390 Geographical and Environmental Factors Associated with Melanoma Incidence in Canada

Background: We sought to examine the relationship between environmental factors and Canada's distribution of melanoma incidence between 1992 and 2010. Methods: Data was obtained from the Canadian Cancer Registry, Canadian Vital Statistics, and the Canadian Urban Environmental Health Research Consortium. Crude melanoma incidence rates were obtained for forward sortation areas (FSAs). Enviromental variables included: normalized difference vegetation index (NDVI) as a proxy for green space, precipitation, yearly temperature, and number of weather events between 1992-2010. Environmental exposures were modeled as tertiles via a two-level random-effect generalized linear model to evaluate a dose-response relationship. Results: Across Canada, average annual temperature increased significantly over time (p < 0.0001). Other significant increases included: absolute annual temperature, average amount of precipitation, as well as the average number of weather events of heat and rain. Greatest increases were observed in Newfoundland, PEI and Manitoba. A positive significant relationship between annual average temperature and melanoma incidence rate was confirmed (Beta: 6.23, 95%CI: 5.2, 9.93). With each increase in NDVI, the odds of melanoma doubled in high-risk FSAs compared to those with low-risk (OR: 2.72, 95%CI: 2.49, 2.97; & OR = 4.31, 95%CI: 3.91, 4.76; for tertiles 2 and 3 respectively). Discussion: Consistent strong positive relationships between the changes in enviromental exposures and melanoma incidence were observed in this study. High ambient temperature leads to more time outdoors, less protective clothing, and greater number of sunburns. The presence of parks with an abundance of foliage may encourage the public to spend more time outdoors increasing UVR exposure. Public health advice may be improved by taking account of both temperature and green space accesibility and their implications for behaviour.