Eri tutkimusten mukaan useissa ammateissa on kohonnut riski sairastua suusyöpään. Alkoholi ja tup... more Eri tutkimusten mukaan useissa ammateissa on kohonnut riski sairastua suusyöpään. Alkoholi ja tupakka ovat suusyövän tärkeimmät riskitekijät. Pohjoismaiseen ammatilliseen syöpätutkimusaineistoon perustuvan tutkimuksen tarkoitus oli selvittää eri ammattien suusyöpäriskiä alkoholinkäytön ja tupakoinnin vakioinnin jälkeen. Aineisto käsittää 14.9 miljoonaa ihmistä ja 28 623 kielen, suuontelon ja nielun syöpätapausta Pohjoismaissa vuosina 1961-2005. Alkoholin kulutusta eri ammateissa on arvioitu maksakirroosikuolleisuuden sekä maksasyöpäilmaantuvuuden perusteella, ja tupakointia keuhkosyöpäilmaantuvuuden perusteella. Useimmissa tapauksissa eri ammattien kohonneet suusyöpäriskit pienenivät alkoholin käytön ja tupakoinnin vakioinnin jälkeen, mutta joihinkin ammatteihin jäi kohonnut riski vielä vakioinnin jälkeenkin. Tälläisiä ammatteja olivat taiteilijat, journalistit, tarjoilijat ja hammaslääkärit. Hammaslääkäreiden kohonnut riski sairastua kielisyöpään on uusi löydös, joka saattaa selittyä ammattiin liittyvällä kemiallisella tai papilloomavirus (HPV) altistuksella. Taiteilijoilla, journalisteilla ja tarjoilijoilla ei löytynyt suusyövälle altistavia tekijöitä, mutta on mahdollista, ettei tutkimuksessa pystytty eliminoimaan kaikkea tupakoinnin ja alkoholinkäytön vaikutusta
Introduction The ambiguity in carcinogenicity of softwood dust intrigued the current study to exp... more Introduction The ambiguity in carcinogenicity of softwood dust intrigued the current study to explore stronger evidence on risk of nasal cancer attributable to lifetime cumulative exposure (CE) to softwood-predominated mixed wood dust across broad wood-processing industries in four Nordic countries. Method A population-based case-control study was conducted on all male cases with nasal adenocarcinoma (393 cases), other types of nasal cancer (2446), and nasopharyngeal cancer (1747) diagnosed in Finland, Sweden, Norway, and Iceland between1961 and 2005. For each case, five male controls, who were alive at the time of diagnosis of the case (index date), were randomly selected, matched by birth-year and country. CEs to wood dust and formaldehyde before the index date were quantified with job-exposure matrix based on occupational titles derived from population censuses. Results Hazard ratios (HRs) and 95% confidence intervals (CIs) for the CE of wood dust were estimated by conditional logistic regression, adjusted for CE to formaldehyde. There was an increasing risk of nasal adenocarcinoma related to wood dust exposure. The HR in the highest CE category of wood dust (≥ 28.82 mg/m3-years) was 16.5 (95% CI: 5.05–54.1). Neither non-adenocarcinoma of the nose nor nasopharyngeal cancer could be linked to wood dust exposure. Conclusion Lifetime CE to softwood-predominated mixed wood dusts is strongly linked to risk of nasal adenocarcinoma but not other types of nasal or nasopharyngeal cancer.
