Temperature-mortality associations by age and cause: a multi-country multi-city study

Area of Science:

• Environmental Epidemiology
• Public Health
• Biostatistics

Background:

• Temperature-mortality relationships vary globally due to demographic and vulnerability differences.
• This study represents the largest epidemiological investigation into ambient temperature and mortality by age and cause.

Purpose of the Study:

• To investigate the association between ambient temperature and mortality across diverse age groups and causes of death.
• To quantify temperature-related mortality risks by cause and age globally.

Main Methods:

• Utilized daily temperature and mortality data from 532 cities in 33 countries.
• Employed quasi-Poisson regression and multivariate meta-regression to estimate location-specific and pooled temperature-mortality associations.
• Analyzed mortality data stratified by age groups and cause of death (cardiovascular, respiratory, noncardiorespiratory).

Main Results:

• Cardiovascular and respiratory causes exhibited higher temperature-related mortality risks compared to noncardiorespiratory causes.
• Cold-related mortality risks were highest for cardiovascular causes; heat-related risks were highest for respiratory causes.
• Mortality risks generally increased with age, particularly for cold exposure and noncardiorespiratory causes, with the oldest age group (85+) showing the highest risks at both temperature extremes.

Conclusions:

• Significant age and cause-specific variations exist in temperature-mortality risks.
• Cardiorespiratory conditions are more sensitive to temperature extremes than noncardiorespiratory conditions.
• Older adults face disproportionately higher mortality risks from both heat and cold, with excess mortality fractions highest for cold exposure in this demographic.