However, the observed elevated risk did not reach statistical significance for HF hospitalizations. 43 In another meta-analysis that included 100 studies covering 20 countries worldwide, 81 of which investigated short-term exposure and 19 long-term exposure to various air pollutants (including PM 2.5 , PM 10 , NO 2 , SO 2 , CO, and O 3 ), the relationship between these pollutants and HF hospitalization, incidence, or mortality was explored.
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