Abstract Background There are studies suggesting that participation in musical activities may pro... more Abstract Background There are studies suggesting that participation in musical activities may protect from cancer. On the other hand, some musicians have a lifestyle that might increase the risk of cancer. The objective of this study was to assess the cancer pattern of musicians in four Nordic countries. Material and methods This study combines census and cancer registry data from 1961 to 2005 for 13 million people from Finland, Iceland, Norway, and Sweden. Standardized incidence ratio (SIR) analyses were conducted with the cancer incidence rates for entire national populations used as reference rates. Results There were 11,401 male and 3105 female musicians with 2039 cancer cases. The SIR for all sites combined was 1.02 (95% confidence interval 0.97–1.07) in men and 1.04 (0.94–1.15) in women. In male musicians, there were statistically significant excesses in oropharyngeal cancer (4.36, 2.73–6.60), esophageal cancer (2.08, 1.51–2.81), liver cancer (1.81, 1.26–2.52), and skin melanoma (1.40, 1.10–1.75). The risk was decreased in lip cancer (0.13, 0.02–0.48), stomach cancer (0.66, 0.50–0.82), and lung cancer (0.77, 0.65–0.90). In female musicians, there were no statistically significant SIRs in any of the cancer types studied, but the risk of breast cancer was significantly elevated in the age category of 70+ (1.52, 1.04–2.15). The overall SIR was stable over the 45 year period of observation, but strong decreases were observed in the SIRs of esophageal cancer, liver cancer, laryngeal cancer, and skin melanoma. Conclusion Musicians have characteristics of indoor workers such as low incidence of lip cancer and high incidence of skin melanoma. The low incidence of lung cancer suggests that the prevalence of smoking among musicians is lower than in the general population while the elevated risk of alcohol-related cancer types suggest that drinking is likely more common among musicians. The cancer risk for all sites combined is still similar to that of the general population in the four countries studied.
Journal of Occupational and Environmental Medicine, 2019
Objective: The aim of this study was to describe the occupational variation in the incidence of k... more Objective: The aim of this study was to describe the occupational variation in the incidence of kidney cancer in the Nordic population. Methods: The population comprised of 14.9 million individuals included in censuses between 1960 and 1990. Standardized incidence ratios (SIRs) were calculated for each occupational group. Results: Significantly increased SIRs were observed in welders [1.24, 95% confidence interval (95% CI) 1.14 to 1.35], public safety workers (1.16, 95% CI 1.08 to 1.25), and seamen (1.16, 95% CI 1.07 to 1.26). Significantly decreased SIRs were found in laboratory assistants (0.76, 95% CI 0.60 to 0.94) and forestry workers (0.77, 95% CI 0.72 to 0.83). Conclusion: A relatively small variation in the incidence of malignancies of the kidney between occupational groups was found in the cohort. There is abundant room for further progress in determining the effect of smoking in particular occupational groups.
We studied the association between occupational exposure to extremely low-frequency magnetic fiel... more We studied the association between occupational exposure to extremely low-frequency magnetic fields (ELF-MF) and electrical shocks and acute myeloid leukemia (AML) in the Nordic Occupational Cancer cohort (NOCCA). We included 5,409 adult AML cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway, and Sweden and 27,045 controls matched by age, sex, and country. Lifetime occupational ELF-MF exposure and risk of electrical shocks were assigned to jobs reported in the censuses using job-exposure matrices. We estimated hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) using conditional logistic regression adjusted for concurrent occupational exposures relevant for AML risk (e.g., benzene, ionizing radiation). We conducted sensitivity analyses with different assumptions to assess the robustness of our results. Approximately 40 % of the subjects were ever occupationally exposed to low levels and 7 % to high levels of ELF-MF, whereas 18 % were ever at low risk and 15 % at high risk of electrical shocks. We did not observe an association between occupational exposure to neither ELF-MF nor electrical shocks and AML. The HR was 0.88 (95 % CI 0.77-1.01) for subjects with high levels of ELF-MF exposure and 0.94 (95 % CI 0.85-1.05) for subjects with high risk of electrical shocks as compared to those with background-level exposure. Results remained materially unchanged in sensitivity analyses with different assumptions. Our results do not support an association between occupational ELF-MF or electric shock exposure and AML.
The age‐adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased durin... more The age‐adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased during the last 60 years. Few prospective population‐based studies have estimated the occupational variation in CM risk over time.
BackgroundConsumption of alcohol and tobacco strongly increases risk of cancer of the tongue, mou... more BackgroundConsumption of alcohol and tobacco strongly increases risk of cancer of the tongue, mouth, pharynx, larynx, and oesophagus, and are established risk factors also 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 do not have information on these potentially important confounders, and may therefore be prone to bias.AimThe aim of the study was to calculate standardized incidence ratios (SIRs) adjusted for alcohol and tobacco by occupation, and to compare to the unadjusted SIRs.Material and methodsThe study is based on the Nordic Occupational Cancer (NOCCA) database.We used confirmatory factor analysis models where the unobserved pattern of alcohol and tobacco consumption were considered a latent common factor, and the potential occupational variation on each cancer type latent site specific factors. Results were used to compute adjusted expected numbers of c...
