The role of infection in the aetiology of childhood leukaemia is unknown. We used prescriptions of antibiotics from Danish pharmacies as a proxy measure for the occurrence of infections.
We investigated the association between exposure to antibiotics, from conception to leukaemia diagnosis, and the risk of leukaemia. Incident cases of leukaemia among children in Denmark, 1995-2008, with mothers having their earliest conception date in 1995, were individually matched to population controls by age, sex and municipality. Conditional logistic regression analyses assessed antibiotic redemptions in different time periods from conception up to 6 months before the diagnoses of all leukaemia types, acute lymphoblastic leukaemia [ALL] and ALL in 2- to 5-year-old children, adjusting for several potential confounders.
A total of 120/360 (33.3%) leukaemia mothers and 1,081/3,509 (30.8%) control mothers redeemed antibiotics during pregnancy (P = 0.32). For children, the equivalent numbers were 276 (76.7%) and 2,665 (75.9%) (P = 0.76). Histograms of antibiotic redemptions showed no temporal differences between leukaemia mothers/children and controls, which was confirmed in adjusted regression analyses (OR [95% CI]: 1.02 [0.75-1.38]). Only antibiotics redeemed during the first year after birth differed from this (OR [95% CI] for ALL diagnosed in 2- to 5-year-old children: 0.46 [0.31-0.66]).
In this hypothesis generating study, the similar amount and pattern of antibiotic redemptions in children with and without leukaemia indicate that infections play a minor role in the aetiology of childhood leukaemia. However, less antibiotic redemptions during the first year of life conform to Greaves' 'delayed infection hypothesis'.
Low participation in population-based follow-up studies addressing psychosocial risk factors may cause biased estimation of health risk but the issue has seldom been examined. We compared risk estimates for selected health outcomes among respondents and the entire source population.
In a Danish cohort study of associations between psychosocial characteristics of the work environment and mental health, the source population of public service workers comprised 10,036 employees in 502 work units of which 4,489 participated (participation rate 45%). Data on the psychosocial work environment were obtained for each work unit by calculating the average of the employee self-reports. The average values were assigned all employees and non-respondent at the work unit. Outcome data on sick leave and prescription of antidepressant medication during the follow-up period (1.4.2007-31.12.2008) was obtained by linkage to national registries.
Respondents differed at baseline from non-respondents by gender, age, employment status, sick leave and hospitalization for affective disorders. However, risk estimates for sick leave and prescription of antidepressant medication, during follow-up, based on the subset of participants, did only differ marginally from risk estimates based upon the entire population.
We found no indications that low participation at baseline distorts the estimates of associations between the work unit level of psychosocial work environment and mental health outcomes during follow-up. These results may not be valid for other exposures or outcomes.
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Commercial fishing is an extremely dangerous economic activity. In order to more accurately describe the risks involved, a specific injury coding based on the working process was developed.
Observation on six different types of vessels was conducted and allowed a description and a classification of the principal working processes on all kinds of vessels and a detailed classification for industrial trawlers. In industrial trawling, fish are landed for processing purposes, for example, for the production of fish oil and fish meal. The classification was subsequently used to code the injuries reported to the Danish Maritime Authority over a 5-year period.
On industrial trawlers, 374 of 394 (95%) injuries were captured by the classification. Setting out and hauling in the gear and nets were the processes with the most injuries and accounted for 58.9% of all injuries. A relatively large number of injuries occurred when embarking and disembarking. Specific risks were identified in a number of other working processes.
Specific areas for risk prevention in fishery may be identified by using a detailed classification system that takes both the specific method of fishing and the working processes into consideration.
The Danish Urogynaecological Database (DugaBase) is a nationwide clinical database established in 2006 to monitor, ensure and improve the quality of urogynaecological surgery. We aimed to describe its establishment and completeness and to validate selected variables. This is the first study based on data from the DugaBase.
The database completeness was calculated as a comparison between urogynaecological procedures reported to the Danish National Patient Registry and to the DugaBase. Validity was assessed for selected variables from a random sample of 200 women in the DugaBase from 1 January 2009 to 31 October 2010, using medical records as a reference.
