{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T05:14:46Z","timestamp":1776402886910,"version":"3.51.2"},"reference-count":53,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,3,11]],"date-time":"2023-03-11T00:00:00Z","timestamp":1678492800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Acute ischaemic stroke (AIS) risk on days with similar environmental profiles remains unknown. We investigated the association between clusters of days with similar environmental parameters and AIS incidence in Singapore. We grouped calendar days from 2010 to 2015 with similar rainfall, temperature, wind speed, and Pollutant Standards Index (PSI) using k-means clustering. Three distinct clusters were formed \u2018Cluster 1\u2019 containing high wind speed, \u2018Cluster 2\u2019 having high rainfall, and \u2018Cluster 3\u2019 having high temperatures and PSI. We aggregated the number of AIS episodes over the same period with the clusters and analysed their association using a conditional Poisson regression in a time-stratified case-crossover design. Comparing the three clusters, Cluster 3 had the highest AIS occurrence (IRR 1.09; 95% confidence interval (CI) 1.05\u20131.13), with no significant difference between Clusters 1 and 2. Subgroup analyses in Cluster 3 showed that AIS risk was amplified in the elderly (\u226565 years old), non-smokers, and those without a history of ischaemic heart disease\/atrial fibrillation\/vascular heart disease\/peripheral vascular disease. In conclusion, we found that AIS incidence may be higher on days with higher temperatures and PSI. These findings have important public health implications for AIS prevention and health services delivery during at-risk days, such as during the seasonal transboundary haze.<\/jats:p>","DOI":"10.3390\/ijerph20064979","type":"journal-article","created":{"date-parts":[[2023,3,13]],"date-time":"2023-03-13T04:35:41Z","timestamp":1678682141000},"page":"4979","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Clustering of Environmental Parameters and the Risk of Acute Ischaemic Stroke"],"prefix":"10.3390","volume":"20","author":[{"given":"Geraldine P. Y.","family":"Koo","sequence":"first","affiliation":[{"name":"Ministry of Health Holdings, Singapore 099253, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huili","family":"Zheng","sequence":"additional","affiliation":[{"name":"National Registry of Diseases Officer, Health Promotion Board, Singapore 168937, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joel C. L.","family":"Aik","sequence":"additional","affiliation":[{"name":"Environmental Epidemiology and Toxicology Division, Environmental Health Institute, National Environment Agency, Singapore 228231, Singapore"},{"name":"Pre-Hospital & Emergency Research Center, Duke-NUS Medical School, Singapore 169857, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1824-9077","authenticated-orcid":false,"given":"Benjamin Y. Q.","family":"Tan","sequence":"additional","affiliation":[{"name":"Division of Neurology, Department of Medicine, National University Hospital, Singapore 119074, Singapore"},{"name":"Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8976-5696","authenticated-orcid":false,"given":"Vijay K.","family":"Sharma","sequence":"additional","affiliation":[{"name":"Division of Neurology, Department of Medicine, National University Hospital, Singapore 119074, Singapore"},{"name":"Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ching Hui","family":"Sia","sequence":"additional","affiliation":[{"name":"Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore"},{"name":"Department of Cardiology, National University Heart Centre Singapore, Singapore 119074, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7874-7612","authenticated-orcid":false,"given":"Marcus E. H.","family":"Ong","sequence":"additional","affiliation":[{"name":"Health Services & Systems Research, Duke-NUS Medical School, Singapore 169857, Singapore"},{"name":"Department of Emergency Medicine, Singapore General Hospital, Singapore 169608, Singapore"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4338-3876","authenticated-orcid":false,"given":"Andrew F. 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