Long-term exposure to airborne metals and risk of cancer in the French cohort Gazel.

BACKGROUND: The specific compounds that make ambient fine particulate matter (PM2.5) carcinogen remain poorly identified. Some metals contribute to ambient PM2.5 and possibly to its adverse effects. But the challenge of assessing exposure to airborne metals limits epidemiological studies. OBJECTIVE: To analyze the relationships between several airborne metals and risk of cancer in a large population. METHODS: We estimated the individual exposure to 12 airborne metals of âˆ¼ 12,000 semi-urban and rural participants of the French population-based Gazel cohort using moss biomonitoring data from a 20-year national program. We used principal component analyses (PCA) to derive groups of metals, and focused on six single carcinogenic or toxic metals (arsenic, cadmium, chromium, lead, nickel, and vanadium). We used extended Cox models with attained age as time-scale and time-varying weighted average exposures, adjusted for individual and area-level covariables, to analyze the association between each exposure and all-site combined, bladder, lung, breast, and prostate cancer incidence. RESULTS: We identified 2,401 cases of all-site cancer between 2001 and 2015. Over the follow-up, median exposures varied from 0.22 (interquartile range (IQR): 0.18-0.28) to 8.68 (IQR: 6.62-11.79) µg.g-1 of dried moss for cadmium and lead, respectively. The PCA yielded three groups identified as "anthropogenic", "crustal", and "marine". Models yielded positive associations between most single and groups of metal and all-site cancer, with e.g. hazard ratios of 1.08 (95% CI: 1.03, 1.13) for cadmium or 1.06 (95% CI: 1.02,1.10) for lead, per interquartile range increase. These findings were consistent across supplementary analyses, albeit attenuated when accounting for total PM2.5. Regarding specific site cancers, we estimated positive associations mostly for bladder, and generally with large confidence intervals. CONCLUSION: Most single and groups of airborne metals, except vanadium, were associated with risk of cancer. These findings may help identify sources or components of PM2.5 that may be involved in its carcinogenicity.

The consumption of coffee and black tea and the risk of lung cancer.

PURPOSE: Coffee and black tea are among the most consumed beverages worldwide. Although their potential role in lung cancer occurrence has been investigated in several studies, results have been inconclusive. We investigated the associations between intake of coffee and black tea with lung cancer in a population-based case-control study in Montreal, Canada. METHODS: These analyses included 1130 cases and 1483 controls. Adjusted odds ratios (ORs) were estimated between four metrics of coffee and black tea consumption (frequency, average daily amount, duration, and cumulative amount) and lung cancer, using unconditional logistic regression. RESULTS: The adjusted ORs (95% confidence intervals) for lung cancer comparing daily to never consumers were 0.73 (0.49-1.10) for coffee and 1.05 (0.85-1.31) for black tea. Analyses of other metrics did not reveal any clear patterns of increasing or decreasing risk with increasing amounts or duration of consumption. There was no strong evidence of OR modification by sex or smoking level. The OR estimates did not materially differ by histological subtype for either of the beverages. CONCLUSION: Our results do not provide strong support for associations between consumption of coffee and black tea and lung cancer.