Brief Report: Ambient PM_2.5 and Risk of Hospital Admissions: Do Risks Differ for Men and Women?

Background: While strong evidence exists for associations between fine particles (PM_2.5) and health, less is known about whether associations differ by sex. Methods: We used Bayesian hierarchical modeling to estimate associations between PM_2.5, based on ambient monitors, and risk of cause-specific cardiovascular and respiratory hospitalizations for about 12.6 million Medicare beneficiaries (>65 years) residing in 213 US counties for 1999-2010. Results: Point estimates were higher for women than men for almost all causes of hospitalization. PM_2.5 risks were higher for women than men for respiratory tract infection, cardiovascular, and heart rhythm disturbance admissions. A 10 μg/m³ increase in same-day PM_2.5 was associated with a 1.13% increased risk of heart rhythm disturbance admissions for women (95% posterior interval [PI]: 0.63%, 1.63%), and 0.03% for men (95% PI:-0.48%, 0.55%). Differences remained after stratification by age and season. Conclusions: Women may be more susceptible to PM_2.5-related hospitalizations for some respiratory and cardiovascular causes.