Risk assessment of silicosis and lung cancer among construction workers exposed to respirable quartz.
OBJECTIVE
The aim of this study was to assess the magnitude of the silicosis and cancer risk among construction workers.


METHODS
In 1998, 1335 of 4173 invited construction workers with expected high cumulative exposure to quartz were studied for early signs of silicosis. In 2002 the study was repeated for 96 persons. Exposure measurements were performed among 34 construction workers. Silicosis risk was assessed by converting study results to the whole group of construction workers and by risk analysis based on exposure data combined with documented exposure response relations. Excess risk for cancer was also calculated from available exposure measures.


RESULTS
The initial study among construction workers revealed a prevalence of 0.8% of workers with rounded opacities on chest X-rays. The follow-up showed a much higher percentage (12%) of persons with rounded opacities on X-rays. The results were confirmed by high-resolution computed tomography. It was estimated that roughly 9% of the population initially studied (N = 1335) would have been observed with rounded opacities at follow-up. On the basis of the exposure data, a lifetime risk of silicosis above 5% is expected for workers exposed to levels above the occupational exposure limits. An excess lifetime risk for lung cancer is expected when workers are exposed to quartz levels above the occupational exposure limit. Due to the scarcity of exposure data, an estimation of the size of the group at risk is not yet possible.


CONCLUSIONS
All available data indicate that construction workers exposed to quartz levels above occupational exposure limits are clearly at elevated risk of silicosis and other respiratory diseases.
Tjoe Nij
Evelyn
E
Division of Environmental and Occupational Health, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
Heederik
Dick
D
D000328:Adult; D003430:Cross-Sectional Studies; D005160:Facility Design and Construction; D006801:Humans; D019570:Inhalation Exposure; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000000981:diagnostic imaging; D008875:Middle Aged; D009426:Netherlands; D016273:Occupational Exposure; D011791:Quartz; D013902:Radiography, Thoracic; D018570:Risk Assessment; D012829:Silicosis / Q000000981:diagnostic imaging / Q000209:etiology*
D011791:Quartz