Showing papers in "Occupational and Environmental Medicine in 1985"

IARC monographs on the Evaluation of Carcinogenic Risk of Chemicals to Humans

Abstract: insignificant); one individual was allergic to mice and one to guinea pigs and IgE antibodies to allergens from these species were not tested; two had skin reactions only (one very mild) and two had mild nasal symptoms only. We would also emphasise that this retrospective group was chosen from individuals who in a previous survey had reported allergic symptoms and our comments about increased antibody levels referred only to this group and should not be taken to indicate that the statement is necessarily true of a larger, controlled population. Even with this proviso our results do not support the statements made by Newman Talor et al in their abstract that \"these findings suggest that the immunological mechanisms responsible for asthmatic reactions to laboratory animals are different from those involved in rhinitis and urticaria.\" ' We fail to see the point of the last paragraph of their letter. There was no intention to conceal anything. The prospective group is, as stated, a clearly defined population of individuals during their first year of employment. We agree that it is crucial to know if those with specific IgE are at particular risk of developing asthma, and this is one of the reasons for the continuing study referred to in our paper. Slovak and Newman Taylor seem to be reading more into our results than is justified from the defined nature of the study. We also agree that the development of specific IgE could become a valuable monitor and that skin prick test conversion may be a significant marker. We are seeking scientific evidence for these assertions. We should further point out that although our observations were \"made on a volunteer sample\" there was a 100% response; all individuals who began employment during the study period agreed to take part.

N-Nitroso compounds: occurrence, biological effects and relevance to human cancer

Abstract: Sir,-Jeyaratnam and coworkers recommend, on the basis of the results of their neurophysiological study in 46 workers exposed to a combination of organic and inorganic lead, that the biological occupational exposure limit for Pb-B of 70,g/dl, as proposed in 1982 in the EEC for male workers, should be lowered.' There are, however, some flaws that limit the way in which the data may be interpretated: (1) The demonstrated mean values of nerve conduction velocities (NCV) show no consistent findings. For instance, the value for the sensory NCV of the median nerve is somewhat greater for the lead exposed workers, by comparison with the controls, whereas in the case of the motor fibres of the median nerve the opposite is found. This is unusual, since most studies concerning NCV and lead showed negative effects in all the nerves investigated.26 (2) The age (mean or distribution or both) of the lead exposed workers and of the control group is not given. It is well known that the NCV decreases with increasing age.7 For this reason, a misinterpretation of the neurophysiological data cannot be excluded. (3) The authors performed no correlation analyses for the detection of possible dose-effect/response relationships. These statistical tests are important for the evaluation of significant causal relationships or trends. (4) Blood lead concentrations (Pb-B) were estimated only once. Seppalainen and coworkers2 and

Cancer mortality of cadmium workers.

Abstract: Several epidemiological studies of workers exposed to cadmium indicate an increased risk of lung and prostatic cancer. The increase is statistically significant in some of the studies but the SMR is greater than 100 in almost all. A cohort study of the mortality among 522 Swedish workers exposed to cadmium for at least one year in a nickel-cadmium battery plant support the earlier findings. The SMR for lung and prostatic cancer increased with increasing dose and latency but did not obtain statistical significance. A combination of all the available data from the most recent follow up of causes of death among cadmium workers in six different cohorts shows 28 cases of prostatic cancer (SMR = 162) and 195 cases of lung cancer (SMR = 121). This new analysis suggests that long term, high level exposure to cadmium is associated with an increased risk of cancer. The role of concomitant exposure to nickel needs further study.

Total contribution of airborne lead to blood lead.

Abstract: A nine year study of blood lead concentrations and isotope ratios carried out on a married couple shows that pulmonary deposition cannot account for all the airborne lead in blood; that lead from bone may comprise 70% of blood lead; and that during pregnancy blood lead may double due to mobilisation of lead from bone.

