As the development in mean age of the population and life expectancy has been less favourable in Denmark than in the rest of Western Europe, the Ministry of Health decided to investigate statistics for the period, 1972-1990, for the main areas where Danish life expectancy was poorer. A sharp increase in the incidence of accidental poisoning with medical drugs and alcohol during the period was found to be a factor contributing to the poorer Danish statistics during the period. In the subcategory, death after a fall, there was an increase in incidence among the elderly, but the loss of life-years remained constant. The subcategory, fatal road accidents, manifested a marked reduction in incidence, despite the increase in traffic density during the period, and there was a reduction in the loss of life-years. Thus, in the category, accidental deaths, the increase in the incidence of accidental poisonings would appear to be the only factor contributing to the poorer development in mean age and life expectancy in Denmark.
During the period from 1978-1984 the incidence of cancer among 2,465 male urban bus drivers in three major cities in Denmark was studied. The information with regard to cancer diagnosis was obtained from the Danish Cancer Registry. Danish men in 1981 were used as reference. Standardized Morbidity Ratio (SMR) for bladder- and skin cancer was significantly elevated among the bus drivers with values of 206 and 202, respectively. As to other cancers, no significant deviations from the expected were found. The same result was found when only drivers with more than ten years' seniority were included in the calculations. The incidence of skin cancer remained significantly elevated when corrected for degree of urbanization. Traffic density and whether the drivers worked in Copenhagen or in the province were not related to cancer incidence.
It has previously been shown that long-term oral exposure to cobalt can cause goiter and myxedema. The effect of industrial cobalt exposure on thyroid volume and function was determined for 61 female plate painters exposed to cobalt blue dyes in two Danish porcelain factories and 48 unexposed referents. Thyroid volume was determined by ultrasonography. The cobalt blue dyes were used in one of two forms, cobalt aluminate (insoluble) and cobalt-zinc silicate (semisoluble). Only the subjects exposed to semisoluble cobalt had a significantly increased urinary cobalt content (1.17 micrograms.mmol-1 versus 0.13 micrograms.mmol-1, P less than 0.0001). These subjects also had increased levels of serum thyroxine (T4) and free thyroxine (FT4I) (P = 0.0001 and 0.0029, respectively), unaltered serum thyroid stimulating hormone (TSH), and marginally reduced 3,5,3'-triiodothyronine (T3), whereas thyroid volume tended to be lower (P = 0.14). The group exposed to insoluble cobalt did not differ significantly in any thyroid-related parameters. No correlation between urinary cobalt and FT4I or thyroid volume was found. The study demonstrates an effect of cobalt on thyroid hormone metabolism.
A commercial radioimmunoassay (RA) for salivary cortisol was evaluated using certified reference material in water and spiked to pooled saliva in the range 2.1-89.1 nmol/L. A variance component model for describing the effects of age, body mass index (BMI), diurnal variation, gender, days of sick leave during the past year, and smoking habits was established. Reference intervals for salivary cortisol in 120 healthy individuals performing their routine work were established according to the International Union of Pure and Applied Chemistry (IUPAC) and the International Federation of Clinical Chemistry (IFCC). The method evaluation of the certified reference material in water did not show any bias of the method, i.e. recovery was 97% [CI: 94%; 100.9%]. LOD (detection limit) was 1.59 nmol/L. The ratio between analytical and within-subject variation (CVa/CVi) was 0.14, indicating that the method was adequate for measurement in healthy subjects. Reference intervals were estimated to be from 3.6 to 35.1 nmol/L for samples at the time of awakening (05.27-07.27), 7.6-39.4 nmol/L for peak level in saliva samples collected 20 min after awakening (05.47-07.47), and LOD 10.3 nmol/L for late afternoon samples (17.00-19.00). Reactivity (increase from awakening to 20 min after awakening) was estimated to be 82% [CI: -179; 345%] and recovery (decrease from 20 min after awakening to 18.00) to be 80% [CI: 51; 109%]. Eighteen percent of the subjects showed a decrease in cortisol in saliva from awakening to 20 min after awakening. Salivary cortisol was not affected by age, body mass index, gender, smoking habits or days of sick leave during the past year.
