Meningitis, sepsis and endocarditis among workers occupationally exposed to pigs.

BACKGROUND: Workers exposed to pigs can develop meningitis, sepsis or endocarditis due to infection with Streptococcus suis transmitted from pigs to man. AIMS: To estimate the risk of these diseases. METHODS: We used the Occupational Hospitalization Register (OHR) which holds information about occupation and hospital treatments for all adults in Denmark. A dynamic population of male workers exposed to pigs was identified every year from 1995 to 2006 by occupational and industrial groups. First hospital treatment or death in the following year due to meningitis, sepsis or endocarditis was identified by ICD-10 codes from the OHR. By comparison with all other economically active men in Denmark, the standardized incidence ratio (SIR) was calculated for these diseases. RESULTS: Among those exposed, we observed 32 cases of meningitis, sepsis and endocarditis during 140,118 person-years. In the reference group, we observed 2680 cases during 15,209,394 person-years. The SIR of the exposed group was 1.35 (95% CI: 0.95-1.92). Among the 32 cases, 7 cases of meningitis and sepsis were specified as caused by infection with streptococci. The SIR for these seven cases was 2.4 (95% CI: 1.1-5.0). CONCLUSIONS: Our study did not find that workers exposed to pigs had an overall increased risk of developing meningitis, sepsis or endocarditis.

A 15-year prospective study of shift work and disability pension.

OBJECTIVE: To estimate the hazard ratio for disability pension associated with shift work. METHODS: Cohorts of shift and day workers were identified in three waves of the Danish Work Environment Cohort Study and followed up for incidence of disability pension in a national register of social transfer payment. A total of 3980 female and 4025 male employees were included in the cohorts. Information about shift work status, age, smoking habits, body mass index and ergonomic work environment were updated according to responses in subsequent waves of the survey when possible. Respondents reporting shift work were classified as shift workers in the following waves as well. Respondents were followed in the register from the time of first interview and were censored at the time of their 60th birthday, emigration, death or end of follow-up (18 June 2006). The authors used the Cox proportional hazards model to estimate hazard ratios for incidence of disability pension and 95% confidence intervals. RESULTS: The authors observed 253 new disability pensions among women and 173 among men during 56 903 and 57 886 person-years at risk respectively, Among women, shift work predicted disability after adjustment for age, general health and socioeconomic status HR 1.39 (95% CI 1.07 to 1.82). After further adjustment for body mass index, smoking habits, socioeconomic status and ergonomic exposures the association remained statistically significant HR 1.34 (95% CI 1.02 to 1.75). Shift work was not associated with disability among men. CONCLUSION: Shift work might be moderately associated with disability pension among women; however, more powerful studies are needed to establish the possible association.

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.

Stroke among male professional drivers in Denmark, 1994-2003.

OBJECTIVES: (1) To estimate the relative risk of stroke among various groups of professional drivers; (2) to determine if any excess risk should be attributed to infarction or haemorrhage; (3) to estimate the relative risk ratio for stroke among professional drivers living in Greater Copenhagen compared to those living outside the metropolis. METHODS: A cohort of 6285 bus drivers, 4204 car, taxi, and van drivers, and 25,879 heavy truck and lorry drivers were followed up for hospital admission due to stroke and sub-diagnoses in the period 1994-2003. Using hospital admission for all economically active men as the standard, the standardised hospitalisation ratios (SHR) were calculated, taking age and county into consideration. RESULTS: There was a high SHR for stroke among all groups of professional drivers (SHR = 132; 95% CI 121-141). Among car, taxi, and van drivers the SHR was 157 (95% CI 132-189), among bus drivers it was 139 (95% CI 119-163), and among heavy truck and lorry drivers it was 124 (95% CI 113-136). The excess risk for all groups of professional drivers was highest for cerebrovascular infarction (SHR = 139; 95% CI 124-155) and lowest for non-traumatic intracranial haemorrhage (SHR = 113; 95% CI 96-133). The excess risks for all groups were significantly higher for cerebrovascular infarction than for non-traumatic intracranial haemorrhage (relative risk ratio (RRR) 1.23; 95% CI 1.01-1.51). The RRR of stroke among drivers in the metropolitan area compared to rural areas was 1.13 (95% CI 0.94-1.36). The RRR for stroke among car, taxi, and van drivers compared to drivers of heavy trucks and of lorries was 1.28 (95% CI 1.03-1.57). CONCLUSION: All groups of professional drivers are at increased risk of stroke. The excess risk is more due to cerebral infarctions than to non-traumatic intracranial haemorrhage. The risk of stroke is higher among drivers carrying passengers than among drivers carrying goods.

