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 PM2.5 (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 PM2.5 and fatal ICH incidence in Shanghai, China.
Results: A total of 5286 fatal ICH cases occurred during our study period. The averaged concentration of PM2.5 was 77.45 μg/m3. The incidence of fatal ICH was significantly associated with PM2.5 concentration. Substantial differences were observed among subjects with diabetes compared with those without; following the increase of PM2.5 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 PM2.5 exposure. Our results also suggested that diabetes may increase the risk for ICH incidence in relation to PM2.5.
Keywords: Air pollution; Effect modifiers; Fine particulate; Intracerebral hemorrhage.