Health problems of pesticide usage in the Third World

Abstract: Pesticides are important to the life of the people and governments of Third World countries where they are extensively used both in agriculture and in public health programmes. Approximately 60% of the workforce of these countries are employed in agriculture' and pesticides are used to control pests that are estimated to devastate at least a third of the potential crops in the countries in the Third World,2 so that benefits result from increased crop yields. In the field of public health great suffering results from vector borne diseases. It is estimated that malaria results in some 150 million clinical cases a year whereas filariasis affects about 250 million people and schistosomiasis causes debilitating and sometimes fatal disease in some 250 million people. The eradication of these and other vector borne diseases depends to a great extent on the use of pesticides. This then is the promise of pesticides but their use is, at the same time, associated with hazards to human health. It is important to appreciate that the type and extent of health hazards arising from the use of pesticides and their consequent impact on national health priorities in the countries of the Third World differ from those encountered in the industrialised countries. Though the industrialised countries use 80% of the world's agrochemicals,3 they probably suffer only 1% or less of all deaths due to acute pesticide poisoning, so that acute pesticide poisoning is not a major health problem in the countries of the industrialised world. The same is not necessarily true for the Third World. Firstly, accurate data on the extent of acute pesticide poisoning in these countries are lacking, which is why WHO had to use a mathematical model to estimate the problem.4 On the basis of this model, WHO believe that about 500 000 cases of pesticide poisoning resulting in at least 5000 deaths occur each year. These figures are probably an underestimate. Recent studies showed that in Sri Lanka (population around 14.5 million) there were about 13 000 hospital admissions each year for acute pesticide poisoning, resulting in about 1000 deaths.5 The extrapolation of these figures to the countries of the developing world would suggest that about 2.9 million cases of acute pesticide poisoning requiring admission to hospital with about 220 000 deaths are likely to occur annually. Though the Sri Lankan study observed that only 25% of the cases of acute pesticide poisoning resulted from occupational and non-occupational accidents, this percentage nevertheless constitutes a large number of people. An indication of its importance as an occupational health problem in Sri Lanka is the estimate that each year five of every 1000 agricultural workers are admitted to hospital for acute pesticide poisoning. These figures indicate that acute pesticide poisoning is a high priority health issue in Sri Lanka as well as in other countries of the Third World. To achieve effective control of acute pesticide poisoning in these countries the extent of the problem must be established to provide data for the national decision makers to use to set priorities and take appropriate corrective action. For instance, in Sri Lanka in the year when about 1000 deaths occurred from acute pesticide poisoning only 572 deaths were recorded as being due to poliomyelitis, diphtheria, tetanus, and whooping cough; not a single death occurred from malaria. But the anomaly is that whereas health expenditure to control malaria is substantial, virtually no budgetary allocation exists for the control of acute pesticide poisoning. It is appropriate to consider some of the factors that contribute to occupational and other accidental pesticide poisoning. Studies in Sri Lanka have shown that most farmers are aware of the simple precautionary measures necessary to prevent the hazards arising from pesticide use but were unable to put this knowledge into practice.6 For example, although aware that they should not use leaking knapsack sprayers, the farmers continued to use them and this was one of the commonest causes of poisoning. Often the workers were sparsely clothed and the pesticide from the leaking knapsack sprayers came into direct contact with the skin. Similarly, the workers knowing of the dangers of spraying into a head wind continued to do so even when the wind changed direction.' The workers take these risks because reasonable alternatives are not readily available. Spray equipment is expensive, repair

Dust exposure, pneumoconiosis, and mortality of coalminers.

