Benzene exposure and risk of lung cancer in the Norwegian Offshore Petroleum Worker cohort: a prospective case-cohort study.

OBJECTIVE: The objective of our study was to examine whether occupational exposure to benzene is associated with lung cancer among males in the Norwegian Offshore Petroleum Workers cohort. METHODS: Among 25 347 male offshore workers employed during 1965-1998, we conducted a case-cohort study with 399 lung cancer cases diagnosed between 1999 and 2021, and 2035 non-cases sampled randomly by 5-year birth cohorts. Individual work histories were coupled to study-specific job-exposure matrices for benzene and other known lung carcinogens. Weighted Cox regression was used to estimate HRs and 95% CIs for the associations between benzene exposure and lung cancer, by major histological subtypes, adjusted for age, smoking and occupational exposure to welding fumes, asbestos and crystalline silica. Missing data were imputed. RESULTS: For lung cancer (all subtypes combined), HRs (95% CIs) for the highest quartiles of benzene exposure versus unexposed were 1.15 (0.61 to 2.35) for cumulative exposure, 1.43 (0.76 to 2.69) for duration, and 1.22 (0.68 to 2.18) for average intensity (0.280≤P-trend≤0.741). For 152 adenocarcinoma cases, a positive trend was observed for exposure duration (P-trend=0.044). CONCLUSIONS: In this cohort of offshore petroleum workers generally exposed to low average levels of benzene, we did not find an overall clear support for an association with lung cancer (all subtypes combined), although an association was suggested for duration of benzene exposure and adenocarcinoma. The limited evidence might be due to restricted statistical power.

Exposure to benzene and other hydrocarbons and risk of bladder cancer among male offshore petroleum workers.

BACKGROUND: Occupational exposures constitute the second leading cause of urinary bladder cancer after tobacco smoking. Increased risks have been found in the petroleum industry, but high-quality exposure data are needed to explain these observations. METHODS: Using a prospective case-cohort design, we analysed 189 bladder cancer cases (1999-2017) and 2065 randomly drawn non-cases from the Norwegian Offshore Petroleum Workers cohort. Cases were identified in the Cancer Registry of Norway, while work histories (1965-1998) and lifestyle factors were recorded by questionnaire at baseline (1998). Occupational petroleum-related hydrocarbon exposures were assessed by expert-developed job-exposure matrices. Hazard ratios were estimated by weighted Cox-regressions, adjusted for age, tobacco smoking, education, and year of first employment, and with lagged exposures. RESULTS: Increased risks were found in benzene-exposed workers, either long-term exposure (≥18.8 years, HR = 1.89, 95% CI: 1.14-3.13; p-trend = 0.044) or high-level cumulative benzene exposure (HR = 1.60, 95% CI: 0.97-2.63; p-trend = 0.065), compared with the unexposed. Associations persisted with 20-year exposure lag. No associations were found with skin or inhalation exposure to crude oil, mineral oil (lubrication, hydraulics, turbines, drilling), or diesel exhaust. CONCLUSIONS: The results suggest that exposures in the benzene fraction of the petroleum stream may be associated with increased bladder cancer risk.

Night shift work and risk of aggressive prostate cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort.

BACKGROUND: Night shift work may acutely disrupt the circadian rhythm, with possible carcinogenic effects. Prostate cancer has few established risk factors though night shift work, a probable human carcinogen, may increase the risk. We aimed to study the association between night shift work and chlorinated degreasing agents (CDAs) as possible endocrine disrupters in relation to aggressive prostate cancer as verified malignancies. METHODS: We conducted a case-cohort study on 299 aggressive prostate cancer cases and 2056 randomly drawn non-cases in the Norwegian Offshore Petroleum Workers cohort (1965-98) with linkage to the Cancer Registry of Norway (1953-2019). Work history was recorded as years with day, night, and rollover (rotating) shift work, and CDA exposure was assessed with expert-made job-exposure matrices. Weighted Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for aggressive prostate cancer, adjusted for education and year of first employment, stratified by 10-year birth cohorts, and with 10, 15, and 20 years of exposure lag periods. RESULTS: Compared with day work only, an increased hazard of aggressive prostate cancer (HR = 1.86, 95% CI 1.18-2.91; P-trend = 0.046) was found in workers exposed to ≥19.5 years of rollover shift work. This persisted with longer lag periods (HR = 1.90, 95% CI 0.92-3.95; P-trend = 0.007). The exposure-hazard curve for a non-linear model increased linearly (HRs ≥1.00) for 18-26 years of rollover shift work. No association was found with CDA exposure. CONCLUSIONS: Long-term exposure to rollover shift work may increase the hazard of aggressive prostate cancer in offshore petroleum workers.

