Mortality risk attributable to high and low ambient temperature: a multicountry observational study

Area of Science:

• Environmental epidemiology
• Public health

Background:

• Previous studies estimated heat or cold-related deaths in specific countries.
• No systematic assessment covered the entire temperature range across diverse climates.

Purpose of the Study:

• Quantify total mortality burden from non-optimum ambient temperature.
• Assess relative contributions of heat, cold, moderate, and extreme temperatures.

Main Methods:

• Analyzed 74,225,200 deaths across 384 locations (1985-2012).
• Used time-series Poisson models and distributed lag non-linear models.
• Pooled results using multivariate metaregression, accounting for country-specific factors.

Main Results:

• Non-optimum temperatures accounted for 7.71% of total mortality.
• Cold temperatures caused significantly more deaths (7.29%) than heat (0.42%).
• Extreme temperatures (cold and hot) were responsible for 0.86% of mortality.

Conclusions:

• Cold weather is the primary driver of temperature-related mortality.
• Milder, non-optimum temperatures pose a greater risk than extreme temperatures.
• Findings inform public health interventions and climate change impact assessments.