Nordic Occupational Cancer Research Articles

Socio-economic status and head and neck cancer incidence in the Nordic countries.

The impact of societal factors on the occurrence of head and neck cancers (HNCs) remains understudied, especially in the Nordic countries. To quantify the association between socio-economic status (SES) and the occurrence of HNCs, this cohort study uses data from the Nordic Occupational Cancer project that combine occupational and cancer registry data from 1961 to 2005 of 14.9 million individuals aged between 30 and 64 years. Occupational categories were combined into seven socio-economic categories. Standardized incidence ratio (SIR) analyses were conducted with the cancer incidence rates for the entire national study populations used as reference rates. Altogether, 83 997 HNCs-72% in men and 28% in women-were recorded. Among men, a gradient of risk associated with SES was observed for cancers of the tongue, other oral cavity subsites, pharynx, oropharynx and larynx in groups with lower SES. Managers showed decreased SIRs of 0.50 to -0.90 also for cancers of the lip, tongue, other oral cavity subsites, oropharynx, nasopharynx, nose and larynx. In contrast, excess risks of tongue, other oral cavity subsites, pharyngeal, oropharyngeal and laryngeal cancers were observed among clerical (SIRs 1.05-1.16), skilled workers (1.04-1.14), unskilled workers (1.16-1.26) and economically inactive men (1.38-1.87). Among women, no risk gradient similar to that in men was revealed. The current study underscores the influence of SES on the incidence of HNCs and highlights the need for targeted interventions, including tobacco and alcohol control policies, and improved access to healthcare services, particularly for socio-economically disadvantaged populations.

Occupation and tongue cancer in Nordic countries.

Almost 200,000 tongue cancers were diagnosed worldwide in 2020. The aim of this study was to describe occupational risk variation in this malignancy. The data are based on the Nordic Occupational Cancer (NOCCA) study containing 14.9million people from the Nordic countries with 9020 tongue cancers diagnosed during 1961-2005. The standardized incidence ratio (SIR) of tongue cancer in each occupational category was calculated using national incidence rates as the reference. Among men, the incidence was statistically significantly elevated in waiters (SIR 4.36, 95% confidence interval (CI) 3.13--5.92), beverage workers (SIR 3.42, 95% CI 2.02-5.40), cooks and stewards (SIR 2.55, 95% CI 1.82-3.48), seamen (SIR 1.66, 95% CI 1.36-2.00), journalists (SIR 1.85, 95% CI 1.18-2.75), artistic workers (SIR 2.05, 95% CI 1.54-2.66), hairdressers (SIR 2.17, 95% CI 1.39-3.22), and economically inactive persons (SIR 1.57, 95% CI 1.42-1.73). Among women, the SIR was statistically significantly elevated only in waitresses (SIR 1.39, 95% CI 1.05-1.81). Statistically significant SIRs ≤ 0.63 were observed in male farmers, gardeners, forestry workers and teachers, and in female launderers. These findings may be related to consumption of alcohol and tobacco, but the effect of carcinogenic exposure from work cannot be excluded.

Cancer incidence among visual artists: 45 years of follow-up in four Nordic countries

Introduction Professional visual artists constitute a heterogeneous vocational group, including, but not limited to painters, photographers, textile artists, and sculptors who may face exposure to workplace hazardous substances and lifestyle factors that may contribute to the development of selected cancers. The objective of this registry-based cohort study was to assess the cancer incidence among Nordic visual artists. Materials and methods This study is based on data from the Nordic Occupational Cancer (NOCCA) project that combines census data of 15 million people from all Nordic countries and cancer registries from 1961 to 2005. For the present study we selected a cohort of visual artists from Finland, Iceland, Norway, and Sweden. Standardized incidence ratio (SIR) analyses were conducted with the cancer incidence rates for the entire national study populations used as reference rates. Results In male visual artists, there were statistically significant excesses in cancers of the tongue (SIR 2.91, 95% confidence interval 1.74–4.55), oral cavity (2.09, 1.26–3.27), pharynx (2.18, 1.45-–3.15), testis (1.91, 1.11–3.05), renal pelvis (2.48, 1.42–4.03) and bladder (1.33, 1.14–1.55). The risk was significantly decreased for cancers of the lip (0.45, 0.18-0.93) and stomach (0.65, 0.50–0.84). In female visual artists, the only significantly increased risk was observed for breast cancer (1.29, 1.13–1.48) and the only significantly decreased risk for stomach cancer (0.43, 0.17–0.88). The incidence of lung cancer was close to the population average in both sexes. Conclusions The non-elevated incidence of lung cancer suggests a similar prevalence of smoking between visual artists and the general population, while the elevated risk of cancers of mouth and pharynx among male visual artists is suggestive of more widespread alcohol drinking. The excess risk of urogenital cancers might be associated with exposure to solvents.