Primary versus secondary muscle-invasive bladder cancer: survival after curative treatment.

PURPOSE: To assess if cancer-specific survival (CSS) following curative intent treatment (CIT) for muscle-invasive bladder cancer (MIBC) differs between patients presenting with MIBC (primary) and patients presenting with non-muscle-invasive bladder cancer who progress to MIBC (secondary). METHODS: This study uses data from the Cancer Registry of Norway on patients initially diagnosed with bladder cancer in 2008-2012 and treated with radical cystectomy (RC) or radiotherapy (RT). To ensure a clinically relevant population, we selected patients with a pre-treatment histology confirming muscle-invasion. Survival models were applied to evaluate differences in observed and adjusted CSS by type of MIBC and stratified by type of CIT. Adjustment was made for age group, sex, previous cancer, diagnostic hospital's academic status and geographical region, and type of CIT. RESULTS: We identified 650 eligible patients: 589 (91%) primary MIBC and 61 (9%) secondary MIBC. A total of 556 (86%) patients underwent RC and 94 (14%) RT. The 5-year CSS for primary MIBC was 56% and 59% for secondary MIBC (p = 0.68). The type of MIBC did not impact the risk of bladder cancer death (HR = 0.85, CI = 0.55-1.33, p = 0.48), nor when stratified for CIT (RC: HR = 0.93, CI = 0.57-1.53, p = 0.78); RT: HR = 0.71, CI = 0.24-2.16, p = 0.55). CONCLUSION: This first nation-wide population-based study comparing CSS between primary and secondary MIBC showed no significant difference in survival regardless of type of CIT. Continued surveillance of patients with non-muscle-invasive bladder cancer is necessary to detect early progression to MIBC. Future studies should include molecular and genetic characteristics in addition to detailed clinicopathologic information.

Night shift work, chemical coexposures and risk of female breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a prospectively recruited case-cohort study.

OBJECTIVES: This study examined the association between night shift work and risk of breast cancer, overall and by hormone receptor subtype, among females in the Norwegian Offshore Petroleum Workers (NOPW) cohort. We also examined the association of coexposure (chlorinated degreasers and benzene) and breast cancer risk, and possible interaction with work schedule. DESIGN: Prospectively recruited case-cohort study within the NOPW cohort. SETTING: Female offshore petroleum workers active on the Norwegian continental shelf. PARTICIPANTS: 600 female workers (86 cases and 514 non-cases) were included in the study. We excluded workers that died or emigrated before start of follow-up, had missing work history, were diagnosed with breast cancer or other prior malignancy (except non-melanoma skin cancer) before start of follow-up. RESULTS: No overall association was found between breast cancer risk and work schedule (HR 0.87, 95% CI 0.52 to 1.46 for work schedule involving night shift vs day shift only). There was no significant association between work schedule and risk of any breast cancer subtype. No significant interactions were found between work schedule and chemical coexposures (breast cancer overall Pinteraction chlorinated degreasers=0.725 and Pinteraction benzene=0.175). CONCLUSIONS: Our results did not provide supporting evidence that work schedule involving night shift affects breast cancer risk in female offshore petroleum workers, but should be considered cautiously due to few cases. Further studies with larger sample sizes are warranted.

Vitamin D and Vitamin D-binding protein and risk of bladder cancer: A nested case-control study in the Norwegian Janus Serum Bank Cohort.