Abstract: General mortality in approximately 25 000 British coalminers over 22 year periods ending in 1980 was 13% lower on average than in English and Welsh men in the same regions of Britain. There were significant within region variations between collieries, and standardised mortality ratios increased during the later years of the follow up, approaching or slightly exceeding 100 in most of the 20 coalmines studied. Age specific comparisons of 22 year survival rates were made in subgroups. Relative risks of death from all non-violent causes for men with the earliest stage of progressive massive fibrosis (PMF category A), compared with risks in miners with no pneumoconiosis (category O), ranged from 1.2 in those aged 55-64 initially to 3.5 for those aged 25-34. Mortality in miners with higher categories of PMF (B or C) was even more severe. Survival rates in men with category 1 simple pneumoconiosis were about 2% to 3% lower than in miners with radiographs classified as category O, but there was no consistent evidence of an increase in mortality with increasing category of simple pneumoconiosis. Mortality from all non-violent causes increased systematically with increases in estimates of exposure to dust before the start of the follow up. That gradient was attributable primarily to deaths certified as due to pneumoconiosis and those recorded as due to bronchitis and emphysema (p less than 0.001). There was some evidence of a dust related increase in deaths from cancers of the digestive system (p approximately equal to 0.05), but none of an association between exposure to coalmine dust and lung cancer. Lung cancer mortality, assessed over 17 year periods, was about 5.5 times higher in smokers than in life long non-smokers. Smokers with no pneumoconiosis had slightly higher lung cancer death rates than smokers with pneumoconiosis. We conclude that miners exposed to excessive amounts of respirable coalmine dust are at increased risk of premature death, either from progressive massive fibrosis or from chronic bronchitis or emphysema.

A job-exposure matrix for use in population based studies in England and Wales.

Abstract: The job-exposure matrix described has been developed for use in population based studies of occupational morbidity and mortality in England and Wales The job axis of the matrix is based on the Registrar General's 1966 classification of occupations and 1968 classification of industries, and comprises 669 job categories The exposure axis is made up of 49 chemical, physical, and biological agents, most of which are known or suspected causes of occupational disease In the body of the matrix associations between jobs and exposures are graded to four levels The matrix has been applied to data from a case-control study of lung cancer in which occupational histories were elicited by means of a postal questionnaire Estimates of exposure to five known or suspected carcinogens (asbestos, chromates, cutting oils, formaldehyde, and inhaled polycyclic aromatic hydrocarbons were compared with those obtained by detailed review of individual occupational histories When the matrix was used exposures were attributed to jobs more frequently than on the basis of individual histories Lung cancer was significantly more common among subjects classed by the matrix as having potential exposure to chromates, but neither method of assigning exposures produced statistically significant associations with asbestos or polycyclic aromatic hydrocarbons Possible explanations for the failure to show a clear effect of these known carcinogens are discussed The greater accuracy of exposures inferred directly from individual histories was reflected in steeper dose response curves for asbestos, chromates, and polycyclic aromatic hydrocarbons The improvement over results obtained with the matrix, however, was not great For occupational data of the type examined in this study, direct exposure estimates offer little advantage over those provided at lower cost by a matrix

Neurobehavioural effects of repeated occupational exposure to toluene and paint solvents.

Abstract: In studies of two workforces 44 men exposed to paint solvents and 52 men working with toluene were compared with age matched comparison groups of non-exposed workers. Scores on a series of performance tests were examined, the solvent exposed in each study functioning less well than their comparison group. The apparent deficit among the paint exposed workers was substantial, but this was reduced after allowance for estimated intellectual capacity. No deficit was apparent on rematching with a second comparison group of more appropriate measured capacity. No evidence was found of impaired nerve conduction in the ulnar or median nerves, and few clinical signs of neurological damage were apparent. Nevertheless, in an associated inquiry of neuropsychological symptoms among 236 painters and 128 non-exposed workers a highly significant excess of symptoms was found among those exposed to paint solvents.

Silica, silicosis, and progressive systemic sclerosis.

Abstract: An inquiry into the relation between exposure to silica dust, the presence of silicosis, and progressive systemic sclerosis was conducted in white South African gold miners by means of a case-control study. Seventy nine cases of progressive systemic sclerosis were matched by year of birth with an equal number of control miners selected randomly but bearing in mind the administrative channel through which the case had come to be identified. Analysis showed no association between silicosis and PSS but did show that the cumulative life time silica exposure was significantly higher in the cases compared with controls. This difference was due to a difference in the intensity of exposure to silica during mining service rather than a difference in duration of service. The results are discussed in the context of current thought on the aetiology of progressive systemic sclerosis, particularly in relation to autoimmune and genetic factors.

Minor psychiatric morbidity in employed young men and women and its contribution to sickness absence.

