<b>Short-term exposure to wildfire-specific PM</b><sub><strong>2.5</strong></sub><b> and hospitalization for diabetes morbidity: a study in multiple countries/territories</b>

Abstract

<p dir="ltr">Objective</p><p dir="ltr">To evaluate associations of wildfire fine particulate matter (PM2.5) with diabetes across multi-countries/territories. </p><p dir="ltr">Research Design and Methods</p><p dir="ltr">We collected 3,612,135 diabetes hospitalization data across 1008 locations in Australia, Brazil, Canada, Chile, New Zealand, Thailand, and Taiwan during 2000‒2019. Daily wildfire-specific PM2.5 were estimated through chemical transport models and machine learning calibration. Quasi-Poisson regression with distributed lag non-linear models and random-effects meta-analysis were applied to estimate associations between wildfire-specific PM2.5 and diabetes hospitalization. Subgroup analyses were by age, sex, location income-level, and country/territory. Diabetes hospitalizations attributable to wildfire-specific PM2.5 and non-wildfire PM2.5 were compared. </p><p dir="ltr">Results</p><p dir="ltr">Each 10 µg/m3 increase in wildfire-specific PM2.5 over the current and previous three days was associated with relative risks of 1.017 (95% confidence interval [CI]: 1.011‒1.022), 1.023 (1.011‒1.035), 1.023 (1.015‒1.032), 0.962 (0.823‒1.032), 1.033 (1.001‒1.066), 1.013 (1.004‒1.022) for all-cause, type 1, type 2, malnutrition-related, other specified, and unspecified diabetes hospitalization, respectively. Stronger associations were observed for all-cause, type 1, and type 2 diabetes in Thailand, Australia, and Brazil; unspecified diabetes in New Zealand; and type 2 diabetes in high-income locations. 0.67% (0.16%‒1.18%) all-cause and 1.02% (0.20%‒1.81%) type 2 diabetes hospitalizations were attributable to wildfire-specific PM2.5. Wildfire-specific PM2.5 posed greater risks of all-cause, type 1, and type 2 diabetes than non-wildfire PM2.5, responsible for 38.7% of PM2.5-related diabetes hospitalizations.</p><p dir="ltr">Conclusions</p><p dir="ltr">We show the relatively underappreciated links between diabetes and wildfire air pollution, which can lead to a non-negligible proportion of PM2.5¬-related diabetes hospitalizations. Precision prevention and mitigation should be developed for those in advantaged communities, or Thailand/Australia/Brazil</p>