Associations between depressive complaints and indicators of labour participation among older Dutch employees: a prospective cohort study.

PURPOSE: European policy measures have led to an increased net labour participation of older employees. Yet, via different routes (for instance disability schemes) employees still often leave the labour market early. Mental health may be an important factor hindering labour participation. Aims of this study are twofold: first, to examine the relationship between mental health-particularly depressive complaints-and indicators of labour participation among older employees over a 2-year follow-up period and second, to explore the impact of different work contexts when studying this relation. METHODS: A subsample of older employees (aged > 45 years; n = 1253) from the Maastricht Cohort Study was studied. Depressive complaints were assessed using the Hospital Anxiety and Depression scale. Logistic and Cox regression analyses covered 2 years of follow-up and were also stratified for relevant work-related factors. RESULTS: Employees with mild depressive complaints showed statistically significantly higher risks for poor mental workability (HR 2.60, 95% CI 1.14-5.92) and high psychological disengagement levels (HR 2.35, 95% CI 1.21-4.57) over time compared to employees without depressive complaints. Within various work contexts, for instance in which employees perform physically demanding work or have high psychological job demands, significantly stronger associations were found between depressive complaints and poor mental workability over time. CONCLUSIONS: This study shows strong longitudinal associations between depressive complaints and indicators of labour participation, also within different work contexts over time. Results provide valuable input for developing preventive measure aiming to enhance sustainable labour participation of older employees.

Need for recovery and different types of early labour force exit: a prospective cohort study among older workers.

PURPOSE: This study examines the relationship between need for recovery (NFR) and labour force exit (LFE) among older workers. Different types of LFE (early retirement, work disability and unemployment) are considered, and the role of potential confounding and modifying factors, including the availability of early LFE schemes, is examined. Also, associations between NFR and the intention and ability to prolong one's working life, which are known determinants of LFE, are assessed. METHODS: A subsample of older workers from the Maastricht Cohort Study was examined (n = 2312). The relationship between NFR and LFE was investigated by means of Cox regression analyses. Logistic regression analyses were performed to investigate cross-sectional associations between NFR and the intention and ability to prolong working life. RESULTS: Elevated NFR was associated with a higher risk of overall LFE during a 4-year follow-up period (HR 1.39, 95% CI 1.09-1.78), and specifically with a higher risk of leaving the labour force through early retirement and work disability. When early retirement schemes were available, strong and significant associations between NFR and LFE were observed (HR 2.79, 95% CI 1.29-6.02), whereas no significant associations were found when such schemes were unavailable. Older workers with a higher NFR also had earlier retirement intentions and lower self-assessed abilities (both physical and mental) to prolong their working life until the mandatory retirement age. CONCLUSIONS: Because this study shows that NFR is a precursor of LFE among older workers, monitoring NFR is important for timely interventions aimed at reducing NFR to facilitate extended labour participation.

Prevalence of lymphoedema more than five years after breast cancer treatment.

AIM: A lack of consistency in the definition of breast cancer related lymphoedema (BCRL) and of uniform measurement criteria contribute to the wide prevalence range found in current literature. This report aims to describe the long-term prevalence of BCRL and secondly, to compare the long-term prevalence of BCRL when assessed by two objective measures and one subjective measure. METHODS: The upper-limbs of 145 post-surgical breast cancer patients were evaluated for the presence of lymphoedema using the water displacement method. Two circumference methods and patient perceived swelling were applied secondarily for comparison. Limb measurements were performed once, more than five years after surgery. RESULTS: The long-term prevalence of BCRL using water displacement was 8%. Prevalence varied when the sum of arm circumference (SOAC), the arm circumference and the self-report methods were used: 16, 31 and 17% [P < 0.001], respectively. Of the women identified with BCRL using the water displacement technique, 82% were detected with the SOAC method, 82% with the arm circumference method and 91% by self-report. Using water displacement as the gold standard the methods with the highest specificities were the SOAC (90%) and self-report method (89%), arm circumference resulted in a low specificity of 73%. CONCLUSION: The prevalence of BCRL more than five years after surgical treatment differs depending on the measuring method used. Our data underlines the necessity for consensus on the diagnostic criteria for BCRL.