Occupational variation in the incidence of lip cancer in the Nordic countries

Introduction While certain occupations, such as agriculture and fishery, have been associated with an increased risk of lip cancer, the occupational risk profile of lip cancer and its change over time remain poorly known. This study aims to evaluate the incidence of lip cancer across different occupations in the Nordic countries. Methods The Nordic Occupational Cancer Study (NOCCA) covers 14.9 million people and includes 45 years of cancer incidence data, from 1961 to 2005, linked to occupational categories for all the five Nordic populations. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were used to quantify the risk of lip cancer across occupational categories relative to the entire national populations. Results There were a total of 14,477 male and 3008 female lip cancer patients identified during follow up. The highest SIRs were observed among male fishermen (SIR 2.26, 95% CI: 2.04–2.50), gardeners (SIR 1.60, 95% CI: 1.48–1.72), and farmers (SIR 1.60, 95% CI: 1.55–1.66). A significantly reduced risk of lip cancer (SIR < 0.50) was observed among male physicians, teachers, religious workers, artistic workers, journalists, administrators, printers, waiters, and hairdressers. Among women, no occupations were associated with an increased risk of lip cancer. Conclusions The incidence of lip cancer varies widely between outdoor and indoor occupations. Occupations involving outdoor activity and exposure to sunlight show the most elevated SIRs.

Occupational risk variation of nasopharyngeal cancer in the Nordic countries

BackgroundThe aim of this study was to estimate occupational risk variation in the incidence of nasopharyngeal cancer (NPC) in a large population-based cohort of the Nordic Occupational Cancer (NOCCA) study.MethodsThis study is based on a cohort of almost 15 million persons from Denmark, Finland, Iceland, Norway and Sweden, with 2898 nasopharyngeal cancer cases diagnosed in 1961–2005. The data on occupations were gathered from population censuses and cancer data from the national cancer registries. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were estimated using the national NPC incidence rates as the reference.ResultsThere were 1980 male and 918 female NPC patients. The highest SIRs of NPC were observed among male waiters (SIR 3.69, 95% CI 1.91–6.45) and cooks and stewards (SIR 2.24, 95% CI 1.16–3.91). Among women, launderers had the highest SIR of NPC (2.04, 95% CI 1.02–3.65). Significantly decreased SIRs were found among male farmers (SIR 0.79, 95% CI 0.68–0.92) and male textile workers (SIR 0.49, 95% CI 0.22–0.93).ConclusionsThis study suggests that NPC may be associated with several work-related exposure agents such as smoking, kitchen air pollution and solvents. In future, occupational exposure-risk relations should be studied to understand more about causality and to assess effective prevention strategies.

Incidence of cancer among Nordic police officers.

