Table 2. Risk ratio (95% CI) of the 2010 heat wave on stroke mortality in Nanjing.

Region	Heat wave cases	Reference period casesa	RRb
Urban districts	96	102	0.94(0.76,1.15)
Suburban districts	125	105.5	1.18(0.99,1.41)
Rural districts	197	104.5	1.89(1.63,2.17)
Nanjing	418	312	1.34(1.21,1.47)

^aUsing average cases of A2 period and A3 period.

^bRR was calculated as the ratio between stroke deaths in the heat wave and in the reference period.