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Biomedical subjects

O Axelson

Publications and source records attributed to O Axelson.

At least 55 records · Page 3Linked to original sources

Some hygienic observations from the glass industry.

Metallic compounds and other agents used in the manufacturing of glass are probably responsible for the cancer risks observed for glassworkers, especially glassblowers. Few hygienic observations have been reported from the art glass industry. Three glassworks were therefore studied with regard to air concentrations of lead, arsenic, nickel and manganese. The hygienic conditions of the blow-pipes were investigated at these glassworks and another two with regard to inside deposits of slag containing lead, arsenic, manganese and nickel as possible transporters that cause oral exposure. Atomic absorption spectrophotometry was used for the analyses. Apart from lead, the metal concentrations in the air were around the detection limit. Glassworks producing heavy crystal glass usually had higher concentrations of lead in the air than the semi-crystal glassworks. Seven out of 12 samples from heavy crystal glassworks exceeded the Swedish threshold limit of 50 micrograms/m3, while only four out of 28 samples from the semi-crystal glassworks exceeded this limit. Regarding metals in the slag from inside the blow-pipes, the concentrations (geometrical means) of lead and nickel were higher in the heavy crystal glassworks (6.9 micrograms lead/mg slag, and 5.0 micrograms nickel/mg slag versus 0.7 micrograms lead/mg slag and 0.6 micrograms nickel/mg slag in semi-crystal glassworks, respectively). The concentration of arsenic was similarly low in the pipes from all the glassworks (approximately 0.30 micrograms/mg slag) and the concentration of manganese was only slightly higher in heavy crystal glassworks (5.4 micrograms/mg slag versus 3.6 micrograms/mg slag in semi-crystal glassworks).

Air Pollutants, Occupational

Facial skin complaints and work at visual display units. An epidemiologic study of office employees.

A questionnaire about skin rashes and their symptoms was sent to 3877 randomly selected office employees with different degrees of exposure to video display units (participation rate 96.6%). From this group 809 randomly selected persons were examined and interviewed. Itching and burning sensations with few visible signs were more common among persons who were highly exposed than among those in the nonexposed category. Objective facial signs were not significantly more common among persons in the highly exposed category. No dose-response effect was observed regarding the amount of video display unit exposure and objective skin signs. Unilateral skin rashes and skin malignancies were found in the same frequency in both highly exposed and the nonexposed persons. This study does not provide support for the hypothesis that video display unit work induces any recognized type of facial skin disease.

Adult

Evaluation of a questionnaire for facial skin complaints related to work at visual display units.

A questionnaire about facial skin problems was answered by 3745 office employees, with the aim of discovering whether VDU work causes skin disease. From this group, 809 randomly selected persons were examined and interviewed by a dermatologist. There was a relatively good correspondence (87%) between the results from the interviews and the questionnaires, but the questionnaire results corresponded to current status in only 46% of the cases. No important difference was seen between those who were informed and those who were not informed about the purpose of the investigation. There was a relatively wide variation in the correlation between 2 responses to the same questions. In conclusion, the self-administered questionnaire seems to give reasonably adequate answers regarding the occurrence of more clear-cut symptoms over a period of time, rather than answers regarding the presence of signs at a particular point in time. However, less marked changes might not be picked up particularly well.

Computer Systems

Interpretation of "negative" studies in occupational epidemiology.

Two criteria for an interpretation of noneffect are that the relative risk estimate be near unity and that the confidence interval be narrow; lack of statistical significance has no bearing on this issue. A further requirement is that the relative risk estimate not be near the null value as an effect of non-differential exposure misclassification, negative confounding, or some other systematic error. Occasionally, when results are unexpected or difficult to accept, studies are "underinterpreted" as negative or inconclusive on the basis of arguments such as "confounding," "crude exposure assessment," or "lack of a known mechanism." The present paper supports the position that these arguments are commonly invalid. Scientific standards should be used to separate causal associations from noncausal ones, but in public health decisions this practice has to be balanced by the principle that the "benefit of the doubt" should be given to the persons subject to potential risk.

Bias

A case-referent study on lung cancer mortality among ceramic workers.

A case-referent study has been carried out to test the hypothesis that silica-exposed ceramic workers have an increased risk of lung cancer. Next-of-kin interviews were conducted for 72 lung cancer cases and 319 referents, all deceased, to collect work histories and smoking habits. The diagnosis of silicosis was ascertained by checking the individual files of cases of silicosis where compensation had been received. It was found that, after controlling for age, period of death and smoking, workers in the ceramic industry had a higher lung cancer risk than those in other occupations in which there was no exposure to silica (Mantel-Haenszel rate ratio = 2.0; 95% confidence interval (CI) = 1.1-3.5). This increased risk was mainly due to a rate ratio of 3.9 (95% CI = 1.8-8.3) for silicotic individuals, while for non-silicotic ceramic workers it was only 1.4 (95% CI = 0.7-2.8). Exposure to other carcinogens in the workplace seems not to play any role in the development of lung cancer. Furthermore, the data do not suggest an increased risk for silicotic non-smokers. The results of the study tend to confirm previous evidence of an excess risk among silicotic subjects and points to a possible etiological role of the silicotic process itself in lung cancer.

