Papers by Kristina Kjærheim
children's paraoccupational exposure to chlorpyrifos or 2,4-Dichlorophenoxyacetic Acid (2,4-D) in... more children's paraoccupational exposure to chlorpyrifos or 2,4-Dichlorophenoxyacetic Acid (2,4-D) in a study of farm families who used one of these pesticides as part of their usual practice. Methods The sample included 34 applicators applying 2,4-D (n=53 children) or chlorpyrifos (n=50 children). Sequential 24 hour urine samples were collected on the day preceding application through the third day after application of chlorpyrifos or 2,4-D. Maximum post-application urine concentrations of 3,5,6-trichloropyridinol (TCP), a chlorpyrifos metabolite, and 2,4-D (log-transformed) were used to examine the association of children's exposure with applicator exposure using mixed model regression including a random intercept for farm to account for correlation. The final adjusted model included children's age, gender, and presence during the application as covariates. Separate models were fit based on children's presence or absence during the application. Results Adjusted models revealed positive associations between children's exposure with applicators' exposure (TCP: b=0.257; 95% CI=0.052, 0.462; 2,4-D: b=0.593, 95% CI=0.364, 0.822). The association persisted among children who were absent during the application process (TCP: b=0.218, 95% CI=À0.029, 0.466; 2,4-D: b=0.547, 95% CI=0.283, 0.811). Conclusions Specific pesticide exposure pathways to children living on farms are difficult to identify, but these data indicate that applicator exposure is associated with exposures to their children absent any known direct exposure to the children. Applicators protecting themselves from exposures may also protect their children.
Cancer Causes & Control, Aug 27, 2018
Objective This study aimed to determine occupational variations in the incidence of breast cancer... more Objective This study aimed to determine occupational variations in the incidence of breast cancer in the population-based cohort of Nordic Occupational Cancer Study (NOCCA). Methods The study included long-term follow-up data from almost 7.5 million Nordic women. Participants were assigned to one of the 54 occupational categories based on census records at the ages of 30-64 years. 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. Results 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. Conclusions 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.
European Urology Supplements, Mar 1, 2018
Occupational and Environmental Medicine, Sep 1, 2011
BJUI, Oct 3, 2018
The study cohort comprised 14.9 million individuals. Data on occupational history were obtained f... more The study cohort comprised 14.9 million individuals. Data on occupational history were obtained from national censuses. Standardized incidence ratios (SIRs) were calculated for each occupation. Results The highest SIRs were found in seamen (1.51, 95% confidence interval [CI] 1.23-1.82), printers (1.39, 95% CI 1.11-1.71), welders (1.37, 95% CI 1.03-1.78), and public safety workers (1.35, 95% CI 1.12-1.62). The lowest SIRs were observed in forestry workers (0.47, 95% CI 0.35-0.62), gardeners (0.72, 95% CI 0.62-0.83) and woodworkers (0.81, 95% CI 0.72-0.91). Conclusions The study suggests that there is an association between profession and risk of malignancy of the renal pelvis. The possible associations between exposure to asbestos, heavy metals and welding fumes, and risk of developing the disease should be studied further.
Abstracts, Mar 1, 2023
Conclusions These is the preliminary results of RUCAN Study, first Brazilian cohort of rural work... more Conclusions These is the preliminary results of RUCAN Study, first Brazilian cohort of rural workers. After with the complete sampling and the follow up, we hope to identify the health endpoints due pesticides exposure, as well each pesticides effects in the health endpoints.
Abstracts, Mar 1, 2023
40.2%, 40.4%, and 37.5%, respectively. 96.3% of them were full-vaccinated or get a booster shot. ... more 40.2%, 40.4%, and 37.5%, respectively. 96.3% of them were full-vaccinated or get a booster shot. There was no significant difference in the breakthrough infection rate of workers in these three work settings no matter getting two or three shots of vaccine. Conclusions Workplace infection especially after full vaccination is not an important SARS-CoV-2 transmission pathway.
Cancer incidence and mortality in the Norwegian Fire Departments cohort: Are incidence versus mortality outcome measures contributing to variability in risk estimates?
