Article
Titanium dioxide dust exposure and lung cancer in an industrial cohort study in Germany
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Authors
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Stefanie Klug
- Institut für Medizinische Biometrie, Epidemiologie und Informatik, Mainz
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M. Blettner
- Mainz
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M. Hetzer
- Mainz
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A. Soutar
- Edinburgh, Großbritannien
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I. Langner
- Bremen
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P. Boffetta
- Lyon, Frankreich
| Published: | September 8, 2005 |
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Outline
Text
Introduction
Titanium dioxide (TiO2) is a white pigment widely used in paints, plastics, ceramics, rubber and cosmetics. Industrial production includes a step of heavy TiO2 dust exposure of the industrial workers. Animal experiments suggested controversy results on the relation between TiO2 dust exposure and lung cancer. So far, epidemiological studies have shown no evidence of increased risk of lung cancer.
Methods
A historical cohort study of workers employed in the TiO2 production industry was performed in six European countries. The German cohort was the largest within the study. Workers from three German TiO2 producing factories, with first employment before 1990 and starting as early as 1927, who had been employed for at least one month, were followed up for vital status. Cause of death was obtained for workers who had been deceased. Exposure to TiO2 dust, other dust, welding fume, sulphuric acid, hydrochloride acid and asbestos was assessed. Information on smoking habits was collected. Internal analysis using Cox regression models was performed to assess the effect of these agents on cancer of the lung. Analysis was restricted to male workers who had been employed for at least one year.
Results
4845 male workers were employed for at least one year. During the observed time 1010 deaths occurred in this cohort. No association between TiO2 and lung cancer was observed. Neither analysis for duration of employment, time since first employment nor estimate cumulative exposure to respirable TiO2 dust showed an increased risk for lung cancer. Hazard ratio for exposure to other dust was 3.3 [95% Confidence interval: 1.1-9.8]. This association disappeared after adjusting for smoking. Ever smoking was the strongest risk for lung cancer in this industrial cohort.
Discussion
TiO2 dust and other industrial dust showed no association with lung cancer. In this multi-center European cohort study a large effort had been given to the assessment of exposure. Underestimation of exposure seems unlikely, however can not be ruled out complete. Although data on smoking habits were not available for the entire cohort, adding smoking to the models gave, as expected, a strong and stable risk in this analysis.
