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Biomedical subjects

C Hogstedt

Publications and source records attributed to C Hogstedt.

At least 73 records · Page 4Linked to original sources

Frequency of extrasystoles in healthy male employees.

To determine reference values for ectopic activity 147 actively employed healthy men aged from 15 to 65 years were examined by 24 hour Holter monitoring during their ordinary daily activities. Age was the only risk factor significantly associated with supraventricular and ventricular extrasystoles. During a six year follow up only two men died. In both the frequency of ventricular extrasystoles had been high, but neither of them died from cardiovascular disease. Because the distribution of the frequency of extrasystoles in the study group was highly skewed a percentile distribution was used to determine normal values. This distribution showed that 95% of men aged 15-39 years had less than 2.9 ventricular extrasystoles per hour and the same proportion of men aged 40 years or older had less than 36 ventricular extrasystoles per hour. For field studies values above the 90th percentile (that is more than 10 ventricular extrasystoles per hour for men 40 years or older) may be a more appropriate cut off point.

Adolescent↗

Mortality and incidence of cancer among Swedish rubber workers, 1952-1981.

The mortality and incidence of cancer was studied among 8,734 workers from two Swedish rubber manufacturing companies. Mortality was investigated from 1952 to 1981 and cancer incidence from 1959 to 1980. The expected numbers of deaths were calculated from national statistics. No significant risk excesses were detected when the cohort was analyzed without consideration of employment time or latency period. However, the mortality from coronary heart disease and the incidence of lung cancer were increased when the study period was limited to greater than or equal 40 years since first employment. The standardized mortality ratio for coronary heart disease correlated positively with employment duration. The mortality from asthma, bronchitis, and emphysema was nonsignificantly increased. The incidence of bladder cancer was increased among individuals with heavy and long-term exposure in the weighing and mixing departments. Twenty-five percent of the individuals in the cohort were not Swedish citizens at the time of employment, and an analysis of the mortality and cancer incidence in this group showed a markedly increased lung cancer incidence for certain immigrant groups, probably mainly due to ethnic factors. The results indicate that ethnic factors must be considered in the analysis of occupational groups when a high proportion of the workers are immigrants.

Female↗

Cancer mortality of cadmium workers.

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.

Cadmium↗

Urinary screening for potentially genotoxic exposures in a chemical industry.

Mutagenic activity, measured by the bacterial fluctuation assay and thioether concentration in urine from workers at a chemical plant producing pharmaceuticals and explosives, was determined before and after exposure. Of 12 groups only those exposed to trinitrotoluene (n = 14) showed a significant increase in mutagenic activity using Salmonella typhimurium TA 98 without any exogenous metabolic system. The same strain responded only weakly when the S-9 mix was used; with Escherichia coli WP2 uvrA no effect of exposure was observed. Urinary thioether concentration was higher among smokers than among non-smokers, but occupational exposure had no effect. Urinary mutagenicity testing may be a useful tool for screening potentially genotoxic exposures in complex chemical environments.

Chemical Industry↗

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

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.

Asbestos↗

Ventilatory decrements in former asbestos cement workers: a four year follow up.

A four year follow up of the ventilatory function in former asbestos cement workers has been performed to determine whether any further decrease occurred after cessation of exposure. Seventy five of 125 subjects were eligible for re-examination and were compared with local referents. None showed signs of asbestosis but 32% had pleural plaques at the renewed examination. Cumulative asbestos exposure calculated as fibre x years had been estimated individually in the original examination. After adjustment for age, height, tracheal area, and smoking category the FVC and FEV1 for all exposed subjects were on average 7% v 6% less than predicted from the referents and twice as much for the subjects with the highest exposure. The four year declines in FVC and FEV1 were larger than in the referents, significantly so for FEV1. There were no significant correlations between pleural plaque and ventilatory function after adjustment for exposure. Thus the age adjusted reduction in ventilatory function had progressed during the follow up period despite the cessation of exposure and the lack of radiological signs of asbestosis.

Adult↗

Decreased lung function in long-term asbestos cement workers: a cross-sectional study.

The effect on lung function of exposure in an asbestos cement plant was investigated in male workers, employed more than 10 years. The exposed group was selected to exclude subjects with pneumoconioses and ex-smokers and consisted of 77 smokers and 48 never-smokers. Referents were chosen from plants where asbestos had not been in use and restricted to those without X-ray signs of chest disease. The primary type of asbestos used was chrysotile and the general dust level in the two decades 1950-1970 seems to have been around 10 mg/m3 while the asbestos fiber concentration averaged 2 fibers/ml. The mean differences between exposed and referents were statistically significant for forced vital capacity and forced expiratory volume, -0.25 and -0.30 liters, respectively, after adjustment for age, height, tracheal area, and smoking category. No significant differences were detected between those with and without pleural plaques. Smokers and never-smokers were similarly affected. In conclusion, the group exposed to dust with comparatively low asbestos fiber concentration had a minor impairment of lung function, mainly due to obstructive changes.

Air Pollutants, Occupational↗

Mortality among asbestos-exposed workers in a railroad workshop.