BACKGROUND: High circulating levels of vitamin D (25(OH)D) are suggested to reduce the risk of urinary bladder cancer (BC), but the evidence is weak, and several studies lack sufficient adjustment for potential confounders (e.g., smoking, body mass index (BMI), and physical activity). Moreover, few studies have investigated the role of vitamin D-binding protein (DBP) in this context. We conducted a matched nested case-control study including 378 cases and 378 controls within the Norwegian population-based Janus cohort, using serum collected 5-41 years prior to diagnosis, to study 25(OH)D and BC risk, by taking circulating DBP into account. METHODS: Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), for 25(OH)D, DBP, and the molar ratio of 25(OH)D:DBP, an estimate of unbound (free) 25(OH)D levels. We adjusted for smoking (status and pack-years), BMI, physical activity, education and (mutually) for 25(OH)D and DBP. Restricted cubic splines were employed to examine nonlinear associations. RESULTS: High optimal levels of circulating 25(OH)D (≥100 nmol/L) (HR 0.35, 95% CI 0.19-0.64) were associated with decreased BC risk, when compared with insufficient concentrations (50-74 nmol/L). This association was less pronounced for optimal levels (75-99 nmol/L) (HR = 0.69, 95% CI 0.47-1.01). Moreover, estimated free 25(OH)D, was associated with decreased BC risk for molar ratio 17-21 (HR 0.66, 95% CI 0.44-0.97) and ≥22 (HR 0.50, 95% CI 0.29-0.82), compared to molar ratio 11-16. The HR function for BC risk was not linear, rather reversed u-shaped, with the highest HR at 62.5 nmol/L and 13.5 molar ratio, respectively. CONCLUSION: High levels of total and estimated free 25(OH)D were associated with reduced risk of BC, compared with insufficient concentrations. DBP was not associated with BC risk. We did not observe any impact of DBP or any of the studied lifestyle factors on the association between 25(OH)D and BC.

The use of reTURB in T1 bladder cancer: a Norwegian population-based study.

AIM: To evaluate the use of repeat transurethral resection of the bladder (reTURB) in stage T1 bladder cancer and its impact on treatment and survival in a Norwegian population-based cohort. MATERIAL AND METHODS: 1130 patients registered at the Cancer Registry of Norway between 2008 and 2012 with primary urothelial T1 cancer were included. Information on surgical and medical procedures was provided by the Norwegian Patient Registry. Descriptive statistics were used to evaluate characteristics of patients receiving reTURB or not within 12 weeks from primary TURB (primTURB). Survival models identified risk factors and estimated cause-specific survival rates (CSS) adjusted for sex, age, WHO grade, concomitant cis and detrusor muscle at primTURB and treatment. RESULTS: The 648 (57%) T1 patients with reTURB were significantly younger and had more WHO high grade tumors compared to those without reTURB. Of 275 patients without detrusor muscle at primTURB 114 (41%) had no reTURB. Of reTURB patients, 45 (7%) had muscle invasive tumor, 110 (17%) T1 and 378 (58%) Ta, cis or T0. Two-thirds of 81 patients receiving early cystectomy after reTURB had T1 or muscle invasive bladder cancer at reTURB. ReTURB did not impact adjusted CSS, but patients with T1 at reTURB had significantly lower CSS than those with < T1 conditions. CONCLUSIONS: Almost half of the T1 patients did not undergo reTURB as recommended in guidelines. We show that reTURB makes the histology result more reliable with impact on both treatment and survival. Our results support the use of reTURB as recommended by EAU guidelines.

Ultraviolet radiation and risk of cutaneous melanoma and squamous cell carcinoma in males and females in the Norwegian Offshore Petroleum Workers cohort.

BACKGROUND: Increased risk of cutaneous melanoma and squamous cell carcinoma (SCC) has been reported among petroleum workers, but few studies include females, exposure data on ultraviolet radiation (UVR), and potential confounding factors. We aimed to examine UVR exposure in relation to risk of melanoma and SCC among male and female offshore petroleum workers. We also examined the association between UVR exposure and melanoma (Breslow) thickness. METHODS: The Norwegian Offshore Petroleum Workers (NOPW) cohort (n = 27,917) holds information on sunbathing, indoor tanning, sunburns, sunscreen use, and other lifestyle factors recorded in 1998. Linkage to the Cancer Registry of Norway gave information on cancer diagnosis through 2017. We used Cox and logistic regression to estimate hazard ratios (HRs) of skin cancer and odds ratios (OR) of thick (≥1 mm) melanomas, respectively, with 95% confidence intervals (CIs). RESULTS: Melanoma risk increased with increasing frequency of sunbathing after age 20 (ptrend = 0.031), sunburn average intensity (ptrend = 0.028), and sunscreen use (HR = 2.16; 95% CI: 1.42 -3.27 for almost always vs. never/rarely). The risk of thick melanoma was inversely associated with sunbathing frequency after age 20 (OR = 0.38; 95% CI: 0.16 - 0.90 for ≥4 weeks/year vs. 1 week/year). SCC risk increased with increasing frequency of indoor tanning after age 20 (HR = 2.72; 95% CI: 1.22 - 6.05 for ≥3 times/months vs. never), sunburn average intensity (ptrend < 0.001), and sunscreen use (ptrend < 0.001). CONCLUSIONS: Our results support associations between UVR exposure and skin cancer risk in male and female offshore petroleum workers. This occupational group may be especially relevant for targeted sun protection advice.