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.

Disability retirement among former employees at the construction of the Great Belt Link.

OBJECTIVE: To investigate incidences of disability retirement among men who had been employed at the construction of a large traffic link in Denmark, which involved long working hours and long distances between home and work place. METHODS: Men aged 20-54 years at baseline who had been engaged in the construction of the Great Belt Link (n = 5882) were followed-up for disability retirements from 1996 to 2000. Age-standardized incidence ratios (SIR) were calculated and compared with those of other construction workers (n = 117,157). All economically active men in Denmark were used as the standard population. RESULTS: The SIRs for the two groups were 2.29 (95% confidence intervals (CI): 1.95-2.67) and 0.98 (95% CI: 0.93-1.03), respectively. CONCLUSIONS: The Great Belt construction workers had an elevated risk for disability retirement compared with other construction workers and with economically active men in general.

Hospitalisations among seafarers on merchant ships.

AIMS: To study morbidity among active seafarers in the merchant navy in order to clarify possible work related morbidity and the morbidity related to work and lifestyle where possible preventive measures may be initiated. METHODS: From a register in the Danish Maritime Authority a cohort of Danish merchant seafarers who had been actively employed at sea in 1995 was identified. For each seafarer, information on all employment periods at sea, charge aboard, and ship was available. The cohort was linked with the National In-patient Register in Denmark. Standardised hospitalisation ratios (SHRs) were calculated for all major diagnostic groups using all gainfully employed as reference. RESULTS: Seafarers were shown to be inhomogeneous, with significant differences in SHRs for the same disease groups between different groups of seafarers depending on charge and ship type. SHRs for lifestyle related diseases were high, although rates for acute conditions, such as acute myocardial infarction, were low, probably due to referral bias, as acute conditions are likely to cause hospitalisation abroad, and thus are not included in the study. SHRs for injury and poisoning were high, especially for ratings and officers aboard small ships. CONCLUSION: Despite pre-employment selection, a large proportion of the seafarers constitute a group of workers with evidence of poor health probably caused by lifestyle. The subgroups with high risk of hospitalisation due to lifestyle related diseases also had an increased risk of hospitalisation due to injury and poisoning.

Building camps and work related injuries.

AIMS: To focus on one possible predictor of reported work related injuries--the role of living in building-site camps versus daily commuting from home to construction sites. METHODS: A cohort of construction workers was collected, based on personnel files from contractors involved in the building of the Great Belt Bridge. The files included information on employment periods and whether or not the employees lived in building-site camps. The cohort was followed up for injuries reported to the National Work Environment Authority. RESULTS: Construction workers living in camps reported 217 accidents, of which 24 were serious or fatal. Among those not living in camps we found 262 accidents, of which 29 were serious or fatal. The relative risk for all accidents for camp versus non-camp was 0.84 (95% CI 0.69 to 1.00). The respective figure for serious or fatal accidents was RR = 0.85 (95% CI 0.47 to 1.52). CONCLUSION: Results suggest that high accident rates at large construction sites may be reduced, if commuting is replaced by living on-site.

Socioeconomic status, occupation, and risk of hospitalisation due to coxarthrosis in Denmark 1981-99.

OBJECTIVES: To predict the relative risk and time trend in hospitalisation due to coxarthrosis (CA) among groups of different socioeconomic status and occupations in order to test existing aetiological hypotheses. METHODS: Four consecutive cohorts of all gainfully employed Danish men were followed up for CA. Standardised hospitalisation ratios (SHR) and time trends were calculated. RESULTS: Self employed men had an SHR due to CA of 140 (95% confidence interval (CI) 130 to 151) in 1994-99. It changed -1.2% (95% CI -2 to -0.4) annually from 1981 to 1999. Self employed farmers had an SHR of 286 (95% CI 262 to 313) during 1994-99, increasing 0.14% a year (95% CI -0.9 to 1.1) from 1981 to 1999. Unskilled men had an SHR of 121 (95% CI 113 to 130) in 1994-99. The SHR increased 1.6% annually (95% CI 0.7 to 2.4) from 1981 to 1999. Employed agricultural workers had an SHR of 189 (95% CI 158 to 227) from 1994 to 1999. The SHR increased 3.7% annually (95% CI 1.2 to 6.2) from 1981 to 1999. CONCLUSIONS: The relative risk of hospitalisation due to CA was consistently high among farmers in four successive analyses spanning an 18 year period. The relative risks remained stable over time despite the fact that the number of farmers decreased. The risk increased among employed workers in agriculture and horticulture over that period, and an increased risk was also found among tractor drivers and a few other occupations.

