Effects of climate and fine particulate matter on hospitalizations and deaths for heart failure in elderly: A population-based cohort study
Introduction
It has already been shown through multiple lines of evidence that climate is changing across the planet, largely as a result of human activities (Intergovernmental Panel on Climate Change, 2013). Global temperature is warming. Climate is more variable and unpredictable. Donat et al. (2013) predict that days and nights will be warmer, not to mention an increase in the occurrence and the duration of heat waves. In some parts of the world as in the province of Quebec, Canada, winters will remain cold and extreme cold snaps will occur despite the global warming (Ouranos, 2015).
Natural environment of the province of Quebec is characterized, among others, by the vastness of the landscape. With an area of 1,667,441 square kilometers (km), the province of Quebec extends to nearly 2000 km from south to north and 1500 km from east to west. As a result of its extensive area and the relief of the territory, Quebec has several distinct climate areas and ecosystems. In the center of Quebec, average temperatures vary from − 16 °C in winter to 12 °C in summer whereas it fluctuates from − 8 °C to 20 °C in the south of the province (Ouranos, 2015).
Climate changes affect, above all, vulnerable populations, including individuals with chronic diseases, elderly and disadvantaged people (Basu and Samet, 2002, Kenny et al., 2010, Doyon et al., 2008). Extreme temperatures, such as extended heat waves or cold snaps, increase morbidity, mortality and health resource utilization for heart failure (HF) when combined with an advanced age and a low-income neighbourhood (Hawkins et al., 2012). Moreover, several atmospheric pollutants sensitive to weather conditions are affected by the global warming (Luber and Lemery, 2015). These air pollutants can exacerbate cardiovascular diseases (CVDs) and, according to Luber and Lemery (2015), are associated with an increase in emergency visits, hospitalizations and premature deaths.
Sensitivity to extreme climate is apparent in the field of CVDs, a research thematic prioritized in a recent report published by the National Institute of Environmental Health Sciences (Portier et al., 2010). There are multiple evidences of the negative impact of meteorology as well as air pollution on HF hospital admissions and mortality (i.e., Goggins and Chan, 2017, Das et al., 2014, Qiu et al., 2013, Gotsman et al., 2010, Inglis et al., 2008, Kolb et al., 2007). However, to our knowledge, there is no study that investigates the impact of meteorological parameters and fine particulate matter on morbidity and mortality for HF at a neighbourhood scale considering both individual and contextual factors.
In this study, we measured the effect of several meteorological parameters on the occurrence of a hospitalization or death for the main cause of HF in elderly, aged 65 years and older, known to be diagnosed with this condition in Quebec (Canada) over a ten-year period (2001 − 2011). The main objective was to evaluate the effect of mean temperature, relative humidity and atmospheric pressure as well as air pollutant PM2.5, on HF negative outcomes controlling for several contextual and individual covariates. This is particularly relevant for purposes of surveillance in public health in a context of climate changes.
Section snippets
Methods
To measure the association between climate, PM2.5 exposure and the occurrence of HF events, a population-based retrospective cohort study was conducted.
Results
Between April 1st 2001 and December 31st 2011 in Quebec, 112,793 elderly of 65 years and older diagnosed with HF were included in the study cohort. During the follow-up period, 21,157 HF events occurred, representing 18.7% of this population (only the first following events were considered by person). Overall, 18,309 individuals were hospitalized and 4297 died of HF out of a total of 71,696,780 person-days, corresponding to a daily incidence of 0.03% (in some cases, hospitalization and death
Meteorological parameters and HF events
Several studies have found a positive association between temperature and HF negative outcomes (e.g.: Goggins and Chan, 2017, Das et al., 2014, Qiu et al., 2013, Zanobetti et al., 2012, Gotsman et al., 2010, Inglis et al., 2008, Kolb et al., 2007). In the present study, multiple individual and contextual covariates, including the consideration of cardiovascular risk factors and drugs potentially dangerous in situations of extreme climate, were took into account in the measure of the effect of
Conclusions
This study has shown an increased risk of HF events in elderly of 65 years and older diagnosed with this disease in Quebec for each drop of 1 °C in the mean temperature of the previous 3 days as well as of the previous 7 days independently of the presence of individual risk factors. To our knowledge, this is the first study of this kind performed in Canada. It paves the way to the realization of further studies in order to support the surveillance of chronic cardiovascular diseases in a context of
Funding source
This study was financially supported by the Green Fund as part of the action plan of 2006–2012 on climate changes of the government of Quebec, Canada.
Conflict of interest
The authors declare no conflict of interest.
Acknowledgment
The authors would like to acknowledge the INSPQ for the access granted to the QICDSS database to conduct this study.
References (67)
- et al.
The seasonality in heart failure deaths and total cardiovascular deaths
Aust. N. Z. J. Public Health
(2008) - et al.
Assessing the burden of hospitalized and community-care heart failure in Canada
Can. J. Cardiol.
(2014) - et al.
The association between meteorological events and acute heart failure: new insights from ASCEND-HF
Int. J. Cardiol.
(2014) - et al.
A study of the short-term associations between hospital admissions and mortality from heart failure and meteorological variables in Hong Kong: weather and heart failure in Hong Kong
Int. J. Cardiol.
(2017) - et al.
Worldwide risk factors for heart failure: a systematic review and pooled analysis
Int. J. Cardiol.
(2013) - et al.
Global association of air pollution and heart failure: a systematic review and meta-analysis
Lancet
(2013) - et al.
Heart failure in a cold climate
J. Am. Coll. Cardiol.
(2002) Information theory and an extension of the maximum likelihood principle
- et al.
Weather-related mortality: how heat, cold, and heat waves affect mortality in the United States
Epidemiology
(2009) - et al.
Relation between elevated ambient temperature and mortality: a review of the epidemiologic evidence
Epidemiol. Rev.
(2002)