Psychosocial work characteristics as risk factors for being injured in an occupational accident.

The aim of this study was to investigate the relationship between psychosocial work characteristics and the risk for being injured in an occupational accident. We performed this study within the framework of the Maastricht Cohort Study of Fatigue at Work, a prospective cohort study on employees (n = 7051) from a wide range of companies and organizations. One hundred eight workers reported being injured in an occupational accident for which the subject consulted a physician or physiotherapist. Adjustments were made for work environment and demographic variables. High psychologic job demands were a risk factor for being injured in an occupational accident. Low decision latitude had a crude relative risk for being injured in an occupational accident of 2.02 (95% confidence interval [CI] = 1.23-3.39). This relationship almost completely disappeared after adjustment for the confounders mentioned here. Coworker and supervisor support were inversely related to the risk of being injured in an occupational accident but did not reach statistical significance. Other psychosocial work characteristics that had a significant effect on the risk for being injured in an occupational accident were conflicts with the supervisor (relative risk [RR] = 2.49; 95% CI = 1.42-4.37) or colleagues (RR = 2.62; 95% CI = 1.58-4.35), job satisfaction (RR = 1.43; 95% CI = 1.08-1.91), and high emotional demands (RR = 2.45; 95% CI = 1.52-3.94). We conclude that after adjustment for demographic variables, fatigue, and factors that describe the type of work environment that high psychologic job demands, emotional demands, and conflicts with the supervisor and/or colleagues are risk factors for being injured in an occupational accident.

Mortality update of workers exposed to acrylonitrile in The Netherlands.

A retrospective cohort study investigating the cause-specific mortality patterns of 2842 workers occupationally exposed to acrylonitrile for at least 6 months before 1 July 1979 was updated. The comparison group consisted of 3961 workers from a nitrogen fixation plant during the same time interval. Industrial hygiene assessments quantified past exposure to acrylonitrile, the use of personal protective equipment, and exposure to other potential carcinogenic agents. All 6803 workers were followed for mortality until 1 January 1996. The follow-up was almost complete (99.6%), and for 99.3% the cause of death was ascertained. Age distribution, follow-up period, and temporal changes in background mortality rates were adjusted for in calculations of standardized mortality ratios for separate causes of death. Cumulative dose-effect relations were determined for 3 exposure categories and 3 latency periods. The results showed that, although cancer mortality fluctuated slightly, no cancer excess seems related to exposure to acrylonitrile.

Mortality of workers exposed to dieldrin and aldrin: a retrospective cohort study.

OBJECTIVE: To investigate the occurrence of long term health effects in humans exposed to aldrin and dieldrin, with an update of an earlier retrospective cohort mortality study. METHODS: A group of 570 workers employed between 1 January 1954 and 1 January 1970 either in a production or formulation plant were followed up for mortality until 1 January 1993. There were extensive industrial hygiene data available and biological monitoring data of aldrin and dieldrin for most of the workers. From these data individual estimates were made of the total intake of dieldrin. A total number of 2539.37 person-years at risk was added to the original study. RESULTS: 118 deaths were observed compared with 156 expected. No increase in mortality from liver cancer was found. However, there was an excess in mortality from rectal cancer. This excess was inversely related to the dose gradient. An analysis by job title did not show any excess cancer in any particular job. CONCLUSION: The study does not support a carcinogenic effect of dieldrin and aldrin in humans.

Mortality of Dutch coal miners in relation to pneumoconiosis, chronic obstructive pulmonary disease, and lung function.

