Table 4

 Pneumoconiosis and other respiratory diseases 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
<33–<1616–<6060–<100100–<150⩾150
*Cutpoints of cumulative exposure were selected to approximately divide the deaths from pneumoconiosis and other respiratory diseases into six cumulative exposure groups. The numbers of workers in each cumulative exposure group were 1125, 997, 491, 181, 155 and 123, respectively; the person-years at risk in each cumulative exposure group were 43524, 38133, 19209, 6959, 6097 and 4591, 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).
‡Workers with 1 year or more of exposure.
§Reference category for long-term workers was cumulative exposure <16 fibre-years/ml due to few deaths (n = 1) in the <3 fibre-years/ml category.
White-males0O/E†9/3.04/2.16/1.07/0.64/0.311/0.3
SMR3.05 (1.39–5.78)1.92 (0.52–4.92)6.10 (2.24–13.3)11.5 (4.64–23.8)12.3 (3.34–31.4)38.9 (19.4–69.6)<0.0001
RR10.64 (0.20–2.07)1.90 (0.68–5.36)3.62 (1.32–9.93)3.88 (1.17–12.9)12.1 (4.86–30.4)<0.0001
Non-white-males0O/E0/0.63/1.52/1.01/0.33/0.23/0.3
SMR0.00 (0.00–5.96)1.94 (0.40–5.68)1.94 (0.23–7.00)3.32 (0.08–18.5)14.4 (2.97–42.1)11.2 (2.30–32.6)0.0003
Females0O/E5/2.57/2.15/1.16/0.35/0.44/0.1
SMR2.02 (0.66–4.72)3.29 (1.32–6.78)4.67 (1.52–10.9)17.4 (6.39–37.9)14.2 (4.61–33.1)36.6 (9.97–93.7)<0.0001
RR11.69 (0.54–5.34)2.47 (0.71–8.54)9.02 (2.73–29.8)8.21 (2.36–28.6)21.4 (5.65–81.0)<0.0001
Overall0O/E14/6.014/5.813/3.114/1.312/0.918/0.7
SMR2.32 (1.27–3.89)2.43 (1.33–4.08)4.21 (2.24–7.20)11.2 (6.11–18.8)13.5 (6.99–23.7)27.2 (16.1–43.1)<0.0001
RR11.20 (0.57–2.52)2.14 (1.00–4.58)5.61 (2.65–11.9)6.89 (3.15–15.1)15.6 (7.51–32.5)<0.0001
Overall5O/E15/6.214/5.714/3.115/1.39/0.818/0.6
SMR2.41 (1.35–3.97)2.46 (1.35–4.16)4.54 (2.48–7.62)11.9 (6.68–19.7)10.8 (4.93–20.5)30.1 (17.8–47.6)<0.0001
RR11.22 (0.59–2.54)2.29 (1.10–4.79)5.99 (2.89–12.4)5.68 (2.45–13.2)17.4 (8.47–35.9)<0.0001
Overall10O/E15/6.514/5.616/3.116/1.210/0.814/0.5
SMR2.32 (1.30–3.83)2.49 (1.36–4.18)5.17 (2.96–8.40)13.0 (7.42–21.1)13.0 (6.21–23.8)27.4 (15.0–45.9)<0.0001
RR11.38 (0.66–2.89)2.88 (1.40–5.90)7.29 (3.52–15.1)7.84 (3.44–17.9)17.5 (8.11–37.9)<0.0001
Long-term‡0O/E1/0.3310/3.513/2.914/1.312/0.918/0.7
SMR2.99 (0.08–16.7)2.83 (1.36–5.21)4.41 (2.35–7.54)11.2 (6.11–18.8)13.5 (6.99–23.7)27.2 (16.1–43.1)<0.0001
RR1.75 (0.78–3.92)4.54 (2.04–10.1)5.55 (2.41–12.8)13.1 (5.95–28.8)<0.0001