Cancer incidence and mortality of patients with suspected solvent-related disorders.

OBJECTIVE: The aim of this study was to study the incidence of cancer and deaths from cancer and other diseases among patients referred to the 11 clinics of occupational medicine in Sweden between 1967 and 1987 for examination because of exposure to organic solvents. METHODS: The cohort comprised 5791 persons, 5283 men and 508 women. Information about cancer incidence and causes of death was collected from the Cancer Register of the National Board of Health and Welfare and the National Death Register of Statistics Sweden, respectively. The expected values were calculated from the national death rates and incidence rates of cancer. RESULTS: The overall mortality rate was close to expected, but the mortality rate was decreased for diseases of the circulatory system [standardized mortality ratio (SMR) 0.7, 95% confidence limit (95% CI) 0.5-0.9] and increased for suicide (SMR 2.0, 95% CI 1.2-3.2). The total cancer incidence was slightly elevated [standardized incidence ratio (SIR) 1.2, 95% CI 0.99-1.4], and some specific cancer sites showed an increased incidence, although the lower confidence limits surpassed one. Malignancies of the lymphohematopoietic system and cancer of the uterine cervix had an increased risk (SIR 1.9, 95% CI 1.2-3.2, and SIR 3.7, 95% CI 2.2-6.2, respectively). Patients with presumerably high solvent exposure had an SIR of 1.4 for all malignancies (95% CI 0.9-2.1) and those with presumerably low exposure had an SIR of 1.1 (95% CI 0.9-1.4). CONCLUSIONS: The study showed an increased risk for malignancies of the hematopoietic system and the uterine cervix among patients originally examined with regard to solvent-induced disorders. There was also an increased risk of suicide and a decreased risk of death from diseases of the circulatory system. There was no increased risk for deaths from mental or neurological disorders.

Respiratory symptoms and asthma among workers exposed to paper dust: a cohort study.

The aim of the present cohort study was to investigate whether exposure to paper dust causes increased risk for respiratory symptoms or asthma. The cohort included all workers at a soft paper mill who had worked there for more than 1 year 1960-1986 (n = 1,697). Randomly selected inhabitants of the mill town (n = 781) were used as unexposed referents. Both groups were investigated using a postal questionnaire. From the paper mill cohort, workers with high cumulative exposure (n = 313), with medium cumulative exposure (n = 321), and with low cumulative exposure (n = 338) to paper dust were selected. In the 1960s and 1970s, the dust levels were between 5 and 10 mg/m3. After adjustment for smoking and gender, paper dust exposure resulted in elevated prevalence ratios for chronic cough, chronic phlegm, wheeze, and breathlessness. The prevalence ratios ranged from 1.3 to 2.5. No significantly increased risk of asthma was found among the exposed, incidence rate ratio 1.4 (95% confidence interval 0.93-1.8). Among the exposed, there was an insignificantly increasing incidence rate ratio, 1.0, 1.4, 2.1, with increasing cumulative exposure. In conclusion, an increased risk for respiratory symptoms was observed among workers exposed to paper dust, but the study does not permit any definite conclusions regarding asthma and paper dust exposure.

Mental and psychosomatic work injuries in Sweden.

In Sweden, persons who incur illness or injury at work or on the way to or from work may claim indemnity under a work injuries insurance scheme. A new law in 1977 included mental and psychosomatic illnesses. Looking into the records of reported work injuries in Gothenburg 10 years later, we found 67 cases diagnosed as mental or psychosomatic illnesses. One third of these were accepted as work injuries. The cited harmful influence mostly referred to mental and/or physical strain from work itself. Traumatic incidents, maltreatment by the employer, and persecution also were accepted as harmful influences. Comparison with an earlier study revealed that although the rate of approbation for mental and psychosomatic work-related illnesses (about 30%) is much lower than for all work-related illnesses (about 90%), there has been a considerable increase over the years.

The risk of lung cancer and mesothelioma after cessation of asbestos exposure: a prospective cohort study of shipyard workers.

A prospective cohort study of 3,893 shipyard workers, mainly exposed to chrysotile, indicated no increased risk of lung cancer 7-15 yrs after exposure to asbestos had ceased. The shipyard workers, however, had an increased risk of pleural mesotheliomas with 11 observed cases versus 1.5 expected. An explanation for these observations may be that asbestos may have different carcinogenic mechanisms in causing lung cancer and mesothelioma. A non-increased risk of lung cancer some years after exposure to asbestos has stopped is in accordance with asbestos acting as a promotor. The high risk of mesothelioma, on the other hand, may indicate that asbestos acts as a complete carcinogen in developing this disease.

Effects of occupational exposure to mercury vapor on lymphocyte micronuclei.

