Cancer mortality in a population exposed to nephrite processing

Objectives

Although asbestos has been recognised as a strong carcinogen, many asbestos minerals exist in concrete masses, and the health risks of these materials remain inconclusive. Nephrite jade is a concrete mass of amphibole that consists of asbestiform and non-asbestiform particles. The objective of the study was to explore the carcinogenetic effect of nephrite.

Methods

We examined cancer mortality between 1979 and 2011 in Fengtian, where nephrite was mass produced from 1970 to 1980, and calculated standardised mortality ratios (SMRs).

Results

We observed significantly elevated mortality risks for cancer of the hypopharynx (SMR 2.31; 95% CI 1.37 to 3.65), larynx (SMR 2.51; 95% CI 1.55 to 3.83), oesophagus (SMR 2.04; 95% CI 1.62 to 2.54) and stomach (SMR 1.38; 95% CI 1.17 to 1.63). This study analysed the lengths, widths, structures, chemical compositions, aerodynamic diameters and distributions of elongated mineral particles (EMPs) in airways. The majority of the EMPs (68%) were short (<5 μm) and thin (<0.5 µm), and possessed asbestiform structures. The median aerodynamic diameter of the EMPs was 1.2 μm. The total deposition proportion in airways was 51.3%. The major deposition sites were the head airway (37.5%), followed by the alveolar region (10.6%) and the tracheobronchial region (3.2%).

Conclusions

The results have shown an association between EMPs and increased risk of respiratory and digestive cancers. Further research is needed that includes information on smoking habits and exposure to asbestos.

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