The extent of agreement between International Labour Office (ILO) and clinical readings of chest x ray films from construction workers was studied. From a survey of 5898 workers 258 subjects with a profusion of small opacities of > or = 1/1 and a stratified sample of subjects with profusion < 1/1 were selected. Only 41% of the films classified as ILO profusion category > or = 1/1 were clinically recorded as non-normal for the parenchyma. The proportion of films recorded as pneumoconiotic (or possibly so) was especially low for irregular opacities (22%), but increased with the profusion category (both rounded and irregular) as well as with the size of rounded opacities (p 3/11, q 12/25, r 3/4). Only with the profusion category > or = 2/1 were most of the films recorded as pneumoconiotic. The specificity and sensitivity were highest in the geographical areas where a few clinical readers had assessed many films each. The proportion of false negative clinical reports was low for circumscribed pleural thickening of the chest wall (9%) and diaphragmatic pleural thickening (6%). For calcified pleural changes and for the combination of diffuse pleural thickening and obliteration of the costophrenic angle, false negative reports were absent. The present study shows an unsatisfactory sensitivity for clinical compared with ILO readings as a means for screening the parenchyma of workers with a risk of pneumoconiosis.

During the past decades conclusive evidence has accumulated that alkylating antineoplastic drugs (ADs) can cause cancer, most notably acute non-lymphocytic leukaemia, and that most ADs are reprotoxic. Studies on health workers handling ADs have shown significantly increased risks for miscarriages (two studies) and malformations (two studies). The present study monitored the risk for cancer and adverse reproductive outcome among Danish nurses handling ADs. No increased risks were found for miscarriages, malformations, low birth weight, or preterm birth among the offspring of nurses handling ADs during pregnancy. The sex ratio was normal. The relative risk (RR) for leukaemia was significantly increased (10.65) but based on only two cases, one of acute myeloblastic and one of chronic myeloid leukaemia. From the available exposure data occupational exposures to ADs were apparently higher in the studies that have reported increased risks for miscarriages and malformations than in the present one. Regarding reproductive outcome the study gives some confidence that the safety measures which were implemented in the oncology departments around 1980 can protect the health personnel against adverse effects of ADs on reproduction. As the study is as yet the only negative one in a well protected setting, it should be followed up by other studies of well protected health personnel handling ADs. The findings concerning the leukaemia risk, although based on small numbers, encourage larger studies.

In this investigation the effects of repeated exposure to 1.5 ppm NO2 on immune competent cells in bronchoalveolar lavage (BAL) fluid was studied. Special attention was focused on effects on lymphocyte subpopulations. Eight healthy subjects were exposed to 1.5 ppm NO2 every second day on six occasions. Bronchoalveolar lavage fluid was collected at least three weeks before the exposure series as reference and 24 hours after the last exposure. The results obtained were analysed using a non-parametric test for paired observations, with each subject as his own control. Significant reductions were found in the total number and percentage of T cytotoxic-suppressor cells in BAL fluid; this caused an increase in the ratio of T helper-inducer: cytotoxic-suppressor cells. The total number of natural killer cells in the BAL fluid was also reduced. The numbers of all other cell types were unchanged after exposure. No reduction of phagocytosis of opsonised yeast particles by alveolar macrophages in vitro was detected. It is concluded that repeated short term exposures to 1.5 ppm NO2, a moderate occupational concentration, induces significant effects on immune competent bronchoalveolar lymphocytes. This indicates that previous findings of changes in the lymphoid immune system induced by NO2 in animals may well be applicable to humans.

Antibodies to Toxoplasma were measured by enzyme linked immunosorbent assay (ELISA) in sera from 159 abattoir workers, 142 pig farmers, and 106 grain or berry farmers. Farmers occupationally exposed to pigs had antibodies in 53 (37%) cases, abattoir workers in 40 (25%) cases, and farmers not exposed to pigs in 24 (23%) cases. In each group antibodies were more prevalent among those who had a cat or cats in the household. Controlling for age and cat contacts changed the prevalences less than one percent. The results indicate that pig farmers might have an occupational risk of toxoplasmosis. As the prevalence of antibodies among abattoir workers was about the same as among the referent farmers, it seems unlikely that infection from Toxoplasma could be acquired by mere handling of raw meat.

