Table 2

Cumulative relative risks (RRs) and 95% CIs for cold and heat effects on daily hospitalisations for coronary heart disease (CHD), acute myocardial infarction (AMI), stroke and ischaemic stroke over a lag of 21 days in Ontario, Canada, 1996–2013

Cardiovascular-related hospitalisations	Percentile of the optimal temperature*	Cold effect†		Heat effect‡
		RR (95% CI)		RR (95% CI)
		1^st versus 25^th	1^st versus optimal temperature	99^th versus 75^th	99^th versus optimal temperature
CHD	79	1.06 (1.01 to 1.10)	1.09 (1.01–1.16)	1.06 (1.01 to 1.11)	1.06 (1.01–1.11)
AMI	94	1.09 (1.03 to 1.16)	1.29 (1.15–1.45)	0.99 (0.92 to 1.06)	1.01 (0.96–1.05)
Stroke	74	1.09 (1.01 to 1.18)	1.11 (1.01–1.22)	1.08 (0.99 to 1.17)	1.08 (0.99–1.17)
Ischaemic stroke	76	1.06 (0.96 to 1.17)	1.12 (0.97–1.28)	1.07 (0.96 to 1.19)	1.12 (0.97–1.18)

*The temperature corresponding to the lowest risk from the pooled Ontario-wide temperature-hospitalisation curve.
†RRs associated with the 1^st percentile of temperature distribution relative to the 25^th percentile and the optimal temperature, respectively.
‡RRs associated with the 99^th percentile of temperature distribution relative to the 75^th percentile and the optimal temperature, respectively.