OBJECTIVES: To analyse the mortality patterns of former Dutch coal miners, focusing on coal workers' pneumoconiosis (CWP) and chronic obstructive pulmonary diseases (COPD) in relation to pre-existing impairment of lung function. METHODS: 3790 selected miners, medically examined between 1952 and 1963, were followed up to the end of 1991 with the municipal population registries and the causes of death from the death certificates were ascertained and converted to the codes from the ninth revision of the international classification of diseases (ICD-9). Mortality comparisons were made with the male population in The Netherlands, resulting in standardised mortality ratios (SMRs). 3367 miners had radiological manifestation of CWP at medical examinations. RESULTS: 80% of the miners died during the follow up period. Excess mortalities from CWP (SMR 4523) and COPD (SMR 179) were found. Coal miners without CWP also showed an increased mortality from COPD (SMR 2913). A diminished lung function (forced expiratory volume in one second (FEV1), or FEV1/FVC (forced vital capacity) ratio) at medical examination resulted in a significantly increased SMR for COPD (322 and 212 respectively) whereas normal lung function yielded expected mortalities from COPD. A positive correlation also emerged between diminished lung function and the SMR due to CWP. The body mass index (BMI) at the moment of medical examination was correlated with the risk of dying of COPD and CWP: a decreasing BMI resulting in an increased SMR. CONCLUSIONS: Not only infectious diseases and CWP but also COPD is an important cause of occupational mortality in miners with extensive exposure to coal mine dust. No obvious connection between pre-existing CWP and the COPD mortality exists. Impaired FEV1 and FEV1/FVC ratios are predictors of an increased risk of COPD death. The BMI seems to indicate the severity of the COPD, resulting in premature death.

Mortality and lung cancer in ceramic workers in The Netherlands: preliminary results.

A retrospective cohort study in 1794 male ceramic workers in the Netherlands was carried out to analyze the lung cancer risk in relation to crystalline silica exposure and silicosis. They had all been employed for two years or longer in ceramic industries between 1972 and 1982. During a health survey, 124 cases of simple pneumoconiosis were diagnosed; after 14 years of follow-up, 161 deaths had occurred. No increased overall and cause-specific mortality was found in the total group of ceramic workers, and a statistically significant cumulative dose-response relation for silica exposure and lung cancer did not emerge. An excess lung cancer mortality appeared among workers with simple pneumoconiosis. The authors conclude that the disease process resulting in silicosis in the ceramic industry carries an increased risk of lung cancer, which is supportive of a nongenotoxic pathway.

Risk of gastric cancer in pneumoconiotic coal miners and the effect of respiratory impairment.

OBJECTIVES: This study was carried out to investigate the mortality patterns in a group of 3790 coal miners. The study population had abnormal chest x ray films at a routine medical examination that was performed in the 1950s. METHODS: The total group of 3790 coal miners were followed up for mortality up to 1 January 1992. Causes of death, determined and coded at time of death, were traced with help from the Central Bureau of Statistics. RESULTS: Total mortality in this group of coal miners with abnormal chest x ray films was significantly higher than expected (SMR 127.1, 95% CI 122.5-131.6), mainly a reflection of the increase in mortality from non-malignant respiratory disease (SMR 411.0, 95% CI 382.3-441.3). Mortality from gastric cancer was also significantly increased (SMR 147.5, 95% CI 122.3-176.3). This risk of mortality from gastric cancer was confined to workers with no pneumoconiosis or only a mild form. Despite the strong relation to duration of employment and pneumoconiosis the group of workers with more severe manifestations of pneumoconiosis did not experience an excess in mortality from gastric cancer. CONCLUSION: This study confirms the earlier reported risk of gastric cancer in coal miners. Also it confirms the hypothesis that this risk of gastric cancer is limited to workers with a mild degree of pneumoconiosis or none. In workers with severe forms of pneumoconiosis the pulmonary clearance system is impaired in such a way that the inhaled coal dust does not reach the digestive tract.

Gasoline consumption and leukemia mortality and morbidity in 19 European countries: an ecological study.

