Association between incidence of fatal intracerebral hemorrhagic stroke and fine particulate air pollution

Objective Few studies investigating associations between fine particulate air pollution and hemorrhagic stroke have considered subtypes. Additionally, less is known about the modification of such association by factors measured at the individual level. We aimed to investigate the risk of fatal intracerebral hemorrhage (ICH) incidence in case of PM 2.5 (particles ≤ 2.5 μm in aerodynamic diameter) exposure. Methods Data on incidence of fatal ICH from 1 June 2012 to 31 May 2014 were extracted from the acute stroke mortality database in Shanghai Municipal Center for Disease Control and Prevention (SCDC). We used the time-stratified case-crossover approach to assess the association between daily concentrations of PM 2.5 and fatal ICH incidence in Shanghai, China. Results A total of 5286 fatal ICH cases occurred during our study period. The averaged concentration of PM 2.5 was 77.45 μg/m 3 . The incidence of fatal ICH was significantly associated with PM 2.5 concentration. Substantial differences were observed among subjects with diabetes compared with those without; following the increase of PM 2.5 in lag2, the OR (95% CI) for subjects with diabetes was 1.26 (1.09–1.46) versus 1.05 (0.98–1.12) for those without. We did not find evidence of effect modification by hypertension and cigarette smoking. Conclusions Fatal ICH incidence was associated with PM 2.5 exposure. Our results also suggested that diabetes may increase the risk for ICH incidence in relation to PM 2.5 .