To determine whether specific jobs and occupational exposures are associated with laryngeal cancer lifetime occupational histories from a population-based case-control study in western Washington were examined. The study included 235 cases diagnosed between September 1983 and February 1987, and 547 controls identified by random digit dialing. After controlling for alcohol use, cigarette smoking, age and education, significantly increased risks were found for painters in construction (odds ratio (OR)) = 2.8, (95% confidence interval (95% CI) 1.1-6.9), supervisors and miscellaneous mechanics (OR = 2.3, 95% CI 1.1-4.8), construction workers (OR = 3.4, 95% CI 1.4-8.1), metalworking and plastic working machine operators (OR = 2.6, 95% CI 1.3-4.9) and handlers, and equipment cleaners and labourers (OR = 1.5, 95% CI 1.0-2.2). Allowing for a 10 year induction and latent period did not have a consistent effect on the associations. Potential exposures to asbestos, chromium, nickel, formaldehyde, diesel fumes, and cutting oils were assessed by using a job exposure matrix developed for this study. Three measures of exposure were examined--namely, peak, duration, and an intensity weighted exposure score. No significantly raised risks were seen, although increased risk was suggested among those exposed long term to formaldehyde in jobs with the highest exposures.

Forty two of 125 former workers in a factory in Syracuse, New York, which manufactured hard metal parts from tungsten carbide and cobalt, were studied by chest radiographs, spirometry, and plethysmographically determined lung volumes. The plant was closed in 1982 and the studies were performed in 1983-5. Recorded measurements of carbide dust concentrations were only mildly excessive by modern standards, but deceitful efforts to reduce the apparent concentration of dust were known to have occurred during an inspection by the Occupational Safety and Health Administration. Lung biopsies in four cases in the study and necropsy in one of the 83 cases not studied during life showed giant cell interstitial pneumonia and appreciable concentrations of tungsten carbide. This information indicates that exposure was substantial. Four workers had evidence of pulmonary fibrosis by chest radiographs; two of these workers had normal pulmonary function. Fourteen had abnormal pulmonary function, five of whom had a restrictive pattern, eight a pattern of air trapping, and one a combined pattern. Thus radiographic, or functional abnormalities, or both occurred in 16 of the 42 cases studied. No correlation with duration of exposure was established. Progressive clinically important disease (one fatal) has been found in four ex-workers, two in each of the restrictive and air trapping groups. These findings suggest that poorly regulated dust concentrations in a hard metals factory possibly cause pulmonary abnormalities and sometimes severe illness.

Thirty nine phenotypes of human leucocyte antigens (HLA)-A-B-DR and DQ were obtained from 99 asbestos workers (one woman and 98 men). Presence or absence of antinuclear antibodies and rheumatoid factor was determined in 91 of them. Workers were divided into five groups: asbestos workers with no apparent disease (AW; n = 17), diffuse benign pleural disease (PD; n = 31), asbestosis (AS; n = 24), asbestosis with lung cancer (AS-CA; n = 14), and mesothelioma (M; n = 13). Compared with AW, several trends of differences of HLA antigen prevalence were found in patients with asbestos related disease, but these did not achieve statistical significance when p was corrected (pcorr) by number of analyses undertaken. Analysis of the results obtained in previous studies together with the results of this study showed that compared with AW, AS patients had decreased prevalence of HLA-DR5 (pcorr < 0.02). Reasons for the differences in results of previous studies and statistical methods commonly used to compare prevalences of HLA antigen are discussed.

