Extreme weather and mortality among a nationwide cohort of Veterans with COPD

Abstract

Climate change is increasing the frequency, severity and duration of extreme weather events. Individuals with climate sensitive diseases such as chronic respiratory diseases are at an enhanced risk of health challenges due to climate change. However, there is a lack of individual level studies examining how extreme weather events such as heat and cold waves may increase the risk of mortality among individuals with chronic obstructive pulmonary disease (COPD), a climate sensitive respiratory disease. Using nationwide individual level health data from the Veterans Health Administration, three studies were designed to estimate heat and cold wave associated mortality risk among this susceptible population.The first study evaluated heat and cold wave mortality risk among the entire population of patients with COPD and examined health disparities by individual characteristics including gender, age, race and ethnicity. Results indicated cisgender females had an increased heatwave associated mortality risk. While some racial disparities in mortality risk were detected, the evidence was weak. The second study further examined disparities in heat and cold wave associated mortality via less commonly studied effect measure modifiers including comorbidities, smoking status and urbanicity. Patients with concurrent COPD and asthma had a greater risk of heatwave related mortality whereas patients with COPD alone had the greatest cold wave associated mortality risk. Smokers and patients living in urban settings had enhanced risk of both heat and cold wave related mortality. The third study assessed the added mortality risk incurred during compound climate hazards (droughts and heatwaves) among this susceptible population. Results indicated heatwaves that occurred during droughts had larger mortality risks compared to heatwaves during non-drought conditions. These three studies provide evidence that individuals with COPD are at risk of adverse health events from heat and cold waves and identified heterogeneities in risk based on characteristics including social, biological and geographical constructs. There is an apparent need in climate and health epidemiology for more large-scale individual level assessments of people with climate sensitive diseases. As contemporary impacts of climate change are realized, it is imperative to devote resources and energy into elucidating health risks associated with extreme weather events to identify and protect at-risk segments of the population.