Project 458884

Arsenic is an established carcinogen for the skin, bladder and lungs; however, the impact of arsenic exposure on cancer risk at other sites, including the breast, remains inconclusive. Recently, our team found a highly significant, increased risk of breast cancer among women with the highest levels of blood arsenic. This study was conducted in a country with low levels of arsenic exposure, suggesting that even at low doses, arsenic may be an important risk factor for breast, and potentially other cancers. Importantly, the primary source of arsenic within these populations remains unclear. In Canada (and other countries), the impact of arsenic exposure on total and site-specific cancer risk is also unknown. Therefore, the overarching aim of this project is to: (1) identify key predictors of arsenic status, and (2) delineate the overall, and site-specific, cancer risk associated with arsenic exposure, in two populations with low levels of arsenic. To assess the Canadian predictors of arsenic status, exposure data will be extracted from the Canadian Health Measures Survey, and arsenic levels will be quantified using total blood and urinary arsenic biomarkers. A critical, novel linkage to the Canadian Cancer Registry will be performed to ascertain incident cancers for this cohort. Expanding on our previous publication with the International Hereditary Cancer Centre in Poland, the second study will examine predictors of arsenic status in a cohort of 1,702 Polish women. Multivariable regression will be used to determine predictors of arsenic status, and Cox proportional hazards modelling will be used to estimate the association between arsenic levels and cancer risk. Results from this proposal will provide essential insight into key sources of arsenic and validate cancer risk associated with this environmental carcinogen. Ultimately, this information is needed to develop critical population-level intervention strategies to reduce the Canadian, and global burden of cancer.