Long-term exposure to low concentrations of air pollutants and hospitalisation for respiratory diseases: A prospective cohort study in Australia

Farhad Salimi; Geoffrey Morgan; Margaret Rolfe; Evangelia Samoli; Christine T Cowie; Ivan Hanigan; Luke Knibbs; Martin Cope; Fay H Johnston; Yuming Guo; Guy B Marks; Jane Heyworth; Bin Jalaludin

doi:10.1016/j.envint.2018.08.050

Long-term exposure to low concentrations of air pollutants and hospitalisation for respiratory diseases: A prospective cohort study in Australia

Environ Int. 2018 Dec;121(Pt 1):415-420. doi: 10.1016/j.envint.2018.08.050. Epub 2018 Sep 25.

Authors

Farhad Salimi¹, Geoffrey Morgan², Margaret Rolfe³, Evangelia Samoli⁴, Christine T Cowie⁵, Ivan Hanigan⁶, Luke Knibbs⁷, Martin Cope⁸, Fay H Johnston⁹, Yuming Guo¹⁰, Guy B Marks⁵, Jane Heyworth¹¹, Bin Jalaludin¹²

Affiliations

¹ University Centre for Rural Health - North Coast, School of Public Health, University of Sydney, Australia; Menzies Institute for Medical Research, University of Tasmania, Australia; Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia.
² University Centre for Rural Health - North Coast, School of Public Health, University of Sydney, Australia; Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia. Electronic address: Geoff.Morgan@sydney.edu.au.
³ University Centre for Rural Health - North Coast, School of Public Health, University of Sydney, Australia.
⁴ Department of Hygiene and Epidemiology, University of Athens Medical School, Greece.
⁵ Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; South West Sydney Clinical School, University of New South Wales, Sydney, Australia; Woolcock Institute of Medical Research, University of Sydney, Australia.
⁶ University Centre for Rural Health - North Coast, School of Public Health, University of Sydney, Australia; Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; Centre for Research and Action in Public Health, University of Canberra, Australia.
⁷ Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; School of Public Health, The University of Queensland, Australia.
⁸ Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; CSIRO Oceans & Atmosphere, PMB1, Aspendale, VIC, Australia.
⁹ Menzies Institute for Medical Research, University of Tasmania, Australia; Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia.
¹⁰ Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Australia.
¹¹ Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; School of Population and Global Health, The University of Western Australia, Australia.
¹² Centre for Air Pollution, Energy and Health, Glebe, NSW 2037, Australia; School of Public Health and Community Medicine and Ingham, Institute for Applied Medical Research, University of New South Wales, Australia.

PMID: 30261462
DOI: 10.1016/j.envint.2018.08.050

Abstract

Background: Short- and long-term spatiotemporal variation in exposure to air pollution is associated with respiratory morbidity in areas with moderate-to-high level of air pollution, but very few studies have examined whether these associations also exist in areas with low level exposure.

Objectives: We assessed the association between spatial variation in long-term exposure to PM_2.5 and NO₂ and hospitalisation for all respiratory diseases, asthma, chronic obstructive pulmonary disease (COPD), and pneumonia, in older adults residing in Sydney, Australia, a city with low-level concentrations.

Methods: We recorded data on hospitalisations for 100,084 participants, who were aged >45 years at entry in 2006-2009 until June 2014. Annual NO₂ and PM_2.5 concentrations were estimated for the participants' residential addresses and Cox proportional hazards regression was used to model the association between exposure to air pollutants and first episode of hospitalisation, controlling for personal and area level covariates. We further investigated the shape of the exposure-response association and potential effect modification by age, sex, education level, smoking status, and BMI.

Results: NO₂ and PM_2.5 annual mean exposure estimates were 17.5 μg·m^-3 and 4.5 μg·m^-3 respectively. NO₂ and PM_2.5 was positively, although not significantly, associated with asthma. The adjusted hazard ratio for a 1 μg·m^-3 increase in PM_2.5 was 1.08, 95% confidence interval 0.89-1.30. The adjusted hazard ratio for a 5 μg·m^-3 increase in NO₂ was 1.03, 95% confidence interval 0.88-1.19. We found no positive statistically significant associations with hospitalisation for all respiratory diseases, and pneumonia while negative associations were observed with COPD.

Conclusions: We found weak positive associations of exposure to air pollution with hospitalisation for asthma while there was no evidence of an association for all respiratory diseases.

Keywords: Air pollution; Cohort study; Hospitalisation; Low concentration; Particulate matter; Respiratory.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Aged, 80 and over
Air Pollutants / adverse effects*
Air Pollution / adverse effects*
Australia / epidemiology
Environmental Exposure / adverse effects*
Female
Hospitalization / statistics & numerical data*
Humans
Male
Middle Aged
Morbidity
New South Wales / epidemiology
Prospective Studies
Respiratory Tract Diseases / chemically induced
Respiratory Tract Diseases / epidemiology*

Substances

Air Pollutants