Smoothed conditional mean plots visualizing the variation of nationwide daily incidence rates of MI at different temperatures by season. Unadjusted and adjusted incidence rate ratio (IRR) and 95% CI from regression analyses are presented. Results from the regression analyses are interpreted as change per increase in standard deviation. One standard deviation of air temperature in January through March, 5.2°C; April through June, 4.4°C; July through September, 3.1°C; October through December, 5.4°C. Seasonal analyses of remaining weather parameters are shown in eTable 3 in the Supplement. IRR1 indicates univariable model; IRR2, multivariable model; NSTEMI, non–ST-elevation MI; and STEMI, ST-elevation MI.
aP < .05.
bP < .01.
cP < .001.