Association between cumulative fiber exposure and respiratory outcomes among Libby vermiculite workers.
OBJECTIVE
To examine the association between cumulative fiber exposure and health outcomes in workers (n = 336) with Libby amphibole exposure.


METHODS
Exposure-response relationships were explored by the use of logistic regression, with cumulative fiber exposure modeled in categories and as a continuous variable.


RESULTS
The use of spline functions with lifetime cumulative fiber exposure as a continuous variable showed that the odds of localized pleural thickening were significantly elevated at less than 1 f/cc-y. Odds of parenchymal abnormalities, restrictive spirometry, and chronic bronchitis were also significantly elevated at 108, 166, and 24 f/cc-y, respectively.


CONCLUSIONS
The odds of several pulmonary health outcomes are correlated with cumulative exposure to Libby amphibole. That relatively low-lifetime cumulative exposures are associated with localized pleural thickening has implications for the non-cancer-risk assessment for Libby amphibole.
Division of Health Studies, Agency for Toxic Substances and Disease Registry, Atlanta, Georgia 30341, USA. thl3@cdc.gov
Theodore C
TC
Larson
Vinicius C
VC
Antao
Frank J
FJ
Bove
Caroline
C
Cusack
D000368:Aged; D000538:Aluminum Silicates / Q000633:toxicity*; D017636:Asbestos, Amphibole / Q000633:toxicity*; D001991:Bronchitis / Q000139:chemically induced* / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced* / Q000453:epidemiology; D016273:Occupational Exposure; D010995:Pleural Diseases / Q000139:chemically induced*; D012129:Respiratory Function Tests; D018570:Risk Assessment; D013147:Spirometry
D000538:Aluminum Silicates; D017636:Asbestos, Amphibole; C003760:vermiculite