Ambient particulate matter air pollution exposure and ovarian cancer incidence in the USA: An ecological study.

Objective: To investigate associations between air particulate matter of ≤2.5 μm in diameter (PM _2.5 ) and ovarian cancer.
Design: County-level ecological study.
Setting: Surveillance, epidemiology, and end results from a collection of state-level cancer registries across 744 counties. Data from the Environmental Protection Agency's network for PM _2.5 monitoring was used to calculate trailing 5- and 10-year PM _2.5 county-level values. County-level data on demographic characteristics were obtained from the American Community Survey.
Population: A total of 98 751 patients with histologically confirmed ovarian cancer as a primary malignancy from 2000 to 2016.
Methods: Generalised linear regression models were developed to estimate the association between PM _2.5 and PM ₁₀ levels, over 5- and 10-year periods of exposure, and ovarian cancer risk, after accounting for county-level covariates.
Main Outcome Measures: Risk ratios for associations between ovarian cancer (both overall and specifically epithelial ovarian cancer) and PM _2.5 levels.
Results: For the 744 counties included, the average PM _2.5 level from 1990 through 2018 was 11.75 μg/m ³ (SD = 3.7) and the average PM ₁₀ level was 22.7 μg/m ³ (SD = 5.7). After adjusting for county-level covariates, the overall annualised ovarian cancer incidence was significantly associated with increases in 5-year PM _2.5 (RR = 1.11 per 10 units (μg/m ³ ) increase, 95% CI 1.06-1.16). Similarly, when the analysis was limited to epithelial cell tumours and adjusted for county-level covariates there was a significant association with trailing 5-year PM _2.5 exposure models (RR = 1.12 per 10 units increase, 95% CI 1.08-1.17). Likewise, 10-year PM _2.5 exposure was associated with ovarian cancer overall and with epithelial ovarian cancer.
Conclusions: Higher county-level ambient PM _2.5 levels are associated with 5- and 10-year incidences of ovarian cancer, as measurable in an ecological study.
(© 2023 John Wiley & Sons Ltd.)