Three hundred and eighty one men admitted to hospital for the first time with any psychiatric diagnosis were individually matched for age and year to patients admitted to general hospitals. An occupational history was obtained from 90% of this study group by telephone interview or mail. Exposure to solvents was assessed by three methods, individual rating of each job recorded, application of an exposure matrix based on job title, and assessment of lifetime job histories of selected case-referent pairs. A sample of individual ratings used in the analysis was compared with ratings made by five experts. The panel values tended to be lower but all six sets of ratings correlated well. There was no increased risk of psychiatric illness among subjects exposed to moderate or greater solvent concentrations for at least 10 years (odds ratio (OR) 1.0, 90% confidence interval (90% CI) 0.7-1.4, individual rating; OR 1.1, 90% CI 0.6-2.0, job title matrix; OR 0.9, 90% CI 0.5-1.7, lifetime assessments). At higher exposures the risk was increased--although not to a statistically significant degree--especially for cases with non-psychotic diagnoses (ICD-9 codes 300-316). This negative result, by all three methods of assessment of exposure, contrasted with that from a parallel investigation of cases of organic psychoses and cerebral degeneration.

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Rates of spontaneous abortions were determined using a reproductive questionnaire administered by personal interview to 55 married women with 105 pregnancies. They were employed in an audio speaker factory and were exposed to high concentrations of toluene (mean 88, range 50-150 ppm). These rates of spontaneous abortion were compared with those among 31 women (68 pregnancies) who worked in other departments in the same factory and had little or no exposure to toluene (0-25 ppm), as well as with a community control group of women who underwent routine antenatal and postnatal care at public maternal health clinics (190 women with 444 pregnancies). Significantly higher rates for spontaneous abortions were noted in the group with high exposure to toluene (12.4 per 100 pregnancies) compared with those in the internal control group (2.9 per 100 pregnancies) and in the external control group (4.5 per 100 pregnancies). Among the exposed women, significant differences were also noted in the rates of spontaneous abortion before employment (2.9 per 100 pregnancies) and after employment in the factory (12.6 per 100 pregnancies). Almost all the women were nonsmokers and did not drink; other known risk factors such as maternal age at pregnancy, order of gravidity, and race were not likely to explain the results. Thus, specific exposure to toluene seems to be associated with a risk of foetal loss.

Rates of menstrual disorders were studied in 231 female production workers with high exposure to toluene (mean 88 (range 50-150 ppm) in a factory manufacturing audio speakers and compared with a control group of 58 female production workers in other departments in the same factory who had little or no exposure to toluene (0-25 ppm). An external community control group of 187 working class women under routine care at public maternal and child health centres were also studied. Detailed menstrual and reproductive histories were obtained by personal interview using a structured questionnaire. The rates for dysfunctional uterine bleeding (cycle irregularity and prolonged or heavy menstrual bleeding) were similar in all groups. Dysmenorrhoea seemed to occur more often in the women highly exposed to toluene compared with women at maternal and child health centres, but not compared with factory controls with low exposure to toluene. There was no evidence that dysfunctional uterine bleeding was likely to result from exposure to toluene. It is uncertain whether dysmenorrhoea was associated specifically with exposure to toluene, as other behavioural and work related factors may also result in dysmenorrhoea.

Motor neurone disease (MND) was studied in relation to various determinants in a case-control study covering nine counties in southern Sweden. A questionnaire about occupational exposures, medical history, lifestyle factors etc was given to all cases in the age range 45-79 and to a random sample of 500 population controls in the same age range. The questionnaires were answered by 92 cases and 372 controls, a response rate of 85% and 75% respectively. Among men high Mantel-Haenszel odds ratios (MHORs) were obtained for electricity work (MHOR = 6.7, 95% confidence interval (95% CI) 1.0-32.1), welding (MHOR = 3.7, 95% CI 1.1-13.0), and impregnating agents (MHOR = 3.5, 95% CI 0.9-13.1). Heritability with regard to a neurodegenerative disease or thyroid disease seemed to predispose to a risk of developing MND (OR = 2.1, 95% CI 1.0-4.3). The highest OR was found for the combination of such heritability, exposure to solvents, and male sex (OR = 15.6, 95% CI 2.8-87.0), a combination that occurred for seven cases and three controls. Hereditary factors and external exposures had a different distribution among cases with the spinal type of MND than among cases with involvement of the pyramidal tract or bulbar paresis also.