It is widely recognized that exposure to benzene is a risk factor for leukemia; however, much remains to be clarified about the possible long-term health effects of exposures to low concentrations of benzene. With this in mind an ecological study was carried out in which both gasoline consumption data and data on leukemia mortality and incidence were collected for 19 European countries. Gasoline consumption was taken as an indication for exposure to benzene in ambient air. There appeared to be a weak inverse association between temporal trends in gasoline consumption and temporal trends in leukemia mortality. On the other hand, a weak positive association was found between the age-adjusted myeloid leukemia incidence in 14 areas and the gasoline consumption per square kilometer. However, both findings can easily be explained by other factors, such as changes in prognosis or differences in leukemia case ascertainment. This study is not supportive of an association between gasoline consumption and reported leukemia incidence and mortality rates.

Mortality of Dutch workers exposed to carbon disulfide.

Epidemiological studies carried out in Great Britain, Scandinavia and the United States indicate that workers exposed to carbon disulfide are at an increased risk for cardiovascular disease (CVD) mortality, and in particular for ischemic heart disease (IHD) mortality. In the epidemiological study reported here a retrospective cohort design was used. The total study population consisted of 3322 workers from a Dutch viscose textile plant who had all been employed for at least half a year between 1 January 1947 and 1 January 1980. Only production and maintenance workers were selected for the study. A group of 1434 workers who had been exposed to carbon disulfide was identified from the files available at the plant. The remaining 1888 workers who had not been exposed to carbon disulfide were used as a reference group. The total study population was followed for mortality until 1 January 1988. For the 762 workers who had died before that date, the causes of death were checked at the Central Bureau of Statistics. The results show a slightly but significantly increased risk for CVD mortality (CVD-specific SMR of 115), despite the observation of the so-called healthy worker effect and the statistical uncertainties inherent to this type of study. The results are in accordance with those reported by other investigators. The results indicate that exposure to relatively low levels of carbon disulfide increases the risk of CVD mortality.

Respiratory effects and serum type III procollagen in potato sorters exposed to diatomaceous earth.

Exposure to diatomaceous earth with low crystalline silica content (< 1%) is rarely reported to cause pneumoconiotic disease, whereas airway obstruction and bronchitis are more frequently reported. We investigated the occurrence of pneumoconiosis and airflow limitation in 172 male workers from 5 potato sorting plants (55 controls, 29 salesmen, 72 currently exposed, and 16 retired exposed) exposed to inorganic dust from former sea terraces (7.7-15.4 mg/m3), high in diatomaceous earth. The presence of fibrosis was evaluated by chest radiographs (exposed only) and serum levels of type III procollagen (P-III-P) were measured as an estimate of fibrogenetic activity. Lung function was assessed by flow volume curves and impedance measurements. A validated questionnaire was used to record respiratory symptoms. No pneumoconiotic abnormalities were demonstrated by chest radiographs. In line with this finding, serum P-III-P levels were not elevated in exposed workers as compared to controls, suggesting no differences in fibrogenetic activity. In fact, serum P-III-P levels decreased significantly (P < 0.03) with increasing cumulative exposure. Flow volume parameters indicated airflow obstruction, dose-related to (cumulative) dust exposure; the annual decline in forced expiratory flow volume (FEV1) was estimated at 10.5 ml/year (P < 0.05). Airway obstruction was confirmed by impedance analysis: In the retired group impedance changes were compatible with airway obstruction extending into the peripheral airways. We conclude that this exposure to quartz during potato sorting does not result in an increased risk for pneumoconiosis, but that (prolonged) surveillance in this group is desirable in order to detect early indications of airflow obstruction.

Cancer mortality and residence near electricity transmission equipment: a retrospective cohort study.

