Season, Sex, Age, and Education as Modifiers of the Effects of Outdoor Air Pollution on Daily Mortality in Shanghai, China: The Public Health and Air Pollution in Asia (PAPA) Study

• Published in: Environmental health perspectives Vol. 116; no. 9; pp. 1183 - 1188
• Main Authors: Kan, Haidong, London, Stephanie J., Chen, Guohai, Zhang, Yunhui, Song, Guixiang, Zhao, Naiqing, Jiang, Lili, Chen, Bingheng
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01.09.2008; National Institute of Environmental Health Sciences
• Subjects: Adolescent; Adult; Age; Age Factors; Aged; Air pollutants; Air Pollution; Child; Child, Preschool; China; Confidence intervals; Cool season; Copyrights; Death; Diseases; Education; Educational attainment; Educational Status; Epidemiology; Female; Health; Health aspects; Health benefits; Humans; Humidity; Male; Mathematical models; Methods; Middle Aged; Mortality; Nitrogen dioxide; Outdoor; Ozone; Particulate matter; Policies; Pollutants; Public Health; Risk factors; Seasons; Sex; Sex Factors; Splines; Sulfur dioxide; Time-series analysis; Warm seasons; China; China, People's Rep., Shanghai; China, People's Rep; mortality; air pollution; modifiers; time-series studies
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.10851

Background: Various factors can modify the health effects of outdoor air pollution. Prior findings about modifiers are inconsistent, and most of these studies were conducted in developed countries. Objectives: We conducted a time-series analysis to examine the modifying effect of season, sex, age, and education on the association between outdoor air pollutants [particulate matter < 10 μm in aerodynamic diameter (PM₁₀), sulfur dioxide, nitrogen dioxide, and ozone] and daily mortality in Shanghai, China, using 4 years of daily data (2001-2004). Methods: Using a natural spline model to analyze the data, we examined effects of air pollution for the warm season (April-September) and cool season (October-March) separately. For total mortality, we examined the association stratified by sex and age. Stratified analysis by educational attainment was conducted for total, cardiovascular, and respiratory mortality. Results: Outdoor air pollution was associated with mortality from all causes and from cardio-respiratory diseases in Shanghai. An increase of 10 μg/m³ in a 2-day average concentration of PM₁₀, SO₂, NO₂, and O₃ corresponds to increases in all-cause mortality of 0.25% [95% confidence interval (CI), 0.14-0.37), 0.95% (95% CI, 0.62-1.28), 0.97% (95% CI, 0.66-1.27), and 0.31% (95% CI, 0.04-0.58), respectively. The effects of air pollutants were more evident in the cool season than in the warm season, and females and the elderly were more vulnerable to outdoor air pollution. Effects of air pollution were generally greater in residents with low educational attainment (illiterate or primary school) compared with those with high educational attainment (middle school or above). Conclusions: Season, sex, age, and education may modify the health effects of outdoor air pollution in Shanghai. These findings provide new information about the effects of modifiers on the relationship between daily mortality and air pollution in developing countries and may have implications for local environmental and social policies.