Exposure indicator (f-y/ml) | β | SE (β) | ∆ | LR | p | AIC |

PCM fibres | 0.00101 | 0.00028 | 0.0333 | 9.6 | 0.002 | 2343.1 |

Total TEM fibres | 0.00005 | 0.00002 | 0.0310 | 7.6 | 0.006 | 2345.1 |

TEM fibres ≥5 μm | 0.00039 | 0.00012 | 0.0312 | 8.5 | 0.004 | 2344.2 |

TEM fibres <5 μm | 0.00006 | 0.00002 | 0.0297 | 7.4 | 0.010 | 2345.3 |

AIC, Akaike Information Criterion (smaller values indicate better fit);

*β*and SE, regression coefficient and associated standard error; ∆, change in lung cancer risk for increment in exposure equal to 1 IQR; LR, likelihood ratio test statistic (equivalent to χ^{2}with 1 degree of freedom) and associated p value; PCM, phase-contrast light miscroscopy; TEM, transmission electron microscopy.