Use of cellular and cordless telephones and risk of testicular cancer.

A case-control study on testicular cancer included use of cellular and cordless telephones. The results were based on answers from 542 (92%) cases with seminoma, 346 (89%) with non-seminoma, and 870 (89%) controls. Regarding seminoma the use of analog cellular phones gave odds ratio (OR) = 1.2, 95% confidence interval (CI) = 0.9-1.6, digital phones OR = 1.3, CI = 0.9-1.8, and cordless phones OR = 1.1, CI = 0.8-1.5. The corresponding results for non-seminoma were OR = 0.7, CI = 0.5-1.1, OR = 0.9, CI = 0.6-1.4, and OR = 1.0, CI = 0.7-1.4, respectively. There was no dose-response effect and OR did not increase with latency time. No association was found with place of keeping the mobile phone during standby, such as trousers pocket. Cryptorchidism was associated both with seminoma (OR = 4.2, CI = 2.7-6.5) and non-seminoma (OR = 3.3, CI = 2.0-5.6), but no interaction was found with the use of cellular or cordless telephones.

Polybrominated diphenyl ethers--plasma levels and thyroid status of workers at an electronic recycling facility.

OBJECTIVES: Personnel working with electronic dismantling are exposed to polybrominated diphenyl ethers (PBDEs), which in animal studies have been shown to alter thyroid homeostasis. The aim of this longitudinal study was to measure plasma level of PBDEs in workers at an electronic recycling facility and to relate these to the workers' thyroid status. METHODS: PBDEs and three thyroid hormones: triiodothyronine (T(3)), thyroxin (T(4)) and thyroid stimulating hormone (TSH) were repeatedly analysed in plasma from 11 workers during a period of 1.5 years. RESULTS: Plasma levels of PBDEs at start of employment were <0.5-9.1 pmol/g lipid weight (l.w.). The most common congener was PBDE #47 (median 2.8 pmol/g l.w.), followed by PBDE #153 (median 1.7 pmol/g l.w.), and PBDE #183 had a median value of <0.19 pmol/g l.w. After dismantling the corresponding median concentrations were: 3.7, 1.7 and 1.2 pmol/g l.w., respectively. These differences in PBDE levels were not statistically significant. PBDE #28 showed a statistically significantly higher concentration after dismantling than at start of employment (P=0.016), although at low concentrations (start 0.11 pmol/g l.w. and dismantling 0.26 pmol/g l.w.). All measured levels of thyroid hormones (T(3), T(4) and TSH) were within the normal physiological range. Statistically significant positive correlations were found between T(3) and #183 in a worker, between T(4) and both #28 and #100 in another worker and also between TSH and #99 and #154 in two workers. CONCLUSIONS: The workers' plasma levels of PBDEs fluctuated during the study period. Due to small changes in thyroid hormone levels it was concluded that no relevant changes were present in relation to PBDE exposure within the workers participating in this study.

Exposure to tremolite asbestos and respiratory health in Swedish dolomite workers.

OBJECTIVES: Deposits of carbonate rock like limestone and dolomite may contain tremolite asbestos. This study assessed the exposure to tremolite asbestos and the respiratory health of Swedish dolomite workers. METHODS: 95% of 137 eligible workers at two dolomite producing companies completed a self administered questionnaire that included questions on respiratory symptoms and were examined with spirometry as well as chest radiography. Total exposure to dust was gravimetrically measured and the tremolite asbestos content of the dust was assessed with polarisation and phase contrast microscopy. RESULTS: Dolomite dust concentrations were moderate (median 2.8 mg/m3) and tremolite asbestos concentrations were generally below the limit of detection (<0.03 fibres/ml). Somewhat higher values, around 0.1 fibres/ml, were obtained in manual stone sorting and bagging. Respiratory symptoms suggestive of chronic bronchitis were more related to smoking than to estimates of individual exposure to dust. The mean vital capacity was 0.2 l lower than expected after adjustment for sex, age, height, and smoking but the decline in lung function was not associated with current or cumulative exposure to dust in a clear cut way. Two definite cases of pleural plaques and one possible case of simple pneumoconiosis were noted, but the plaques could not be attributed exclusively to exposure to tremolite asbestos. CONCLUSIONS: Dolomite mining and milling may indeed entail low levels of exposure to tremolite asbestos, but this exposure was not a strong determinant of respiratory symptoms, lung function, or pneumoconiosis in exposed Swedish workers. This was true also for dolomite dust. The hazards of exposure to tremolite asbestos may vary across deposits, however, and additional studies at other sites of carbonate rock exploitation are warranted.

