Exposure-response of silicosis mortality in Swedish iron ore miners.
OBJECTIVE
To assess the exposure-response relationship between exposure to quartz and fatal silicosis.


METHODS
The mortality from silicosis in 7729 miners was analyzed and compared to their estimated exposure to respirable quartz. The miners had been working as a miner for at least 1 year between 1923 and 1996. Their mortality between 1952 and 2001 was studied by using information from the national cause of death register. Both underlying and contributing causes of death were considered in the analysis. The exposure to quartz was estimated from job titles and using 3239 measurements of personal exposure to respirable quartz from 1965 to 1999. The mortality rates were adjusted to attained age and years of birth using a Poisson regression.


RESULTS
The median cumulative exposure among the 7729 miners was 0.9 mg x years m(-3). There were 58 deaths from silicosis. Their median cumulative exposure was 4.8 mg x years m(-3). The crude mortality rate was 53 cases per 100,000 person-years with an exposure-response relationship.


CONCLUSIONS
There seems to be an increased risk of fatal silicosis at exposure levels around 3 mg x years m(-3) for respirable quartz.
Occupational Medicine, Department of Public Health and Clinical Medicine, Umeå University, SE-901 85 Umeå, Sweden. ulf.hedlund@envmed.umu.se
Ulf
U
Hedlund
Håkan
H
Jonsson
Kåre
K
Eriksson
Bengt
B
Järvholm
D000328:Adult; D002423:Cause of Death; D006801:Humans; D007501:Iron; D008297:Male; D008875:Middle Aged; D008906:Mining; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis; D012829:Silicosis / Q000209:etiology / Q000401:mortality*; D013548:Sweden / Q000453:epidemiology
D007501:Iron