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Objective: To investigate the risk of cancer associated with exposure to air pollution among bus drivers and tramway employees.Methods: A retrospective cohort study of 18,174 bus drivers or tramway employees in Copenhagen in the period 1900-94. Data on employment were obtained from company files. Information on cancer was obtained from the Danish Cancer Registry.Results: Findings showed that bus drivers or tramway employees had an increased risk of all malignant neoplasms (standardised incidence ratio (SIR) 1.24, 95% confidence interval (95% CI) 1.19 to 1.30). The relative risk was significantly increased for both men and women (SIR 1.24, 95% CI 1.19 to 1.30 and 1.28, 1.06 to 1.53, respectively). People employed for < 3 months had no increased risk of cancer (1.04, 0.81 to 1.31). For men who were employed for > 3 months the risk of lung cancer (1.6, 1.5 to 1.8), laryngeal cancer (1.4, 1.0 to 1.9), kidney cancer (1.6, 1.3 to 2.0), bladder cancer (1.4, 1.2 to 1.6), skin cancer (1.1, 1.0 to 1.2), pharyngeal cancer (1.9, 1.2 to 2.8), rectal cancer (1.2, 1.0 to 1.5) and liver cancer (1.6, 1.2 to 2.2) was significantly increased. For women employed for > 3 months the risk of lung cancer was significantly increased (2.6, 1.5 to 4.3).Conclusion: This cohort study shows that bus drivers and tramway employees are at an increased risk of developing several types of cancer. This might be due to the exposure to air pollution during working hours or to other risk factors, primarily smoking. [ABSTRACT FROM AUTHOR]

Background: Both perceived job insecurity and unemployment has been associated with an increased risk of developing mental ill health. It has, moreover, been proposed that an insecure employment may be as detrimental as unemployment itself., Objective: To estimate incidence rate ratios (RRs) of (i) redeemed prescriptions for psychotropic drugs and (ii) psychiatric hospital treatment due to mood, anxiety, or stress-related disease, among fixed-term contract workers (as an operationalization of insecure job) vs. unemployed, in the general population of Denmark., Methods: Data on baseline employment status were drawn from the Danish Labor Force Surveys in the years 2001-2013. Participants (10,265 fixed-term contract workers and 7926 unemployed) were followed for up to 5 years in national registers (2439 cases of psychotropic drug use, 71,516 person years; 311 cases of psychiatric hospital treatment, 86,790 person years). Adjusted RRs were obtained by Poisson regression. We aspired to minimize health selection effects by (i) exclusion of survey participants who received sickness benefits, social security cash benefits, psychiatric hospital treatment or a prescription for psychotropic drugs, within 1-year prior to baseline (n = 11,693), (ii) adjustment for age, gender, level of education, calendar year, disposable family income and maternity/paternity benefits within 1-year prior to baseline., Results: The adjusted RR for fixed-term contract workers vs. unemployed was 0.98 (99.5% CI: 0.87-1.11) for psychotropic drugs and 0.93 (99.5% CI: 0.67-1.30) for psychiatric hospital treatment., Conclusion: The present study did not find significant differences in the risk of developing mental ill health between fixed-term contract workers and unemployed, and thus suggests that fixed-term contracts may be as detrimental as unemployment., Trial Registration: International Registered Report Identifier (IRRID): DERR2-10.2196/24392., (© 2022. The Author(s).)

