Association between levels of PM2.5 and cardiovascular diseases in a developing megacity

HAIDER KHWAJA (1), Zafar Fatmi (2), Zafar Aminov (3), David Carpenter (3)

(1) Wadsworth Center, New York State Department of Health, Albany, NY 12201 (2) Aga Khan University, Karachi, Pakistan (3) Institute for Health and the Environment, University at Albany, 5 University Place, Rensselaer, NY 12144

     Abstract Number: 109
     Last modified: November 3, 2009

Abstract
Particulate air pollution is an important public health issue. Population-based studies have documented health risks resulting from short-term exposure to particulate matter. Research using large-scale data sets has shown a relationship between total suspended particulate matter (TSP) and various size fractions with pulmonary and cardiovascular diseases in a variety of communities in the industrialized world. We have previously shown that particulate levels in Karachi, Pakistan are among the highest TSP loading of any megacity in the world. There have, however, not been major studies of the health effects of particulate pollution in the major developing megacity. We have investigated the short-term effects of fine particulate matter with aerodynamic diameter less than 2.5 micron (PM2.5) on hospital admissions and emergency room (ER) visits among adults and children living in one of the largest cities in the developing world, Karachi, Pakistan. Daily records of hospitalizations and ER visits for cardiovascular and respiratory diseases at the three major hospitals serving the city were collected. In addition 24 h concentrations of PM2.5 were collected at two different residential and industrial/residential sites. Daily counts of hospital data along with daily levels of meteorological variables and PM2.5 were analyzed using Poisson regression. Final models were adjusted for the effects of time trends, weekdays, holidays, meteorological factors, seasonal patterns, serial correlation, age and gender. Averaged mass concentration of PM2.5 concentrations at two different sites in the city ranged from 45 to 256 microgram/m3. Both sites showed peaks at similar times.
Poisson regression was performed using 0, 1, 2 and 3 day lags. There was a positive association between PM2.5 particulate levels with hospitalization and ER visits for cardiovascular diseases (myocardial infarction, cardiac failure, ischemic heart disease), but it was statistically significant only with 0 and 1 day lag. The association was positive for all ages, but strongest among men ages 40-60 years. The relation was stronger in the fall than the winter, and lowest on Sunday and Monday. Preliminary analysis of the relationship between PM2.5 and respiratory disease with a one-day lag showed a weak and marginally significant association, but further data collection is needed in order to provide further insight into this association.
Our study is one of the first to investigate the relationship between particulate air pollution and cardiovascular and respiratory disease in a developing megacity where particulate levels are extraordinarily high. There is a significant adverse health impact, particularly among the working age population.