Work Conditions and Practices in Norwegian Fire Departments From 1950 Until Today: A Survey on Factors Potentially Influencing Carcinogen Exposure.

BACKGROUND: Meta-analyses have shown firefighters to be at an increased risk of several cancer types. Occupational carcinogen exposure may explain these increased risks. This study aims to describe Norwegian fire departments' work conditions from 1950 until today, focusing on factors relevant for potential occupational carcinogen exposure. METHODS: With the help of a reference group, we developed a questionnaire on topics related to occupational exposure to carcinogens for the period 1950-2018. Selected Norwegian fire departments provided department-specific responses. RESULTS: Sixteen departments, providing fire services for 48% of the Norwegian population as of 2019 and mainly consisting of professional firefighters, responded to our questionnaire. The introduction of synthetic firefighting foams, more regular live fire training, the introduction of chemical diving, and a higher number of diesel-driven fire service vehicles were identified as changes thought to increase exposure to occupational carcinogens. Changes thought to decrease exposure included the switch from negative to positive pressure self-contained breathing apparatuses, the use of self-contained breathing apparatuses during all phases of firefighting, the use of ventilating fans during firefighting, increased attention to flammable materials used during live fire training, increased attention to handling and cleaning of turnout gear and other equipment, and installment of exhaust removal systems in apparatus bays. CONCLUSION: Norwegian fire departments' work conditions have seen several changes since 1950, and this could influence firefighters' occupational carcinogen exposure. A peak of carcinogen exposure may have occurred in the 1970s and 1980s before recent changes have reduced exposure.

Prediagnostic serum 25-hydroxyvitamin D and melanoma risk.

Previous studies of serum 25-hydroxyvitamin D (25(OH)D) in relation to melanoma have shown conflicting results. We conducted a nested case-control study of 708 cases and 708 controls, using prediagnostically collected serum, to study 25(OH)D and melanoma risk in the population-based Janus Serum Bank Cohort. Stratified Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for ultraviolet radiation (UVR) indicators and stratified by ambient UVB of residence and body mass index (BMI). Non-linear associations were studied by restricted cubic splines. Missing data were handled with multiple imputation by chained equations. We found an HR of melanoma risk of 1.01 (95% CI: 0.99, 1.04) and an HRimputed of 1.02 (95% CI: 1.00, 1.04) per 5-nmol/L increase. The spline model showed exposure-risk curves with significantly reduced melanoma risk between 60 and 85 nmol/L 25(OH)D (reference 50 nmol/L). Non-significant J-shaped curves were found in sub-analyses of subjects with high ambient UVB of residence and of subjects with BMI < 25 kg/m2. Our data did not yield persuasive evidence for an association between 25(OH)D and melanoma risk overall. Serum levels within the medium range might be associated with reduced risk, an association possibly mediated by BMI.

Education, income and risk of cancer: results from a Norwegian registry-based study.

INTRODUCTION: Several studies have shown an association between socioeconomic status and incidence of cancer. In this study, we have examined the association between socioeconomic factors, using income and education as proxies, and cancer incidence in Norway, a country known to be egalitarian, with universal access to health care and scoring high on the human development index. METHODS: We linked individual data for the total Norwegian population with information on all cancer patients registered in the Cancer Registry of Norway (CRN) with any cancer diagnosed between 2012 and 2016. Data on education, and individual income, were provided from Statistics Norway. We used Poisson regression to obtain incidence rate ratios (IRR) across education and income levels for 23 cancer sites. RESULTS: A total of 9 cancers among men and 13 cancers among women were observed to have significantly higher incidence rates in cases with the lowest level of education. Melanoma for both sexes, testis and prostate cancer in men, and breast cancer in women were found to have a higher incidence rate among those with the highest level of education. The largest differences in IRR were found for lung cancer, where men and women with college or university education as their highest completed education had a two- to threefold decreased risk, compared to those with primary school (IRR men; 0.40 [0.37-0.43], women 0.34 [0.31-0.37]). The results for income mirrored the results for education among men, while for women we did not observe many differences in cancer risk across income groups. CONCLUSION: Our findings were consistent with findings from other studies showing that the incidence rate of cancer differs across levels of socioeconomic status. We may need behavioral change campaigns focused on lifestyle changes that lower the risk of cancer and target perhaps to those with lower socioeconomic status.

