Finn Tüchsen

A 12 year prospective study of circulatory disease among Danish shift workers

Background: Previous studies of the risk of heart disease after shift work reached different estimates and review authors disagree about the validity of some of the studies. A cross sectional study showed that shift workers had a higher prevalence of nearly every unfavourable work environment factor investigated. Conflicts at work and low decision latitude were more frequent among shift workers, and all-day walking or standing work and part-time jobs were more often found among female shift workers. Objectives: To estimate the risk of circulatory disease in a prospective follow up of a representative sample of gainfully employed Danes, considering known or suspected confounding factors. Methods: A cohort of 5517 people who were gainfully employed in 1990 were followed up for all hospital treatments due to circulatory diseases (390–458, ICD-8; I00–I99, ICD-10) from 1991 to 2002 inclusive. A log linear Poisson regression model was applied to control confounding factors and calculate the relative risk for 927 men and women working nights, evenings, or other non-day shifts compared to 4579 day workers. Results: Non-day workers compared to day workers had a relative risk (RR) for all circulatory diseases of 1.31 (95% CI 1.06–1.63). Without control for BMI and smoking, the RR estimate was 1.33 (95% CI 1.07–1.65). For a subgroup of workers with at least three years’ seniority, the RR was 1.40 (95% CI 1.09–1.81). The population based aetiological fraction of shift work was estimated to 5%. Conclusion: This study adds to a growing body of evidence suggesting that shift work carries an excess risk of circulatory diseases.

Work related violence and threats and the risk of depression and stress disorders

Objective: To examine the risk of depression and stress related disorders as a function of occupational exposure to violence and threats. Design: Population based nested case-control study. Setting: All gainfully employed Danes. Cases and controls: 14 166 hospital inpatients and outpatients, aged 18–65, treated for affective or stress related disorders during 1995–1998 selected from The Danish Psychiatric Central Research Register and 58 060 controls matched for age, sex, and time, drawn from Statistics Denmark’s Integrated Database for Labour Market Research. Main outcome measure: Clinical psychiatric diagnosis (WHO ICD-10) of affective (F30–39) or stress related (F40–48) disorders compared with controls by the occupation held the year before treatment. The occupation held the year before treatment was used as exposure proxy. Results: Potential exposure to occupational violence is associated with significantly increased relative risks of both disorders in either sex (women: depression RR 1.45 CI 1.27 to 1.65, stress RR 1.32 CI 1.19 to 1.46; men: depression RR 1.48 CI 1.18 to 1.86, stress RR 1.55 CI 1.29 to 1.84). Work related threats are associated with increase in the risk of depression in women (RR 1.48 CI 1.23 to 1.79) and the risk of stress related disorders in men (RR 1.59 CI 1.32 to 1.91). Risks rose with increasing prevalence of violence and threats. The results remain significant and only slightly attenuated after controlling for extent of professional contact with people other than colleagues. Conclusions: Employment in occupations involving exposure to work related threats and violence is a risk factor for depression and stress related disorders in both sexes. These findings have implications for health and safety at work policies.

Psychosocial working conditions and the risk of depression and anxiety disorders in the Danish workforce

BackgroundTo examine the risk of depressive and anxiety disorders according to psychosocial working conditions in a large population-based sample.MethodsJob Exposure Matrix was applied to assess psychosocial working conditions in a population-based nested case-control study of 14,166 psychiatric patients, diagnosed with depressive or anxiety disorders during 1995–1998 selected from The Danish Psychiatric Central Research Register, compared with 58,060 controls drawn from Statistics Denmarks Integrated Database for Labour Market Research.ResultsLow job control was associated with an increased risk of anxiety disorders in men (IRR 1.40, 95% CI 1.24–1.58).In women an elevated risk of depression was related to high emotional demands (IRR 1.39, 95%CI 1.22–1.58) and to working with people (IRR 1.15, 95% CI 1.01–1.30). In both sexes high demands were associated with a decreased risk of anxiety disorders. There was a weak association between job strain and anxiety disorders in men (IRR 1.13, 95%, CI 1.02–1.25)ConclusionPsychosocial work exposures related to the risk of depressive and anxiety disorders differ as between the sexes. The pattern of risks is inconsistent. The results give rise to rethinking both study designs and possible causal links between work exposures and mental health.

Cancer incidence in urban bus drivers and tramway employees: a retrospective cohort study

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.

Prolonged standing at work and hospitalisation due to varicose veins: a 12 year prospective study of the Danish population.

Background: Recent studies suggest that prolonged standing at work is associated with the development of diseases of varicose veins (VV). Aims: To assess the risk of hospitalisation due to VV in the lower extremities prospectively in workers standing or walking at least 75% of their time at work. Methods: A representative random sample of 9653 working age adults was drawn from the Central Population Register of Denmark in 1991. Of these, 8664 accepted to be interviewed by telephone (response rate 90%). Respondents (2939 men and 2708 women) were 20–59 years old and employed in 1990. Risk ratios for VV were estimated by log-linear Poisson regression models separately for men and women with adjustment for smoking status, body mass index (BMI), heavy lifting, and, for females only, number of children at baseline. Results: During 12 years of follow up, 40 hospitalisations due to VV were observed among the men and 71 among the women. For employees with jobs that require prolonged standing or walking compared to all other employees, the relative risk was 1.75 (95% CI 0.92 to 3.34) for men and 1.82 (95% CI 1.12 to 2.95) for women. The pooled estimate of the relative risk was 1.78 (95% CI 1.19 to 2.68). The aetiological fraction of prolonged standing or walking at work was estimated as 22.5% for men and 22.6% for women. Conclusions: This prospective study confirms that prolonged standing at work constitutes an excess risk of hospital treatment due to varicose veins and accounts for more than one fifth of all cases of working age.