Background: In 2018, 14% of employees in the European Union had fixed-term contracts. Fixed-term contract positions are often less secure than permanent contract positions. Perceived job insecurity has been associated with increased rates of mental ill health. However, the association between fixed-term contract positions and mental ill health is uncertain. A recent review concluded that the quality of most existing studies is low and that the results of the few studies with high quality are contradictory., Objective: This study aims to estimate the incidence rate ratios (RRs) of psychotropic drug use and psychiatric hospital treatment. These ratios will be considered, first, in relation to the contrast fixed-term versus permanent contract and, second, to fixed-term contract versus unemployment., Methods: Interview data with baseline information on employment status from the Danish Labor Force Surveys in the years 2001-2013 will be linked to data from national registers. Participants will be followed up for up to 5 years after the interview. Poisson regression will be used to estimate incidence RRs for psychiatric hospital treatment for mood, anxiety, or stress-related disorders and redeemed prescriptions for psychotropic drugs, as a function of employment status at baseline. The following contrasts will be considered: full-time temporary employment versus full-time permanent employment and temporary employment (regardless of weekly working hours) versus unemployment. The analyses will be controlled for a series of possible confounders. People who have received sickness benefits, have received social security cash benefits, have redeemed a prescription for psychotropic drugs, or have received psychiatric hospital treatment for a mental disorder sometime during a 1-year period preceding baseline will be excluded from the study. The study will include approximately 134,000 participants (13,000 unemployed, 106,000 with permanent contracts, and 15,000 with fixed-term contracts). We expect to find approximately 16,400 incident cases of redeemed prescriptions of psychotropic drugs and 2150 incident cases of psychiatric hospital treatment for mood, anxiety, or stress-related disorders., Results: We expect the analyses to be completed by the end of 2021 and the results to be published in mid-2022., Conclusions: The statistical power of the study will be large enough to test the hypothesis of a prospective association between fixed-term contract positions and mental illness in the general workforce of Denmark., International Registered Report Identifier (irrid): DERR1-10.2196/24392., (©Harald Hannerz, Hermann Burr, Helle Soll-Johanning, Martin Lindhardt Nielsen, Anne Helene Garde, Mari-Ann Flyvholm. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 05.02.2021.)

Purpose: A recent study among female nurses in Denmark found an increased mortality among night-time workers, which has raised concerns about the sufficiency of the EU Working Time Directive. The aim of the present study was to examine the relationship between night-time work and all-cause mortality among full-time employees in the general workforce of Denmark., Methods: Interview data from the Danish Labour Force Surveys, 1999-2013, were linked to national registers with individual-level data on occupation, industry, socioeconomic status (SES), emigrations and deaths. The participants (N = 159,933) were followed from the end of the calendar year of the interview until the end of 2014. Poisson regression was used to estimate rate ratios for all-cause mortality, with and without stratification by sex and socioeconomic status. A likelihood ratio test was used to test the overall null-hypothesis, which stated that the mortality rates were independent of night-time work, SES × night-time work and sex × night-time work., Results: The likelihood ratio test did not reject the null hypothesis (p = 0.14). The rate ratio for all-cause mortality among employees with vs. without night-time work was estimated at 1.07 (95% CI 0.97-1.19) after adjustment for age, sex, SES, calendar time, weekly working hours and time passed since the start of follow-up., Conclusions: The present study did not find any statistically significant associations between night-time work and all-cause mortality among employees in the general workforce of Denmark.

Background: In keeping with the need to protect the safety and health of workers, the EU Working Time Directive stipulates that a worker's average working time for each 7-day period, including overtime, does not exceed 48 h. It has, however, not been settled whether or not the threshold at 48 working hours a week is low enough to protect against excess mortality from long work weeks. The aim of the present study was to examine all-cause mortality in relation to weekly working hours among employees in the general population of Denmark. A special attention was given to mortality rates among employees with moderately long work weeks, 41-48 h., Methods: Interview data from cohorts of 20-64 year-old employees were drawn from the Danish Labour Force Survey. The participants (N = 159 933) were followed through national registers from the end of the calendar year of the interview (1999-2013) until the end of 2014. Rate ratios (RRs) for all-cause mortality were estimated as a function of weekly working hours while controlling for age, sex, social class, night-time work and calendar year., Results: We found 3374 deaths during an average follow-up time of 7.7 years. With 32-40 working hours a week as reference, the RRs for all-cause mortality were 0.75 (95% CI: 0.66-0.85) for 41-48 and 0.92 (0.80-1.05) for >48 h., Conclusion: Mortality rates in Denmark are significantly lower among employees with moderately long work weeks than they are among full-time employees without overtime work.

Colonoscopy is recommended for persons with a familial risk of colorectal cancer (CRC). A familial risk is identified by a family history with CRC and/or predisposing mutation(s). However, such information may not be available. We analysed whether MSI (MicroSatellite Instability) and/or CIN (Chromosome INstability=LOH (loss of heterozygosity) and/or DNA-aneuploidy (abnormal nuclear DNA contents)) could be used as predictors of familial CRC. Formalin-fixed tissue from 97 patients with CRC (29 patients with 2 or more affected first-degree relatives (="cases"), 29 matched CRC controls without a family history, and 39 relatives to cases) were analysed for MSI and CIN. In this small case-control study, no significant differences in the frequencies of MSI and CIN were observed between cases with a family history and their controls without a family history. MSI+;CIN- was observed in 6/29 cases and in 0/29 controls (p=0.02), most frequently in cases with affected siblings, only (3/7). However, for 13 patients from whom several CRC tumours were analysed, concordant results for MSI/LOH/DNA-ploidy were obtained only in 10/9/9. Among cases and relative(s), concordant results for MSI, LOH and DNA-ploidy were obtained in 16/26, 16/26, and 14/25 families, respectively.Although MSI+;CIN- appeared to predict familial CRC with a high specificity, neither MSI, CIN, or MSI+;CIN- are likely to be sufficiently sensitive predictors of familial CRC.