A total of 16,509 urogynaecological procedures were registered in the DugaBase by 31 December 2010. The database completeness has increased by calendar time, from 38.2 % in 2007 to 93.2 % in 2010 for public hospitals. All medical records were retrievable for the validation study. The overall percent agreement was at least 90 % for the following variables: surgical procedure code, hospital department, date of surgery, use of antibiotic prophylaxis, prior gynaecological surgery, height, weight, parity and smoking.
The database completeness of the DugaBase has improved over time, now with a nearly complete registration from all public hospitals in Denmark. The overall percent agreement between selected variables and medical records is high. We conclude that due to the high degree of database completeness and data of high validity the DugaBase offers a unique possibility for continuing quality assessment of urogynaecological surgery in Denmark and future research.
At temperate latitudes, 1-5% of the population suffer from winter depression; during winter, mood difficulties tend to increase but may be alleviated by bright light therapy. Unlike indoor workers, outdoor workers are exposed to therapeutic levels of sunlight during winter. We hypothesized that outdoor work may protect against mood difficulties and depression.
We studied this hypothesis among 2910 civil servants from Århus, Denmark, who participated in a survey in January-February 2009. Mental symptoms (N=422) defined a common case category that we broke down into two parts: depression (N=66) and mood difficulties but no depression (N=356). A total of 222 controls were also sampled from the study population. All 644 participants reported the extent of outdoor work.
The confounder-adjusted odds ratio (OR) of mood difficulties showed a decreasing trend by increasing hours of outdoor work of borderline statistical significance. The OR was 0.63 [95% confidence interval (95% CI) 0.34-1.18)] for those working outdoors for >2 hours a day. No such effect was suggested for depression.
Our study is limited by its cross-sectional design and low statistical power but nevertheless suggests that outdoor work during winter may protect against mood difficulties. If this finding holds true it may have significant impact on workers' health as well as public health in general. Therefore, further studies are recommended.
Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Bispebjerg Bakke (Vammen, Drs Mikkelsen, Bonde, Thomsen); Department of Public Health, University of Copenhagen (Drs Hansen, Grynderup, Rugulies); National Research Centre for the Working Environment, Copenhagen (Drs Hansen, Rugulies); Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital (Dr Kolstad); Research Unit of Clinical Epidemiology, Institute of Clinical Research, University of Southern Denmark (Dr Kærlev); Center for Clinical Epidemiology, Odense University Hospital (Dr Kærlev); Research Department P, Aarhus University Hospital, Risskov (Dr Mors); and Department of Psychology, University of Copenhagen, Denmark (Dr Rugulies).
This study is a 2-year follow-up study of different dimensions of work-related emotional demands as a predictor for clinical depression.
In a two-wave study, 3224 (72%) public employees from 474 work-units participated twice by filling in questionnaires. Sixty-two cases of clinical depression were diagnosed. Emotional demands were examined as perceived and content-related emotional demands, individually reported and work-unit based. Support, meaningful work, and enrichment were considered as potential effect modifiers.
Individually reported perceived emotional demands predicted depression (odds ratio: 1.40; 95% confidence intervals: 1.02 to 1.92). The work-unit based odds ratio was in the same direction, though not significant. Content-related emotional demands did not predict depression. Support, meaningful work, and enrichment did not modify the results.
The personal perception of emotional demands was a risk factor for clinical depression but specific emotionally demanding work tasks were not.
To search for occupational risk factors, we conducted a case-control study in nine European countries of cancers of the small intestine, male gall bladder, thymus, bone, male breast, melanoma of the eye, and mycosis fungoides. Recruitment was population based in Denmark, Latvia, France, Germany, Italy, and Sweden, from hospital areas in Spain and Portugal, and from one United Kingdom (UK) hospital. We recruited 1457 cases (84% interviewed). Numbers identified corresponded to those in the EUROCIM database for Denmark, but were below those observed for France, Italy and Sweden in the database. We recruited 3374 population (61% interviewed) and 1284 colon cancer controls (86% interviewed). It was possible to undertake this complicated study across Europe, but we encountered three main problems. It was difficult to ensure complete case ascertainment, for population controls, we found a clear divide in the response rate from 75% in the South to only 55% in the North, and a somewhat selective recruitment was noted for the colon cancer controls. The study showed there is a clear dose-response relationship between alcohol intake and the risk of male breast cancer, and an excess risk of mycosis fungoides among glass formers, pottery and ceramic workers. Further data are expected.