Abstract: An epidemiological survey of male and female executive officers in the Civil Service showed a prevalence of 33% of minor psychiatric disorders. Follow up one year later found that only half were better. The presence of minor psychiatric disorder was associated with increased rates of sickness absence, particularly certified absence. Such a high prevalence, associated as it is with handicap to the individual and consequences for the working environment, indicates the need for early medical detection and treatment.

Combined effect of asbestos and smoking on mortality from lung cancer and mesothelioma in factory workers

Abstract: The mortality of over 1250 male and 420 female asbestos factory workers was observed over the period 1971-80. Smoking habits were obtained from the subjects in 1971 before the start of the follow up period. Mortality due to lung cancer and to mesothelioma was related to smoking habits. After allowing for the effect of smoking on lung cancer the relative risk due to asbestos was highest for those who had never smoked, lowest for current smokers, and intermediate for ex-smokers; the trend was statistically significant (p less than 0.05). There was no significant association between smoking and deaths due to mesothelioma. Data from several studies are reviewed, and although overall non-smokers have a relative risk of lung cancer due to asbestos that is 1.8 times that of smokers, there is some uncertainty on the accuracy of this figure because of possible biases and sampling variation. Overall the evidence is that mesothelioma risk is independent of smoking.

Mortality of factory workers in east London 1933-80

Abstract: The mortality of 3000 male factory workers, 1400 laggers, and 700 women factory workers in east London has been studied. The men were first employed between 1933 and 1964, the women between 1936 and 1942. Textiles were produced until the late 1950s as well as other asbestos products. Laggers were employed on contract in increasing numbers in later years. Crocidolite asbestos was used until the late 1950s as well as asmosite and chrysotile. Exposure of workers was graded according to the job into two categories, low/moderate and severe, and subdivided by duration of employment up to two years or longer. Mesothelial tumours accounted for 7.5% of the total mortality in men, and 9% in women with their longer follow up period. Lung cancer accounted for 20% of deaths in men and 14% in women. Both mesothelial tumours and lung cancer showed a dose response relationship. Histopathological examination of a series of predominantly postmortem specimens showed 22% of adenocarcinomas of lung among men and 21% in women. There was an excess of gastrointestinal tumours but no dose response relationship could be shown. Among severely exposed male factory workers there was an excess of deaths from cancer of the larynx and among severely exposed women of carcinoma of the breast and ovary. Twenty four deaths (2%) were due to asbestosis. There is an indication that the incidence of mesothelial tumours is declining but a further period of observation is required for confirmation.

Cancer morbidity among workers in the telecommunications industry.

Abstract: A retrospective cohort study of 2918 workers in the telecommunications industry in Sweden recorded the cancer morbidity for the period 1958-79. Cases of cancer were collected from the Swedish Cancer Registry for this period and information on work characteristics was collected for the entire period of employment. The total cancer morbidity was as expected. There was no excess risk of lung cancer but an excess risk of malignant melanoma of the skin was detected (SMR = 2.6, 12 cases). This excess risk was particularly associated with work environments where soldering was practised. Estimates of the SMR became larger with the assumption of a longer induction/latency period.

Occupational lead neurotoxicity: improvement in behavioural effects after reduction of exposure.

Abstract: To evaluate critical exposure levels and the reversibility of lead neurotoxicity a group of lead exposed foundry workers and an unexposed reference population were followed up for three years. During this period, tests designed to monitor neurobehavioural function and lead dose were administered. Evaluations of 160 workers during the first year showed dose dependent decrements in mood, visual/motor performance, memory, and verbal concept formation. Subsequently, an improvement in the hygienic conditions at the plant resulted in striking reductions in blood lead concentrations over the following two years. Attendant improvement in indices of tension (20% reduction), anger (18%), depression (26%), fatigue (27%), and confusion (13%) was observed. Performance on neurobehavioural testing generally correlated best with integrated dose estimates derived from blood lead concentrations measured periodically over the study period; zinc protoporphyrin levels were less well correlated with function. This investigation confirms the importance of compliance with workplace standards designed to lower exposures to ensure that individual blood lead concentrations remain below 50 micrograms/dl.

Partition coefficients of some industrial aliphatic hydrocarbons (C5-C7) in blood and human tissues.