T1 bladder cancer in Norway: treatment and survival.

AIM: Evaluation of treatment and survival of pT1 stage (T1) bladder cancer (BC) patients diagnosed with transitional cell carcinoma of the urinary bladder in Norway. MATERIAL AND METHODS: According to the Cancer Registry of Norway, 1,108 patients were diagnosed with T1 BC between 2008-2012. Information on surgical and medical procedures was provided by the Norwegian Patients Registry. Regression and survival models were applied to characterize patients receiving bacillus Calmette-Guerin (BCG) and radical cystectomy (RC) as early and delayed treatment and to estimate overall and cause specific survival rates (OS; CSS). Adjustments for sex, age, WHO grade and concomitant cis were made. RESULTS: In total, 449 (41%) patients received BCG treatment, 162 (15%) as early treatment. RC represented the early treatment in 96 (9%) patients and the delayed treatment in 84 (8%). Overall, 850 (77%) patients received neither BCG nor RC as early treatment, of whom 287 (26%) were treated with BCG and 66 (6%) with RC during follow-up. Patients <75 years and patients with high grade tumors or concomitant cis were more likely to receive BCG and RC as early treatment. 5-year survival rates for all T1 BC patients were 84% (CSS) and 65% (OS). Delayed RC was associated with the lowest 5-year CSS (70%). After adjustment, gender did not impact treatment choice and CSS. CONCLUSIONS: The use of BCG as early treatment indicates low adherence to existing guidelines. Delayed RC was associated with low survival rates. An increased focus on the management of T1 patients is needed in Norway.

Waiting times and treatment following cancer diagnosis: comparison between immigrants and the Norwegian host population.

Background: There are concerns about timely access to appropriate cancer treatment for the growing immigrant population in Norway. This study aims to compare waiting times between cancer diagnosis and start of cancer treatment, as well as treatment patterns between immigrants in Norway and the host population.Material and methods: We performed a nationwide, registry-based study with individual-level data, including 213,320 Norwegians and 8324 immigrants diagnosed with breast, colorectal, lung or prostate cancer in 1990-2014. Differences in time from diagnosis to treatment and in treatment patterns were described for the selected cancer sites. The Cox and logistic regressions were used to adjust for patient and tumour characteristics.Results: After adjustment for covariates, hazard ratios for time from diagnosis to treatment for non-Western immigrants compared to Norwegians were 0.88 (95% confidence interval (CI): 0.82-0.95) for breast cancer and 0.84 (95% CI: 0.75-0.95) for lung cancer, indicating longer waiting times. Treatment patterns in the four major cancer sites were similar among immigrants and the Norwegian host population, except for breast cancer, where women from East and South Asia received less breast-conserving surgery than the Norwegian host population (adjusted odds ratios 0.65 (95% CI: 0.46-0.93) for East Asians and 0.75 (95% CI: 0.50-1.13) for South Asians).Conclusions: The present study reports delayed treatment for lung and breast cancer among immigrants from non-Western countries in Norway. Systematic differences in cancer treatment were not detected. However, less breast-conserving surgery among breast cancer patients from Asia compared to Norwegians was observed.

Serum 25-hydroxyvitamin D levels predict cancer survival: a prospective cohort with measurements prior to and at the time of cancer diagnosis.

PURPOSE: Circulating 25-hydroxyvitamin D (25-OHD) levels have been inversely associated with cancer death, but the nature of this relationship is unclear. We investigated this association using repeated measurements of serum 25-OHD. PATIENTS AND METHODS: Pre-diagnostic serum samples were collected in population health surveys in Norway (1973-2004). Participants who subsequently developed cancer (1984-2004) provided a second serum sample at the time of cancer diagnosis. Samples were stored in the Janus Serum Bank. Repeated samples existed from 202 breast cancers, 193 lung cancers, 124 lymphomas, and 37 colon cancers. Serum 25-OHD was measured via competitive radioimmunoassay. Cox regression models assessed associations between 25-OHD and cancer-specific death (case fatality) through 2012, given as hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: The median time between pre-diagnostic and diagnostic samples was 14.4 years. The median 25-OHD levels were 63.3 and 62.5 nmol/L, respectively. During follow-up, 313 cancer deaths occurred. Compared to low pre-diagnostic 25-OHD levels (<46 nmol/L), higher levels (≥46 nmol/L) had significantly lower HRs (39-54%) of case fatality. This result was also seen for the diagnostic samples. Donors who had both samples at high (≥62 nmol/L) levels had 59% lower HR of case fatality, compared to those for whom both samples were at low levels (<46 nmol/L). Furthermore, versus a decline in serum 25-OHD (median -22.4 nmol/L) from pre-diagnostic to diagnostic samples, a rise (median 22.3 nmol/L) was associated with lower case fatality (HR 0.57, 95% CI 0.43-0.75). CONCLUSION: Our findings suggest a causal relationship between vitamin D and cancer case fatality.