This study aimed to examine the course of workplace bullying and health correlates among Danish employees across a four-year period.
In total, 7502 public service and private sector employees participated in a 3-wave study from 2006 through 2011. Workplace bullying over the past 6-12 months and data on health characteristics were obtained by self-reports. We identified major depression using Schedules for Clinical Assessment in Neuropsychiatry interviews and the Major Depression Inventory. We performed cross-sectional and longitudinal analyses of outcomes according to self-labelled bullying at baseline using logistic regression.
Reports of bullying were persistent across four years in 22.2% (57/257) of employees who initially reported bullying. Baseline associations between self-labelled bullying and sick-listing, poor self-rated health, poor sleep, and depressive symptoms were significant with adjusted odds ratios (OR) ranging from 1.8 [95% confidence interval (95% CI) 1.5-2.4] for poor sleep quality among those bullied "now and then" to 6.9 (95% CI 3.9-12.3) for depression among those reporting being bullied on a daily to monthly basis. In longitudinal analyses adjusting for bullying during follow-up, all health correlates except poor sleep quality persisted up to four years.
Self-reported health correlates of workplace bullying including sick-listing, poor self-rated health, depressive symptoms, and a diagnosis of depression tend to persist for several years regardless of whether bullying is discontinued or not. Independent measures of bullying and outcomes are needed to learn whether these findings reflect long lasting health consequences of workplace bullying or whether self-labelled workplace bullying and health complaints are correlated because of common underlying factors.
We studied musculoskeletal diseases (MSD) and injuries among fishermen and seamen with focus on low back disorders, carpal tunnel syndrome (CTS), rotator cuff syndrome and arthrosis.
Cohorts of all male Danish seamen (officers and non-officers) and fishermen employed 1994 and 1999 with at least six months employment history were linked to the Occupational Hospitalisation Register. We calculated standardised incidence ratios (SIR) for the two time periods, using rates for the entire Danish workforce as a reference.
Among fishermen, we found high SIRs for knee arthrosis, thoraco-lumbar disc disorders, injuries and statistically significant SIRs above 200 were seen for both rotator cuff syndrome and CTS. The SIR was augmented for injuries and reduced for hip arthrosis between the two time periods. The SIRs for injuries and CTS were high for non-officers. A sub-analysis revealed that the highest risk for CTS was found among male non-officers working as deck crew, SIR 233 (95% CI: 166-317) based on 40 cases. Among officers, the SIRs for injuries and MSDs were low. The number of employed Danish fishermen declined with 25% 1994-1999 to 3470. Short-term employments were common. None of the SIRs increased with increasing length of employment.
Both fishermen and non-officers have high SIRs for injuries and fishermen also for MSD. Only the SIR for injuries among fishermen was augmented between 1994 and 1999. Our findings suggest an association between the incidence of rotator cuff syndrome and CTS and work within fishery. Long-term cumulative effects of employment were not shown for any of the disease outcomes. Other conditions may play a role.
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Personal lifestyle and working conditions are closely linked for long haul truck drivers. We compare lifestyle related diseases in long haul drivers with other drivers of goods and the working population at large. Standardized hospital treatment ratios (SHR) for lifestyle related diseases were compared for long haul truck drivers and other truck drivers to the working population at large. The follow up group comprised of 2,175 long haul drivers and 15,060 other truck drivers. An increased risk was found for lifestyle related diseases among truck drivers except for alcohol related diseases. We identified a strong association between hospital treatment for obesity and working as a driver and an association between diabetes and working as a driver. No major differences in lifestyle related diseases were found in long haul drivers compared to other truck drivers with the exception of a significant lower risk for alcohol-related diseases and a possibly higher risk for lung cancer in long haul drivers. It is concluded that diseases related to excess caloric intake or lack of exercise may be a problem for truck drivers. This risk is preventable and of importance both in occupational medicine as in public health.