Mortality risks associated with floods in 761 communities worldwide: time series study

Area of Science:

• Environmental epidemiology
• Public health
• Global health

Background:

• Floods are increasing globally due to climate change.
• Understanding the health impacts of floods is crucial for public health preparedness.

Purpose of the Study:

• To evaluate the lag-response associations between flood exposure and mortality risks.
• To assess effect modifications of flood exposure on all-cause, cardiovascular, and respiratory mortality globally.

Main Methods:

• A multi-country time series study analyzed data from 761 communities across 35 countries.
• Quasi-Poisson models with distributed lag non-linear functions were used to assess mortality risks.
• Random effects meta-analyses pooled community-specific associations.

Main Results:

• Mortality risks increased for up to 60 days post-flood, with cumulative relative risks of 1.021 (all-cause), 1.026 (cardiovascular), and 1.049 (respiratory).
• Associations varied by country, climate type, socioeconomic status, and age, being stronger in low-income countries and among older populations.
• Floods were attributed to 0.10% of all-cause, 0.18% of cardiovascular, and 0.41% of respiratory deaths.

Conclusions:

• Flood exposure is linked to sustained increases in mortality risks.
• Climate type, socioeconomic status, and population age modify flood-related mortality risks.
• Public health interventions should consider these factors for vulnerable populations.