Harmonizing work history data in epidemiologic studies with overlapping employment records.

BACKGROUND: Work history data often require major data management including handling of overlapping jobs to avoid overestimating exposure before linkage to job-exposure matrices (JEMs) is possible. METHODS: In a case-cohort study of 1825 male Norwegian offshore petroleum workers, 3979 jobs were reported (mean duration 2417 days/job; maximum 8 jobs/worker). Each job was assigned to one of 27 occupation categories. Overlapping jobs of the same category (1142 jobs) were collapsed and overlapping jobs of different categories (1013 jobs) were split. The resulting durations were weighted by a factor accounting for the number of overlapping jobs. RESULTS: Collapsing overlapping jobs within the same category resulted in 3295 jobs (mean 2629 days/job). Splitting overlapping jobs of different categories increased the number to 4239 jobs (mean 2043 days/job), while the total duration in days dropped by 10%. CONCLUSIONS: We demonstrated that overlapping employment data structures can be harmonized in a systematic and unbiased way, preparing work history data for linkage to several JEMs.

Differences in cancer survival between immigrants in Norway and the host population.

Cancer survival is an important indicator for quality of cancer care. We sought to determine if there are differences in cancer survival between immigrants and the host population in Norway. We performed a nationwide registry-based study comprising subjects diagnosed with cancer between 1990 and 2014, and followed until the end of 2016. Survival was estimated for 13 cancer sites with cause-specific survival. Adjustments were made for common confounders (age, sex, year of diagnosis and place of residence) and defined mediators (stage at diagnosis, comorbidity and socioeconomic factors). A total of 500,255 subjects were available for analysis, of which 11,252 were Western and 8,701 non-Western immigrants. We did not find differences in cancer survival between Western immigrants and Norwegians, while non-Western immigrants, with some exceptions, had similar or better survival. Better lung cancer survival in non-Western immigrants than Norwegians was notable (hazard ratio (95% confidence interval): 0.78 (0.71-0.85)), and not explained by defined mediators. Immigrants from Eastern Europe and Balkan with melanoma (hazard ratio: 1.54 (1.12-2.12)) and prostate cancer (hazard ratio: 1.34 (1.08-1.67)), and possibly from sub-Saharan Africa with breast cancer (hazard ratio: 1.41 (0.94-2.12)) had worse survival than Norwegians. The results suggest that immigrants in Norway have good cancer survival relative to the host population. Poor survival in immigrants from Eastern Europe and Balkan with melanoma and prostate cancer, and sub-Saharan Africa with breast cancer might be a concern.

Anthropometric factors and cutaneous melanoma: Prospective data from the population-based Janus Cohort.

The aim of the present study was to prospectively examine risk of cutaneous melanoma (CM) according to measured anthropometric factors, adjusted for exposure to ultraviolet radiation (UVR), in a large population-based cohort in Norway. The Janus Cohort, including 292,851 Norwegians recruited 1972-2003, was linked to the Cancer Registry of Norway and followed for CM through 2014. Cox regression was used to estimate hazard ratios (HRs) of CM with 95% confidence intervals (CIs). Restricted cubic splines were incorporated into the Cox models to assess possible non-linear relationships. All analyses were adjusted for attained age, indicators of UVR exposure, education, and smoking status. During a mean follow-up of 27 years, 3,000 incident CM cases were identified. In men, CM risk was positively associated with body mass index, body surface area (BSA), height and weight (all ptrends < 0.001), and the exposure-response curves indicated an exponential increase in risk for all anthropometric factors. Weight loss of more than 2 kg in men was associated with a 53% lower risk (HR 0.47, 95% CI: 0.39, 0.57). In women, CM risk increased with increasing BSA (ptrend = 0.002) and height (ptrend < 0.001). The shape of the height-CM risk curve indicated an exponential increase. Our study suggests that large body size, in general, is a CM risk factor in men, and is the first to report that weight loss may reduce the risk of CM among men.