Long-Term Trends in Mortality Risk Associated with Short-Term Exposure to Air Pollution in 10 Japanese Cities between 1977 and 2015

25 Pages Posted: 5 Oct 2022

See all articles by Hironori Nishikawa

Hironori Nishikawa

Nagasaki University - Department of Global Health; University of Tokyo - Department of Global Health Policy

Xerxes Tesoro Seposo

Nagasaki University - Department of Global Health

Lina Madaniyazi

Nagasaki University - Department of Global Health

Yoonhee Kim

The University of Tokyo -Department of Global Environmental Health

Aurelio Tobias

Nagasaki University - Department of Global Health

Makiko Yamagami

Nagoya City Institute for Environmental Sciences

Satbyul Estella Kim

University of Tsukuba

Akinori Takami

National Institute for Environmental Studies

Seiji Sugata

National Institute for Environmental Studies

Yasushi Honda

Nagasaki University - Department of Global Health

Kayo Ueda

Hokkaido Univeristy

Masahiro Hashizume

University of Tokyo - Department of Global Health Policy

Chris Fook Sheng Ng

Nagasaki University - Department of Global Health

Date Written: September 30, 2022

Abstract

Background and aim: Short-term associations between air pollution and mortality have been well reported in Japan, but the historical changes in mortality risk remain unknown. We examined temporal changes in the mortality risks associated with short-term exposure to four criteria air pollutants in selected Japanese cities.

Methods: We collected daily mortality data for non-accidental causes (n=5,748,206), cardiovascular (n=1,938,743) and respiratory diseases (n=777,266), and air pollutants (sulfur dioxide [SO2], nitrogen dioxide [NO2], suspended particulate matter [SPM], and oxidants [Ox]) in 10 cities from 1977 to 2015. We performed two-stage analysis with 5-year stratification to estimate the relative risk (RR) of mortality per 10-unit increase in the 2-day moving average of air pollutant concentrations. In the first stage, city-specific associations were assessed using a quasi-Poisson generalized linear regression model. In the second stage, city-specific estimates were pooled using a random-effects meta-analysis. Linear trend and ratio of relative risks (RRR) were computed to examine temporal changes.

Results: When stratifying the analysis by every 5 years, average concentrations in each sub-period decreased for SO2, NO2, and SPM (14.2–2.3 ppb, 29.4–17.5 ppb, 52.1–20.6 µg/m3, respectively) but increased for Ox (29.1–39.1 ppb) over the study period. We found evidence of a negative linear trend in the risk of cardiovascular mortality associated with SPM across sub-periods. However, the risks of non-accidental and respiratory mortality per 10-unit increase in SPM concentration were significantly higher in the most recent period than in the earliest period. Other gaseous pollutants did not show such temporal risk change. The risks posed by these pollutants were slightly to moderately heterogeneous in the different cities.

Conclusions: The mortality risks associated with short-term exposure to SPM changed, with different trends by cause of death, in 10 Japanese cities over 39 years whereas the risks for other gaseous pollutants were relatively stable.

Keywords: Air pollution, daily mortality, time-varying effects, long-term trend

Suggested Citation

Nishikawa, Hironori and Seposo, Xerxes Tesoro and Madaniyazi, Lina and Kim, Yoonhee and Tobias, Aurelio and Yamagami, Makiko and Kim, Satbyul Estella and Takami, Akinori and Sugata, Seiji and Honda, Yasushi and Ueda, Kayo and Hashizume, Masahiro and Ng, Chris Fook Sheng, Long-Term Trends in Mortality Risk Associated with Short-Term Exposure to Air Pollution in 10 Japanese Cities between 1977 and 2015 (September 30, 2022). Available at SSRN: https://ssrn.com/abstract=4234619 or http://dx.doi.org/10.2139/ssrn.4234619

Hironori Nishikawa (Contact Author)

Nagasaki University - Department of Global Health ( email )

University of Tokyo - Department of Global Health Policy ( email )

Xerxes Tesoro Seposo

Nagasaki University - Department of Global Health ( email )

Lina Madaniyazi

Nagasaki University - Department of Global Health ( email )

Yoonhee Kim

The University of Tokyo -Department of Global Environmental Health ( email )

Aurelio Tobias

Nagasaki University - Department of Global Health

Makiko Yamagami

Nagoya City Institute for Environmental Sciences ( email )

Satbyul Estella Kim

University of Tsukuba ( email )

Akinori Takami

National Institute for Environmental Studies ( email )

Seiji Sugata

National Institute for Environmental Studies ( email )

Yasushi Honda

Nagasaki University - Department of Global Health ( email )

Kayo Ueda

Hokkaido Univeristy ( email )

Masahiro Hashizume

University of Tokyo - Department of Global Health Policy ( email )

Chris Fook Sheng Ng

Nagasaki University - Department of Global Health ( email )

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