Police work may expose officers to various circumstances that have potential for increasing their risk of cancer, including traffic-related air pollution, night shift work and radiation from radars. In this study, we examined the incidence of cancer among Nordic male and female police officers. We utilize data from the Nordic Occupational Cancer (NOCCA) project, which linked census data on occupations from Finland, Iceland, Norway and Sweden to national cancer registries for the period 1961 to 2005. We report standardized incidence ratios (SIR) and 95% confidence intervals (CI) of selected cancers for each country by sex, age and calendar period. The cohort included 38 523 male and 1998 female police officers. As compared with the general population, male police officers had a 7% (95% CI: 4-9%) excess cancer risk, with elevated SIRs for various cancer sites, including prostate (SIR 1.19, 1.14-1.25), breast (SIR 1.77, 1.05-2.80), colon (SIR 1.22, 1.12-1.32) and skin melanoma (SIR 1.44, 1.28-1.60). Conversely, male police officers had a lower risk of lung cancer than the general population (SIR 0.72, 0.66-0.77). In female police officers, the SIR for cancer overall was 1.15 (0.98-1.34), and there was a slight excess of cancers of the breast (SIR 1.25, 0.97-1.59) and colon (SIR 1.21, 0.55-2.30). In conclusion, cancer incidence among the police officers was slightly higher than in the general population. Notably, SIRs were elevated for cancer sites potentially related to night shift work, namely colon, breast and prostate cancer.

Socioeconomic status and risk of lung cancer by histological subtype in the Nordic countries.

BackgroundWhile the excess in lung cancer risk among lower socioeconomic status individuals has been widely described, the magnitude of this association across lung cancer subtypes, as well as histotype‐related long‐term incidence trends, are inconclusively reported.AimsWe explored the variation in the incidence of the three main lung cancer histotypes (i.e. squamous cell carcinoma, small cell carcinoma and adenocarcinoma) by socioeconomic status (SES, i.e. upper and lower white collar, upper and lower blue collar, and farming/forestry/fishing) in the adult population of four Nordic countries (i.e. Sweden, Norway, Finland and Denmark).Materials & MethodsWe have used data from the Nordic Occupational Cancer Study (NOCCA), computing age‐standardized incidence rates per 100,000 person‐years truncated at ages 50–69 years, by sex, histotype, country and SES, for the period 1971–2005. We estimated relative risks and the corresponding 95% confidence intervals through Poisson regression models, including terms for SES, age, sex and country, as indicated.ResultsA clear socioeconomic gradient, with a progressive increase in lung cancer risk as SES level decreases, was observed in all subtypes and in both sexes. Favourable lung cancer incidence trends were seen among men for squamous cell and small cell carcinomas, although for adenocarcinomas rates were increasing everywhere except for Finland. Among women, upward temporal trends were seen in all SES groups and for all subtypes, although rates increased to a greater extent for low, compared to high, SES, especially in Denmark and Norway. Farmers showed comparatively lower risks compared to other SES categories.DiscussionThis prospective cohort study shows that substantial socioeconomic inequalities in the incidence of the most important lung cancer histotypes exist in the Nordic Countries, and that these inequalities are on the rise, especially among women.ConclusionSmoking habits are likely to largely explain the observed social gradient for lung cancer histotypes in both sexes.

Parental occupational exposures in wood-related jobs and risk of testicular germ cell tumours in offspring in NORD-TEST a registry-based case–control study in Finland, Norway, and Sweden

ObjectiveWe assessed the association between parental prenatal exposures in wood-related jobs and risk of testicular germ cell tumours (TGCT) in offspring.MethodsNORD-TEST, a registry-based case–control study in Sweden, Finland and Norway, included 8112 TGCT cases diagnosed at ages 14–49 years between 1978 and 2012 with no history of prior cancer, and up to four controls matched to each case on year and country of birth. Parents of cases and controls were identified via linkages with the population registries and their occupational information was retrieved from censuses. The Nordic Occupational Cancer Study Job-Exposure Matrix was used to assign occupational exposures to each parent. Logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI).ResultsMaternal wood-related job was not associated with the risk of TGCT in offspring (OR 1.08, CI 0.55–2.14), while paternal wood-related job was associated with a decreased risk of TGCT in offspring (OR 0.85, CI 0.75–0.96). None of the specific wood-related jobs, such as upholsterers, sawyers, or construction carpenters, were significantly associated with a risk of TGCT. Only exception was observed in a sensitivity analysis which showed an increased risk in the small group of sons of fathers working as ‘cabinetmakers and joiners’ the year before conception (OR of 2.06, CI 1.00–4.25).ConclusionThis large-scale NORD-TEST analysis provided no evidence of an association between parental prenatal exposures in wood-related jobs and TGCT in sons.

