Skip to main content
. 2023 Mar 11;20(6):4979. doi: 10.3390/ijerph20064979

Table 2.

Incidence risk ratios (IRR) of AIS in Cluster 2 (high rainfall) and Cluster 3 (high temperature and PSI) compared to Cluster 1 (high wind speed).

Cluster 1 Cluster 2 Cluster 3
Number of AIS episodes 9116 13,330 6825
Average number of AIS per day 13 13 15
Entire cohort 1.00 0.98 (0.95–1.00) 1.09 (1.05–1.13) b,c
Subgroups
Age
<65 years 1.00 1.01 (0.97–1.05) 1.06 (1.01–1.12) b,c
≥65 years 1.00 0.95 (0.92–0.99) a 1.12 (1.07–1.17) b,c
Gender
Male 1.00 0.98 (0.94–1.02) 1.08 (1.04–1.14) b,c
Female 1.00 0.97 (0.93–1.01) 1.10 (1.05–1.16) b,c
Ethnicity
Chinese 1.00 0.95 (0.92–0.99) a 1.09 (1.05–1.14) b,c
Malay 1.00 1.00 (0.95–1.06) 1.05 (0.98–1.12)
Indian 1.00 1.04 (0.98–1.10) 1.03 (0.96–1.10)
History of stroke/TIA
Yes 1.00 0.96 (0.91–1.01) 1.05 (0.99–1.12)
No 1.00 0.98 (0.93–1.03) 1.07 (1.01–1.14) b,c
History of IHD/AF/VHD/PVD
Yes 1.00 0.92 (0.88–0.97) a 1.07 (1.02–1.14) b,c
No 1.00 1.02 (0.97–1.07) 1.15 (1.09–1.22) b,c
History of diabetes
Yes 1.00 1.00 (0.96–1.04) 1.10 (1.05–1.16) b,c
No 1.00 0.98 (0.94–1.03) a 1.12 (1.06–1.19) b,c
History of hypertension
Yes 1.00 0.96 (0.93–0.99) a 1.09 (1.04–1.13) b,c
No 1.00 1.01 (0.96–1.07) 1.04 (0.98–1.11)
History of hyperlipidaemia
Yes 1.00 0.95 (0.92–0.99) a 1.10 (1.05–1.15) b,c
No 1.00 1.00 (0.95–1.06) 1.07 (1.00–1.13) b,c
Current/former smoker
Yes 1.00 0.98 (0.94–1.03) 1.05 (1.00–1.11) b,c
No 1.00 0.96 (0.93–1.00) 1.12 (1.07–1.17) b,c

a Significant difference in IRR between Cluster 1 and Cluster 2 (p < 0.05). b Significant difference in IRR between Cluster 1 and Cluster 3 (p < 0.05). c Significant difference in IRR between Cluster 2 and Cluster 3 (p < 0.05). Poisson regression test was used to obtain the p-values. AIS: acute ischaemic stroke; IQR: interquartile range; TIA: transient ischaemic attack; IHD: ischaemic heart disease; AF: atrial fibrillation; VHD: valvular heart disease; PVD: peripheral vascular disease. The bolded represents a significant difference in the IRR.