Spatially differentiating the effects of long-term air pollution on specific causes of death from cardiovascular and respiratory mortality in Hong Kong: a territory-wide register-based study

Abstract

Previous studies have evaluated the effects of air pollution on various causes of death. However, there are few studies directly differentiating the regional effects of air pollution on specific causes of death from cardiovascular and respiratory mortality. It is important to target specific diseases and air pollutants for environmental management, in order to develop a sustainable environment. Therefore, a territory-wide register-based study was developed with cause-specific mortality data in Hong Kong between 2007 and 2014 (n = 257,090). Five groups of decedents were directly compared with the two control groups (cardiovascular and respiratory deaths), separately, based on binomial logistic regressions. Three air pollutants (NO2, PM2.5, black carbon (BC)) were selected to evaluate how spatial distribution of long-term air pollution exposure can induce the difference in mortality risks from two control groups. Based on the results, different air pollutants can contribute to different impact on mortality risk. PM2.5 and BC contributed to higher effects on mortality associated with mental and behavioral disorders than those linked to cardiovascular and respiratory diseases. BC can contribute to a higher mortality risk for mortality associated with diseases of the nervous and digestive systems than with respiratory diseases. There was also a stronger influence of neighborhood PM2.5 on mortality associated with diseases of the genitourinary system than with cardiovascular and respiratory diseases, and a stronger impact of neighborhood NO2 and BC on cancer-related mortality than on respiratory mortality. In conclusion, several air pollutants have greater impact on cause-specific mortality than cardiovascular and respiratory mortality. Therefore, it is necessary to have a comprehensive and systematic investigation to evaluate how different types of air pollutants influence various types of cause-specific mortality. In addition, specific health protocols, enhancement of urban design and improvement of environmental hygiene should be conducted for specific types of air pollution and deprived populations, rather than targeting solely the people with cardiorespiratory diseases.