Stress markers in relation to job strain in human service organizations.

BACKGROUND: Workers in human service organizations are often confronted with conflicting demands in providing care or education. The aim of this cross-sectional study was to relate levels of endocrine stress markers to perceived job strain in two human service organizations. METHODS: Employees in two local units of the social insurance organization and two local units of the individual and family care sections of the social welfare in Sweden were selected and 103 employees participated (56% participation rate). The perceived job strain was assessed with a standardized questionnaire containing questions of the demand-control model. Questions specially designed to measure emotional demands were also included. The stress markers cortisol, prolactin, thyroid-stimulating hormone, testosterone and IgA and IgG were analysed in blood samples. RESULTS: The main finding was an association between high emotional strain and increased levels of prolactin. The levels of cortisol, but none of the other four stress markers, increased slightly with emotional strain. CONCLUSIONS: Emotional strain experienced in human service work may cause psychological stress. The increase in prolactin was modest but consistent with findings in other published studies on stress-related endocrine alterations.

Prevalence of contact dermatitis among dental personnel in a Swedish rural county.

The use of acrylate-based polymers in dental care in Sweden has increased dramatically in recent years. Acrylate monomers are sensitizers and can cause contact dermatitis. Allergy to latex, e.g. in rubber gloves, is also an increasing problem in health care and especially in dental care. The aim was to estimate the prevalences of work related allergies in dental personnel in a Swedish county with almost 700 dentists, dental nurses and dental hygienists. A questionnaire was distributed to all dental care units in the county and 98% of the population completed it. Specific allergy was verified with standard patch and prick testing. Work related allergy symptoms were reported by 189 subjects, 28%. The prevalences of acrylate eczema and latex allergy were 3,0% and 3,7% respectively. The prevalence of all work related skin allergy was estimated to 8%. The estimated prevalence of acrylate allergy was close to those of a few other published reports. However, the prevalence of hypersensitivity to latex rubber was lower than those reported from other studies. It is concluded that almost one dental care worker out of ten has a risk of contact dermatitis, unless measures to reduce hazardous exposure have been taken.

Testicular cancer and occupational exposures with a focus on xenoestrogens in polyvinyl chloride plastics.

In a case-control study of 148 cases of testicular cancer and 314 healthy controls information was collected on lifetime working histories and specific exposures. The main finding was a six-fold increase in the risk for seminoma, one type of testicular cancer, among plastic workers exposed to polyvinyl chloride (PVC). No overrisks were observed for other plastics than PVC. There may be an aetiological link to xenoestrogens, i.e. chemicals in the environment with oestrogenic properties. Phthalates are used in PVC as plasticizer and have oestrogenic properties that could promote the growth of endocrine sensitive tumour cells. However, this "endocrine disruptors" hypothesis must be further evaluated in experimental models with regard to the causative mechanisms of the oestrogenic tumour promotion.

Case-control study on risk factors for testicular cancer.

