Long-term exposure to low air pollutant concentrations and hospitalisation for respiratory diseases in older men: A prospective cohort study in Perth, Australia

Farhad Salimi; Ania Stasinska; Geoffrey G Morgan; Graeme J Hankey; Osvaldo Almeida; Bu Yeap; Leon Flicker; Jane Heyworth

doi:10.1016/j.heliyon.2022.e10905

Long-term exposure to low air pollutant concentrations and hospitalisation for respiratory diseases in older men: A prospective cohort study in Perth, Australia

Heliyon. 2022 Oct 7;8(10):e10905. doi: 10.1016/j.heliyon.2022.e10905. eCollection 2022 Oct.

Authors

Farhad Salimi^{1

2}, Ania Stasinska³, Geoffrey G Morgan¹, Graeme J Hankey⁴, Osvaldo Almeida⁴, Bu Yeap⁴, Leon Flicker⁴, Jane Heyworth³

Affiliations

¹ University Centre for Rural Health, Faculty of Medicine and Health, The University of Sydney, Australia Sydney School of Public Health, Faculty of Medicine and Health, The University of Sydney, Australia.
² Occupational and Environmental Health Sciences, Public Health and Preventive Medicine, Monash University, Australia.
³ School of Population and Global Health, The University of Western Australia, Perth, Western Australia, Australia.
⁴ Medical School, The University of Western Australia, Perth, Western Australia, Australia.

Abstract

Background: Acute exposure to ambient air pollution even at low concentrations has been associated with increased hospitalisation for respiratory diseases but the effects of long-term exposure are less certain. In this study, we investigated the associations between long-term exposures to PM_2.5, PM_2.5 absorbance and NO₂ and hospitalisation for asthma, chronic obstructive pulmonary disease and pneumonia in a cohort of older men living in Perth, Western Australia, a city where the levels of air pollutants are well below the world standards.

Materials and methods: The study population of 11,156 men with no prior hospitalisation for respiratory disease was drawn from the Health in Men Study (HIMS) cohort of men aged >65 years living in Perth, Western Australia between 1996-1999. PM_2.5, PM_2.5 absorbance (PM_2.5a) and NO₂ were measured across the Perth metropolitan area over three seasons in 2012. Land use regression (LUR) models were used to estimate annual concentrations of PM_2.5, PM_2.5 absorbance and NO₂ at the residential address of each participant from inception (1996) to 2015. Hospitalisation for respiratory disease between inception and 2015 was ascertained using the Western Australian Data Linkage System. The association between exposure to air pollution with hospitalisation for respiratory disease was examined using Cox regression analysis.

Results: No statistically significant associations were observed in the fully adjusted models. However, positive associations were observed with first hospitalisation for pneumonia (HR 1.08, 95% CI: 1.01-1.16) when adjusted for age, year of enrolment, smoking status, education, BMI and physical activity.

Conclusions: In this longitudinal study of older men we found no evidence of associations between increased long-term exposure to low-level air pollution with increased risk of hospitalisation for respiratory diseases in Perth, Australia. More studies on respiratory morbidity associated with exposure to low levels of air pollution are needed for more comprehensive understanding of the overall risk.

Keywords: Air pollution; Low concentration; Respiratory disease; Survival model.