Introduction: Various established occupational lung carcinogens are also suspected risk factors f... more Introduction: Various established occupational lung carcinogens are also suspected risk factors for laryngeal cancer. However, individual studies are often inadequate in size to investigate this relatively rare outcome. Other limitations include imprecise exposure assessment and inadequate adjustment for confounders. Methods: This study applied a quantitative job exposure matrix (SYN-JEM) for four established occupational lung carcinogens to five case–control studies within the International Head and Neck Cancer Epidemiology Consortium. We used occupational histories for 2256 laryngeal cancer cases and 7857 controls recruited from 1989 to 2007. We assigned quantitative exposure levels for asbestos, respirable crystalline silica, chromium-VI, and chromium-VI and nickel combined (to address highly correlated exposures) via SYN-JEM. We assessed effects of occupational exposure on cancer risk for males (asbestos, respirable crystalline silica, chromium-VI, and chromium-VI and nickel com...
Background Pesticides are commonly used in agriculture, and previous studies endorsed the need to... more Background Pesticides are commonly used in agriculture, and previous studies endorsed the need to further investigate the possible association between their use and risk of lymphoid malignancies in agricultural workers. Methods We investigated the relationship of ever use of 14 selected pesticide chemical groups and 33 individual active chemical ingredients with non-Hodgkin lymphoid malignancies (NHL) overall or major subtypes, in a pooled analysis of three large agricultural worker cohorts. Pesticide use was derived from self-reported history of crops cultivated combined with crop-exposure matrices (France and Norway) or self-reported lifetime use of active ingredients (USA). Cox regression models were used to estimate cohort-specific hazard ratios (HRs) and 95% confidence intervals (CIs), which were combined using random effects meta-analysis to calculate meta-HRs. Results During follow-up, 2430 NHL cases were diagnosed in 316 270 farmers accruing 3 574 815 person-years under risk...
Eri tutkimusten mukaan useissa ammateissa on kohonnut riski sairastua suusyöpään. Alkoholi ja tup... more Eri tutkimusten mukaan useissa ammateissa on kohonnut riski sairastua suusyöpään. Alkoholi ja tupakka ovat suusyövän tärkeimmät riskitekijät. Pohjoismaiseen ammatilliseen syöpätutkimusaineistoon perustuvan tutkimuksen tarkoitus oli selvittää eri ammattien suusyöpäriskiä alkoholinkäytön ja tupakoinnin vakioinnin jälkeen. Aineisto käsittää 14.9 miljoonaa ihmistä ja 28 623 kielen, suuontelon ja nielun syöpätapausta Pohjoismaissa vuosina 1961-2005. Alkoholin kulutusta eri ammateissa on arvioitu maksakirroosikuolleisuuden sekä maksasyöpäilmaantuvuuden perusteella, ja tupakointia keuhkosyöpäilmaantuvuuden perusteella. Useimmissa tapauksissa eri ammattien kohonneet suusyöpäriskit pienenivät alkoholin käytön ja tupakoinnin vakioinnin jälkeen, mutta joihinkin ammatteihin jäi kohonnut riski vielä vakioinnin jälkeenkin. Tälläisiä ammatteja olivat taiteilijat, journalistit, tarjoilijat ja hammaslääkärit. Hammaslääkäreiden kohonnut riski sairastua kielisyöpään on uusi löydös, joka saattaa selittyä ammattiin liittyvällä kemiallisella tai papilloomavirus (HPV) altistuksella. Taiteilijoilla, journalisteilla ja tarjoilijoilla ei löytynyt suusyövälle altistavia tekijöitä, mutta on mahdollista, ettei tutkimuksessa pystytty eliminoimaan kaikkea tupakoinnin ja alkoholinkäytön vaikutusta
Introduction The ambiguity in carcinogenicity of softwood dust intrigued the current study to exp... more Introduction The ambiguity in carcinogenicity of softwood dust intrigued the current study to explore stronger evidence on risk of nasal cancer attributable to lifetime cumulative exposure (CE) to softwood-predominated mixed wood dust across broad wood-processing industries in four Nordic countries. Method A population-based case-control study was conducted on all male cases with nasal adenocarcinoma (393 cases), other types of nasal cancer (2446), and nasopharyngeal cancer (1747) diagnosed in Finland, Sweden, Norway, and Iceland between1961 and 2005. For each case, five male controls, who were alive at the time of diagnosis of the case (index date), were randomly selected, matched by birth-year and country. CEs to wood dust and formaldehyde before the index date were quantified with job-exposure matrix based on occupational titles derived from population censuses. Results Hazard ratios (HRs) and 95% confidence intervals (CIs) for the CE of wood dust were estimated by conditional logistic regression, adjusted for CE to formaldehyde. There was an increasing risk of nasal adenocarcinoma related to wood dust exposure. The HR in the highest CE category of wood dust (≥ 28.82 mg/m3-years) was 16.5 (95% CI: 5.05–54.1). Neither non-adenocarcinoma of the nose nor nasopharyngeal cancer could be linked to wood dust exposure. Conclusion Lifetime CE to softwood-predominated mixed wood dusts is strongly linked to risk of nasal adenocarcinoma but not other types of nasal or nasopharyngeal cancer.
