Risk and burden of hospital admissions associated with wildfire-related PM2·5 in Brazil, 2000–15: a nationwide time-series study

Abstract

Background In the context of climate change and deforestation, Brazil is facing more frequent and unprecedented wildfires. Wildfire-related PM 2•5 is associated with multiple adverse health outcomes; however, the magnitude of these associations in the Brazilian context is unclear. We aimed to estimate the association between daily exposure to wildfire-related PM 2•5 and cause-specific hospital admission and attributable health burden in the Brazilian population using a nationwide dataset from 2000 to 2015.Methods In this nationwide time-series analysis, data for daily all-cause, cardiovascular, and respiratory hospital admissions were collected through the Brazilian Unified Health System from 1814 municipalities in Brazil between Jan 1, 2000, and Dec 31, 2015. Daily concentrations of wildfire-related PM 2•5 were estimated using the 3D chemical transport model GEOS-Chem at a 2•0° latitude by 2•5° longitude resolution. A time-series analysis was fitted using quasi-Poisson regression to quantify municipality-specific effect estimates, which were then pooled at the regional and national levels using random-effects meta-analyses. Analyses were stratified by sex and ten age groups. The attributable fraction and attributable cases of hospital admissions due to wildfire-related PM 2•5 were also calculated. FindingsAt the national level, a 10 μg/m³ increase in wildfire-related PM 2•5 was associated with a 1•65% (95% CI 1•51-1•80) increase in all-cause hospital admissions, a 5•09% (4•73-5•44) increase in respiratory hospital admissions, and a 1•10% (0•78-1•42) increase in cardiovascular hospital admissions, over 0-1 days after the exposure. The effect estimates for all-cause hospital admission did not vary by sex, but were particularly high in children aged 4 years or younger (4•88% [95% CI 4•47-5•28]), children aged 5-9 years (2•33% [1•77-2•90]), and people aged 80 years and older (3•70% [3•20-4•20]) compared with other age groups. We estimated that 0•53% (95% CI 0•48-0•58) of allcause hospital admissions were attributable to wildfire-related PM 2•5 , corresponding to 35 cases (95% CI 32-38) per 100 000 residents annually. The attributable rate was greatest for municipalities in the north, south, and centralwest regions, and lowest in the northeast region. Results were consistent for all-cause and respiratory diseases across regions, but remained inconsistent for cardiovascular diseases.Interpretation Short-term exposure to wildfire-related PM 2•5 was associated with increased risks of all-cause, respiratory, and cardiovascular hospital admissions, particularly among children (0-9 years) and older people (≥80 years). Greater attention should be paid to reducing exposure to wildfire smoke, particularly for the most susceptible populations.

Short-term exposure to wildfire-related PM2.5 increases mortality risks and burdens in Brazil

“…We observed geographic variation in the relationship between wildfire-related PM 2.5 exposure and mortality, with individuals in the Southeast most susceptible, whereas those in the North and Northeast were less susceptible to wildfire-related PM 2.5 . Similar result has been reported in our previous study for hospital admissions 19 .…”

Exposure to landscape fire smoke reduced birthweight in low- and middle-income countries: findings from a siblings-matched case-control study

“…Since fire-sourced PM 2.5 is mixed with particles from other sources, it cannot be easily measured. Although the CTM-based approach has been widely utilized in a few large-scale studies ( Xue et al, 2021a ; Ye et al, 2021 ) to assess the LFS exposure, accuracy of its results cannot be evaluated directly. Therefore, in this study, we assessed the overall performance of the GEOS-Chem model by comparing the simulated PM 2.5 concentrations with the satellite-based estimates ( van Donkelaar et al, 2016 ).…”

Protecting Cardiovascular Health From Wildfire Smoke

“…49 A recent time-series analysis of 148 million hospital admissions across Brazil from 2000 to 2015 found that cardiovascular hospital admissions in the day after exposure were higher by 1.1% (95% CI, 0.8 to 1.4) per 10 μg/m³ increase in wildfire-related PM 2.5 . 47 A separate meta-analysis found that smoky days were associated with a 5.5% elevated risk of hospitalization for ischemic heart disease, although the CI crossed the null (95% CI, 0.8 to 10.1). 50 Severe wildfire events may result in hospitals exceeding capacity: a recent study projected that a simulated severe 7-day wildfire smoke event (120 µg/m 3 ) would raise local intensive care unit admissions by 131%.…”