dc.contributor.author | Saint-Jacques, Nathalie | |
dc.date.accessioned | 2016-08-15T15:09:05Z | |
dc.date.available | 2016-08-15T15:09:05Z | |
dc.date.issued | 2016-08-15T15:09:05Z | |
dc.identifier.uri | http://hdl.handle.net/10222/72066 | |
dc.description.abstract | Background: Nova Scotia (NS), a province of Atlantic Canada, has high rates of urinary bladder and kidney cancers. The causes driving this excess burden are unknown. Exposure to high-levels of arsenic—a naturally occurring carcinogen in drinking water—is associated with a range of health effects, including bladder and potentially, kidney cancer. The threshold at which cancer develops is uncertain at lower-levels of exposure, but recent studies suggest health risks at levels previously considered safe (i.e. current regulatory guidelines of 10 μg/L). NS arsenic-rich geology contributes to elevated levels of arsenic in some private water wells—the source upon which 45% of the population is reliant. This thesis quantifies the risk of developing urinary cancers from exposure to arsenic-contaminated drinking water; contributes knowledge about cancer risk at lower levels of exposure and sheds light on the excess of urinary cancers in NS.
Methods: First, using a meta-analytical literature review framework, this study quantifies the risk of bladder/kidney cancer at varying levels of arsenic exposure. Second, using socio-demographic data, the study develops and validates proxies to smoking to adjust for variations in cancer risk due to this important co-factor. Third, geospatial methods—Besag York and Mollié model and Local Expectation maximization algorithm—are applied to examine spatial and spatio-temporal patterns of urinary cancers in NS. Fourth, using a Bayesian approach, urinary cancer risk is modeled at levels around 10 μg/L.
Results: Based on meta-analytical findings, exposure to 10 μg/L of arsenic in drinking water may increase the risk of bladder cancer by at least 40%. Based on findings from NS, exposure to 2–5 µg/L and >5 µg/L of arsenic may increase the risk of bladder cancer by 16% and 18%, respectively and; similarly, the risk of kidney cancer by 5% and 14%, respectively
Conclusions: The study suggests an increased urinary cancer risk from exposure to arsenic-levels around regulatory limits. It also suggests that 115,000 Nova Scotians may be at an increased risk of urinary cancer due to arsenic-contaminated well water. The findings contribute to the international body of evidence suggesting the need for a reassessment of regulatory limits for arsenic in drinking water. | en_US |
dc.subject | Bladder - Cancer | en_US |
dc.subject | Kidneys - Cancer | en_US |
dc.subject | Urinary tract cancer | en_US |
dc.subject | Cancer risk | en_US |
dc.subject | Systematic review | en_US |
dc.subject | Meta-analysis | en_US |
dc.subject | Deprivation index | en_US |
dc.subject | Small-areas analysis | en_US |
dc.subject | Disease mapping | en_US |
dc.subject | BYM model | en_US |
dc.subject | Local-EM algorithm | en_US |
dc.subject | Geostatistical analysis | en_US |
dc.title | RISK OF URINARY TRACT CANCER FROM EXPOSURE TO ARSENIC IN DRINKING WATER | en_US |
dc.date.defence | 2016-07-29 | |
dc.contributor.department | Interdisciplinary PhD Programme | en_US |
dc.contributor.degree | Interdisciplinary PhD | en_US |
dc.contributor.external-examiner | Dr. Christopher Brunsdon | en_US |
dc.contributor.graduate-coordinator | Dr. Lynne Robinson | en_US |
dc.contributor.thesis-reader | Dr. Patrick Brown | en_US |
dc.contributor.thesis-reader | Dr. Mark Gibson | en_US |
dc.contributor.thesis-supervisor | Dr. Louise Parker | en_US |
dc.contributor.thesis-supervisor | Dr. Trevor JB Dummer | en_US |
dc.contributor.ethics-approval | Received | en_US |
dc.contributor.manuscripts | Yes | en_US |
dc.contributor.copyright-release | Not Applicable | en_US |