Objectives: Our objective was to study the risk of cancer associated with exposure to air pollution among mail carriers., Methods: We carried out a retrospective cohort study of 17,233 persons who had been mail carriers during the period 1898-1996. Data on employment was obtained from company files. Data on cancer was obtained from the Danish Cancer Registry., Results: Male mail carriers employed for more than 3 months had a low incidence of cancer, standardised incidence ratio (SIR) 0.92. For cancers related to air pollution the risk estimates were 0.96 for lung cancer, 0.91 for laryngeal cancer and 0.98 for bladder cancer. A significant low risk for cancer of the oesophagus (SIR 0.50), kidney (SIR 0.73), prostate (SIR 0.81) and skin (melanoma) (SIR 0.87) was seen. Among female mail carriers the risk pattern showed a significant excess of cancer of the cervix uteri (SIR 2.24)., Conclusion: In our study of mail carriers who had spent most of their day doing physical hard work outside in the general air pollution we saw no excess in cancers related to air pollution compared with the general population of Copenhagen. This might be due to the protective effect of physical activity., (Copyright 2004 Springer-Verlag)

Introduction: The Danish National Hospital Register contains four patient types: full-time inpatients, part-time inpatients, outpatients and emergency ward patients. The aim of the present study was to investigate whether results from comparative hospital register studies depend on which patient types we choose to include in the analysis., Methodology: The hospital register was linked to the centralised civil register and the employment classification module. All economically active persons in Denmark aged 20-59 years 1st January 1995 (N = 2,281,480) were followed for six years. We calculated SIRs, first by county then by industry and finally by industry adjusted for county, for a variety of diagnostic groups and for each of the following types of cases: A) full-time inpatients, B) all inpatients, C) all inpatients and outpatients, D) all patients. The ratio between the maximum and the minimum of the four types of SIRs was calculated for each combination of the examined population groups and diseases. A max/min ratio was regarded as a sign of referral bias if it was above 1.2 and statistically significant., Results: When calculating SIRs by county 46.7 percent of the max/min ratios signified referral bias. The percentage was 5.5 when calculating SIRs by industry and only 1.7 when they were calculated by industry adjusted for county., Conclusions: Estimates of geographical health differences are often distorted by differences in the health care organisation. Estimates of industrial health differences tend to be robust with a few identifiable exceptions. Standardisation for county will eliminate bias.

Background: The combustion of fossil fuels produces small amounts of mutagenic and carcinogenic compounds. We investigated the association between employment and lung and bladder cancer in Danish bus drivers and tramway employees., Methods: We carried out a nested case-control study of 153 lung and 84 bladder cancer cases, and 606 controls sampled in a cohort of 18 174 bus drivers or tramway employees employed in Copenhagen during the period 1900-1994. The cases and controls or their next of kin were interviewed about smoking, along with occupational and residential history. An exposure index based on which bus routes the bus drivers had mainly been driving was established. Relative risks (RRs) were estimated by conditional logistic regression., Results: The analysis showed decreasing risk for lung cancer with increasing years of employment as a bus driver (RR = 0.97 for each added year, 95% confidence interval = 0.96-0.99). The air pollution index based on main bus for the bus drivers showed no positive correlation with risk.

Objectives: To evaluate the validity of information about employment obtained from self-respondents and proxies in a nested case-control study., Methods: We interviewed 230 self-respondents and 652 proxies covering 237 cancer cases and 645 controls. Questions about employment as a bus driver, other jobs, and residence were asked. Golden standard was employment data obtained from personnel records., Results: All categories of respondents tended to over-report the length of employment, and respondents aged above 70 years had significantly decreased odds ratio for disagreement between interview and company files compared with respondents below the age of 60 years. There were no significant differences in whether the respondent was a case or control as there were no differences in whether the respondent was a self-respondent or a proxy. The validity of the reported employment time was statistically independent of the interval between death and proxy contact. Compared with the self-responders, the proxies reported significantly fewer jobs and residential areas., Conclusions: In general, data obtained from cases and controls not knowing that the study was about cancer and without the interviewer's knowing who were cases and who were controls appeared good. The quality of information obtained from proxies appeared good as well. There seems to be no problem in interviewing very old people about a specific job when they are mentally prepared for it. The time interval between death and proxy contact was without importance.