Work environment of Danish shift and day workers.

OBJECTIVES: Both shift work and other work environment factors have been shown to be related to heart disease. This study examined whether shift work is associated with other work environment factors related to heart disease in a random sample of the population. If so, shift work could be acting as a proxy for work environment differences. METHODS: Data on 5940 employees in the Danish Work Environment Cohort Study from 1990 were reanalyzed. The information included work schedules [permanent day work, irregular workhours (including morning work), 2-shift or fixed evening and 3-shift or fixed night], length of workweek, physical factors (noise, heat, dust, passive smoking, walking, standing and monotonous repetitive tasks), and psychosocial factors (including demands and control dimensions, social support, conflicts and job insecurity). RESULTS: At least 1 group of shift workers had a higher prevalence of nearly every unfavorable work environment factor investigated. Exceptions were dust exposure and quantitative demands. Especially conflicts at work and low decision latitude were higher among all the groups of shift workers, and all-day walking or standing work and part-time jobs were more often found among female shift workers. The 3 different shiftwork groups were exposed to different parts of the work environment, and also men and women in shift work differed in relation to the work environment. Age and social class influenced the relationship, but not in any particular pattern. CONCLUSIONS: In a heterogenous population shift work was found to be associated with other work environment factors suspected to cause heart disease.

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.

Standing at work and varicose veins.

OBJECTIVES: This study attempts to determine whether or not prolonged standing at work involves an excess risk for the occurrence of varicose veins. METHODS: A cohort of 1.6 million 20-to-59-year-old Danes gainfully employed in 1991 were followed for 3 years according to first hospitalization due to varicose veins of the lower extremities. The exposure data came from a representative sample of the baseline population. Altogether 5940 people were interviewed about occupational exposure and confounding factors. RESULTS: For men working mostly in a standing position, the risk ratio for varicose veins was 1.85 [95% confidence interval (95% CI) 1.33-2.36] in a comparison with all other men. The corresponding risk ratio for women was 2.63 (95% CI 2.25-3.02). The results were adjusted for age, social group, and smoking. CONCLUSIONS: Working in a standing position is associated with subsequent hospitalization due to varicose veins for both men and women.

Use of a national hospitalization register to identify industrial sectors carrying high risk of severe injuries: a three-year cohort study of more than 900,000 Danish men.

BACKGROUND: Data indicates that Denmark has relatively high risks of occupational injuries. We evaluated all injuries resulting in hospitalization by occupation. METHODS: All gainfully employed men younger than 60 in 1990 were divided into 47 industrial groups and followed using the National Inpatient Registry, for hospitalized injuries 1991-1993. Following ICD-8, injuries were grouped into six categories: head, upper extremities, back, trunk, lower extremities and ruptures, sprains and strains. Standardized industrial hospitalization ratios (SHRs) were calculated and Pearson's independence test was performed for each category. RESULTS: Industrial differences were ascertained for each injury category. The highest associated injury category was upper extremity injuries ranging from SHR = 43 (fire services and salvage corps) to SHR = 209 (slaughterhouse industry). Carpentry, joinery, bricklaying and construction work had significantly high SHRs for all injury categories, whereas administrative work was significantly low throughout. CONCLUSIONS: Occupational surveillance systems based on hospitalized injuries can be used to identify high-risk industries, and thereby suggest where to direct prevention efforts.

Agricultural work and the risk of Parkinson's disease in Denmark, 1981-1993.

OBJECTIVES: This study examined the possible association between agricultural and horticultural work and the subsequent morbidity of Parkinson's disease. METHODS: Fixed cohorts of 2,273,872 men and women aged 20-59 years on 1 January 1981 and identified in the Central Population Register of Denmark were followed, and all first-time hospitalizations with Parkinson's disease as the principal diagnosis during the 13 years until 31 December 1993 were recorded. Standardized hospitalization ratios (SHR) were calculated using all gainfully employed persons as the standard and by multiplying the ratio by 100. Ninety-five percent confidence intervals (95% CI) were calculated on the assumption of a Poisson distribution. RESULTS: A high risk of Parkinson's disease was found for the men and women in agriculture and horticulture (134 cases, SHR 132, 95% CI 111-156). Statistically significantly high risks were found for farmers (79 cases, SHR 130, 95% CI 103-163) and for all men in agriculture and horticulture (109 cases, SHR 134, 95% CI 109-162). CONCLUSIONS: A consistent pattern of high Parkinson's disease morbidity was found among occupational groups employed in agriculture and horticulture.