Abstract: Saline/air, blood/air, olive oil/air, and tissue/air (lung, kidney, liver, brain, muscle, heart, and fat) partition coefficients were determined for nine aliphatic hydrocarbons: n-pentane, 2,2-dimethylbutane, 3-methylpentane, 2-methylpentane, methylcyclopentane, n-hexane, cyclohexane, 3-methylhexane, and n-heptane. Blood/air partition coefficients were found to range between 0.38 (n-pentane) and 1.9 (n-heptane) and the value of the tissue/air partition coefficients rose from n-pentane to n-heptane. The tissue/air partition coefficients were significantly correlated with the blood/air partition coefficients (r = 0.92-0.98). According to the slope of the regression lines, the mean solubility of the nine aliphatic hydrocarbons in the different tissues was higher than in blood by the factors: lung 1.4 (range 1.2-2.1) heart 3.9 (range 0.5-4.5), liver 5.6 (range 5.5-13.5), kidney 5.2 (range 1.6-5.8), brain 6.5 (range 5.8-10.7), muscle 7.6 (range 1.8-8.8), and fat 205 (range 104-254). The blood/air and olive oil/air partition coefficients were significantly correlated with the boiling points and the molecular weights of the aliphatic hydrocarbons studied.

Prostatic cancer and chronic respiratory and renal disease in British cadmium workers: a case control study.

Abstract: Deaths due to prostatic cancer, renal cancer, bronchitis or emphysema, and nephritis or nephrosis in three cohorts of cadmium workers have been investigated in a case-control study. Evidence of an association of risk for these diseases with intensity and duration of exposure to cadmium was sought. The only clearly statistically significant finding was of an association of deaths coded as bronchitis or emphysema with "high" levels of exposure to cadmium fume, which was related also to duration of exposure. There was suggestive evidence also (p congruent to 0.10) of an increased risk for nephritis or nephrosis after high exposure. Marginally increased risks were observed for prostatic cancer after high or "medium" exposure, but these were not statistically significant.

Dissolution of metals by human and rabbit alveolar macrophages.

Abstract: The ability of human and rabbit alveolar macrophages to dissolve 0.1-0.5 micron MnO2 particles in vitro was compared. The amount of Mn added and dissolved from the particles over periods of nought, one, and three days was determined by flame atomic absorption spectrophotometry. The amount dissolved by human and rabbit macrophages was similar; on average 43.1% and 43.9%, respectively, were dissolved within three days. But rabbit and human macrophages dissolved significantly more Mn than was dissolved in the respective culture medium without macrophages after one and three days. It is suggested that the dissolution of particles by alveolar macrophages should be one basic component in any model of alveolar clearance of inorganic particles.

Mortality among members of a heavy construction equipment operators union with potential exposure to diesel exhaust emissions.

Abstract: A historical prospective mortality study was conducted on a cohort of 34 156 male members of a heavy construction equipment operators union with potential exposure to diesel exhaust emissions. This cohort comprised all individuals who were members of the International Union of Operating Engineers, Locals 3 and 3A, for at least one year between 1 January 1964 and 31 December 1978. The mortality experience of the entire cohort and several subcohorts was compared with that of United States white men, adjusted for age and calendar time. The comparison statistic was the commonly used standardised mortality ratio (SMR). Historical environmental measurements did not exist, but partial work histories were available for some cohort members through the union dispatch computer tapes. An attempt was made to relate mortality experience to the union members' dispatch histories. Overall mortality for the entire cohort and several subgroups was significantly lower than expected. When cause specific mortality was examined, however, the study provided suggestive evidence for the existence of several potential health problems in this cohort. Mortality from liver cancer for the entire cohort was significantly high. Although mortality from lung cancer for the entire cohort was similar to expected, a positive trend by latency was observed for lung cancer. A significant excess of mortality from lung cancer was found among the retirees and the group for whom no dispatch histories were available. Other dispatch groups showed no evidence of lung cancer excess. In addition, the total cohort experienced significant mortality excess from emphysema and accidental deaths.

Mortality of welders and other craftsmen at a shipyard in NE England.