For 26 chloralkali workers exposed to inorganic mercury and 26 age-matched, occupationally unexposed referents, the frequency and size distribution of micronuclei were determined in peripheral lymphocytes stimulated with either phytohemagglutinin or pokeweed mitogen. For the exposed workers the mean concentrations of mercury in urine, plasma, and erythrocytes were 16 nmol/mmol of creatinine, 48 nmol/l, and 78 nmol/l, respectively, and their mean exposure time was 10 years. Neither the frequency nor the size of micronuclei was significantly different in the two groups; nor were there any correlations to current mercury levels. However, in the exposed group, and with phytohemagglutinin as the mitogen, a statistically significant correlation between previous exposure to mercury (cumulative exposure or number of blood mercury peaks) and the frequency of micronuclei was found. This association was also present when the effects of age and smoking were allowed for, and it may indicate an accumulation of cytogenetic effects in T-lymphocytes.

Comparison of methods for the biomonitoring of nurses handling antitumor drugs.

Urinary mutagenicity, thioethers in urine, and sister chromatid exchanges and micronuclei in peripheral lymphocytes were determined for 60 nurses handling cytostatic drugs and 60 referents matched for sex, age, and smoking habits. Safety hoods were used by most of the nurses. The exposed nurses had more sister chromatid exchanges and higher urinary mutagenicity, as measured by Salmonella typhimurium TA 98, than the referents. There were no differences in the other tests. No dose-response relationship was established for any parameter. It was concluded that urinary mutagenicity with the Salmonella strain is the most sensitive test for monitoring nurses handling cytostatic drugs. Determining sister chromatid exchanges may also be a viable test, but it has the drawback of uncertainty as to whether the changes are attributable to present or past exposure. Only comparisons of rather large groups are useful, and a study design requiring matched referents would seem to be optimal.

Cerebrospinal fluid proteins in men with chronic encephalopathy after exposure to organic solvents.

Cerebrospinal fluid was examined for 23 patients with chronic toxic encephalopathy after heavy exposure to organic solvents and 23 healthy age-matched referents. No differences were found between the patients and referents with respect to the levels of albumin, immunoglobulin, prealbumin, alpha-1-antitrypsin, beta-2-microglobulin, haptoglobin, or the astroglial cell proteins S100 and glial fibrillary acidic protein in the cerebrospinal fluid. The albumin ratio was normal for both the patients and the referents. The patient group had had heavy exposure to organic solvents, but its members had not been exposed for at least one year before the study. It was concluded that, if exposure to organic solvents affects proteins in cerebrospinal fluid, such effects are probably reversible.

Radiographic appearance and lung function after non-malignant pleural effusion.

In order to study factors associated with changes in radiographic appearance and lung function after pleural effusion, we investigated 178 consecutive patients with non-malignant pleural effusion. At the initial examination etiology, smoking habits, asbestos exposure, ESR, blood eosinophils, size of effusion and other X-ray lesions were registered. At a 3-year follow-up, chest radiographs and lung function values were obtained and the association with the initially registered factors was evaluated. At follow-up, 20% of the patients had developed major additional X-ray lesions and/or significantly reduced lung function. Prognostically unfavourable factors were idiopathic etiology as compared to infectious, medium and large-size effusions and initial radiographs showing converging pleural linear structures and/or rounded atelectasis as compared to no or minor radiographic lesions. Converging pleural linear structures and rounded atelectasis were seen almost exclusively in association with idiopathic effusions. The obvious differences noted between patients with idiopathic and infectious effusions suggest that these effusions represent separate clinical entities.

Asbestos pleural effusion: a clinical entity.

In a case-control study asbestos exposure in 64 consecutive men with idiopathic pleural effusion and 129 randomly sampled age matched male controls was compared. Furthermore, seven women and 64 men with idiopathic pleural effusion were studied, including a three year re-examination, in an attempt to identify characteristics that might distinguish asbestos exposed from non-exposed patients. Asbestos exposure was significantly (p less than 0.01) more frequent in men with idiopathic effusions than in controls. The idiopathic effusions seen in asbestos exposed patients were compatible with the diagnosis "asbestos pleural effusion." Two features were characteristic of patients with asbestos pleural effusion: a chest radiograph at the initial examination showing converging pleural linear structures or rounded atelectasis or a history of recurrent pleural effusion, or both.

Peak expiratory flow and risk of cardiovascular disease and death. A 12-year follow-up of participants in the population study of women in Gothenburg, Sweden.

A longitudinal population study of 1,462 women, aged 38-60 years at entry, was begun in Gothenburg, Sweden, in 1968-1969. This paper deals with the first 12-year follow-up period. In univariate analysis, peak expiratory flow showed a significant negative correlation with the 12-year incidences of myocardial infarction, electrocardiographic changes suggesting ischemic heart disease, stroke, and death. The association with incidence of myocardial infarction, stroke, and death remained in multivariate analysis, and was independent of age, body height, body mass index, adipose tissue distribution, chest deformity, history of pulmonary disease, smoking habit, serum cholesterol concentration, serum triglyceride concentration, systolic blood pressure, diabetes, and physical activity. The findings indicate that measuring peak expiratory flow is a simple procedure to identify women with an increased risk of cardiovascular disease or death. It seems urgent to find out what preventive measures might be taken as a consequence of these observations.

Differentiation between malignant and non-malignant pleural effusion.