Abstract Background There are studies suggesting that participation in musical activities may pro... more Abstract Background There are studies suggesting that participation in musical activities may protect from cancer. On the other hand, some musicians have a lifestyle that might increase the risk of cancer. The objective of this study was to assess the cancer pattern of musicians in four Nordic countries. Material and methods This study combines census and cancer registry data from 1961 to 2005 for 13 million people from Finland, Iceland, Norway, and Sweden. Standardized incidence ratio (SIR) analyses were conducted with the cancer incidence rates for entire national populations used as reference rates. Results There were 11,401 male and 3105 female musicians with 2039 cancer cases. The SIR for all sites combined was 1.02 (95% confidence interval 0.97–1.07) in men and 1.04 (0.94–1.15) in women. In male musicians, there were statistically significant excesses in oropharyngeal cancer (4.36, 2.73–6.60), esophageal cancer (2.08, 1.51–2.81), liver cancer (1.81, 1.26–2.52), and skin melanoma (1.40, 1.10–1.75). The risk was decreased in lip cancer (0.13, 0.02–0.48), stomach cancer (0.66, 0.50–0.82), and lung cancer (0.77, 0.65–0.90). In female musicians, there were no statistically significant SIRs in any of the cancer types studied, but the risk of breast cancer was significantly elevated in the age category of 70+ (1.52, 1.04–2.15). The overall SIR was stable over the 45 year period of observation, but strong decreases were observed in the SIRs of esophageal cancer, liver cancer, laryngeal cancer, and skin melanoma. Conclusion Musicians have characteristics of indoor workers such as low incidence of lip cancer and high incidence of skin melanoma. The low incidence of lung cancer suggests that the prevalence of smoking among musicians is lower than in the general population while the elevated risk of alcohol-related cancer types suggest that drinking is likely more common among musicians. The cancer risk for all sites combined is still similar to that of the general population in the four countries studied.
Journal of Occupational and Environmental Medicine, 2019
Objective: The aim of this study was to describe the occupational variation in the incidence of k... more Objective: The aim of this study was to describe the occupational variation in the incidence of kidney cancer in the Nordic population. Methods: The population comprised of 14.9 million individuals included in censuses between 1960 and 1990. Standardized incidence ratios (SIRs) were calculated for each occupational group. Results: Significantly increased SIRs were observed in welders [1.24, 95% confidence interval (95% CI) 1.14 to 1.35], public safety workers (1.16, 95% CI 1.08 to 1.25), and seamen (1.16, 95% CI 1.07 to 1.26). Significantly decreased SIRs were found in laboratory assistants (0.76, 95% CI 0.60 to 0.94) and forestry workers (0.77, 95% CI 0.72 to 0.83). Conclusion: A relatively small variation in the incidence of malignancies of the kidney between occupational groups was found in the cohort. There is abundant room for further progress in determining the effect of smoking in particular occupational groups.