The link between occupation and cutaneous melanoma

British Journal of DermatologyVolume 184, Issue 4 p. e135-e135 Plain Language Summary The link between occupation and cutaneous melanoma First published: 09 April 2021 https://doi.org/10.1111/bjd.19846AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Abstract Cutaneous melanoma (CM) is a type of skin cancer. The occurrence of CM in the Nordic countries has increased during the last 60 years. Studies of large populations can help us to understand how the proportion of people with a disease varies over time. However, few studies have examined the risk of CM in people of different occupations in this way. Our aim was to perform such a study in a large Nordic population. Our data were obtained from the Nordic Occupational Cancer Study – ‘NOCCA’. NOCCA links census data with data from cancer registries for Nordic residents aged 30–64 years in Denmark, Finland, Iceland, Norway and Sweden. The data we used covered 45 years of records, from 1961 to 2005. The occupations of the individuals were recorded and grouped into 53 categories, and classed as either indoor, outdoor or mixed (indoor and outdoor) work. The occupations were also sorted by social class. The average of all persons was used for comparison. In total, 83,898 new cases of CM were identified. In all countries combined, men doing outdoor work had a lower than expected risk of CM (21% lower), and men doing indoor work had a higher than expected risk (9% higher). Differences in women pointed in the same direction. Higher social class was associated with a greater than expected risk, by 34% in men and by 31% in women. Technical, transport, military and public safety workers with potential skin exposure to causes of cancer had a risk of CM that was greater than expected. Variation in the risk of CM across people of different occupations may be partly explained by factors linked to personal differences, social class and skin exposure. The risk of getting CM reduced slightly over time. Linked Article: Alfonso et al. Br J Dermatol 2021; 184:672–680. Volume184, Issue4April 2021Pages e135-e135 RelatedInformation

Occupation and cutaneous melanoma: a 45-year historical cohort study of 14·9 million people in five Nordic countries.

The age-adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased during the last 60years. Few prospective population-based studies have estimated the occupational variation in CM risk over time. To determine occupational variation in CM risk. A historical prospective cohort study with a 45-year follow-up from 1961 to 2005 (Nordic Occupational Cancer Study, NOCCA) based on record linkages between census and cancer registry data for Nordic residents aged 30-64years in Denmark, Finland, Iceland, Norway and Sweden. National occupational codes were converted to 53 occupational categories, and stratified into indoor, outdoor and mixed work, and into socioeconomic status. The standardized incidence ratios (SIRs) were estimated as observed number of CM cases divided by the expected number calculated from stratum-specific person-years and national CM incidence rates. During a follow-up of 385 million person-years, 83898 incident cases of CM were identified. In all countries combined, men with outdoor work had a low SIR of 0·79 [95% confidence interval (CI) 0·77-0·81] and men with indoor work had a high SIR of 1·09 (95% CI 1·07-1·11). Differences in women pointed in the same direction. High socioeconomic status was associated with an excess risk: SIR 1·34 (95% CI 1·28-1·40) in men and SIR 1·31 (95% CI 1·26-1·36) in women. Technical, transport, military and public safety workers with potential skin exposure to carcinogens had excess risks. Occupational variation in CM risk may be partly explained by host, socioeconomic and skin exposure factors. Differences in CM risk across socioeconomic groups attenuated slightly over time.