In a prospective study of 334 consecutive patients with chronic pleural effusion 156 or 47% had a malignant etiology. The sensitivity of cytological examination of pleural fluid in detecting malignancies was 43%. Thoracoscopy had a sensitivity of 80% and could reveal malignancy in 37 of 47 patients with malignant effusions and a negative cytology. A malignant etiology must also be suspected when atypical cells are found in the pleural fluid as in our study 16 out of 19 fluid samples with atypical cytology represented malignant effusions. The predictive value for a malignant etiology was estimated for the following variables: sex, size of effusion, colour and eosinophils of pleural fluid, smoking habits and asbestos exposure. The predictive value of each variable was estimated separately, combining two by two and by a logistic regression function to exclude correlation to yet another variable. The single variable with the strongest positive predictability towards malignancy was a bloody fluid. Conversely, more than 30 per cent eosinophils in the fluid had the strongest negative predictability towards malignancy. The ability of our statistical method, a logistic regression function to discriminate between malignant and non-malignant etiology was 79%. The estimated probability of a malignant etiology should influence the choice of invasive procedures and the duration and intensity of follow-up.

Lung function of sheet metal workers exposed to fiber glass.

Out of 532 registered and contacted sheet metal workers, 251 responded, but only seven pairs were acceptable for the present study due to the following requirement: no history of smoking, pleural plaques or asbestos exposure. Seven of these workers were exposed daily to fiber glass, and seven were almost never exposed. In a second step nine additional exposed workers were included. Ordinary spirometry, lung volumes, closing volumes and the slope of the alveolar plateau, the maximum expiratory flow in air and after helium-oxygen breathing, and the elastic recoil pressures were measured. No evidence of small airway dysfunction or restrictive or obstructive ventilatory impairment was found, but the elastic recoil pressures of the exposed group were slightly increased. Fiber glass can conceivably cause a corresponding faint and probably harmless fibrous reaction in the lung parenchyma.

Respiratory symptoms and lung function in oil mist-exposed workers.

The prevalence of respiratory symptoms was registered and ventilatory function was determined in 164 men exposed to oil mist. The average exposure time was 16.2 years. One hundred fifty-nine office workers served as controls. The exposed men reported more respiratory symptoms: 14% of the exposed nonsmokers v. 2% of the non-smoking controls having cough at least three months a year. There were no significant differences between spirometric measurements and chest roentgenograms of the men exposed to oil mist and those of the office workers. The lung function of 25 nonsmoking exposed men was further examined with other lung function tests. The mean values for closing volume, slope of the alveolar plateau, total lung capacity, residual volume, elastic recoil at various lung volumes, and diffusion capacity did not differ significantly.

Cancer morbidity among polishers.

The mortality pattern among 86 men was determined to investigate the possible hazards of polishing steel. The men had polished steel with polishing paste for at least five years. The polishing pastes had contained tallow, beeswax, carnauba wax, alundum, carborundum, ferric oxide, and chalk. A total of 18 men had died compared with 13.3 expected. Four had died of stomach cancer compared with 0.44 expected (p less than 0.005). The mortality for other causes of death was not increased. The study does not permit any definite conclusion but indicates a possible cancer hazard among polishers.

Cancer morbidity among men exposed to oil mist in the metal industry.

The cancer morbidity pattern among 788 men with at least five years' exposure to oil mist was investigated. Based on measurements, interviews of workers and a survey of changes over the years, the average exposure level was estimated to have been 5 mg/m3 or more prior to 1965. Exclusive of cancer of the scrotum, there were 39 observed cases of cancer compared to 52.9 expected. There were four cases of cancer of the scrotum among the turners but none among the grinders. Three cases of lung cancer were found, compared to 5.4 expected. Among the grinders there was a doubled, but not statistically significant, increase in cancer of the stomach. The mortality from all causes showed a so-called "healthy worker effect," that is, 126 deaths compared to 154.3 expected.

[Effects of metoprolol, practolol, and propranolol after isoprenaline injections in asthmatic patients (author's transl)]. / Effets du métoprolol, du practolol et du propranolol après injection d'isoprènaline chez des asthmatiques.

The effects of two beta-blockers, one non-selective, propranolol, the other beta 1 selective, metoprolol, were studied in 8 asthmatic patients. Practolol and a placebo were used as reference products. Heart rate, blood pressure, MEV, and muscle tremor were measured at rest and after isoprenaline infusions at different concentrations. In patients receiving placebo, isoprenaline caused an increase in heart rate, MEV, systolic BP, and muscle tremor, and a reduction in diastolic BP. After propranolol, the effects of isoprenaline on heart rate, MEV, and muscle tremor were almost completely blocked, and modifications in systolic and diastolic BP were only slightly affected. Metoprolol and practolol did not inhibit the increase in MEV induced by isoprenaline, but they reduced the increase noted in the heart rate. These results demonstrate the beta 1 selectivity of these two beta-blockers. Contrary to propranolol, metoprolol and practolol did not block the increased muscle tremor provoked by isoprenaline: muscle tremor must be dependent on beta 2-receptor activity. As the effect of isoprenaline on the MEV was not inhibited by beta 1-selective beta-blockers, these can be prescribed for asthmatic patients in association with beta 2 stimulants.