Quantitative relationships of exposure to chrysotile asbestos and mesothelioma mortality

Am J Ind Med. 2019 Jun;62(6):471-477. doi: 10.1002/ajim.22985. Epub 2019 May 13.


Background: While asbestos has long been known to cause mesothelioma, quantitative exposure-response data on the relation of mesothelioma risk and exposure to chrysotile asbestos are sparse.

Methods: Quantitative relationships of mortality from mesothelioma and pleural cancer were investigated in an established cohort of 5397 asbestos textile manufacturing workers in North Carolina, USA. Eligible workers were those employed between 1950 and 1973 with mortality follow-up through 2003. Individual exposure to chrysotile fibres was estimated on the basis of 3420 air samples covering the entire study period linked to work history records. Exposure coefficients adjusted for age, race, and time-related covariates were estimated by Poisson regression.

Results: Positive, statistically significant associations were observed between mortality from all pleural cancer (including mesothelioma) and time since first exposure (TSFE) to asbestos (rate ratio [RR], 1.19; 95% confidence interval [CI], 1.06-1.34 per year), duration of exposure, and cumulative asbestos fibre exposure (RR, 1.15; 95% CI, 1.04-1.28 per 100 f-years/mL; 10-year lag). Analyses of the shape of exposure-response functions suggested a linear relationship with TSFE and a less-than-linear relationship with cumulative exposure. Restricting the analysis to years when mesothelioma was coded as a unique cause of death yielded stronger but less precise associations.

Conclusions: These observations support with quantitative data the conclusion that chrysotile causes mesothelioma and encourage exposure-response analyses of mesothelioma in other cohorts exposed to chrysotile.

Keywords: asbestos; cancer; epidemiology; mesothelioma; risk assessment.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Age Factors
  • Asbestos, Serpentine / adverse effects*
  • Asbestos, Serpentine / analysis
  • Cohort Studies
  • Confidence Intervals
  • Environmental Monitoring / methods
  • Evaluation Studies as Topic
  • Female
  • Humans
  • Lung Neoplasms / chemically induced*
  • Lung Neoplasms / mortality*
  • Lung Neoplasms / physiopathology
  • Male
  • Maximum Allowable Concentration
  • Mesothelioma / chemically induced*
  • Mesothelioma / mortality*
  • Mesothelioma / physiopathology
  • Mesothelioma, Malignant
  • Middle Aged
  • North Carolina / epidemiology
  • Occupational Diseases / etiology
  • Occupational Diseases / mortality
  • Occupational Exposure / adverse effects*
  • Occupational Exposure / analysis
  • Pleural Neoplasms / chemically induced*
  • Pleural Neoplasms / mortality*
  • Pleural Neoplasms / physiopathology
  • Retrospective Studies
  • Risk Assessment
  • Sex Factors
  • Survival Analysis
  • Textile Industry


  • Asbestos, Serpentine