Fig. 1

Incident rate ratios (IRR) for cardiovascular emergency hospitalization considering three exposures: cold spells, cold spells and the next 3 days, and cold spells and the next 7 days. All models were adjusted by age, fortnight and air pollution. Results are shown stratified by gender, age groups and cardiovascular (CV) event type. ^aAge groups used for adjustment in models restricted to population < 65 years old: 18–35, 36–55; 56–64. ^bAge groups used for adjustment in models restricted to population ≥65 years old; 65–70, 71–75, 76–80, >80