Occupational exposures and male breast cancer: A nested case-control study in the Nordic countries

BackgroundMale breast cancer (MBC) is a rare and understudied disease. There is limited evidence on association between environmental and occupational agents and MBC. Some similarities in risk factors may be shared with female breast cancer. We evaluated solvents, metals, exhaust gases and other agents in relation to MBC within the large Nordic Occupational Cancer Study (NOCCA). MethodsThe study included 1469 MBC cases and 7345 controls from Finland, Iceland and Sweden, matched for the date of birth, sex and country. Cases were identified through national cancer registries. Data on occupation and other demographic indicators were collected from census records and population registries. Overall, 24 occupational exposures were assessed. Exposure estimates were assigned by linking job titles to job-exposure matrices (NOCCA-JEM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated by using conditional logistic regression models. ResultsSignificantly decreased overall OR was observed for physical workload (OR = 0.78, 95% CI 0.67–0.91). Protective effect of physical workload was stronger by increasing exposure level with significant dose-response relationship (p-trend<0.01). Non-significantly increased ORs were observed for trichloroethylene, iron, lead, chromium, welding fumes and wood dust, and decreased ORs for asbestos, silica dust and perchloroethylene. However, these results were not consistent across all analyses. ConclusionsThe current study showed 20–25% protective effect for physical workload at work, while no strong evidence for other agents was observed.

Cancer incidence among Swedish firefighters: an extended follow-up of the NOCCA study

ObjectivesTo evaluate cancer incidence among Swedish firefighters and analyze risk in relation to work duration as a proxy for cumulative exposure.MethodsThis cohort study is based on the Swedish component of the Nordic Occupational Cancer (NOCCA) project. The cohort includes six million people who participated in one or more of the population censuses in 1960, 1970, 1980 and 1990. The census data were linked to the Swedish Cancer Registry for the 1961–2009 period, extending a previous NOCCA follow-up time by 4 years. We identified 8136 male firefighters. SIRs were calculated using cancer incidence rates in the national population as a reference.ResultsWe found a statistically significant excess of non-melanoma skin cancer (SIR = 1.48, 95% CI 1.20–1.80) but no positive relationship between risk and work duration. There was a small, yet statistically significant increased risk of prostate cancer among firefighters with service times of 30 years or more. The first follow-up period (1961–1975) showed an increased risk of stomach cancer relative to the reference group, while the last period (1991–2009) showed an increased risk of non-melanoma skin cancer. There was no excess risk for all cancer sites combined (SIR = 1.03, 95% CI 0.97–1.09).ConclusionsOur results do not support an overall risk of cancer among Swedish firefighters, but a possible risk of non-melanoma skin cancer exists. The previously noted excess of prostate cancer among Swedish firefighters in NOCCA was no longer statistically significant in this extended follow-up but was present among those with the longest service times.

Heavy metals, welding fumes, and other occupational exposures, and the risk of kidney cancer: A population-based nested case-control study in three Nordic countries

ObjectivesTo determine whether occupational exposure to heavy metals (chromium (VI), iron, nickel, lead) and welding fumes is associated with the risk of kidney cancer and to describe whether other occupational exposures included in the Job Exposure Matrix of the Nordic Occupational Cancer (NOCCA) study are associated with the risk. Materials and methodsNested case-control study among individuals registered in population censuses in Finland, Iceland, and Sweden in 1960–1990. A total of 59,778 kidney cancer cases, and 298,890 controls matched on sex, age, and country. Cumulative occupational exposures to metals (chromium (VI), iron, nickel, lead), welding fumes, and 24 other occupational exposure covariates, lagged 0, 10, and 20 years. ResultsOverall, there was no or very little association between kidney cancer and exposures studied. The risk was elevated in individuals with high exposure to asbestos (OR 1.19, 95%CI 1.08–1.31). The risk was significantly decreased for individuals characterized with high perceived physical workload (OR 0.86, 95%CI 0.82–0.91), high exposure to ultraviolet radiation (OR 0.85, 95%CI 0.79–0.92), and high exposure to wood dust (OR 0.82, 95%CI 0.71–0.94). The risk of kidney cancer under the age of 59 was elevated in individuals with high exposure to nickel (OR 1.49, 95%CI 1.03–2.17). The risk of kidney cancer in age 59–74 years was elevated for individuals with high exposure to iron (OR 1.41, 95%CI 1.07–1.85), and high exposure to welding fumes (OR 1.43, 95%CI 1.09–1.89). ConclusionsThe only markedly elevated risks of kidney cancer were seen for the highest exposures of nickel and iron/welding fumes in specific age strata.