Abstract: Personnel records of over 1000 welders and electricians but only 235 caulkers and 557 platers employed at a shipyard in NE England between 1940 and 1968 were obtained and the mortality followed up to December 1982. The observed number of deaths (13 from mesothelial tumours, nine among the electricians) were compared with the number to be expected in the Newcastle connurbation. Welders and caulkers were most exposed to welding fumes, electricians to asbestos. The study was limited by the lack of accurate job exposure details, and there was no record of smoking habits, but welders and caulkers showed a higher standardised mortality ratio for all causes, lung cancer, ischaemic heart disease, pneumonia, and accidents than platers and electricians.

Behavioural evaluation of workers exposed to mixtures of organic solvents.

Abstract: Reports from Scandinavia have suggested behavioural impairment among long term workers exposed to solvents below regulatory standards. A cross sectional study of behavioural performance was conducted among printers and spray painters exposed to mixtures of organic solvents to replicate the Scandinavian studies and to examine dose-response relationships. Eligible subjects consisted of 640 hourly workers from four midwestern United States companies. Of these, 269 responded to requests to participate and 240 were selected for study based on restrictions for age, sex, education, and other potentially confounding variables. The subjects tested had been employed on average for six years. Each subject completed an occupational history, underwent a medical examination, and completed a battery of behavioural tests. These included the Fitts law psychomotor task, the Stroop colour-word test, the Sternberg short term memory scanning test, the short term memory span test, and the continuous recognition memory test. Solvent exposure for each subject was defined as an exposed or non-exposed category based on a plant industrial hygiene walk-through and the concentration of solvents based on an analysis of full shift personal air samples by gas chromatography. The first definition was used to maintain consistency with Scandinavian studies, but the second was considered to be more accurate. The average full shift solvent concentration was 302 ppm for the printing plant workers and 6-13 ppm for the workers at other plants. Isopropanol and hexane were the major components, compared with toluene in Scandinavian studies. Performance on behavioural tests was analysed using multiple linear regression with solvent concentration as an independent variable. Other relevant demographic variables were also considered for inclusion. No significant (p greater than 0.05) relation between solvent concentration and impairment on any of the 10 behavioural variables was observed after controlling for confounding variables. Exposed/non-exposed comparisons showed a significantly poorer digit span among those exposed, but this has not been generally reported in the Scandinavian studies. The medical examination showed no abnormalities of clinical significance. The inability to replicate the findings of the Scandinavian studies could have been due to the shortness of the duration of workers' exposure, the type of solvents in the mixtures, use of different behavioural tests, or to selection factors.

Lung cancer among asbestos cement workers. A Swedish cohort study and a review.

Abstract: A cohort study of 1176 Swedish asbestos cement workers did not indicate any asbestos related excess mortality. Possible explanations of the negative outcome are relatively low exposure levels and the predominant use of chrysotile in production. Such a tentative conclusion is supported by a review of five mortality studies of workers exposed to asbestos cement that report considerable differences in relative risks for lung cancer. These differences could be explained by various degrees of cumulative exposure, the amount of amphiboles in the production, and methodological shortcomings. A median exposure of 10-20 fibre-years does not seem to cause an increased risk of lung cancer, particularly when only chrysotile is used.

Cytogenetic, immunological, and haematological effects in workers in an ethylene oxide manufacturing plant

Abstract: Samples of blood were collected from a group of plant workers engaged in the manufacture of ethylene oxide (EO) for periods of up to 14 years and also from a group of control personnel matched by age and smoking habits. Peripheral blood lymphocytes were cultured for cytogenetic analysis. Selected immune and haematological parameters were also investigated. The results of these studies showed no statistically significant difference between the group of plant workers and the control group in respect of any of the biological parameters investigated in this study. Nevertheless, duration of employment in EO manufacturing was positively correlated (p less than 0.05) with the frequency of chromosome breaks and with the percentage of neutrophils in a differential white blood cell count and negatively correlated (p less than 0.05) with the percentage of lymphocytes. As the values of these parameters remained within the normal limits of control populations, the correlations were considered to have no significance for health. Atmospheric concentrations of EO were determined using personnel air samplers and were generally below the detection limit (less than 0.05 ppm) during stable plant operations, although transient concentrations of up to 8 ppm were occasionally recorded. The amount of alkylation (2-hydroxyethyl groups) of the Nt atom of histidinyl residues in haemoglobin was also measured in an attempt to gauge recent individual exposures to EO. Variable but, in most instances, readily measurable amounts of Nt-(2'-hydroxyethyl)-L-histidine (Nt represents the N3 atom of histidine) were found in the haemoglobin of plant workers and in the control group who had not knowingly been exposed to an exogenous source of EO. There was no statistically significant difference between the results obtained in the control group and in the group of plant workers.

