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

Occupational exposure to metals and risk of meningioma: a multinational case-control study

The aim of the study was to examine associations between occupational exposure to metals and meningioma risk in the international INTEROCC study. INTEROCC is a seven-country population-based case-control study including 1906 adult meningioma cases and 5565 population controls. Incident cases were recruited between 2000 and 2004. A detailed occupational history was completed and job titles were coded into standard international occupational classifications. Estimates of mean workday exposure to individual metals and to welding fumes were assigned based on a job-exposure-matrix. Adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated using conditional logistic regression. Although more controls than cases were ever exposed to metals (14 vs. 11 %, respectively), cases had higher median cumulative exposure levels. The ORs for ever vs. never exposure to any metal and to individual metals were mostly greater than 1.0, with the strongest association for exposure to iron (OR 1.26, 95 % CI 1.0–1.58). In women, an increased OR of 1.70 (95 % CI 1.0–2.89) was seen for ever vs never exposure to iron (OR in men 1.19, 95 % CI 0.91–1.54), with positive trends in relation with both cumulative and duration of exposure. These results remained after consideration of other occupational metal or chemical co-exposures. In conclusion, an apparent positive association between occupational exposure to iron and meningioma risk was observed, particularly among women. Considering the fact that meningioma is a hormone dependent tumor, the hypothesis that an interaction between iron and estrogen metabolism may be a potential mechanism for a carcinogenic effect of iron should be further investigated