BACKGROUND:
Climate change has increased the frequency and severity of extreme temperature events, significantly impacting health, particularly among older adults. However, comprehensive quantitative evidence on the health impacts of extreme temperatures, including extreme heat, heatwaves, extreme cold, and cold spells, remains limited.

METHODS:
This systematic review and meta-analysis quantitatively assessed the global associations between extreme temperature exposure and health outcomes among older adults (≥60 years). We analyzed the impacts on mortality, morbidity, and healthcare utilization based on data from 176 studies, categorizing extreme temperature events into six distinct exposure types.

RESULTS:
Each 1°C rise in ambient temperature was associated with a 2.4% increase in excess mortality risk among older adults (RR = 1.024, 95% CI: 1.013–1.034, n = 89). Extreme heat (above the 90th percentile) further elevated mortality risk by 25% (RR = 1.25, 95% CI: 1.18–1.32), while heatwave events increased it by 23% (RR = 1.23, 95% CI: 1.15–1.30). Each 1°C decrease in temperature raised mortality risk by 2.5% (RR = 1.025, 95% CI: 1.014–1.036). Exposure to extreme cold temperatures (below the 10th percentile) and cold spells significantly increased mortality risks by 24% (RR = 1.24, 95% CI: 1.16–1.33) and 34% (RR = 1.34, 95% CI: 1.25–1.43), respectively. Extreme temperatures notably increased morbidity and mortality risks related to circulatory and respiratory diseases, alongside heightened demands for emergency and hospital care. The IPCC uncertainty framework classified this evidence as having medium to high agreement and confidence.

CONCLUSIONS:
This review provides robust evidence highlighting that increasingly frequent and intense extreme temperature events pose substantial health threats to older adults. Strengthening protective public health measures and integrating them into climate adaptation strategies is urgently required.