Workplace Diesel Exhausts and Gasoline Exposure and Risk of Colorectal Cancer in Four Nordic Countries.

BackgroundEvidence on associations between occupational diesel exhaust and gasoline exposure and colorectal cancer is limited. We aimed to assess the effect of workplace exposure to diesel exhaust and gasoline on the risk of colorectal cancer.MethodsThis case–control study included 181,709 colon cancer and 109,227 rectal cancer cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway, and Sweden. Cases and controls were identified from the Nordic Occupational Cancer Study cohort and matched for country, birth year, and sex. Diesel exhaust and gasoline exposure values were assigned by country-specific job-exposure matrices. Odds ratios and 95% confidence intervals were calculated by using conditional logistic regression models. The results were adjusted for physical strain at work and occupational exposure to benzene, formaldehyde, ionizing radiation, chlorinated hydrocarbons, chromium, and wood dust.ResultsDiesel exhaust exposure was associated with a small increase in the risk of rectal cancer (odds ratio = 1.05, 95% confidence interval 1.02-1.08). Gasoline exposure was not associated with colorectal cancer risk.ConclusionThis study showed a small risk increase for rectal cancer after workplace diesel exhaust exposure. However, this finding could be due to chance, given the limitations of the study.

Variation in Nordic Work-Related Cancer Risks after Adjustment for Alcohol and Tobacco.

Background: Alcohol and tobacco strongly increases the risk of cancers of the tongue, mouth, pharynx, larynx, and oesophagus, and are also established risk factors for cancer of the liver, colon, and rectum. It is well documented that these habits are unequally distributed among occupational groups. Most occupational cohort studies lack information on these potentially important confounders, and may therefore be prone to bias. Aim: The aim of the study is to present Nordic standardized incidence ratios (SIRs) for alcohol and tobacco related cancer by occupation, after adjustment for alcohol and tobacco, and to compare to the unadjusted SIRs. Material and Methods: The study is based on the Nordic Occupational Cancer (NOCCA) database. We used confirmatory factor analysis models for simultaneous analysis of the cancer sites related to alcohol and tobacco, to obtain factors that allow for computation of adjusted expected numbers from the reference rates. We then calculated adjusted SIRs for the relevant cancer sites for each occupation. Results: For some occupations and cancers, the changes of risk estimates were striking, from significantly high to significantly low and vice versa. Among Nordic farmers, unadjusted SIRs for cancer of the mouth and oesophagus were 0.56 (95% confidence interval (CI) 0.51–0.61) and 0.67 (CI 0.63–0.70), respectively. After adjustment, estimates changed to 1.10 (CI 1.01–1.21) and 1.16 (CI 1.10–1.22). Unadjusted SIR for pharynx cancer among wood workers was 0.83 (CI 0.75–0.91), adjusted SIR was 1.14 (CI 1.03–1.25). For larynx cancer, results in the opposite direction were seen: unadjusted SIR for economically inactive was 1.38 (CI 1.31–1.46) while the adjusted SIR was 0.91 (CI 0.86–0.96). Conclusions: Adjustment for the latent indicators of alcohol and tobacco consumption changed risk estimates for several occupations, gave a less confounded description of risk, and may guide in the identification of true risk factors.

