Correlation between suspended particles in the environmental air and causes of disease among inhabitants: Cross-sectional studies using the vital statistics and air pollution data in Japan

To identify the diseases that correlate with suspended particle concentration in the ambient air, a cross-sectional epidemiological study was conducted using the annual vital statistics and air pollution estimates of 1881 points throughout Japan. The concentration of suspended particulate matters (SPMs) 10 mu m or less in diameter were hypothetically converted to PM2.5 values (converted PM2.5 or cPM(2.5)) by using a conversion factor obtained from 25 estimates in Japan. Among various causes of death, a significant correlation was observed between both the SPM and cPM(2.5) (SPM/cPM(2.5)) levels and the age-adjusted death rates of ischemic heart disease or hypertensive heart disease in both genders. Correlation was noted with pneumonia, asthma, chronic bronchitis/emphysema, or lung cancer only in females. Unexpectedly, breast, endometrial, and ovarian cancer also showed significant increases in-mortality rates related to the SPM/cPM(2.5) level, suggesting a role for suspended particles in the ambient air with or without gaseous component,as a possible endocrine-disrupting, estrogenic agent. Multivariate regression analysis of confounding factors, smoking rate, population density, and hormone-related factors revealed consistent significance Of SPM/cPM(2.5) in these diseases. (c) 2004 Elsevier Inc. All rights reserved.