Drought effects on specific-cause mortality in Lisbon from 1983 to 2016: Risks assessment by gender and age groups

Area of Science:

• Environmental Health
• Epidemiology
• Climate Science

Background:

• Portugal faces frequent drought, a global health concern linked to increased morbidity and mortality.
• Previous studies have not specifically assessed drought's impact on mortality in the Lisbon district.

Purpose of the Study:

• To analyze the association between drought indices (SPI and SPEI) and daily mortality in Lisbon.
• To evaluate these impacts across different genders and adult age groups (45-64, 65-74, ≥75).
• To investigate the influence of heatwaves and air pollution on drought-related mortality.

Main Methods:

• Time-series analysis from 1983 to 2016 using Standardised Precipitation Index (SPI) and Standardised Precipitation-Evapotranspiration Index (SPEI).
• Generalized linear models with Poisson link to estimate relative and attributable risks.
• Inclusion of heatwave and atmospheric pollution data (2007-2016) for a comprehensive analysis.

Main Results:

• Statistically significant links found between drought conditions and all-cause, circulatory, and respiratory mortality.
• The Standardised Precipitation-Evapotranspiration Index (SPEI) demonstrated a better capacity to reflect mortality risks.
• Older age groups (65+) faced the highest mortality risk; men were generally more affected than women.

Conclusions:

• Drought poses a significant public health risk in Lisbon, impacting mortality rates across various causes.
• Age and gender are critical factors in vulnerability to drought-related mortality.
• Understanding these associations is crucial for developing targeted public health interventions and mitigation strategies against drought impacts.