Safety and health at work, 2022
Occupational risk for oral cancer : dentists have an increased 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
P048 Lifetime occupational exposure to wood dust and risk of nasal and nasopharyngeal cancer – a case-control study among men in four nordic countries
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.
Cancer incidence among musicians: 45 years of follow-up in four Nordic countries
Acta Oncologica, Jun 23, 2021
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.
Acta Oncologica, Feb 3, 2020
Background Evidence suggests that among some occupational groups, there is an elevated risk of ki... more Background Evidence suggests that among some occupational groups, there is an elevated risk of kidney cancer. This might, however, derive from a difference in smoking habits across occupational groups. The objective of this study was to determine smoking-adjusted occupational variation in the incidence of kidney cancer in Nordic males. Materials and Methods The source population for this study consisted of 7.4 million men from Denmark, Iceland, Finland, Norway, and Sweden. Data on occupation were obtained from national censuses conducted in the years 1960-1990. Data on cancer cases came from national cancer registries. A proxy for the occupation-specific smoking prevalence among all Nordic men was calculated based on the occupationspecific smoking prevalence and lung cancer incidence data for Finnish men.
Occupation and Risk of Kidney Cancer in Nordic Countries
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.
Occupational exposure to extremely low-frequency magnetic fields and electrical shocks and acute myeloid leukemia in four Nordic countries
Cancer Causes & Control, May 14, 2015
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.
Occupation and cutaneous melanoma: a 45‐year historical cohort study of 14·9 million people in five Nordic countries*
British Journal of Dermatology, Sep 10, 2020
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.
Anticancer Research, May 29, 2017
Aim: To evaluate occupational risk for cancer of the tongue, oral cavity or pharynx after adjustm... more Aim: To evaluate occupational risk for cancer of the tongue, oral cavity or pharynx after adjustment for alcohol and tobacco use. Materials and Methods: The data covered 14.9 million people and 28,623 cases of cancer of the tongue, oral cavity and pharynx in the Nordic countries 1961-2005. Alcohol consumption by occupation was estimated based on mortality from liver cirrhosis and incidence of liver cancer. Smoking by occupation was estimated based on the incidence of lung cancer. Results: Only few occupations had relative risks of over 1.5 for cancer of the tongue, oral cavity and pharynx. These occupations included dentists, artistic workers, hairdressers, journalists, cooks and stewards, seamen and waiters. Conclusion: Several occupational categories, including dentists, had an increased relative risk of tongue cancer. This new finding remains to be explained but could be related to occupational chemical exposures, increased consumption of alcohol and tobacco products, or infection with human papilloma virus. There are several occupations that are associated with excess risk of cancer of the tongue, oral cavity or pharynx in different studies (1-6). Lower social class has been related to an increased risk of cancer of the mouth and pharynx in some studies (4, 5, 7, 8), but not in all (1, 9). In our previous study, which evaluated the incidence of cancer of the mouth and pharynx in relation to 393 occupational titles and 43 chemical agents in Finland in 1971-95, occupations with high standardized incidence ratios (SIRs) were mostly the ones with high consumption of alcohol (10). Alcohol and tobacco are well-known risk factors for cancer of the mouth and pharynx (11). The objective of this study, based on data of the Nordic Occupational Cancer (NOCCA) study, was to determine if occupational risk variation exists in cancer of the tongue, oral cavity or pharynx after adjustment for alcohol and tobacco consumption. Alcohol consumption in different occupations was estimated at aggregate level on the basis of mortality from liver cirrhosis and incidence of liver cancer in these categories, available in NOCCA data. Smoking by occupation was estimated based on the incidence of lung cancer. Materials and Methods The NOCCA project presented up to 45 years of cancer incidence data by occupational category for the Nordic populations (12). The data covered 14.9 million people aged 30-64 years in Denmark,
Abstracts
Conclusions These is the preliminary results of RUCAN Study, first Brazilian cohort of rural work... more Conclusions These is the preliminary results of RUCAN Study, first Brazilian cohort of rural workers. After with the complete sampling and the follow up, we hope to identify the health endpoints due pesticides exposure, as well each pesticides effects in the health endpoints.
Occupational and Environmental Medicine, 2019
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...
Epidemiology, 2019
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...
International Journal of Epidemiology, 2019
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