018 across 3106 United States counties were analyzed. Both PM (β (SE) 7.584 (0.938), P < .001) and SDI scores (β (SE) 0.591 (0.140), P < .001) were independently associated with age-adjusted CV mortality (R = 0.341). The association between PM and CV mortality were stronger among counties with highest SDI, P value for interaction = .012.

CONCLUSION

Social deprivation and PM exposures were independently associated with county level age-adjusted CV mortality. The associations between PM and CV mortality were stronger in counties with high vs low social deprivation. SDI and PM represent potential targets to reduce CV mortality disparities and interventions to reduce PM exposure may be most impactful in communities of low socioeconomic status.