Occupational exposures were assessed in a case-control study on testicular cancer using self administered questionnaires. Answers were obtained for 148 (91%) cases and 314 (87%) controls. Of the cases 101 had seminoma and 47 had embryonal testicular cancer. Occupational plastics work yielded odds ratio (OR) 2.9 with 95% confidence interval (CI) 1.3-6.5. Increased risk was found for embryonal cancer regarding farming (OR 3.1; CI 1.03-9.1) and contact with farm animals (OR 3.3; CI 1.00-10.9), but not for seminoma. For all testicular cancer exposure to insects repellents, mostly containing N,N-diethyl-m-toluamide (DEET) gave OR 1.7; CI 1.03-2.8, with a dose-response effect. Somewhat increased risks were found for amateur radio operators (OR 2.2; CI 0.7-6.6), work with radar equipment (OR 2.0; CI 0.3-14.2) and engineers in electronics and telecommunication industry (OR 2.3; CI 0.8-6.7) based on few exposed subjects, however. Video display unit work gave OR 1.5; CI 0.98-2.3 and for exposure 480 working days (median number) the risk increased further to OR 1.8; CI 1.1-3.2. Because of low numbers of exposed subjects in some calculations some of these results might be spurious and need to be further studied.

Occupational exposure to polyvinyl chloride as a risk factor for testicular cancer evaluated in a case-control study.

Occupational exposures were assessed in a case-control study on testicular cancer using self-administered questionnaires. In total, answers were obtained for 148 (91%) cases and 315 (87%) controls. Of the cases, 101 had seminoma and 47 had embryonal testicular cancer. An increased odds ratio (OR) was found for exposure to polyvinyl chloride (PVC) yielding an OR of 6.6 (95% confidence interval, 1.4-32). The risk increased further if cases with self-reported cryptorchidism or orchitis were excluded. Six of the 7 exposed cases had seminoma. Exposure to other types of plastics did not significantly increase the risk of testicular cancer.

Does organization matter? A multilevel analysis of the demand-control model applied to human services.

The demand-control model (DC model) in occupational epidemiology suggests that health, an individual attribute, is partly determined by work organization, via the interplay of demand and control, job strain. The objective of this study was empirical assessment of the model's tenet of an organizational determination of individual health. An emerging analytic method, multi-level modelling, permits such an assessment. The study encompasses two large Swedish human service organizations. It was based on a nationally representative sample of 291 local organizational units (level 2) with 8296 employees (level 1), a median of 18 employees per unit. 5730 persons (69.1%) completed the questionnaire. Listwise deletion of missing data left a net study base of 4756 individuals in 284 units. Missing data were largely random. Demand and control were measured by standard questions and combined into a job strain index. Two such indices were calculated, one for quantitative demands and one for emotional demands. Individual attributes included age, gender, marital status, having children, social anchorage, and education. There were two dependent variables, self-assessed psychovegetative symptoms (worry, anxiousness, sadness, sleep difficulties, restlessness, and tension) and exhaustion (fatigue, feelings of being used up and overworked), both measured as summative indices. For psychovegetative health, a null model yielded 2.2% level 2 variance, unchanging when individual attributes were included in a random intercepts model. Inclusion of the strain variables rendered level 2 variance non-significant, decreasing level 1 variance by 23% and level 2 variance by 62%. For exhaustion, level 2 variation was 8.3% in the null model and 1.6% in the final model, with strain variables. The strain variables utilized in the DC-model thus draw a substantial part of their variation from the organizational level. It is concluded that the claim of the DC model to rely on organizational factors receives support.

The factor structure of the Maslach Burnout Inventory in two Swedish human service organizations.

The Maslach Burnout Inventory, MBI, is a well established measure of burnout. Its validity outside the USA is, however, uncertain. The aim of the present study was therefore to apply the MBI on personnel in two Swedish human service organizations, comparing factor solutions and scoring norms to the original results. The population consisted of 5730 employees in the Social Insurance Organization (SIO) and the Individual and Family Care section (IFC) of the social welfare agencies. Principal components analysis, principal axes and alpha factor analyses were performed, all with varimax rotation. The suggested three factor solution showed to be remarkably stable irrespective of type of analysis. Score levels were somewhat lower on two subscales in the Swedish population. The conclusion is that the psychometric properties of the MBI seem to be very satisfactory and stable, at least in comparison between Sweden and USA. It is suggested that the dimensionality of MBI is rather invariant, but that the score levels covary with national, cultural, or professional contexts within the human services.