The mortality experience of a cohort of 3 297 railroad maintenance shopworkers exposed to asbestos was investigated. The study period was 1951-1980, and the vital status was assessed for 99.6% of the men. Individual estimates of cumulative asbestos exposure were based on detailed records on work tasks and divisions. Dust measurements were scanty in earlier decades, and estimates of average fiber levels were therefore based on information on the amount and kind of asbestos used, job descriptions, and interviews with older workers. The overall mortality was lower than expected from the national death rates (standardized mortality ratio = 82). The mortality from lung cancer increased as cumulative exposure increased in consistent dose-response relationships. Employment times of less than 30 years in workplaces with moderate levels of mainly chrysotile asbestos was not associated with any apparent increase in the risk of lung cancer. A subgroup exposed for more than 30 years in workplaces repairing steam engines, where amphiboles were used as well, had a standardized mortality ratio of 192 for lung cancer. This figure may be an underestimation due to healthy worker selection and fewer smokers than normal. The "true" standardized mortality ratio was estimated to be about 300. Five cases of mesothelioma were observed.

Aged↗

Mortality from cardio-cerebrovascular diseases among dynamite workers--an extended case-referent study.

Increased mortality from cardio-cerebrovascular diseases among male dynamite workers was reported in 1977 and was supported two years later by findings in a small cohort study from another Swedish dynamite population. The excess risk was confined to those with long-term employment. The original case-referent study comprised the years between 1955-1975 and the register of deaths and burials in the parish around the dynamite factory was used as the source of subjects. The same register has now been used for the time period 1976-1980. We have used identical requirements for this extension as in the original study, i.e., confined to men with more than one year of employment and aged 36-70. Cases were those who died from ischaemic heart diseases and cerebrovascular diseases according to WHO classification rules and referents those who died from all other diseases remaining after the primary exclusions. 102 men had died in the parish during the extension period. 15 were excluded. There were 36 deaths from heart diseases, 12 from cerebrovascular diseases and 39 referent diagnoses. Six of the "heart-cases", three of the "c-v-cases" and six of the referents were exposed. The Mantel-Haenszel estimation of the risk ratio for cerebrovascular diseases during the period 1955-80 is 2.9 (95% confidence interval 0.9-6.4) and 2.7 for cardio-vascular diseases (1.4-5.4). Among 25 men exposed more than 20 years only one died from anything else but a cardio-cerebrovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Neuropsychological test results and symptoms among workers with well-defined long-term exposure to lead.

Lead intoxication is a classical environmental hazard that can cause encephalopathy. During recent years several studies have suggested poor performances in psychological tests and increased numbers of subjective symptoms among workers with comparatively low blood lead concentrations. Forty-nine long-term lead-exposed male workers with time-weighted average blood lead concentrations between 1.3 and 3.3 mumol/l calculated from at least seven years' results have been compared with a referent group of 27 male industrial workers with normal blood lead concentrations and comparable intellectual backgrounds. Several indices of exposure were used. Both groups were examined with neuropsychological tests and a questionnaire covering neuropsychiatric symptoms. The exposed group performed less well in 11 of 14 non-verbal tests, and there were significant differences in tests of memory and reaction time. A non-linear dose-effect trend was indicated. The results are in accordance with those found in similar studies, and it is concluded that the blood lead concentration should be below 2.5 mumol/l to avoid the effects shown in this study.

Adult↗

A cohort study on mortality among long-time employed Swedish chimney sweeps.

A cohort study on mortality among all members of the Swedish Chimney Sweeps Union who were active in 1950 or later and have been members for at least 10 a has been performed; 2,071 chimney sweeps fulfilled the criteria and the loss in the follow-up was less than 1 %. The observed numbers of death before the age of 80 were compared with sex-, calendar year-, and age class specific expectancy values from the national statistics of 1951-1979. Two hundred and thirty deaths were observed versus 197.6 expected. This result was due to a significant excess of deaths from tumors, particularly lung and esophageal cancer, and from nonmalignant chronic respiratory diseases. The multifold increased risk from these diseases could hardly be explained by extreme smoking or alcohol habits but rather by exposure to polycyclic aromatic hydrocarbons, nitrogen compounds, arsenic, and asbestos in combination with exposure to sulfur dioxide. The excess mortality had occurred in spite of favorable selection factors as demonstrated in different subcohorts. Preventive actions to diminish inhalation of soot and combustion gases should be taken.

Adult↗

Parkinson's disease and occupational exposure to organic solvents, agricultural chemicals and mercury--a case-referent study.

Parkinson's disease has been associated with heavy occupational exposure to carbon disulfide, and this solvent, as well as other organic solvents, may cause neurotoxic effects. Therefore, the hypothesis was raised that organic solvents in general may be associated with Parkinson's disease. A case-referent study design was applied, and some other suspected exposures were studied as well. The diagnosis registers of two Swedish hospitals were used as the source of subjects. Male in-patients with Parkinson's disease (the cases) or subarachnoid hemorrhage (referents), with symptom appearance between 35-69 a of age and residence in the vicinity of the hospitals, were included in the study. Occupational exposure to the chemicals under study were determined from questionnaire answers of 91 cases and 75 referents. No differences in exposure frequency to organic solvents in general were observed, but three cases had been exposed to carbon disulfide compared to none of the referents. Six cases, but only two referents, had been exposed to mercury, and further exploration of a possible association between exposure to mercury and Parkinson's disease is recommended. The outcome of the study does not support the hypothesis that occupational exposure to organic solvents in general increases the risk of Parkinson's disease, but the confidence intervals of the odds ratios do not rule out such possibilities.

Adult↗