Increased Standardised Incidence Ratio of Malignant Pleural Mesothelioma in Taiwanese Asbestos Workers: A 29-Year Retrospective Cohort Study

Table 4

Observed and expected numbers and the SIR with the 95% CI for malignant pleural mesothelioma among the male workers employed in asbestos-related factories, by duration of employment in the factory and time since first employment: follow-up for 1980–2009.

Duration of employment	Time since first employment
	10–20 years			20–30 years			>30 years			Total
	Obs. ()	Exp. ()	SIR (95% CI)	Obs. ()	Exp. ()	SIR (95% CI)	Obs. ()	Exp. ()	SIR (95% CI)	Obs. ()	Exp. ()	SIR (95% CI)
<1 year	0	0.49	0.00 (0.00–7.45)	4	1.0446	(1.04–9.80)	3	0.9784	3.07 (0.63–8.96)	7	2.678	(1.05–5.39)
1–10 years	0	0.37	0.00 (0.00–9.85)	1	0.7856	1.27 (0.03–7.09)	5	0.9531	(1.70–12.24)	6	2.2586	2.66 (0.97–5.78)
11–20 years	0	0.13	0.00 (0.00–28.64)	0	0.1695	0.00 (0.00–21.76)	1	0.196	5.10 (0.13–28.42)	1	0.4943	2.02 (0.05–11.27)
>20 years	0	0.00		1	0.1623	6.16 (0.16–34.34)	2	0.3569	5.60 (0.68–20.24)	3	0.5192	(1.19–16.89)
Total	0	1.00	0.00 (0.00–3.70)	6	2.162	(1.02–6.04)	11	2.4845	(2.21–7.92)	17	5.9501	(1.66–4.57)

, . Obs. (): observed numbers. Exp. (): expected numbers; SIR: standardized incidence ratio; 95% CI: 95% confidence interval.