Sickle Cell Disease-Related Hospital Admissions and Acute Particulate Matter 2.5 Exposures

Abstract

BackgroundFew studies have examined the impact of ambient air pollution exposures on sickle cell disease (SCD)- related hospital admissions. The findings of these studies have suggested potential relationships between SCD-related hospital admissions with acute exposures to ozone and particulate matter but the findings have been inconsistent. MethodsWe evaluated the association between acute exposure to ambient particulate matter 2.5 (PM2.5) air pollution and SCD-related hospital admissions among residents of South Carolina (SC). We obtained data on the first incident hospital admission between 2003 and 2006. PM2.5 exposures were estimated at the residential zip code level using spatio temporal statistical modeling. We used a semi-symmetric bidirectional case-crossover design to examine the association between hospital admissions and PM2.5 exposures 0 to 7 days prior to hospital admission (for the case period) and an equivalent 0 to 7 day control period within the same month, same days of the week. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).ResultsAmong 1,937 individuals with at least one SCD hospital admission, the median age was 22 years, and the median percentage of persons living below poverty in the census tract of residence was about 16%. The average PM2.5 estimated exposure was about 10.1 ug/m3 on the day of hospital admission. The OR between admission and PM2.5 exposures on the day prior was 1.02 (95%CI: 1.00,1.03) while all other time windows examined hovered around 1.00 and were not statistically significant. ConclusionsWe observed some suggestion of increased risk for SCD-related hospital admission with an increase in PM2.5 exposures on the day prior to admission. However further investigation is needed to confirm these results.