Cardio-oncology & otherResearch article
Compound Exposure to Extreme Heat and Substantial Landscape Fire-Sourced Air Pollution on Cardiovascular Mortality
- Multicountry time-series study
- 6 countries
- quasi-Poisson regression
- additive interaction (RERI, attributable proportion, synergy index)
Authors' conclusion
Compound exposure to heat waves and SFAP was associated with higher cardiovascular mortality than single exposures, with stronger additive interaction signals for HF.
Study context
- Population
- National representative daily cardiovascular disease (CVD) mortality data across 6 countries
- Participants
- 5.9 million CVD death records
- Comparison
- Compound heat wave + SFAP exposure vs single-hazard exposure vs no hazard
- Outcome
- CVD mortality
Main finding
As reported in the abstract
CV mortality
Each group vs no hazardRelative risk (95% CI)
Compound exposure11.5% increase
1.115(1.100–1.130)
Heat wave-only
1.083(1.074–1.091)
SFAP-only
1.014(1.008–1.021)
- Compound exposure · modest positive additive interaction; 1.598% (95% CI: 0.181%-3.129%) of CV mortality on compound exposure days
- RERI 0.018 (95% CI 0.002–0.035)
Further findings
| Outcome | RR (95% CI) | |
|---|---|---|
| HF mortality — Compound exposure vs No hazard | 1.245 (1.191–1.301) | |
| 0.512Relative risk (log scale) |
| Outcome | RERI (95% CI) |
|---|---|
| HF mortality — Compound exposure vs No hazard | 0.096 (0.040–0.161) |
- Heart failure (HF) mortality: 7.731% (95% CI: 3.293%-12.488%) of HF deaths on compound exposure days attributable to additive interaction
Ischemic heart disease and stroke mortality
- Smaller but positive interaction effects
Interaction by country
- Interaction magnitude varied across countries; largest in Australia
Sensitivity analyses
- Consistent across alternative buffering windows and heat wave definitions; effects attenuated modestly with wider buffers
Original publication
Compound Exposure to Extreme Heat and Substantial Landscape Fire-Sourced Air Pollution on Cardiovascular Mortality. J Am Coll Cardiol. Published 29 July 2026. doi:10.1016/j.jacc.2026.06.005
Summarised from the published abstract; every number is checked against it