Air Health Trend Indicator: Association between Short-Term Exposure to Ground Ozone and Circulatory Hospitalizations in Canada for 17 Years, 1996⁻2012
- DOI
- Language of the publication
- English
- Date
- 2018-07-24
- Type
- Article
- Author(s)
- Shin, Hwashin Hyun
- Burr, Wesley S.
- Stieb, Dave
- Haque, Lani
- Kalayci, Harun
- Jovic, Branka
- Smith-Doiron, Marc
- Publisher
- MDPI
Abstract
The Air Health Trend Indicator is designed to estimate the public health risk related to short-term exposure to air pollution and to detect trends in the annual health risks. Daily ozone, circulatory hospitalizations and weather data for 24 cities (about 54% of Canadians) for 17 years (1996⁻2012) were used. This study examined three circulatory causes: ischemic heart disease (IHD, 40% of cases), other heart disease (OHD, 31%) and cerebrovascular disease (CEV, 14%). A Bayesian hierarchical model using a 7-year estimator was employed to find trends in the annual national associations by season, lag of effect, sex and age group (≤65 vs. >65). Warm season 1-day lagged ozone returned higher national risk per 10 ppb: 0.4% (95% credible interval, -0.3⁻1.1%) for IHD, 0.4% (-0.2⁻1.0%) for OHD, and 0.2% (-0.8⁻1.2%) for CEV. Overall mixed trends in annual associations were observed for IHD and CEV, but a decreasing trend for OHD. While little age effect was identified, some sex-specific difference was detected, with males seemingly more vulnerable to ozone for CEV, although this finding needs further investigation. The study findings could reduce a knowledge gap by identifying trends in risk over time as well as sub-populations susceptible to ozone by age and sex.
Plain language summary
Health Canada is responsible for providing health information to help Canadians make informed decisions and conducting risk assessments on ambient and indoor air pollution as outlined in the Clean Air Regulatory Agenda. One of the risk assessment goals is to examine the strength of evidence of associations between exposure to ground-ozone and health outcomes, in particular, hospital admission. This study reports the Air Health Trend Indicator on ground level ozone, which has been developed to estimate the public health risk related to short-term exposure to air pollution and to detect trends in the annual health risks. Daily ozone, heart-related hospitalizations and weather data for 24 cities (about 54% of Canadians) for 17 years (1996-2012) were used. This study examined three heart-related causes: ischemic heart disease (IHD, 40% of cases), other heart disease (OHD, 31%) and cerebrovascular disease (CEV, 14%). An advanced statistical analysis (Bayesian hierarchical model using 7-year estimator) was used to find trends in the annual national associations by season, lag of effect, sex and age group (≤65 vs >65). Overall no linear trend was observed for IHD and CEV, but a decreasing trend in association over the period studied appeared for OHD. While little age effect was identified, some difference was detected by sex. The study findings could reduce a knowledge gap by identifying trends in risk over time as well as sub-populations susceptible to ozone by age and sex. This new evidence adds to the body of knowledge used by the Federal Government, in conjunction with the Provinces and Territories, to inform Canadians about health risks associated with ozone.
Subject
- Health,
- Health and safety