Radiation, work experience, and cause specific mortality among workers at an energy research laboratory.

Abstract: A retrospective cohort mortality study was conducted among 8375 white male employees who had worked at the Oak Ridge National Laboratory for at least one month between 1943 and 1972. This plant has been the site of energy related research, including uranium and plutonium reactor technology and radioisotope production. Radiation doses, primarily from gamma rays, were generally low; the median cumulative exposure for workers was 0.16 rems. Historical follow up was conducted for the years 1943-77 and ascertainment of vital status was achieved for 92.3% of the cohort. Standardised mortality ratios (SMRs) were computed to contrast the subjects9 cause specific mortality experience with that of the United States white male population. The observed number of 966 deaths from all causes was 73% of the number expected. Mortality deficits were also seen for arteriosclerotic heart disease (SMR = 0.75; 344 observed) and all cancers (SMR = 0.78; 194 observed). These results are indicative of the healthy worker effect and the favourable influence on health of the cohort9s relatively high socioeconomic status. Non-statistically significant raised SMRs were seen for all leukaemias (SMR = 1.49, 16 observed), cancer of the prostate (SMR = 1.16, 14 observed), and Hodgkin9s disease (SMR = 1.10, 5 observed). Internal comparisons of mortality (standardised rate ratios, SRRs) were made between subgroups of the cohort according to radiation dose level and duration of employment in various job categories. No consistent gradients of cause specific mortality were detected for radiation exposure. Leukaemia mortality was highest among workers with greater than or equal to 10 years employment in engineering (SRR = 2.40) and maintenance (SRR = 3.12) jobs. The association of leukaemia with employment in engineering was unexpected; maintenance jobs entail potential exposures to radiation and to a wide range of organic chemicals; metals, and other substances.

Raised mortality from lung cancer and high sex ratios of births associated with industrial pollution.

Abstract: Geographical and temporal associations were shown between high mortality from lung cancer and a high sex ratio of births both in the town of Bathgate (Scotland) and in the area of that town which was most exposed to polluted air from a local steel foundry. These findings constituted a replication of a similar association in an adjacent town.

Mortality experience of electrical engineers.

Abstract: We have followed up the mortality experience of a group of 1254 electrical engineers during 1930-79, all of whom graduated from the Royal Institute of Technology in Stockholm. The study population consisted of all the men who graduated from this university from 1930 to 1959 with a master of science degree in electrical engineering. These men have been exposed to a variety of laboratory and technical practices in school as well as later, focusing on telecommunication and power engineering. The mortality experience was recorded from the time of graduation to the end of 1979, giving a study period of up to five decades. Of the 1254 men, 11 were lost in follow up, mainly due to emigration. The rest could be certified as either alive or dead at the end of the study period. For those 108 who were dead, death certificates were collected from the local parishes or the National Cause of Death Registry. The mortality in the study group was compared with the expected mortality calculated from age specific (five year groups) and calendar year specific mortality rates of the general Swedish male population for each diagnosis or group of diagnoses studied. The expected mortality for the earliest period (1930-50) was estimated from the rates for 1951-79, adjusted for trend. The standardised mortality ratios (SMR) were calculated for each diagnosis or class of diagnoses, together with a 95% confidence interval as described by Rothman and Boice.' The same was done for the group of 659 male architects who graduated from the same school during the same period to give a comparison with a group similar in background and social position. This group has been described in detail elsewhere.2 Risks for electrical engineers were also compared directly with those for architects and relative risk (RR) estimates were calculated for some diagnoses. When compared with the population at large the mortality of the engineers was found to be considerably lower than expected. As may be seen in the