Psychosocial work environment in human service organizations: a conceptual analysis and development of the demand-control model.

This paper concerns two models that were introduced in two different research domains during the 1970's. The first model regards human service organizations (HSO) as a specific type of organization. The second model, the demand-control model (DC model), concerns the joint effects of job demands and job control on worker health. In the HSO model, there are analyses of the content of jobs, considering the specific characteristics of HSOs, but little is said about the health effects of such work. Those effects stand in focus in the demand-control model. The aim of this paper is to analyze the relevance of the DC model for human service organizations. The paper argues that the object of human service work-the client relation-makes a difference for demand and control in the job. Demand is analyzed into work load, emotional demands and role conflict. Control is divided into administrative control, outcome control, choice of skills, closeness of supervision, control within and over a situation and ideological control. The conclusion is that in applications on HSOs, the basic concepts of the DC model must be developed.

Psychosomatic symptoms in human service work. A study on Swedish social workers and social insurance personnel.

This study reports on subjective health of personnel in human services and other occupations. A mail questionnaire was sent to 8296 employees in the Social Insurance Organization (SIO) and the Individual and Family Care (IFC) in social welfare agencies. The response rate was 69.1% or 5730 persons. Perceived health was measured by a standard form widely used in occupational health services, FHV004D, here split into four principal components, indicating psycho-vegetative, musculoskeletal, immunological, and gastro-intestinal health. In relation to reference data on other human service personnel (nurses, teachers) and white collar workers (bank and insurance personnel), the studied groups scored much higher on psycho-vegetative symptoms (OR:s about 3), higher on musculo-skeletal symptoms (OR:s about 1.7), but had equal scores on the other symptom types. It is concluded that self-reported psychovegetative and musculoskeletal health is especially problematic in SIO and IFC, indicating stress in human service work. It is hypothesized that an adversary relation to clients can be an aggravating factor in that context.

Hand abnormalities are strongly associated with the duration of diabetes mellitus.

OBJECTIVES: To study the prevalence of hand abnormalities in diabetic patients and to evaluate associations between the hand abnormalities and diabetic variables, ergonomic factors and smoking habits. DESIGN: Cross-sectional study of 100 patients selected at random. Setting. Out-patient clinic, Department of Internal Medicine, Orebro Medical Centre Hospital in Sweden. MAIN OUTCOME MEASURES: Presence and extent of carpal tunnel syndrome (CTS), Dupuytren's contracture (DC), flexor tenosynovitis (FTS), and limited joint mobility (LJM). Duration of diabetes, metabolic control, chronic diabetic complications, blood pressure, ergonomic factors and smoking habits. RESULTS: Carpal tunnel syndrome, DC, FTS and LJM were each present in about 20% of the patients. Hand abnormalities were observed in 50 patients and more than one abnormality was found in 26 of the patients. The hand abnormalities were associated with the duration of diabetes but not with the metabolic control or with other diabetic complications. However, the diabetic complications were associated with bad metabolic control and with the duration of diabetes. Hand abnormalities correlated with heavy manual work but not with smoking habits. Twenty-five of the 50 patients with hand syndromes were disabled to such an extent that surgery was recommended. CONCLUSION: The prevalence of hand abnormalities in diabetic patients is high and increases with the duration of diabetes. In many cases patients with hand abnormalities can be helped by surgery.

Cancer incidence among creosote-exposed workers.

Cancer incidence was studied among 922 creosote-exposed impregnators at 13 plants in Sweden and Norway. The subjects had been impregnating wood (eg, railroad cross-ties and telegraph poles), but no data on individual exposures were available. The study population was restricted to men employed during the period 1950-1975, and their cancer morbidity was checked through the cancer registries. The total cancer incidence was somewhat lower than expected, 129 cases versus 137 expected [standardized incidence ratio (SIR) 0.94]. Increased risks in both countries combined were observed for lip cancer (SIR 2.50, 95% confidence interval (95% CI) 0.81-5.83), skin cancer (SIR 2.37, 95% CI 1.08-4.50), and malignant lymphoma (SIR 1.9, 95% CI 0.83-3.78). Exposure to sunlight may have contributed to the risk of lip and skin cancer. The small number of cancer cases does not permit valid conclusions. The findings indicate that impregnating wood with creosote in earlier decades increased the risk of skin cancer.