Hospital admissions among male drivers in Denmark

OBJECTIVES To facilitate decisions about interventions and to establish baseline values for future evaluation of preventive efforts, the aim of the present study was to elucidate the disease pattern among male professional drivers in Denmark. The study differentiated between drivers of goods vehicles and drivers of passenger transport. METHODS Cohorts of all 20–59 year old Danish male professional drivers in the years 1981, 1986, 1991, and 1994 were formed, to calculate age standardised hospital admission ratios (SHRs) and time trends (1981–97) for many diagnostic aggregations. RESULTS SHRs for diseases in practically all systems and organs of the body were higher among professional drivers than they were in the male working population at large. Also drivers of passenger transport, compared with drivers of goods vehicles, had significantly high SHRs due to infectious and parasitic diseases, diseases of the circulatory system, and diseases of the respiratory system, and significantly lower rates of injury. For both driver groups, the SHRs for acute myocardial infarction increased with time whereas the SHR for acute gastritis decreased, and for drivers of passenger transport an increasing SHR for chronic obstructive pulmonary disease, was found over time. CONCLUSION Drivers of passenger transport and drivers of goods vehicles differ in their disease patterns. The results support the hypothesis that preventive efforts are needed in both groups, but underline that different strategies are required for different categories of drivers.

Occupational Factors and 5-Year Weight Change Among Men in a Danish National Cohort

This study explored whether factors related to the work environment could predict changes in body mass index (BMI) and whether the effect of psychosocial factors was dependent on baseline BMI. The sample consisted of 1,980 male employees from the Danish National Work Environment Cohort Study. Changes in BMI between 1995 and 2000 were analyzed, by multiple regression, as a function of background variables and a series of occupational variables obtained in 1995. Age, baseline BMI, job insecurity, and psychological demands predicted changes in BMI. Job insecurity and high or low psychological demands increased the likelihood of weight gain among obese employees, whereas they increased the likelihood of weight loss among employees with a low BMI.

Cobalt Exposure and Cancer Risk

Cobalt is a technically important metal, used mainly as a binder in the hard-metal industry and as a constituent of many alloys. Cobalt compounds are used as drying agents in paints and laquers. Since ancient times, cobalt compounds have been used as coloring agents for pottery, ceramics, and glass. Soluble cobalt salts interfere adversely with cell division, bind irreversibly to nucleic acids in the cell nucleus, induce chromosome aberrations in plants, and are weakly mutagenic in some in vitro tests with cultured animal cells, bacteria, and yeast. Injections or implantation of cobalt metal, cobalt alloys, and cobalt compounds induced local and sometimes metastasizing sarcomas in rats, rabbits, and mice. Mouse is the least susceptible animal. The only published inhalation study with hamsters exposed to CoO aerosols remained non-positive. Indication of possible carcinogenic effects of cobalt alloys or compounds in human populations has arisen from medical use, in hard-metal industries, and at cobalt production. Unfortunately, confounding by nickel and arsenic is a major problem, and the size of most of the investigated populations has been rather small, so none of the investigations alone gives sufficient evidence of a carcinogenic effect in humans, but taken together there is an indication of a carcinogenic potential that should be explored further.

Prolapsed cervical intervertebral disc in male professional drivers in Denmark, 1981-1990. A longitudinal study of hospitalizations.

Study Design This study of professional drivers is a part of a longitudinal record linkage study of all economically active men in Denmark, identified on January 1, 1981. Information about the main occupation was identified in 1980. The cohort was followed for first hospitalization with prolapsed cervical intervertebral disc until December 31, 1990. Objectives To examine the risk of prolapsed cervical intervertebral disc in all Danish professional drivers, and to analyze exposures of the male drivers in a sample of all Danish male drivers. Summary of Background Data Only a few studies on occupation and prolapsed cervical intervertebral disc have been published. These studies suggest that professional driving may be a risk factor for development of prolapsed cervical intervertebral disc. Drivers are exposed to whole‐body vibrations, heavy lifting, and a sedentary position. Other potential exposures are accelerations and decelerations and whiplash accidents. Such exposures may be involved in the causation of prolapsed cervical intervertebral disc. Methods A standardized hospitalization ratio was calculated for each subgroup of drivers using all economically active people as the standard. Additional exposure information was extracted from a national survey on work environment. Results Almost all men in occupations involving professional driving had a statistically significant elevated risk of being hospitalized with prolapsed cervical intervertebral disc. Conclusions Professional driving is a risk factor for prolapsed cervical intervertebral disc.

Occupation and ischemic heart disease in the European Community: A comparative study of occupations at potential high risk

Four longitudinal studies of mortality and morbidity by occupation based on individual record linkage of information and two cross-sectional studies of mortality were compared in order to identify occupations at high risk of ischemic heart disease. In more than one country an increased risk of ischemic heart disease was found in drivers of buses, taxies, and lorries, in bakers, in naval officers and fishermen, in hotel and restaurant workers, in senior police, customs, and other uniformed men, in barbers and hairdressers, in warehouse and wholesale staff, as well as in laboratory assistants and in radio and telegraph operators. Occupations found at high risk in Denmark were also found at high risk in Great Britain and Italy. These occupations may be at genuine high risk. None of these groups work day-work only and several of the groups have psychologically demanding work but unsatisfactory decision authority. Identification of occupations at high risk may help to develop focused preventive strategies.