TY - JOUR T1 - Lung cancer incidence among an Icelandic cohort exposed to diatomaceous earth and cristobalit JO - Scandinavian Journal of Work, Environment & Health PY - 1997/6VL - 23 IS - 3 SP - 187 EP - 192 AU - Rafnsson, Vilhjálmur AU - Gunnarsdóttir, H M3 - doi: 10.5271/sjweh.197 UR - https://www.sjweh.fi/show_abstract.php?abstract_id=197 KW - brain cancer KW - Iceland KW - Lake Myvatn KW - loading ships KW - manufacturing KW - smoking habit KW - squamous-cell skin cancer N2 - '

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OBJECTIVES ': 'The objective of this study was to determine the cancer incidence of a cohort exposed to diatomaceous earth and cristobalite with special focus on lung cancer.'

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METHODS ': 'The cohort was from a diatomaceous plant in northern Iceland and comprised 919 men and 423 women. Diatomite, when heated, is transformed from amorphous to crystalline silica with a high cristobalite content and traces of quartz. With the use of the identification number of all persons, a link was made with the Cancer Registry. The expected number of malignancies was calculated on the basis of person-years of observation for 5-year age categories during the respective calendar period of the study multiplied by the specific incidence of cancer site for men and women in Iceland.'

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RESULTS ': 'There was no increased overall incidence of cancer in the study population; 5 cases of lung cancer were observed versus 4.4 expected, the standardized incidence ratio (SIR) was 1.14 [95% confidence interval (95% CI) 0.37--2.65]. When the men in the cohort were divided according to their length of employment, there was an excess of lung cancer (3 observed versus 1.28 expected, SIR 2.34, 95% CI 0.48--6.85), nonmelanoma skin cancer (2 observed versus 0.19 expected, SIR 10.53, 95% CI 1.27--38.02), and brain cancer (3 observed versus 0.30 expected, SIR 10.00, 95% CI 2.06--29.23) for those who had worked 5 years or longer. A special investigation of smoking habits among the cohort revealed a smoking pattern similar to that of the general population.'

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CONCLUSION ': 'The results concerning lung cancer showed an excess risk for workers exposed to diatomaceous earth and cristobalite; the result was not, however, statistically significant. There was a trend towards a higher incidence of lung cancer with longer exposure to crystalline silica, and, in agreement with the results of a previous study from this industry, the findings indicate a causal relation.

SN - 0355-3140 ER -