We studied the association between occupational exposure to extremely low-frequency magnetic fiel... more We studied the association between occupational exposure to extremely low-frequency magnetic fields (ELF-MF) and electrical shocks and acute myeloid leukemia (AML) in the Nordic Occupational Cancer cohort (NOCCA). We included 5,409 adult AML cases diagnosed between 1961 and 2005 in Finland, Iceland, Norway, and Sweden and 27,045 controls matched by age, sex, and country. Lifetime occupational ELF-MF exposure and risk of electrical shocks were assigned to jobs reported in the censuses using job-exposure matrices. We estimated hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) using conditional logistic regression adjusted for concurrent occupational exposures relevant for AML risk (e.g., benzene, ionizing radiation). We conducted sensitivity analyses with different assumptions to assess the robustness of our results. Approximately 40 % of the subjects were ever occupationally exposed to low levels and 7 % to high levels of ELF-MF, whereas 18 % were ever at low risk and 15 % at high risk of electrical shocks. We did not observe an association between occupational exposure to neither ELF-MF nor electrical shocks and AML. The HR was 0.88 (95 % CI 0.77-1.01) for subjects with high levels of ELF-MF exposure and 0.94 (95 % CI 0.85-1.05) for subjects with high risk of electrical shocks as compared to those with background-level exposure. Results remained materially unchanged in sensitivity analyses with different assumptions. Our results do not support an association between occupational ELF-MF or electric shock exposure and AML.
The age‐adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased durin... more The age‐adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased during the last 60 years. Few prospective population‐based studies have estimated the occupational variation in CM risk over time.
BackgroundConsumption of alcohol and tobacco strongly increases risk of cancer of the tongue, mou... more BackgroundConsumption of alcohol and tobacco strongly increases risk of cancer of the tongue, mouth, pharynx, larynx, and oesophagus, and are established risk factors also 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 do not have information on these potentially important confounders, and may therefore be prone to bias.AimThe aim of the study was to calculate standardized incidence ratios (SIRs) adjusted for alcohol and tobacco by occupation, and to compare to the unadjusted SIRs.Material and methodsThe study is based on the Nordic Occupational Cancer (NOCCA) database.We used confirmatory factor analysis models where the unobserved pattern of alcohol and tobacco consumption were considered a latent common factor, and the potential occupational variation on each cancer type latent site specific factors. Results were used to compute adjusted expected numbers of c...
Introduction: Various established occupational lung carcinogens are also suspected risk factors f... more Introduction: Various established occupational lung carcinogens are also suspected risk factors for laryngeal cancer. However, individual studies are often inadequate in size to investigate this relatively rare outcome. Other limitations include imprecise exposure assessment and inadequate adjustment for confounders. Methods: This study applied a quantitative job exposure matrix (SYN-JEM) for four established occupational lung carcinogens to five case–control studies within the International Head and Neck Cancer Epidemiology Consortium. We used occupational histories for 2256 laryngeal cancer cases and 7857 controls recruited from 1989 to 2007. We assigned quantitative exposure levels for asbestos, respirable crystalline silica, chromium-VI, and chromium-VI and nickel combined (to address highly correlated exposures) via SYN-JEM. We assessed effects of occupational exposure on cancer risk for males (asbestos, respirable crystalline silica, chromium-VI, and chromium-VI and nickel com...
Background Pesticides are commonly used in agriculture, and previous studies endorsed the need to... more Background Pesticides are commonly used in agriculture, and previous studies endorsed the need to further investigate the possible association between their use and risk of lymphoid malignancies in agricultural workers. Methods We investigated the relationship of ever use of 14 selected pesticide chemical groups and 33 individual active chemical ingredients with non-Hodgkin lymphoid malignancies (NHL) overall or major subtypes, in a pooled analysis of three large agricultural worker cohorts. Pesticide use was derived from self-reported history of crops cultivated combined with crop-exposure matrices (France and Norway) or self-reported lifetime use of active ingredients (USA). Cox regression models were used to estimate cohort-specific hazard ratios (HRs) and 95% confidence intervals (CIs), which were combined using random effects meta-analysis to calculate meta-HRs. Results During follow-up, 2430 NHL cases were diagnosed in 316 270 farmers accruing 3 574 815 person-years under risk...
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Papers by Kristina Kjærheim