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Biomedical subjects

H Kjuus

Publications and source records attributed to H Kjuus.

46 records · Page 3Linked to original sources

A case-referent study of lung cancer, occupational exposures and smoking. II. Role of asbestos exposure.

In a hospital-based case-referent study of 176 incident lung cancer cases, ascertained during a five-year period from two county hospitals, the role of asbestos exposure and smoking has been studied. Information on asbestos exposure was obtained from personal interviews, and allocated to four exposure categories, according to the intensity and duration of the exposure. Twenty-five percent of the cases and 10% of the referents had been moderately to heavily exposed to asbestos during their working career. A statistically significant trend in risk ratio related to the degree of exposure was observed, with a more than fourfold risk among the heavily exposed. The strongest association was found between asbestos exposure and small cell carcinoma, and the weakest association between asbestos exposure and adenocarcinoma. Very high risk ratios were observed among asbestos-exposed subjects who were heavy smokers, and the interaction observed between asbestos and smoking conformed more closely to a multiplicative model than to an additive one. The results suggest that the observed association between lung cancer and occupational exposures in this study was, to a large extent, due to asbestos exposure. Information on such exposure was missing in 90% of the medical records of these patients.

Adult↗

A case-referent study of lung cancer, occupational exposures and smoking. I. Comparison of title-based and exposure-based occupational information.

The role of occupational exposures and smoking in the development of lung cancer has been studied among 176 male incident lung cancer cases and 176 referents admitted to two county hospitals in southeast Norway during 1979-1983. After the allocation of all occupational titles in the Nordic Classification of Occupations into three exposure groups according to potential exposure to respiratory carcinogens and other contaminants, each subject was classified according to exposure status of main occupation and number of years in each exposure category. An excess risk of lung cancer was observed both among those in possibly exposed occupations and among those definitely exposed. A more than threefold excess risk was observed among subjects with more than 30 years in exposed occupations. Exposure to 22 agents/processes was further assessed by a separate questionnaire and estimated simultaneously in a logistic regression model. Elevated risks were associated with exposure to asbestos and several other agents/processes, which largely correlated to each other. Smoking was strongly associated with all histological subtypes of lung cancer, while for occupational exposures the risk ratio was highest for small cell carcinoma and lowest for adenocarcinoma. Very high risk ratios for lung cancer were observed among heavy smokers in exposed occupations.

Adult↗

Cancer and polluted work places: a case-control study.

The possible association between selected cancers and polluted work places has been studied in a hospital-based, case-control study. By dividing all jobs in the participants working career into "polluted" and "clean", a crude measure for the total industrial exposure a worker experiences throughout his life was established. Among 103 age-matched, case-control pairs the overall estimated relative risk (RR) for exposed subjects (greater than or equal to 10 years in a polluted work place) of developing cancer compared to nonexposed (less than 10 years in a polluted work place) was 1.1. The only subgroup where a significant difference was found between the cases and the controls was the lung cancer subgroup (RR = 4.0, p = 0.02, two-tailed). When the 30 lung cancer cases were compared to an alternative control group consisting of 60 subjects matched for age and smoking habits, an estimated RR of 4.5 was found. A moderate, but not significant association between lung cancer and definite asbestos exposure was also found (RR: 2.3). As most workers are exposed to a variety of industrial agents throughout their working careers, further development of methods for characterizing combined exposures are needed, both for retrospective and prospective purposes.

Epidemiologic Methods↗

Emphysema and occupational exposure to industrial pollutants.

In a case-referent study, the possible association between the development of emphysema and occupational exposure to industrial pollutants has been studied. Based on complete work histories from the participants, the number of years of employment in a polluted workplace was assessed for 36 patients with emphysema and 72 referents, matched for age (+/- 2 a) and smoking habits. Analyzed as matched triplets, the estimated risk ratio for the exposed (greater than or equal to 10 a in polluted workplaces) subjects developing emphysema in comparison to the nonexposed (less than 10 a in polluted workplaces) was 3.0, a value statistically significant. Estimated risk ratios according to the number of years employed in a polluted workplace did not show any significant trend towards a dose-response relationship. Only one of the emphysema patients had never smoked. In the further study of the relationship between emphysema and occupational exposure, the interaction between cigarette smoke and different occupational exposures seems to be of particular interest.

Aged↗

Birth weight and environmental pollution in the county of Telemark, Norway.

The possible effect of environmental pollution on fetal growth was examined in 3,231 consecutively liveborn single infants (>/=37 weeks' gestation) of Caucasian parents born between 1986 and 1988. The parents lived in an industrial area or in less polluted urban and rural residential areas. Information about lifestyle, health, and work exposures was collected from the parents. A significantly lower arithmetic mean birth weight was observed for newborns in the industrial residential area (3,517 g, SD, 482), compared with the urban (3,592 g, SD 495) and rural (3,618 g, SD 517) areas (P < 0.05). Even controlling for gestational age, sex, parity, maternal smoking habits, and social class, residential area still had a significant effect on birth weight. Among other factors examined, only maternal psychological stress at work had a significant effect on birth weight. If the observed association reflects a causal relationship, birth weight may represent a potential outcome parameter for surveillance of effects on humans of environmental exposures.

Adult↗