Objectives To test the association between occupational exposure to trichloroethylene (TCE) and risk of non Hodgkin lymphoma (NHL), we conducted a pooled analysis of four international case-control studies. Methods Studies were selected which included state-of-the art retrospective assessment of occupational exposure to TCE and histological information on lymphoma subtype. Overall, the pooled study population included 3788 NHL cases and 4279 controls. Summary indicators of exposure were harmonised across studies. We conducted unconditional logistic regression analysis to test the association between the harmonised TCE exposure estimates and NHL and its major subtypes, adjusting by age, gender, and study. Results Among the total study population, risk of follicular lymphoma, but not NHL overall or other subtypes, increased by probability (p = 0.02) and intensity level (p = 0.04) of TCE exposure. When the analysis was restricted to subjects most likely exposed to TCE, risk of NHL overall (p = 0.009), follicular lymphoma (p = 0.04), and chronic lymphocytic leukaemia (CLL) (p = 0.01) showed a linear increase by duration of exposure. No heterogeneity in NHL risk associated with high probability of exposure to TCE (all intensity levels combined) was detected. Conclusion With due caution because of several limitations, our pooled analysis supports the hypothesis of an increased risk of NHL, and particularly of the follicular lymphoma and CLL subtypes, associated with occupational exposure to TCE.

Objectives Although asbestos research has been ongoing for decades, there are remaining questions regarding cancer risk associated with low exposure and cancer subtypes, the influence of potential confounders, and the interaction between asbestos and smoking. We addressed these questions by studying the association between occupational asbestos exposure and pleural mesothelioma, lung and laryngeal cancer in the prospective population-based Netherlands Cohort Study (NLCS). Methods The NLCS includes 58279 men aged 55–69 years at enrollment in 1986. Based on job history information obtained from a self-administered questionnaire, asbestos exposure was estimated by linkage to job-exposure matrices. After 17.3 years of follow-up, 132 cases of pleural mesothelioma, 2324 cases of lung cancer, and 166 cases of laryngeal cancer were available for analysis. Results Overall, occupational asbestos exposure was associated with an increased risk of mesothelioma, lung and laryngeal cancer, also for relatively low exposure. Correcting for potential confounders as age, smoking, alcohol, and several occupational carcinogens hardly influenced these results. Associations with lung cancer subtypes were generally comparable to overall lung cancer, except for adenocarcinoma (HR ever versus never exposed = 1.43, 1.52, 1.49 and 0.94 for small cell, large cell, squamous cell and adenocarcinoma respectively). Adenocarcinoma showed only a weak positive association at higher exposure levels for long duration. For laryngeal cancer, associations were usually stronger for supraglottis cancer (HR = 2.48, 95% CI:1.33–4.65) than glottis cancer (HR = 1.12, 95% CI:0.74–1.69). There was no statistically significant additive or multiplicative interaction between asbestos and smoking for any of the cancers. Conclusions The well-established associations between asbestos and mesothelioma, lung and laryngeal cancer were corroborated at relatively low levels of cumulative exposure in the NLCS. Lung adenocarcinoma may only show an increased relative risk at higher asbestos exposure for long duration. Asbestos exposure may be stronger associated with supraglottis cancer than glottis cancer.

Objectives Established risk factors of leukemia do not explain the majority of leukemia cases. Previous studies have suggested the importance of occupation and related exposures in leukemogenesis. We evaluated possible associations between job title and selected hazardous agents and leukemia in the European Prospective Investigation into Cancer and Nutrition. Methods The mean follow-up time for 241,465 subjects was 11.20 years (SD: 2.42 years). During the follow-up period, 477 incident cases of myeloid and lymphoid leukemia occurred. Data on 52 occupations considered a priori to be at high risk for developing cancer were collected through standardized questionnaires. Occupational exposures were estimated by linking the reported occupations to a Job exposure matrix. Cox proportional hazard models were used to explore the association between occupation and related exposures and risk of leukemia. Results Risk of lymphoid leukemia significantly increased for working in chemical laboratories (HR = 8.35, 95% CI = 1.58–44.24), while the risk of myeloid leukemia increased for working in the shoes or other leather goods industry (HR = 2.54, 95% CI = 1.28–5.06). Exposure specific analyses showed a non-significant increased risk of myeloid leukemias for exposure to benzene (HR = 1.15, 95% CI = 0.75–1.40; HR = 1.60, 95% CI = 0.95–2.69 for the low and high exposure categories respectively). This association was present both for acute and chronic myeloid leukemia at high exposure levels. However, numbers were too small to reach statistical significance. Conclusion Our findings suggest a possible role of occupational exposures in development of both lymphoid and myeloid leukemia. Exposure to benzene seemed to be associated with both acute and chronic myeloid leukemia.

Styrene is widely used in industrial settings, leading to important occupational exposure. Currently it is classified by IARC as "possibly carcinogenic to humans" based on limited evidence of an association with lymphohaematopoietic cancers. Several recent studies suggest increased risk of lung cancer may be associated with exposure to styrene. We conducted a systematic search and a meta-analysis of epidemiologic studies of exposure to styrene and incidence or mortality of lung cancer. Of 167 papers retrieved, 50 were found to provide pertinent data after screening the abstracts; 42 of these were occupational cohort studies conducted in 3 main work settings: chemical production, reinforced plastics manufacturing, and styrene-butadiene rubber production. There was significant overlap in the populations among published papers, which reported data from 7 separate cohorts and one pooled international cohort, some parts of which were also published separately. Meta-analysis showed an excess risk of lung cancer among workers ever exposed to styrene (RR 1.14, 95% CI 1.04-1.24, I 2 63%). The association was stronger when the analysis was limited to the reinforced plastics industry, where co-exposures are less important than in other industries (RR 1.20, 95% CI 1.10-1.31, I 2 72%). Meta-analysis of exposure-response relations in the subset of studies that reported quantitative or categorical exposure data are ongoing and will be reported.