Case-Control Studies

Colon cancer, physical activity, and occupational exposures. A case-control study.

A case-control study on colon cancer was conducted encompassing 329 cases and 658 controls. Occupations and various exposures were assessed by questionnaires. A decreased risk was found in persons with physically active occupations. This effect was most pronounced in colon descendens and sigmoideum with an odds ratio (OR) of 0.49 whereas no reduced risk was found for right-sided colon cancer. Regarding specific jobs, reduced ORs were found for agricultural, forestry, and saw mill workers and increased OR for railway employees. High-grade exposure to asbestos or to organic solvents gave a two-fold increased risk. Regarding exposure to trichloroethylene in general, a slightly increased risk was found whereas such exposure among dry cleaners gave a seven-fold increase of the risk.

Adenocarcinoma

Mortality pattern of silicotic subjects in the Latium region, Italy.

A mortality study was carried out on 595 workers who were compensated for silicosis in the Latium region, Italy, during the period 1946-84 who died between 1 January 1969 and 31 December 1984. Respiratory disorders, tuberculosis, lung cancer, bone cancer, and cirrhosis of the liver showed significantly increased risk ratios (4.1, 3.7, 1.5, 4.1, and 1.9 respectively); excesses of brain cancer and leukaemia did not reach statistical significance. Lung cancer mortality was further analysed by age, period of compensation, final degree of disability, and occupational activity. The possible confounding role of smoking was assessed by comparing the lifetime smoking habits of a sample of silicotic subjects with those of the general male population as estimated by a national health survey; the prevalence of ever smokers among silicotic subjects (70.7%) was similar to that estimated for the general population (68.5%). The present study indicates that silicosis is associated with lung cancer even though it does not clarify the respective roles of exposure to silica and silicosis.

Adult

Malignant lymphomas and occupational exposures.

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

Adult

Multiple sclerosis, solvents, and pets. A case-referent study.

The effect of potential risk factors for multiple sclerosis was evaluated in a case-referent study that encompassed 83 cases and 467 randomized referents. Information on exposure was obtained by questionnaires that were mailed to the subjects. Mantel-Haenszel rate ratios were increased for males for occupational exposure to solvents and welding and for females for leisure time contact with dogs and caged birds. For both sexes, x-ray film examination occurred more frequently among cases than referents, possibly as an effect of early symptoms from the disease itself.

Adult

Indirect methods of assessing the effects of tobacco use in occupational studies.

For various reasons, data on smoking are frequently missing, or only partially available, in retrospective epidemiologic studies of occupational risk factors. In such situations, indirect methods may be used to evaluate the magnitude and direction of the potentially confounding effects of smoking. Such an evaluation can be made quantitatively or qualitatively. Here we describe both approaches. A specific problem relates to case-referent studies, where sampling variation in referent selection may limit the possibility of controlling for confounding by smoking, even when smoking data are available. We present data showing that estimates of risk from occupational exposures which are not controlled for smoking may be as accurate as estimates derived after controlling for smoking, when the number of referents is relatively small. The problem of interaction is also discussed. In the absence of smoking data, the investigator has no indication of how smoking and occupation jointly affect disease risk (eg, additively or multiplicatively). The multiplicative model is usually assumed. However, if exposure and smoking act independently (additively), rate ratios are diminished. In such situations, in the presence of negative confounding by smoking, rate ratios may actually even be less than one--also when exposure and disease are strongly related.

Epidemiologic Methods

Symptoms of bronchial hyperreactivity and asthma in relation to environmental factors.

A questionnaire study regarding airway morbidity in children and environmental factors was performed in April 1985. The parents of 5301 children, aged 6 months to 16 years, from different rural areas in mid Sweden were sent a validated questionnaire and 4990 (94%) responded. The cumulative prevalence of bronchial hyperreactivity was 9.7% and of allergic asthma 5.2%. Children living near a paper pulp plant more often had symptoms suggesting bronchial hyperreactivity (124 (13.0%), relative risk 1.3) and allergic asthma (68 (7.1%), relative risk 1.3). In children living in a damp house problem bronchial hyperreactivity was found in 76 (19.0%) (relative risk 1.9) and allergic asthma in 35 (8.7%) of the children (relative risk 1.9). Children living in a damp house with parents who smoked had the highest figures: bronchial hyperreactivity was found in 44 (23.5%) (relative risk 2.8) and allergic asthma in 22 (11.6%) (relative risk 2.5). The results indicate that various moderate environmental pollutants may act synergistically to increase bronchial hyperreactivity and allergy especially in children with a family history of allergy.

Adolescent