Long-term exposure to ambient air pollution and ischemic heart disease among elderly residents of Tokyo metropolitan area, Japan

摘要

Numerous epidemiological studies have demonstrated an association between traffic-related air pollution and ischemic heart disease (IHD) in the United States and Europe. However, there are few studies describing the association between air pollution and IHD in Japan. The objective of this study was to examine the association between traffic-related air pollution and IHD in elderly people living in Tokyo metropolitan area, Japan. The subjects included 6,000 elderly people (> 65 years old in April 2014) who lived in roadside (< 50 m from highway) and non-roadside (> 500 m from highway) areas. IHD was assessed using self-reported doctor diagnosis and history of medication for myocardial infarction and/or angina pectoris collected by questionnaire. The questionnaire comprised 52 items, including body height, body weight, smoking status, drinking habits, and medical history of both the study participants and their parents. To assess the individual levels of exposure to traffic-related air pollution, the annual concentrations of nitrogen oxides (NOx) and elemental carbon (EC) in fine particles at participants' residential addresses in 2009 were estimated using two plume dispersion models: the National Institute of Advanced Industrial Science and Technology - Atmospheric Dispersion Model for Exposure and Risk Assessment (AIST-ADMER) and the Ministry of Economy, Trade and Industry - Low Rise Industrial Source dispersion model (METI-LIS). A total of 3,190 participants answered the questionnaire (1,589 from roadside areas and 1,601 from non-roadside areas). The estimated annual exposure levels of NOx and EC for each participant varied from 11.5 to 110 ppb, and 0.217 to 3.29 ug/m3, respectively. We stratified all participants into four groups by exposure levels for each pollutant. After adjusting for confounders (sex, age, body mass index, smoking status, and drinking habits), multiple logistic regression analyses revealed that compared to participants with the lowest exposure levels of NOx (11.5-27.9 ppb) and EC (0.217-0.577 μg/m3), odds ratios for participants with the highest NOx exposure (45.7-110 ppb) and participants with the highest EC exposure (1.14-3.29 ug/m3) were 1.47 (95% confidence interval [Cl] 0.96-2.27) and 1.41 (95% Cl 0.92-2.20), respectively. These results suggest that there is a positive association between long-term exposure to traffic-related air pollution and IHD among elderly residents of Tokyo metropolitan area, Japan.