Table 3 Interaction between CO and meteorological factors on risk of stroke hospitalization.

Hemorrhagic stroke

 Temperature

Medium

Low

Reference layer

Reference layer

Reference layer

Reference layer

Reference layer

High

0.992 (0.946–1.041)

1.001 (0.941–1.066)

0.983 (0.918–1.052)

0.982 (0.925–1.043)

1.007 (0.936–1.085)

Low

Low

1.003 (0.858–1.172)

1.052 (0.861–1.286)

0.9501 (0.756–1.193)

1.036 (0.855–1.255)

0.954 (0.741–1.227)

High

1.033 (0.924–1.155)

1.035 (0.895–1.198)

1.031 (0.88–1.2101)

1.1104 (0.968–1.273)

0.914 (0.763–1.095)

RERI^a

0.038 (− 0.058 to 0.12)

− 0.018 (− 0.154 to 0.093)

0.097 (− 0.035 to 0.206)

0.092 (− 0.025 to 0.188)

− 0.047 (− 0.217 to 0.086)

High

Low

0.893 (0.793–1.007)*

0.913 (0.782–1.066)

0.874 (0.736–1.038)

0.908 (0.781–1.055)

0.872 (0.726–1.048)

High

0.938 (0.774–1.137)

0.955 (0.744–1.226)

0.921 (0.698–1.214)

0.9305 (0.728–1.188)

0.9505 (0.7104–1.271)

RERI^b

0.05 (0.033–0.086)*

0.042 (0.023–0.095)*

0.058 (0.038–0.117)*

0.038 (0.02–0.087)*

0.067 (0.045–0.134)*

 Relatively humidity

Medium

Low

Reference layer

Reference layer

Reference layer

Reference layer

Reference layer

High

0.995 (0.949–1.043)

0.985 (0.926–1.047)

1.006 (0.941–1.076)

0.995 (0.938–1.055)

0.995 (0.925–1.071)

Low

Low

1.014 (0.908–1.132)

1.008 (0.871–1.167)

1.0203 (0.872–1.193)

0.941 (0.816–1.085)

1.128 (0.957–1.329)

High

1.201 (1.062–1.359)

1.189 (1.011–1.399)

1.214 (1.018–1.447)

1.111 (0.948–1.303)

1.343 (1.116–1.616)

RERI^a

0.192 (0.184–0.205)*

0.196 (0.185–0.214)*

0.1877 (0.178–0.205)*

0.175 (0.163–0.194)*

0.22 (0.216–0.234)*

High

Low

1.0005 (0.873–1.145)

1.037 (0.868–1.238)

0.963 (0.794–1.168)

1.066 (0.904–1.256)

0.896 (0.719–1.117)

High

0.917 (0.814–1.033)

0.939 (0.805–1.095)

0.893 (0.753–1.061)

0.967 (0.835–1.121)

0.846 (0.702–1.021)

RERI^b

− 0.071 (− 0.147 to − 0.001)*

− 0.077 (− 0.185 to 0.016)

− 0.066 (− 0.173 to 0.028)

− 0.082 (− 0.178 to 0.005)

− 0.045 (− 0.167 to 0.058)

Ischemic stroke

 Temperature

Medium

Low

Reference layer

Reference layer

Reference layer

Reference layer

Reference layer

High

1.02 (0.978–1.063)

1.013 (0.969–1.059)

1.035 (0.987–1.086)

1.018 (0.974–1.063)

1.022 (0.975–1.071)

Low

Low

1.008 (0.884–1.148)

0.951 (0.826–1.095)

1.139 (0.986–1.316)

1.051 (0.918–1.202)

0.9603 (0.827–1.115)

High

0.987 (0.896–1.087)

0.969 (0.874–1.073)

1.031 (0.922–1.152)

0.969 (0.875–1.073)

1.008 (0.904–1.123)

RERI^a

− 0.041 (− 0.124 to 0.034)

0.005 (− 0.081 to 0.079)

− 0.143 (− 0.25 to − 0.051)*

− 0.1 (− 0.192 to − 0.017)*

0.0257 (− 0.063 to 0.102)

High

Low

0.909 (0.828–0.997)

0.902 (0.817–0.996)

0.924 (0.832–1.026)

0.912 (0.828–1.005)

0.905 (0.816–1.005)

High

0.961 (0.811–1.138)

0.972 (0.812–1.163)

0.936 (0.768–1.141)

1.002 (0.842–1.192)

0.913 (0.7501–1.112)

RERI^b

0.035 (0.006–0.08)*

0.059 (0.027–0.111)*

− 0.021 (− 0.05 to 0.031)*

0.076 (0.042–0.128)*

− 0.013 (− 0.0409 to 0.038)

 Relatively humidity

Medium

Low

Reference layer

Reference layer

Reference layer

Reference layer

Reference layer

High

1.023 (0.982–1.066)

1.028 (0.985–1.074)

1.011 (0.964–1.06)

1.021 (0.978–1.066)

1.025 (0.979–1.074)

Low

Low

0.995 (0.903–1.097)

1.012 (0.912–1.122)

0.959 (0.857–1.074)

0.987 (0.89–1.094)

1.005 (0.901–1.121)

High

1.023 (0.918–1.141)

1.022 (0.911–1.147)

1.026 (0.906–1.162)

1.004 (0.894–1.126)

1.045 (0.927–1.178)

RERI^a

0.005 (− 0.022 to 0.033)

− 0.018 (− 0.049 to 0.014)

0.056 (0.028–0.085)*

− 0.004 (− 0.036 to 0.026)

0.015 (− 0.017 to 0.047)

High

Low

1.012 (0.905–1.131)

1.023 (0.909–1.152)

0.987 (0.868–1.123)

0.992 (0.881–1.117)

1.034 (0.913–1.171)

High

0.919 (0.828–1.019)

0.904 (0.809–1.011)

0.952 (0.845–1.073)

0.925 (0.828–1.032)

0.912 (0.811–1.025)

RERI^b

− 0.115 (− 0.176 to − 0.058)*

− 0.147 (− 0.214 to − 0.084)*

− 0.043 (− 0.107 to 0.015)

− 0.088 (− 0.151 to − 0.031)*

− 0.144 (− 0.216 to − 0.079)*