Occupational variation in bladder cancer in Nordic males adjusted with approximated smoking prevalence

Background: Occupational exposure has been identified as the most important risk factor for bladder cancer second to smoking. The objective of this study was to estimate the occupational variation in risk of bladder cancer that is not attributable to smoking.Material and methods: In the Nordic Occupational Cancer study (NOCCA), 111,458 cases of bladder cancer and 208,297 cases of lung cancer cases were observed among men in Denmark, Finland, Iceland, Norway and Sweden during 1961–2005. Relative smoking prevalence in an occupation was estimated based on standardized incidence ratio (SIR) for lung cancer in the given occupation. Crude and smoking-adjusted SIRs with 95% confidence intervals (CI) for bladder cancer were calculated for each occupation.Results: The smoking-adjusted SIR for most of the occupations was closer to 1.00 than the unadjusted SIR. The highest statistically significant smoking-adjusted SIRs were observed among chimney sweeps (SIR 1.29, 95% CI 1.05–1.56), waiters (1.22, 1.07–1.38) hairdressers (1.14, 1.02–1.26), cooks and stewards (1.12, 1.01–1.25), printers (1.11, 1.04–1.18) and seamen (1.09, 1.03–1.14).Conclusions: Smoking is a strong risk factor for bladder cancer but there may also be other factors in some specific occupations in addition to smoking. The occupational variation in risk of bladder cancer is small when adjusted for smoking, but risk increasing factors are indicated in some occupations.

Occupational variation in the risk of female breast cancer in the Nordic countries.

This study aimed to determine occupational variations in the incidence of breast cancer in the population-based cohort of Nordic Occupational Cancer Study (NOCCA). The study included long-term follow-up data from almost 7.5million Nordic women. Participants were assigned to one of the 54 occupational categories based on census records at the ages of 30-64years. Sixty-two thousand cases of breast cancer were identified through record linkages between nationwide cancer registries in Finland, Sweden, Norway, Denmark, and Iceland, followed up between 1961 and 2005. Country-specific standardized incidence ratios (SIRs) with 95% confidence intervals were estimated. Overall, the highest risk elevations were seen among military personnel (SIR 1.58, 95% CI 1.03-2.32), dentists (SIR 1.43, 95% CI 1.31-1.56), and physicians (SIR 1.35, 95% CI 1.26-1.46). The lowest risks were observed among gardeners (SIR 0.76, 95% CI 0.74-0.78), farmers (SIR 0.80, 95% CI 0.78-0.82), and woodworkers (SIR 0.75, 95% CI 0.70-0.81). Welders, tobacco workers, and painters had higher SIRs for breast cancer diagnosed at age < 50. A reduced risk was observed among forestry workers, welders, and fishery workers for breast cancers diagnosed both before and after age 50. The SIRs for breast cancer did not vary substantially by histology. A significantly increased risk of breast cancer was observed among laboratory workers in the latest calendar period (1991-2005) compared with earlier periods (1976-1990 and 1961-1975). Occupations such as farming, forestry, driving, and gardening had low SIRs during all periods. The study suggests that the risk of breast cancer varies by occupation. Heterogeneity is also observed in some occupational categories according to age (before or after 50), histology, and calendar period.

Benzene exposure at workplace and risk of colorectal cancer in four Nordic countries

ObjectiveThe aim of this case-control study was to assess the effect of occupational benzene exposure on the risk of colorectal cancer, including its subtypes. MethodsThe study included 181,709 colon cancer and 109,227 rectal cancer cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway and Sweden. Cases were identified from the Nordic Occupational Cancer Study (NOCCA) cohort. Five controls per case were selected from the same cohort, matched for country, birth year, and sex. Occupational benzene exposure for each study participant was estimated by linking their job titles to country specific job-exposure matrices. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by using conditional logistic regression models. The results were adjusted for physical strain at work, formaldehyde, ionizing radiation and wood dust. ResultsIncreased risk was observed for all colorectal cancer (OR = 1.12, 95% CI 1.05–1.18) for the high decile of cumulative benzene exposure, indicating a statistically significant dose-response relationship. This excess risk was mainly seen in ascending colon (OR = 1.27, 95% CI 1.13–1.43), and transversal colon (OR = 1.21, 95% CI 1.01–1.41). The ORs in the highest exposure category were markedly higher in women than in men in all subsites of colon and rectum. ConclusionThis study showed an association between workplace benzene exposure and colorectal cancer. The risk was restricted to ascending and transversal colon, and was the strongest among women.

