Table 3 Results from Cox models for asbestosis using TEM-based cumulative exposures (fibre-days/ml/10 000) based on combinations of fibre length and diameter*

Diameter (μm)	Length (μm)
Diameter (μm)	⩽1.5	1.5–5	5–10	10–20	20–40	>40	All
<0.25
β	0.032	0.062	0.346	0.679	1.802	5.088	0.020
−2LL	750.2	749.2	748.7	746.9	747.1	741.7	744.8
χ²_1df	78.9	79.8	80.4	82.2	82.0	87.4	84.3
0.25–1.0
β	1.825	0.323	0.848	1.584	4.189	3.710	0.182
−2LL	741.1	767.3	753.3	747.4	735.8	763.8	753.0
χ²_1df	88.0	61.8	75.8	81.7	93.3	65.3	76.1
1.0–3.0
β	NA†	3.009	1.321	2.513	4.737	22.932	0.678
−2LL		782.9	770.2	754.4	751.3	718.5	754.8
χ²_1df		46.2	58.9	74.7	77.8	110.6	74.3
>3.0
β	NA†	NA†	6.768	6.138	10.335	7.057	2.474
−2LL			795.7	784.6	767.6	795.5	772.3
χ²_1df			33.4	44.5	61.5	33.6	56.8
All
β	0.032	0.053	0.215	0.448	0.968	1.691	0.019
−2LL	748.7	749.6	749.7	736.8	742.2	753.4	741.3
χ²_1df	80.4	79.5	79.4	92.3	86.9	75.7	87.8

*Results from models with a 0-year lag that included variables controlling for gender, race, calendar time and time since first employment.
†These categories do not meet the 3:1 length to width fibre definition that was a part of our TEM analysis counting rules. However, a very small percentage (<0.1%) of counted fibres did fall into these categories.