Anthropometric factors and Breslow thickness: prospective data on 2570 cases of cutaneous melanoma in the population-based Janus Cohort.

BACKGROUND: Breslow thickness is the most important prognostic factor of localized cutaneous melanoma (CM), but associations with anthropometric factors have been sparsely and incompletely investigated. OBJECTIVES: To examine prediagnostic body mass index (BMI), body surface area (BSA), and height, weight and weight change in relation to Breslow thickness, overall and by anatomical site and histological subtype; and to assess possible nonlinear associations between these anthropometric factors and Breslow thickness. METHODS: CMs in the Janus Cohort were identified between 1972 and 2014. Linear regression was used to estimate geometric mean ratios (GMRs) of Breslow thickness with 95% confidence intervals (CIs) according to anthropometric factors. Restricted cubic splines in generalized linear models predicted adjusted mean Breslow thickness, and were used to assess possible nonlinear relationships. RESULTS: Of 2570 cases of CM, obese patients had a GMR of 1·16 (95% CI 1·04-1·30) of Breslow thickness vs. normal-weight patients. For BSA and weight, quintile 5 showed GMRs of 1·13 (95% CI 1·00-1·27) and 1·17 (95% CI 1·03-1·33) of Breslow thickness vs. quintile 1, respectively. Associations seemed restricted to superficial spreading melanomas and CMs on the trunk and lower limbs. The associations plateaued at an adjusted mean Breslow thickness of about 2·5 mm (BMI 29 kg m-2 , BSA 2·05 m2 and weight 90 kg), before declining for the highest values. No associations were found for height and weight change. CONCLUSIONS: This large case-series of incident CM demonstrated positive associations between BMI, BSA, weight and Breslow thickness, and suggested that behavioural or other mechanisms apply at high values.

Ultraviolet radiation and skin cancer risk in offshore workers.

BACKGROUND: Excess skin cancer mortality and incidence have been reported among both land-based and offshore petroleum workers. The association between skin cancer and ultraviolet radiation (UVR) exposure has not been examined in these workers, although they have long off-duty periods and high average income that may allow travelling to sunny destinations. In addition, they have access to solariums free of charge on many accommodation platforms. AIMS: To prospectively examine risk of incident cutaneous melanoma (CM) and non-melanoma skin cancer (NMSC), according to sun-tanning habits with adjustment for aromatic hydrocarbon exposure. METHODS: A cohort of men employed offshore from 1965 to 1999 was linked through the Cancer Registry of Norway 1999-2012. Cox regression adapted to a stratified case-cohort design was used to estimate hazard ratios with 95% confidence intervals. RESULTS: The cohort included 24917 men. During 13.5 years of follow-up, 112 CMs and 70 NMSCs occurred. A positive dose-response relationship was seen between sunburn frequency and risk of CM (Ptrend < 0.05) and NMSC (Ptrend < 0.01). Solarium use both before and after age 20 was related to increased risk of NMSC. Sunscreen use was associated with increased risk of NMSC (Ptrend < 0.001). CONCLUSIONS: UVR exposure seems to be a significant contributor to the elevated risk of skin cancer observed in North Sea offshore workers. The positive association between solarium use and NMSC risk adds to the growing body of literature on artificial UV devices as carcinogenic.

Benzene exposure and risk of lymphohaematopoietic cancers in 25 000 offshore oil industry workers.

BACKGROUND: The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers. METHODS: Cancer registry data were used to identify 112 cancer cases diagnosed during 1999-2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case-cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking. RESULTS: Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094). CONCLUSIONS: Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL.

Cancer incidence among 41,000 offshore oil industry workers.

BACKGROUND: Cancer incidence among Norwegian offshore oil industry workers has been studied in two equally sized cohorts of 28000 workers, in a survey-based cohort study followed 1999-2005 and a register-based cohort study followed 1981-2003. AIMS: To determine the overall cancer incidence in both cohorts merged, with an extended follow-up. METHODS: The merged cohort yielded 41,140 individuals followed for cancer diagnoses 1999-2009. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were computed by gender and by period of first employment using cancer registry data. RESULTS: Among female workers, the total number of cancers was slightly higher than expected (SIR 1.17, 95% CI 1.02-1.34), and excesses of acute myeloid leukaemia (AML) (SIR 5.29, 95% CI 1.72-12), malignant melanoma (SIR 2.13, 95% CI 1.41-3.08) and lung cancer (SIR 1.69, 95% CI 1.03-2.61) were observed. Among male workers, the total number of cancer cases was close to that expected (SIR 1.03, 95% CI 0.99-1.08), but cases of pleural cancer (SIR 2.56, 95% CI 1.58-3.91) and bladder cancer (SIR 1.25, 95% CI 1.05-1.49) were higher than expected. Among male workers first employed before 1986, the numbers of observed cancer cases were higher than expected for most sites, while this was not evident among those employed later. CONCLUSIONS: Further studies with exposure data and confounder control are needed to address whether the observed excesses of pleural cancer and AML can be attributed to offshore work.