Extreme temperature exposure and acute myocardial infarction: Elevated risk within hours?

Area of Science:

• Environmental Health
• Cardiology
• Epidemiology

Background:

• Ambient temperature variability is linked to acute myocardial infarction (AMI) risk.
• Limited data exists on the immediate impact of extreme temperatures on AMI occurrence.

Purpose of the Study:

• To investigate the hour-level associations between extreme ambient temperatures and AMI risk.
• To identify vulnerable subgroups susceptible to temperature-related cardiac events.

Main Methods:

• Utilized state-wide AMI patient data and temperature records from Queensland, Australia (2013-2015).
• Employed a fixed time-stratified case-crossover analysis to assess AMI risk within 24 hours of temperature exposure.
• Conducted subgroup analyses based on age, gender, and pre-existing disease conditions.

Main Results:

• Cold exposure showed acute effects on AMI risk for men (9-10h), women (19-22h), and the elderly (4-20h).
• Elevated AMI risk was observed following cold exposure in men (OR=2.1), women (OR=2.5), and the elderly (OR=2.0).
• Heat exposure elevated AMI risk later: 15h for men (OR=3.9) and 23h for adults (OR=4.1).
• Specific populations, including the elderly with diabetes/hyperlipidemia and certain male/female subgroups, exhibited heightened vulnerability to cold and heat, respectively.

Conclusions:

• Extreme temperature fluctuations pose an acute risk for AMI, with distinct temporal patterns for cold and heat exposure.
• Vulnerability to temperature extremes varies significantly across demographic and clinical subgroups.
• Incorporating sub-daily temperature variations into prevention strategies is crucial for mitigating cardiac events.