We have studied the influence of individual susceptibility factors on the genotoxic effects of urban air pollution in 106 nonsmoking bus drivers and 101 postal workers in the Copenhagen metropolitan area. We used the frequency of chromosomal aberrations in peripheral blood lymphocytes as a biomarker of genotoxic damage and dimethylsulfate-induced unscheduled DNA synthesis in mononuclear WBCs, the glutathione S-transferase M1 (GSTM1) genotype, and the N-acetyltransferase 2 (NAT2) genotype as biomarkers of susceptibility. The bus drivers, who had previously been observed to have elevated levels of aromatic DNA adducts in their peripheral mononuclear cells, showed a significantly higher frequency of cells with chromosomal aberrations as compared with the postal workers. In the bus drivers, unscheduled DNA synthesis correlated negatively with the number of cells with gaps, indicating a protective effect of DNA repair toward chromosome damage. Bus drivers with the GSTM1 null and slow acetylator NAT2 genotype had an increased frequency of cells with chromosomal aberrations. NAT2 slow acetylators also showed elevated chromosomal aberration counts among the postal workers. Our results suggest that long-term exposure to urban air pollution (with traffic as the main contributor) induces chromosome damage in human somatic cells. Low DNA repair capacity and GSTM1 and NAT2 variants associated with reduced detoxification ability increase susceptibility to such damage. The effect of the GSTM1 genotype, which was observed only in the bus drivers, appears to be associated with air pollution, whereas the NAT2 genotype effect, which affected all subjects, may influence the individual response to some other common exposure or the baseline level of chromosomal aberrations.

To investigate the familial aggregation of colorectal cancer in Denmark, parents and siblings of colorectal cancer patients diagnosed below age 60 years in the years 1982-1984 were identified through population registries. For 1,470 probands with families eligible for tracing, 1,376 mothers, 1,303 fathers and 3,259 siblings were identified. They contributed 222,634 person-years, and 325 cases of colorectal cancer were observed during the follow-up period 1943-1992. All data were retrieved from population registries and consequently were free from any reporting bias. The overall standardized morbidity ratio (SMR) compared with the Danish population was 2.02 (95% confidence interval [CI] 1.81-2.25), significantly different between the parents (1.78, 95% CI 1.55-2.04) and the siblings (2.65, 95% CI 2.21-3.17). A strong dependence on the proband's age at diagnosis was seen for the sibling risk; siblings of probands less than 50 years old at diagnosis had a 5-fold risk compared with the general population. This dependence was not seen for parents, but the risk tended to be higher for parents of younger ages. No other factor was seen to influence the relative risk. The observation of an 80% increased risk among the parents and a 170% increased risk among the siblings indicates that the genetic component is one source, but probably not the only one, of familial aggregation of colorectal cancer. The cost benefit of screening siblings of colorectal cancer patients is substantially higher than that for the total population.

Cancers of the digestive organs and peritoneum constituted 28% of all cancers in Denmark in 1943-87. The lack of a common trend in incidence rates for the different tumour types indicates different aetiologies. Survival is worst for cancer of the oesophagus and improves gradually for cancer of the stomach, cancer of the small intestine and colorectal cancers. Survival from these tumours differ little between the sexes, but females have a slightly more favourable prognosis, which is most pronounced for sites with the best survival. The changes in survival over the study period, 1943-87, show virtually no change in the prognosis for oesophageal cancer, very slight, if any, improvement in that for stomach cancer, a detectable improvement in survival from cancer of the small intestine and substantial improvements in survival from colorectal cancer. Survival rates after colorectal cancer appear to be lower in Denmark than those seen in the USA. This finding may be due to the exclusion of certain precancerous lesions from the Danish material, which is not possible in US studies. Cancers of the liver, gallbladder and pancreas all carry extremely high mortality rates, with five-year survival rates below 5%, and one-year survival rates below 5% for cancers of the liver and pancreas.