Journal article
Time series analysis of environmental factors and their association with emergency visits for asthma exacerbations in Petaling Jaya, Malaysia
Journal of global health, Vol.16, 04249
2026
PMID: 42565432
Abstract
Background
The burden of respiratory conditions, especially asthma, is likely to increase with urbanisation and pollution unless effectively managed. Petaling Jaya, a metropolitan area, faced heightened risk due to worsening outdoor air pollution, which can trigger asthma exacerbations. We aimed to examine the relationships between environmental factors and emergency visits for asthma exacerbations.
Methods
We used retrospective data over four years (1 January 2014 to 13 April 2017) comprising clinical records from a main hospital in Klang Valley and environmental data (air pollutants and meteorological data) obtained from nearby stations. We used generalised additive models to assess the associations between environmental factors and asthma emergency visits. We used distributed lag nonlinear models to address the delayed effects and non-linearity of particulate matter at 10 & micro;m (PM10) exposure on these visits.
Results
Asthma exacerbations accounted for 2.3% of total emergency visits. Daily mean (x) PM10 level exceeding Malaysian Ambient Air Quality Standard (MAAQS) threshold was associated with a 21.3% (95% confidence interval (CI) = 2.2, 44.0) increase when levels reached 200 & micro;g/m3 and 34.0% (95% CI = 4.7, 71.7) increase when levels reached 300 & micro;g/m3 in asthma emergency visits. The lag effect was associated with PM10 exposure levels, peaking on days two and three at 100 & micro;g/m3 and on the same day at 200 & micro;g/m3 and 250 & micro;g/m3. The cumulative exposure-response curve from lag 0-7 days shows that the increased relative risk of asthma emergency visits began at PM10 levels of 150 & micro;g/m3.
Conclusions
We provide preliminary insights into the respiratory health burden in the Klang Valley. The associations observed between PM10 and asthma emergency visits are exploratory. Our findings suggest that the risk of visits may increase when PM10 levels near or above current MAAQS thresholds, highlighting the potential benefit of aligning local air quality standards with stricter international guidelines. These results may support the value of targeted preventive measures and healthcare resource planning for asthma, though larger multi-year data sets are required to enhance statistical robustness.
Details
- Title
- Time series analysis of environmental factors and their association with emergency visits for asthma exacerbations in Petaling Jaya, Malaysia
- Authors/Creators
- Norita Hussein - University of MalayaWee Cheah - University of MalayaChun Lin - National Institute for Health and Care ResearchChng Saun Fong - University of MalayaNasrin Aghamohammadi - Curtin UniversityNik Sherina Hanafi - University of MalayaYong Kek Pang - University of MalayaMohmmad Salleh Yahya - University Malaya Medical CentreAhmad Tajuddin M. Nor - Tengku Ampuan Rahimah HospitalHilary Pinnock - National Institute for Health and Care ResearchHarry Campbell - National Institute for Health and Care ResearchEe Ming Khoo - University of MalayaRESPIRE Collaboration
- Publication Details
- Journal of global health, Vol.16, 04249
- Publisher
- International Society of Global Health
- Number of pages
- 12
- Grant note
- 16/136/109 / UK National Institute for Health Research (NIHR) (RESPIRE) using UK aid from the UK Government
- Identifiers
- 991005912898507891
- Copyright
- © 2026 The Author(s)
- Murdoch Affiliation
- School of Engineering and Energy
- Language
- English
- Resource Type
- Journal article
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