Long-term exposure to fine particle matter and all-cause mortality and cause-specific mortality in Japan: the JPHC Study
https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-022-12829-2
The International Agency for Research on Cancer (IARC) has identified outdoor PM2.5 as a Group I carcinogenic factor for lung cancer. Outdoor air pollution levels have decreased over the last few decades in developed countries. The research evaluated associations between long-term exposure to particulate matter <2.5 μg/m3 (PM2.5) and mortality in a Japanese cohort with a relatively low exposure level.
The Japan Public Health Center-based Prospective Study (JPHC Study) is a prospective cohort study of men and women aged 40-69 years in 1990 who were followed up through 2013 for mortality. In this cohort of 87,385 subjects who did not move residence during follow-up, average PM2.5 levels from 1998 to 2013 by linkage with 1-km2 grids of PM2.5 concentration were assigned to the residential addresses of all participants. Cox proportional hazards models were used to calculate the association of long-term exposure to PM2.5 on mortality, with adjustment for several individual confounding factors.
Average PM2.5 was 11.6 μg/m3. Average PM2.5 exposure was not associated with all-cause mortality or cancer and respiratory disease mortality. However, average PM2.5 was positively associated with mortality from cardiovascular disease (hazard ratio (HR) of 1.23 (95%CI=1.08-1.40) per 1-μg/m3 increase; in particular, HR in mortality from cerebrovascular disease was 1.34 (95%CI=1.11-1.61) per 1-μg/m3 increase.
The research found evidence for a positive association between PM2.5 exposure and mortality from cardiovascular disease in a Japanese population, even in an area with relatively low-level air pollution.