Several studies in recent years have raised the possibility that exposure to extreme low frequency (ELF) electromagnetic fields may be hazardous to human health, in particular by the promotion or initiation of leukaemia and other cancers. To determine if this exposure creates a long-term hazard to the public, the mortality of a group of people identified as having lived in an urban quarter of Maastricht in which two 150 kiloVolt (kV) powerlines and one transformer substation are located was investigated. Using the Dutch population registry it was possible to identify retrospectively 3549 inhabitants of the quarter who lived there for at least 5 years between 1956 and 1981. Of these 1552 study subjects lived within 100 m of the electricity transmission equipment and were exposed to magnetic field intensity of 1.0-11.0 milliGauss. The overall standardized mortality ratio and cancer mortality ratios were either not or only slightly elevated. The study does not support previously reported associations of exposure to ELF electromagnetic fields with leukaemia, brain cancer and breast cancer.

Mortality of workers exposed to acrylonitrile.

A retrospective cohort study was carried out in The Netherlands to investigate the potential carcinogenic effects in humans of occupational exposure to acrylonitrile (AN). The total study group consisted of 6803 workers "from eight chemical plants and one control plant" of whom 2842 had been exposed to AN between January 1, 1956 and July 1, 1979 for at least 6 months. All workers were employed by one of eight chemical companies. An extensive review of the available industrial hygiene data was conducted to assess the magnitude of past exposure to AN, occurrence of peak exposures, exposure to recognized potential human carcinogens, and respirator use. The total cohort was observed for mortality until January 1, 1988. In collaboration with the Central Bureau of Statistics, the causes of death were traced for the workers who died before 01-01-1988. In the exposed as well as in the nonexposed cohorts the total mortality was lower than expected, based on national mortality statistics. The observed cancer mortality in the exposed cohort was similar to the expected mortality. Specific analyses were carried out to investigate dose-response relationships and latency for total mortality and lung cancer mortality. Overall, no indications were found for a carcinogenic effect in this cohort of workers exposed to AN.

Cancer mortality among licensed herbicide applicators.

This retrospective cohort study investigated the cancer mortality of 1341 herbicide applicators licensed before 1 January 1980. The cohort was followed for mortality until 1 January 1988 by means of the Dutch system of population registers. For the subjects who died before 1 January 1988 the cause of death was obtained from the Central Bureau of Statistics. The cause of death was obtained for 98.4% of the deceased subjects. The total mortality was lower than expected according to mortality rates of the total male Dutch population. The total number of deaths from cancer was however slightly higher than expected [standardized mortality ratio (SMR) 114]. Mortality from several subtypes of cancer was also higher than expected, that for multiple myeloma being statistically significantly higher than unity (SMR 815, 95% confidence interval 164-2382). Occupational exposure to herbicides appears to increase the risk for multiple myeloma and possibly other malignant neoplasms.

Mortality of coke plant workers in The Netherlands.

During the production of coke, large quantities of coke oven gas are emitted. People who work on the top or on the sides of coke ovens are exposed to this oven gas, which contains a range of carcinogenic chemicals. To investigate the cancer risks under these work conditions, a retrospective study was undertaken. In total 11,399 former workers were enrolled in the study. Of these, 5639 had worked in the coke plant for at least six months between 1945 and 1969. The other 5740 had worked in another plant during the same period and formed a non-exposed group for comparison. The study group was followed up until 1984 for mortality. The causes of death were obtained from the Central Bureau of Statistics. Among the coke oven workers significantly higher death rates were found for lung cancer and non-malignant respiratory disease. Mortality in the byproduct section was similar to that expected. Among workers in the tar distillery the rate for lung cancer was higher than expected. The risk for gastric cancer and non-malignant respiratory disease among the workers of the coke shipping department was increased but the SMRs did not reach statistical significance. No data were collected about individual smoking habits or socioeconomic state of the study subjects and the possibility that the risk found could be attributed to these factors cannot be ruled out. It has been stated by other investigators, however, that the effect of not controlling for smoking tends to be modest.

Long-term mortality in miners with coal workers' pneumoconiosis in The Netherlands: a pilot study.

