Residential proximity to naturally occurring asbestos and mesothelioma risk in California.

Title
Residential proximity to naturally occurring asbestos and mesothelioma risk in California

Source
American Journal of Respiratory & Critical Care Medicine. 172(8):1019-25, 2005 Oct 15.

RATIONALE:

Little is known about environmental exposure to low levels of naturally occurring asbestos (NOA) and malignant mesothelioma (MM) risk.

OBJECTIVES:

To conduct a cancer registry-based case control study of residential proximity to NOA with MM in California.

METHODS:

Incident MM cases aged 35 yr or more, diagnosed between 1988 and 1997, were selected from the California Cancer Registry and frequency matched to control subjects with pancreatic cancer by 5-yr age group and sex. Control subjects were selected by stratified random sampling from 28,123 incident pancreatic cancers in the same time period. We located 93.7% of subjects at the house or street level at initial diagnosis. Individual occupational exposure to asbestos was derived from the longest held occupation, available for 74% of MM cases and 63% of pancreatic cancers. Occupational exposure to asbestos was determined by a priori classification and confirmed by association with mesothelioma.

MAIN RESULTS:

The adjusted odds ratios and 95% confidence interval for low, medium, and high probabilities of occupational exposures to asbestos were 1.71, 2.51, and 14.94, respectively. Logistic regression analysis from a subset of 1,133 mesothelioma cases and 890 control subjects with pancreatic cancer showed that the odds of mesothelioma decreased approximately 6.3% for every 10 km farther from the nearest asbestos source, an odds ratio of 0.937, adjusted for age, sex, and occupational exposure to asbestos.

CONCLUSIONS:

These data support the hypothesis that residential proximity to NOA is significantly associated with increased risk of MM in California.