Association of Short-Term Particulate Matter Exposure among 5-Year Cancer Survivors with Incident Cardiovascular Disease: A Time-Stratified Case-Crossover Study.

The association of short-term particulate matter concentration with cardiovascular disease (CVD) among cancer survivors is yet unclear. Using the National Health Insurance Service database from South Korea, the study population consisted of 22,864 5-year cancer survivors with CVD events during the period 2015-2018. Using a time-stratified case-crossover design, each case date (date of incident CVD) was matched with three or four referent dates, resulting in a total of 101,576 case and referent dates. The daily average particulate matter 10 (PM10), 2.5 (PM2.5), and 2.5-10 (PM2.5-10) on the day of case or referent date (lag0), 1-3 days before the case or referent date (lag1, lag2, and lag3), and the mean value 0-3 days before the case or referent date (lag0-3) were determined. Conditional logistic regression was conducted to calculate the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for CVD according to quartiles of PM10, PM2.5, and PM2.5-10. Compared to the 1st (lowest) quartile of lag0-3 PM10, the 4th (highest) quartile of lag0-3 PM10 was associated with higher odds for CVD (aOR 1.13, 95% CI 1.06-1.21). The 4th quartiles of lag1 (aOR 1.12, 95% CI 1.06-1.19), lag2 (aOR 1.09, 95% CI 1.03-1.16), lag3 (aOR 1.06, 95% CI 1.00-1.12), and lag0-3 (aOR 1.11, 95% CI 1.05-1.18) PM2.5 were associated with higher odds for CVD compared to the respective 1st quartiles. Similarly, the 4th quartile of lag0-3 PM2.5-10 was associated with higher CVD events (aOR 1.11, 95% CI 1.03-1.19) compared to the 1st quartile. Short-term exposure to high levels of PM may be associated with increased CVD risk among cancer survivors.