From 1978 to 1985, 2,465 male bus drivers in the three major cities in Denmark were followed with regard to hospital admission due to myocardial infarction (MI) and death due to ischemic heart disease (IHD). In all 2,045 (83%) of these men responded in 1978 to a questionnaire on psychosocial well-being and work conditions. The respondents did not differ from the nonrespondents regarding hospital admissions and death in the follow-up period (1978-1984). Sixty-two cases of MI were registered among the 2,045 bus drivers in 1978-1984. On this basis relative risk for MI was calculated with a multiple regression model for independent variables regarding psychosocial well-being and work conditions. High work load (driving in heavy traffic) was significantly associated with the occurrence of MI. Of the psychosocial factors "no social contact with colleagues" and "increased work pace" were also significantly associated with the occurrence of MI. Smoking habits tended to be associated with the occurrence of MI, while stress symptoms and job dissatisfaction did not. The mental burden on bus drivers working in heavy traffic seems a possible explanation for the findings.
A 5-year follow-up study was conducted among all male busdrivers in Copenhagen, Denmark, in addition to the cross-sectional study. In the follow-up study, the SMR for death due to ischaemic heart disease (ICD 410-414) was 144 and SMR for first clinical episode of acute myocardial infarction (ICD 410) was 139, with men in Copenhagen as controls. 80% of the busdrivers (1396 men) participated in the cross-sectional study. The prevalence of questionnaire-positive angina pectoris was 4.9%; in all age groups this was higher than among the controls, locomotive drivers in Denmark. The high health-related selection of busdrivers is assumed to cause an underestimation of the relative occurrence of ischaemic heart disease. Possible explanations for the findings in this study are discussed.
As part of the World Health Organisation initiated MONICA project, 2000 men and women aged 30, 40, 50, and 60 from the general population were invited to undergo a medical examination with special emphasis on cardiovascular disease. A total of 1504 (75%) participated, 1209 of whom were employed. The participants answered a questionnaire on working, social, and health conditions and underwent clinical examinations that included the measurement of blood pressure and serum cholesterol, triglyceride, high density lipoprotein, fibrinogen, and glycated haemoglobin (HbA1C) concentrations. Using the demand-control model for measuring job strain suggested by Karasek, the employed people were classified according to those who had suffered job strain and those who had not in two different ways. The subjective classification was based on the participants' statements regarding demand and control in their jobs whereas the objective classification was based on job title and mode of payment. More women than men were classified as having high strain jobs. After adjusting for age and sex no significant association was found between coronary risk factors and subjective job strain. A tendency for an association between fibrinogen and job strain was found. Body mass index and HbA1C concentration were significantly associated with objective job strain independent of confounders.
Sudden cardiovascular events among well-known politicians attract much attention--from the mass media and from the public. No previous studies have assessed the job strain profile and level of known cardiovascular risk factors among parliamentary politicians. The study was carried out within the frameworks of the Copenhagen City Heart Study. Some 102 members of the Danish parliament (70 men and 32 women) agreed to participate, giving a response rate of 55%. Three sex- and age-matched participants were drawn for each politician from the Copenhagen City Heart Study. In addition to the completion of large questionnaires on health and working conditions, all participants had a thorough examination, including measurements of height and weight and blood pressure and the drawing of a venous blood sample for the determination of serum lipids, ApolipoproteinA1 and ApolipoproteinB and fibrinogen. Job strain factors and established cardiovascular risk factors were the main outcome factors. Politicians reported much higher job demands, but also much more influence on their job than others. Politicians smoked less, consumed more wine, had higher levels of ApolipoproteinA1, and were taller. With respect to other major cardiovascular risk factors, serum lipids, blood pressure and physical activity, there was no difference between politicians and controls. Politicians had greater job demands, but also more control over their job than others, indicating that the job strain phenomenon should not increase their risk of cardiovascular disease. Other cardiovascular risk factors, job related or conventional, which were unevenly distributed between politicians and controls all favoured politicians. In conclusion, politicians had a more beneficial cardiovascular risk factor profile than a matched random sample from a comparable background population.