Social and occupational differences in chronic obstructive lung disease in Denmark 1981-1993.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a common crippling disorder related to exposure to noxious dust and fumes. The purpose of this study was to estimate relative rates of COPD in socioeconomic groups and in 'classic' high-risk industries. METHODS: Cohorts of all gainfully employed 20-59 year old Danes in the years 1981, 1986, and 1991 were formed, to compare standardized hospitalization ratios (SHR) and time trends (1981-93). RESULTS: The risk ratio (RR) between unskilled workers and senior salaried staff was 2.31, (95% CI 2.13-2.51) for men and 1.62 (1.38-1.92) for women. Among classic high-risk occupations we found a decreasing SHR in farmers and an increasing SHR in the hotel and restaurant industry and for taxi and bus drivers. The study confirmed earlier reports on high risks in the metal, rubber, and bakery industries. CONCLUSIONS: Apart from the reduced SHR among farmers there were no signs of decreasing differences in COPD risk.

Increasing inequality in ischaemic heart disease morbidity among employed men in Denmark 1981-1993: the need for a new preventive policy.

BACKGROUND: In the mid 1980s European governments committed themselves to the WHO goal 'reduced inequality in health by year 2000' according to which inequality in health should be reduced by 25% by the year 2000. The study aim is to estimate the time trend in relative risk due to ischaemic heart disease (IHD) morbidity in employment status groups in Denmark in the period from 1981 to 1993 and to recommend a strategy to reduce inequality in health. MATERIAL AND METHODS: The study dealt with change in relative risk of IHD in main employment status AND groups as measured in three successive cohorts. The cohorts were defined as all METHODS: gainfully employed men in Denmark as of 1 January 1981, 1986 and 1991, respectively. Information on employment was retrieved for the three previous years. The cohorts were followed for first admissions with IHD as the principal cause during 5, 5, and 3 years respectively. RESULTS: Managers and white collar workers had an average or low and decreasing relative risk while male blue collar workers had a high and increasing relative risk. Thus the social inequality in IHD is rapidly increasing. Some occupational groups are known to be at high risk. Some of these high-risk groups, such as bus drivers, even have an increasing relative risk. CONCLUSIONS: The general health education has been successful in the prevention of IHD in the high-status groups but has failed to reduce the risk among blue collar workers. Preventive measures against IHD should focus on occupational groups at high, increasing risk and the measures should tailor to their 'subculture.'

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.

[Prolapsed cervical intervertebral disk in professional drivers in Denmark 1981-1990]. / Cervikal diskusprolaps hos erhvervschauffører 1981-1990.

The aim of this study was to estimate the risk of being hospitalized due to prolapsed cervical interverteral disc among male professional drivers in Denmark. A cohort consisting of all economically active persons in Denmark, identified January 1981, gives information on the most important occupation during 1980. The cohort was followed for ten years. Additional data on occupational exposures were extracted from a national survey. Occupational groups such as bus and taxi-cab drivers were found to have an increased risk, of cervical prolapse as did the group of professional drivers as a whole.

[Occupational and chronic inflammatory bowel disease in Denmark]. / Erhverv og kronisk inflammatorisk tarmsygdom i Danmark.

It has been suggested that some occupational groups have a high risk of contracting chronic inflammatory bowel diseases. A cohort, comprising 2,273,872 male and female Danes aged 20-59 on 1 January 1981, and a cohort similarly defined as of 1 January 1986 were followed up for hospitalizations due to chronic inflammatory bowel disease until 31. December 1990. From 1981 to 1990, 6296 first time admissions occurred. Among 15 groups previously found to be at high or low risk only female office staff and health personnel had statistically significantly increased standardized hospitalization ratios. Occupations with non-daytime work did not have an increased risk. Occupations with predominantly sedentary work had a standardized hospitalization ratio of 125 (95% confidence interval 116.9-133.1) compared to occupations without sedentary work. Self-employed had low hospitalization rates, while 'other salaried staff' and "not economically active" had high rates.