Abstract P664: Radon Exposure and Cerebrovascular Disease - A Systematic Review and Meta-Analysis of Observational Studies in Occupational and General Populations

Abstract

Background: Radon is the second leading cause of lung cancer and one of the top ten causes of cancer mortality in the United States. However, research findings examining the causal relationship between radon exposure and cerebrovascular disease (CeVD) are inconsistent. Hypothesis: Although it is biologically plausible that radon in the blood stream and vascular tissue may cause vascular damage resulting in CeVD, the discrepancy in the previous research highlights a need to systematically review the existing literature. We hypothesized that there was an association between radon exposure and risk of CeVD. Methods: We searched Pubmed, Embase and Google Scholar for original studies on the association between radon and CeVD in both occupational and general populations. We systematically reviewed the literature and quantitatively summarized the available data using weighed random-effect models. Results: A total of 17 studies were identified in the systematic review, including 14 occupational studies among uranium workers. Of the 14 occupational studies, four studies were eligible for the meta-analysis (99,730 participants and 2,745 deaths). The pooled relative risk of CeVD mortality per 100 working level month (WLM) was 1.10 (95% confidence interval [CI]=0.92, 1.31). Three studies conducted in the general population consistently demonstrated a statistically significant association between cumulative residential radon exposure and the prevalence or mortality of CeVD. Conclusion: The existing literature revealed an association between radon exposure and CeVD risk in general population, but not in occupationally-exposed miners. While competing risk of lung cancer and healthy worker effect need to be evaluated in the occupational studies, more scientifically rigorous case-control or cohort studies in the general population are warranted.