Mesothelioma in Sweden: Dose-Response Analysis for Exposure to 29 Potential Occupational Carcinogenic Agents.

BackgroundThere is little information on the dose–response relationship between exposure to occupational carcinogenic agents and mesothelioma. This study aimed to investigate this association as well as the existence of agents other than asbestos that might cause mesothelioma.MethodsThe Swedish component of the Nordic Occupational Cancer (NOCCA) study consists of 6.78 million individuals with detailed information on occupation. Mesothelioma diagnoses recorded in 1961–2009 were identified through linkage to the Swedish Cancer Registry. We determined cumulative exposure, time of first exposure, and maximum exposure intensity by linking data on occupation to the Swedish NOCCA job-exposure matrix, which includes 29 carcinogenic agents and corresponding exposure for 283 occupations. To assess the risk of mesothelioma, we used conditional logistic regression models to estimate hazard ratios and 95% confidence intervals.Results2,757 mesothelioma cases were identified in males, including 1,416 who were exposed to asbestos. Univariate analyses showed not only a significant excess risk for maximum exposure intensity, with a hazard ratio of 4.81 at exposure levels 1.25–2.0 fb/ml but also a clear dose–response effect for cumulative exposure with a 30-, 40-, and 50-year latency time. No convincing excess risk was revealed for any of the other carcinogenic agents included in the Swedish NOCCA job-exposure matrix.ConclusionWhen considering asbestos exposure, past exposure, even for short periods, might be enough to cause mesothelioma of the pleura later in life.

Time trends and occupational variation in the incidence of testicular cancer in the Nordic countries.

To describe the trends and occupational variation in the incidence of testicular cancer in the Nordic countries utilising national cancer registries, NORDCAN (NORDCAN project/database presents the incidence, mortality, prevalence and survival from >50 cancers in the Nordic countries) and NOCCA (Nordic Occupational Cancer) databases. We obtained the incidence data of testicular cancer for 5-year periods from 1960-1964 to 2000-2014 and for 5-year age-groups from the NORDCAN database. Morphological data on incident cases of seminoma and non-seminoma were obtained from national cancer registries. Age-standardised incidence rates (ASR) were calculated per 100 000 person-years (World Standard). Regression analysis was used to evaluate the annual change in the incidence of testicular cancer in each of the Nordic countries. The risk of testicular cancer in different professions was described based on NOCCA information and expressed as standardised incidence ratios (SIRs). During 2010-2014 the ASR for testicular cancer varied from 11.3 in Norway to 5.8 in Finland. Until 1998, the incidence was highest in Denmark. There has not been an increase in Denmark and Iceland since the 1990s, whilst the incidence is still strongly increasing in Norway, Sweden, and Finland. There were no remarkable changes in the ratio of seminoma and non-seminoma incidences during the past 50 years. There was no increase in the incidences in children and those of pension age. The highest significant excess risks of testicular seminoma were found in physicians (SIR 1.48, 95% confidence interval [CI] 1.07-1.99), artistic workers (SIR 1.47, 95% CI 1.06-1.99) and religious workers etc. (SIR 1.33, 95% CI 1.14-1.56). The lowest SIRs of testicular seminoma were seen amongst cooks and stewards (SIR 0.56, 95% CI 0.29-0.98), and forestry workers (SIR 0.64, 95% CI 0.47-0.86). The occupational category of administrators was the only one with a significantly elevated SIR for testicular non-seminoma (SIR 1.21, 95% CI 1.04-1.42). The only SIRs significantly <1.0 were seen amongst engine operators (SIR 0.60, 95% CI 0.41-0.84) and public safety workers (SIR 0.67, 95% CI 0.43-0.99). There have always been differences in the incidence of testicular cancer between the Nordic countries. There is also some divergence in the incidences in different age groups and in the trends of the incidence. The effect of occupation-related factors on incidence of testicular cancer is only moderate. Our study describes the differences, but provides no explanation for this variation.