Neurobehavioural tests were performed by 98 dentists (mean age 32, range 24-49) exposed to elemental mercury vapour and 54 controls (mean age 34, range 23-50) with no history of occupational exposure to mercury. The dentists were exposed to an average personal air concentration time weighted average (TWA) of 0.014 (range 0.0007-0.042) mg/m3 for a mean period of 5.5 (range 0.7-24) years and had a mean blood mercury concentration of 9.8 (range 0.6-57) micrograms/l. In neurobehavioural tests measuring motor speed (finger tapping), visual scanning (trail making), visuomotor coordination and concentration (digit symbol), verbal memory (digit span, logical memory delayed recall), visual memory (visual reproduction, immediate and delayed recall), and visuomotor coordination speed (bender-gestalt time), the performance of the dentists was significantly worse than that of the controls. The dentists scored 3.9 to 38.9% (mean 13.9%) worse in these tests. In trail making, digit span, logical memory delayed recall, visual reproduction delayed recall, and bender-gestalt time test scores were more than 10% poorer. In each of the tests in which significant differences were found and in the block design time, the performance decreased as the exposed dose (product of the TWA of air mercury concentrations and the years of exposure) increased. These results raise the question as to whether the current threshold limit value of 0.050 mg/m3 (TWA) provides adequate protection against adverse effects of mercury.

Three hundred and nine men with organic dementia, cerebral atrophy, or psycho-organic syndrome admitted for five nights or more to one of 18 Quebec hospitals were individually matched with patients admitted (1) with some other psychiatric diagnosis and (2) to a general hospital. Lifetime occupational histories were obtained by telephone. Occupational exposure to solvents was assessed blind to type of case by (1) individual ratings and (2) a job exposure matrix; men who worked in moderate or high solvent concentrations for at least 10 years were considered exposed. With the psychiatric referent series, an odds ratio of 1.4 (90% CI 1.0-2.0) was calculated by individual exposure ratings and 1.4 (90% CI 0.9-2.2) by job matrix. Increased risk was mainly in those with organic dementia or cerebral atrophy and an alcohol related diagnosis. The same pattern of risk was found against the general hospital referents. Adjustment for possible confounders did not alter the risk estimates appreciably. Also, lifetime job histories, compared in selected case-referent pairs, gave similar evidence of increased risk (odds ratio 2.3; 90% CI 1.0-5.5). It is concluded that the combined effect of occupational solvent exposure and alcohol intake is probably an important cause of organic brain damage.

One hundred and forty four current and 26 former workers in a plant producing barrels for rocket guns from an epoxy resin containing methyltetrahydrophthalic anhydride (MTHPA; time weighted average air concentration up to 150 micrograms/m3) were studied. They showed higher frequencies of work related symptoms from the eyes (31 v 0%; p < 0.001), nose (53 v 9%; p < 0.001), pharynx (26 v 6%; p < 0.01), and asthma (11 v 0%; p < 0.05) than 33 controls. Also they had higher rates of positive skin prick test to a conjugate of MTHPA and human serum albumin (16 v 0%; p < 0.01), and more had specific IgE and IgG serum antibodies (18 v 0%; p < 0.01 and 12 v 0%; p < 0.05 respectively). There were statistically significant exposure-response relations between exposure and symptoms from eyes and upper airways, dry cough, positive skin prick test, and specific IgE and IgG antibodies. There was a non-significant difference in reaction to metacholine between exposed workers and non-smoking controls. In workers with and without specific IgE antibodies, differences existed in frequency of nasal secretion (54 v 23%; p < 0.05) and dry cough (38 v 12%; p < 0.05). Workers with specific IgG had more dry cough (38 v 12%; p < 0.05), but less symptoms of non-specific bronchial hyperreactivity (0 v 26%; p < 0.05). Atopic workers sneezed more than non-atopic workers (65 v 30%; p < 0.01). In a prospective study five sensitised workers who left the factory became less reactive to metacholine, and became symptom free. In 41 workers who stayed, there was no improvement, despite a 10-fold reduction in exposure. The results show the extreme sensitising properties of MTHPA.