Association between short-term exposure to fine particulate matter and daily emergency room visits at a cardiovascular hospital in Dhaka, Bangladesh

It has been suggested that exposure to fine particulate matter (PM2.5) adversely affects cardiovascular health. However, the effect modifications by individual characteristics and season have been less studied in developing countries where PM2.5 levels are high. To estimate the risks of cardiovascular emergency room visits in relation to daily concentrations of PM2.5 and to assess how these associations can be modified by age, sex, and nutritional status of patients and by season. The analytic sample was 6774 adults who visited the emergency room at a cardiovascular disease (CVD) hospital in Dhaka throughout one year (n = 364 days). A time-stratified case-crossover design with conditional Poisson regression analysis was used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) of visits while adjusting for temperature. Stratification was performed by gender, age (