Occupational asthma due to an emulsified oil mist

Abstract: A toolsetter developed occupational asthma due to the oil mist generated by his lathe on which it was used as a coolant. The diagnosis was confirmed by serial measurements of peak expiratory flow at home and work, including a prolonged period away from work. Occupational type bronchial provocation tests were performed using the whole emulsified oil and its components separately. He reacted specifically to the whole emulsified oil and to the reodorant, a pine oil preparation. He also reacted to colophony, a constituent of the emulsifier.

Assessment of renal function in workers previously exposed to cadmium.

Abstract: Cadmium induced renal effects were examined in 60 workers (58 men, 2 women) previously exposed to cadmium. Tubular damage in the form of beta 2-microglobulinuria was found in 40%, and urinary albumin and orosomucoid increased significantly with increasing urinary cadmium and increasing relative clearance of beta 2-microglobulin. It is suggested that increased albumin excretion is secondary to the tubular damage. In no case was typical glomerular proteinuria found that could be related to cadmium. Histories of renal stones were more common among the workers with high urinary cadmium concentrations. The glomerular filtration rate was measured in 17 of the workers who had pronounced tubular dysfunction. The average glomerular filtration rate for these men was less than the age adjusted predicted value (mean = 84%). Furthermore, there was a significant (p less than 0.05) correlation (r = -0.47) between tubular reabsorption loss and a decreased glomerular filtration rate.

Kinetics of deposition and clearance of inhaled mineral dusts during chronic exposure.

Abstract: New inhalation studies have been carried out with rats exposed to UICC (Union International Contre le Cancer) amosite asbestos, with the main aim of further elucidating the factors the influence the accumulation of dust in the lung during prolonged chronic exposure. The results show that, for exposure times beyond a few weeks, the lung burden rises linearly and does not level off as predicted by simple models based on ideas taken from the 1966 report of the Task Group on Lung Dynamics. Furthermore, the lung burden is found to scale directly in proportion to the exposure concentration in a way that seems to contradict the overload hypothesis stated earlier. Nevertheless, the general pattern exhibited by our results for asbestos is markedly similar to that found elsewhere for rats inhaling diesel fume, leading to the suggestion that it is general (and not specific to fibrous dust); and the hypothesis that, whereas overload of clearance can take place at high lung burdens after exposure has ceased, it is cancelled by the sustained stimulus to clearance mechanisms provided by the continuous challenge of chronic exposure. The linearity of the increase in lung burden is explained in terms of a kinetic model involving sequestration of some inhaled material to parts of the lung where it is difficult to clear. The particular sequestration model favoured is one where, the longer a particle remains in the lung without being cleared, the more likely it will be sequestrated (and therefore less likely cleared). It is believed that such ideas may eventually be useful in forming exposure-dose relations for epidemiology.

Synthetic pyrethroid insecticides: a dermatological evaluation.

Abstract: Synthetic pyrethroids are lipophilic insecticides whose biological activity seems to be directly related to their chemical structure. In this investigation differences in cutaneous sensation were detected by human participants between synthetic pyrethroids with a cyano group in the (S)-configuration of the 3-phenoxybenzyl alcohol of their molecular structure (fenvalerate) and those that do not (permethrin). A strong relation was noted between insecticidal potency and degree of induced cutaneous sensation for the alpha-cyano and non-cyano pyrethroids, with a prominent difference between the two. No sensation was observed by any of the same participants on topical exposure to the inert ingredients of these agents. A linear correlation between concentration and degree of induced dysaethesia was observed for both pyrethroids. Regressing the cutaneous sensation on the common logarithm of concentration resulted in a regression equation of Y = 84.0 + 31.0X1 for fenvalerate and Y = 27.5 + 15.8X1 for permethrin. A highly efficacious therapeutic agent for pyrethroid exposure was noted to be dl-alpha tocopherol acetate. An impressive degree of inhibition of paraesthesia resulted from the topical application of vitamin E acetate, with a therapeutic index of almost 100%.