Spatial variations in ambient ultrafine particle concentrations and the risk of incident prostate cancer: A case-control study

Background Diesel exhaust contains large numbers of ultrafine particles (UFPs, <0.1 µm) and is a recognized human carcinogen. However, epidemiological studies have yet to evaluate the relationship between UFPs and cancer incidence. Methods We conducted a case-control study of UFPs and incident prostate cancer in Montreal, Canada. Cases were identified from all main Francophone hospitals in the Montreal area between 2005 and 2009. Population controls were identified from provincial electoral lists of French Montreal residents and frequency-matched to cases using 5-year age gr

Does urban vegetation reduce temperature and air pollution concentrations? Findings from an environmental monitoring study of the Central Experimental Farm in Ottawa, Canada

Urban greenness, or vegetation, plays an important role in reducing ambient air pollution and urban heat island temperatures. While several studies have developed land use regression surfaces to describe the intra-urban variability of these environmental exposures, it is less well known how green spaces modify these surfaces. In this study, we investigated these environmental benefits of green spaces for the Canadian Central Experimental Farm, a 4 km2 agricultural facility, located adjacent to the urban core of Ottawa, Canada. Fall, winter and summer mobile monitoring campaigns were conducted in 2016/17 within a 40 km2 area centered on the CEF to characterize the spatial variability of: fine particulate matter (PM2.5), ultrafine particles (UFPs), black carbon (BC) and temperature. We concurrently measured two routes each morning (09:30-10:30) and evening (17:00-18:00) for 14 consecutive days in the three seasons. Median exposure levels for each road segment were calculated and used as inputs for season-specific land use regression models. These models were developed for each combination of environmental variable (PM2.5, UFP, BC, and temperature) and season (fall, winter, and summer). Predictors included land and road types as well as season-specific urban greenness represented by the Normalized Difference Vegetation Index (NDVI). Levels and spatial patterns of air pollution and temperature varied by season. We characterized the spatial relationship between the CEF and ambient air pollution and temperature measures by developing linear regression models with the distance to the closest border of the farm as the main predictor. Other land use variable whic

Dietary patterns and the risk of female breast cancer among participants of the Canadian national enhanced cancer surveillance system

Objectives: The role of diet in the etiology of breast cancer is not well understood despite extensive research. In the majority of this work, a single nutrientbased approach has been used which does not take into account combinations of food that are consumed. An alternative to the single nutrient approach is to identify patterns in the dietary intake information and relate these patterns to disease incidence. This investigation characterized dietary patterns among participants of a Canadian case-control study and related these dietary patterns to the incidence of breast cancer. Methods: Dietary and other risk factor data from cases and controls of the Canadian National Enhanced Cancer Surveillance System were collected using self-administered questionnaires. Principal component factor analysis was used to classify individuals based on their dietary patterns. The relationship between these dietary patterns and breast cancer was evaluated using logistic regression. The derived odds ratios and their 95% confidence limits were adjusted for several factors, such as smoking, alcohol intake, environmental tobacco smoke exposure and obesity. Results: In the 2,009 cases and 2,086 controls, three dietary patterns were identified: western, healthy and vitamin. The highest quartile of the “healthy” dietary pattern was related to a 22% decrease in breast cancer risk (95% CI: 0.61–1.00), relative to the lowest quartile. The fourth quartile of the “vitamin” dietary pattern was associated with a 14% decrease in breast cancer risk (95% CI: 0.70–1.04) relative to the first. No statistically significant associations between the “western” dietary pattern and breast cancer were found. These associations were neither confounded nor modified by menopausal status. Conclusion: Our analyses reveal that individual dietary items tend to cluster together in such a way that there are three distinct dietary patterns in this sample of Canadian women. Some of these patterns, in turn, were associated with the risk of breast cancer

The influence of three e-cigarette models on indoor fine and ultrafine particulate matter concentrations under real-world conditions

Electronic cigarette (e-cigarette) use has steadily increased since 2010. Indoor e-cigarette use exposes bystanders to a new source of particulate matter (PM) air pollution. Elevated short-term exposures to PM with a lower measuremented aerodynamic diameter (≤2.5 μm), PM2.5 and ultrafine particles (UFPs) have been linked to increased risk of adverse respiratory and cardiac events. This exposure study estimated concentrations of PM2.5 and UFPs from indoor e-cigarette use at 0.5 meters (m) and 1 m away from an e-cigarette user and investigated whether these indoor concentrations varied across three common e-cigarette models. One e-cigarette user tested three different e-cigarettes containing the same nicotine solution on three separate occasions and measured concentrations on PM2.5 and UFPs at 0.5 and 1 m in a ∼38 m3 office. Continuous measures of PM2.5 and UFPs were taken for 5.5 min before e-cigarette use, then the user puffed seven times for 6.5 min (exposure), and for 10 min after ceasing e-cigarette use. Following the initiation of e-cigarette use, levels of PM2.5 increased 160-fold at a distance of 0.5 m, and 103-fold at 1 m. The corresponding increases in UFP counts were 5.2, and 3.0-fold higher, respectively. The PM2.5 concentrations and UFP counts between e-cigarette models were statistically significantly different at 1 m, but not at 0.5 m. There was substantial variability between distances, e-cigarettes, and replicates. This study indicates that e-cigarette vapors influence PM2.5 and UFPs concentrations/counts at close proximity distances indoors; additional research is needed to characterize the composition of those particles and evaluate the impacts of other e-cigarette solutions on indoor air quality. Fine particle pollution concentrations at 0.5 and 1 m away from one e-cigarette user were substantially higher than baseline concentrations and demonstrated distinguishable peaks in concentrations following the exhalation of e-cigarette vapors