Abstract
Exposure to ambient ozone (O) is linked to increased mortality risks from various diseases, but epidemiological investigations delving into its potential implications for cancer mortality are limited. We aimed to examine the association between short-term Oexposure and site-specific cancer mortality and investigate vulnerable subgroups in Brazil. In total 3,459,826 cancer death records from 5570 Brazilian municipalities between 2000 and 2019, were included. Municipal average daily Oconcentration was calculated from a global estimation at 0.25°×0.25° spatial resolution. The time-stratified case-crossover design was applied to assess the O-cancer mortality association. Subgroup analyses by age, sex, season, time-period, region, urban hierarchy, climate classification, quantiles of GDP per capita and illiteracy rates were performed. A linear and non-threshold exposure-response relationship was observed for short-term exposure to Owith cancer mortality, with a 1.00% (95% CI: 0.79%-1.20%) increase in all-cancer mortality risks for each 10-μg/mincrement of three-day average O. Kidney cancer was most strongly with Oexposure, followed by cancers of the prostate, stomach, breast, lymphoma, brain and lung. The associated cancer risks were relatively higher in the warm season and in southern Brazil, with a decreasing trend over time. When restricting Oconcentration to the national minimum value during 2000-2019, a total of 147,074 (116,690-177,451) cancer deaths could be avoided in Brazil, which included 17,836 (7014-28,653) lung cancer deaths. Notably, these associations persisted despite observed adaptation within the Brazilian population, highlighting the need for a focus on incorporating specific measures to mitigate Oexposure into cancer care recommendations.
Overview
- The study aimed to examine the association between short-term ambient ozone (O) exposure and site-specific cancer mortality in Brazil, and investigate vulnerable subgroups. The study used a time-stratified case-crossover design and included 3,459,826 cancer death records from 5570 Brazilian municipalities between 2000 and 2019. Municipal average daily O concentration was calculated from a global estimation at 0.25°×0.25° spatial resolution. Subgroup analyses were performed by age, sex, season, time-period, region, urban hierarchy, climate classification, quantiles of GDP per capita and illiteracy rates. The study found a linear and non-threshold exposure-response relationship between short-term O exposure and all-cancer mortality, with a 1.00% (95% CI: 0.79%-1.20%) increase in risks for each 10-μg/min increment of three-day average O. The study also identified specific cancers that were most strongly associated with O exposure, including kidney, prostate, stomach, breast, lymphoma, brain, and lung cancers. The study's findings highlight the need for a focus on incorporating specific measures to mitigate O exposure into cancer care recommendations, particularly in vulnerable subgroups.
Comparative Analysis & Findings
- The study compared the outcomes observed under different experimental conditions or interventions, specifically short-term ambient ozone (O) exposure and site-specific cancer mortality. The study found a linear and non-threshold exposure-response relationship between short-term O exposure and all-cancer mortality, with a 1.00% (95% CI: 0.79%-1.20%) increase in risks for each 10-μg/min increment of three-day average O. The study also identified specific cancers that were most strongly associated with O exposure, including kidney, prostate, stomach, breast, lymphoma, brain, and lung cancers. The study's findings suggest that short-term O exposure is associated with increased cancer mortality risks, and that specific cancers are more strongly associated with O exposure than others.
Implications and Future Directions
- The study's findings have significant implications for the field of research and clinical practice, as they suggest that short-term ambient ozone (O) exposure is associated with increased cancer mortality risks. The study also identified specific cancers that are more strongly associated with O exposure than others, which could inform targeted interventions to mitigate O exposure and reduce cancer risks. However, the study has limitations, such as the use of global estimation for O concentration and the potential for misclassification of cancer types. Future research could address these limitations by using more accurate and specific measures of O exposure and cancer incidence, and by examining the long-term effects of O exposure on cancer mortality.