Table 3

 Lung cancer mortality (underlying cause) through 2001 by cumulative exposure to chrysotile among workers in the South Carolina asbestos textile workers cohort

GroupLag (years)Cumulative exposure (fibre-years/ml)*Trend p value
<1.51.5–<55–<1515–<6060–<120⩾120
*Cutpoints of cumulative exposure were selected to approximately divide the deaths from lung cancer into six cumulative exposure groups. The numbers of workers in each cumulative exposure group were 705, 756, 628, 524, 264 and 195, respectively; the person-years at risk in each cumulative exposure group were 26667, 29188, 24449, 20561, 10295 and 7352, respectively.
†O/E, ratio of observed to expected (based on US referent rates) number of deaths; SMR, standardised mortality ratio from life-table analyses adjusted for sex, race, age and calendar year (95% CI); RR, rate ratio relative to lowest cumulative exposure group from Poisson regression analyses adjusted for sex, race, age and calendar year (95% CI).
‡Reference category for non-white males was cumulative exposure <5 fibre-years/ml due to zero deaths in the <1.5 fibre-years/ml category.
§Workers with one year or more of exposure.
¶Reference category for long-term workers was cumulative exposure <5 fibre-years/ml due to few deaths (n = 2) in the <1.5 fibre-years/ml category.
White males0O/E†22/12.623/14.115/8.419/7.117/4.820/2.5
SMR1.74 (1.09–2.64)1.63 (1.04–2.45)1.79 (1.00–2.94)2.69 (1.62–4.20)3.56 (2.07–5.70)7.85 (4.80–12.1)<0.0001
RR10.94 (0.52–1.69)1.03 (0.53–1.98)1.52 (0.82–2.81)2.00 (1.05–3.80)4.43 (2.37–8.29)<0.0001
Non-white males0O/E0/1.55/4.54/7.43/6.62/2.47/2.4
SMR0.00 (0.00–2.45)1.11 (0.36–2.60)0.54 (0.15–1.38)0.45 (0.09–1.32)0.84 (0.10–3.03)2.96 (1.19–6.11)0.0007
RR1‡1‡0.63 (0.17–2.35)0.54 (0.13–2.27)1.08 (0.21–5.59)3.99 (1.23–12.9)0.0025
Females0O/E11/7.16/6.714/5.911/4.513/2.26/0.9
SMR1.54 (0.77–2.76)0.89 (0.33–1.94)2.35 (1.29–3.95)2.43 (1.21–4.35)5.82 (3.10–9.95)6.64 (2.44–14.4)<0.0001
RR10.59 (0.22–1.61)1.51 (0.69–3.33)1.52 (0.66–3.50)3.40 (1.52–7.60)3.84 (1.41–10.5)0.0004
Overall0O/E33/21.334/25.333/21.833/18.232/9.433/5.8
SMR1.55 (1.07–2.18)1.34 (0.93–1.88)1.52 (1.04–2.13)1.81 (1.25–2.54)3.41 (2.33–4.81)5.68 (3.91–7.98)<0.0001
RR10.95 (0.59–1.54)1.22 (0.75–1.99)1.46 (0.90–2.37)2.50 (1.53–4.08)4.84 (2.94–7.97)<0.0001
Overall5O/E33/21.534/25.333/21.735/18.432/9.431/5.4
SMR1.53 (1.06–2.15)1.34 (0.93–1.88)1.52 (1.05–2.13)1.90 (1.32–2.64)3.41 (2.33–4.82)5.78 (3.93–8.21)<0.0001
RR11.00 (0.62–1.61)1.28 (0.79–2.08)1.59 (0.99–2.58)2.61 (1.60–4.28)5.14 (3.10–8.53)<0.0001
Overall10O/E34/22.133/25.334/21.735/18.837/9.225/4.7
SMR1.54 (1.07–2.15)1.30 (0.90–1.83)1.57 (1.08–2.19)1.86 (1.30–2.59)4.02 (2.83–5.53)5.36 (3.47–7.92)<0.0001
RR11.00 (0.62–1.62)1.37 (0.85–2.21)1.61 (1.00–2.59)3.20 (1.99–5.14)4.91 (2.88–8.35)<0.0001
Long-term§0O/E2/0.567/5.226/15.931/16.732/9.433/5.8
SMR3.56 (0.43–12.9)1.34 (0.54–2.75)1.64 (1.07–2.40)1.85 (1.26–2.63)3.41 (2.33–4.81)5.68 (3.91–7.98)<0.0001
RR1.14 (0.53–2.44)1.39 (0.66–2.95)2.39 (1.13–5.06)4.62 (2.17–9.84)<0.0001