Winter weather conditions and myocardial infarctions.

The daily number of cases of myocardial infarctions admitted to a hospital in middle Sweden over three winter seasons 1984-87 was correlated to the weather conditions on a day-to-day basis. The study encompassed 634 days and all cases younger than 70 years, living within the catchment area, in all 382 subjects. Information on temperature, wind force, precipitation and atmospheric pressure was obtained from the Swedish Institute of Meteorology and Hydrology. A low number of myocardial infarctions was seen on Saturdays and Sundays with a mild wind chill factor and on days with moderate snowfall and high atmospheric pressure. A high number was observed for workdays, especially Mondays, as day of diagnosis. Heterogeneity of the study population and a misclassification of the time relationships between dates of diagnosis and weather changes may have caused an underestimation of the impact of weather conditions. However, weather conditions do not seem to be a major triggering factor of myocardial infarctions in Sweden.

Cardiac arrhythmia in refrigerator repairmen exposed to fluorocarbons.

A field study of 89 refrigerator repairmen was carried out to ascertain whether occupational exposure to fluorocarbons induces cardiac arrhythmia. The concentrations of fluorocarbons in the breathing zones and the heart activity were recorded simultaneously. Most cooling systems contained FC 12 or FC 22. The highest level recorded in one minute was 14,000 ppm and the highest time weighted level during eight hours was 280 ppm. Two types of arrhythmia were recorded, ectopic beats and sudden bradycardia. A within subject comparison design was applied and the main parameter was the difference in arrhythmia frequencies between exposed and unexposed periods. No appreciable differences between exposed and unexposed periods and no consistent dose effect relations were observed, although subjects in the medium exposure category showed a difference of borderline significance (Wilcoxon's test: p = 0.05, one tailed). The frequencies of arrhythmia when unexposed were somewhat higher than previously reported. Misclassification of the exposure and the possible confounding effect of physical workload and psychological strain may have obscured a causal relation and therefore a minor effect cannot be ruled out. The results do not support the notion that fluorocarbons induce cardiac arrhythmia in occupationally exposed refrigerator repairmen.

Malignant lymphomas and occupational exposures.

The effects of potential risk factors for Hodgkin's disease (HD) and for non-Hodgkin lymphomas (NHL) were evaluated in a case-referent study encompassing 54 cases of HD, 106 cases of NHL, and 275 referents, all alive. Exposure information was obtained by questionnaires posted to the subjects. Crude rate ratios were increased for various occupational exposures including solvents, welding, wood preservatives, phenoxy acids, and fresh wood (sawmill workers, lumberjacks, paper pulp workers). After further analyses based on logistic regression occupational exposures to welding and creosote remained as significant risk factors for HD. For NHL, occupational exposures to solvents, phenoxy acids, and creosote but also work as carpenter or cabinet maker and contacts with pets (other than dogs, cats, and birds) were associated with significantly increased risks.

Olfactory function in painters exposed to organic solvents.

The olfactory receptor cells are in direct contact with the exterior environment, and some chemical agents can impair olfactory function. The olfactory function of 54 painters exposed to organic solvents was compared with that of 42 unexposed referents. A new clinical test validated for the sense of smell was used, the University of Pennsylvania Smell Identification Test. Age, smoking habits, exposure to organic solvents, and medical disorders of importance for the sense of smell were recorded. The painters had a somewhat lower test score than the referents. However, the influence of the exposure variable was not statistically significant in a multiple regression analysis including age and smoking habits. The exposure to organic solvents was low, and therefore an effect of high exposure on olfactory function cannot be ruled out. Since some of the painters had earlier been highly exposed, the effects of high exposure are likely to be reversible.