In order to investigate whether the prolonged exposure to coal mine dust increases the cancer risk for coal miners, a pilot study in a selected cohort of 334 Dutch miners with coal workers' pneumoconiosis (CWP), followed from 1956 until 1983, was conducted. In total, 165 miners had died (49.4%); for 162 (98.2%) the cause of death was traced. In comparison to the general Dutch male population, total mortality in the cohort was statistically significantly increased (SMR: 153). This was in general due to the significantly higher than expected cancer mortality (SMR: 163), cancer of stomach and small intestine (SMR: 401) and nonmalignant respiratory disease (SMR: 426). The lung cancer mortality was within the expected range.

[Course and distribution of mortality of pleural mesothelioma in The Netherlands, 1970-1987]. / Verloop en spreiding van de sterfte aan pleura-mesotheliomen in Nederland, 1970-1987.

In this article the sex- and age-specific trends and geographical distribution of asbestos related pleural mesothelioma mortality in the Netherlands between 1970 and 1987 are investigated. For men total mortality increased from 10.8 per million during 1970-1978 to 20.9 per million during 1979-1987. The highest mortality occurred with 147.7 per million in 1987 in the age group between 65 and 74 years. Mortality rates for the age group between 55 and 64 years amounted to 96.5 per million in 1987. The geographical distribution over the country showed a strong concentration of male mesothelioma cases in the regions with many harbours, shipyards and heavy industries round Amsterdam, IJmuiden, Rotterdam, Dordrecht and Walcheren. Using linear regression techniques, it was calculated that several thousands new mesothelioma cases will occur in the Netherlands during the next two decades. A significant decrease in mesothelioma mortality can not be expected before 2010.

Trends and geographical patterns of pleural mesotheliomas in the Netherlands 1970-87.

The sex and age related trends and geographical distribution of asbestos related mortality from pleural mesothelioma in the Netherlands between 1970 and 1987 were investigated. Deaths from pleural malignancies recorded by the Dutch Central Bureau of Statistics (CBS) were used and death rates were age adjusted per year by the indirect method. Standardised mortality ratios (SMRs) were computed for 43 regions over the period 1979-86. For men, total mortality increased from 10.8 per million in the period 1970-8 to 20.9 per million during 1979-87. The highest mortality occurred in the group aged between 65 and 74 with 147.7 per million in 1987. The death rate for the group aged between 55 and 64 was 96.5 per million in 1987. For women, total death rates for pleural mesothelioma showed a moderate increase from 2.5 per million in the period 1970-8 to 3.6 per million during 1979-87. The highest mortality occurred in the group aged over 65, fluctuating around 10-15 per million. For men and women under 45 mortality was very low and presented no upward trend. The geographical distribution over the country for the period 1979-86 showed a pattern with a clear concentration of deaths from mesothelioma in men, in conurbations with many harbours, shipyards, and heavy industry near the river mouths and along the North Sea Coast.

Silica exposure and lung cancer in ceramic workers: a case-control study.

The results are presented from a case-control study, concerning the possible relation between silica exposure in the Dutch fine ceramic industry and lung cancer. For this purpose 381 male, age-matched pairs of primary lung cancer cases and controls were selected from the pathology department of the University Hospital in the region, where two large ceramic companies are located. Information about employment in the ceramic industry was obtained from the personnel and financial administration departments of the two companies. On the basis of job titles a panel of occupational hygiene experts reached consensus about the qualitative exposures of each individual worker. Twenty one per cent of the cases were employed in the ceramic industry, compared with 19% of the controls (odds ratio 1.11; 95% Cl: 0.77-1.61). Although the average employment period of cases and their relative silica exposure surpassed those of controls, odds ratios for long duration of employment and considerable exposure to respirable silica dust did not reach statistical significance. After constructing a qualitative exposure index, based on the amount and duration of exposure, a tendency towards a positive correlation with lung cancer emerged. No relation between specific histological tumour cell types and working in the ceramic industry emerged. Although the study does not suggest a consistent cause-effect relation between silica exposure in the regional, Dutch fine ceramic industry and lung cancer, an increased risk for the high exposure group in the past can not be totally excluded.