Table 3. Standardized incidence rate (SIR) for prostate cancer in a cohort of shift and daytime workers in a large German chemical company.

Prostate cancer, stage T	Daytime workers				Shift workers
	Observed cases	Expected cases	SIR	95% CI	Observed cases	Expected cases	SIR	95% CI
Total	191	126.7	1.51	1.30–1.74	146	101.3	1.44	1.22–1.70
1a	7	14.9	0.47	0.19–0.97	10	12.2	0.82	0.39–1.51
2	126	61.6	2.05	1.71–2.44	84	48.6	1.73	1.38–2.14
3	39	24.5	1.59	1.13–2.18	32	19.5	1.64	1.12–2.31
4	5	3.3	1.50	0.49–3.50	3	2.7	1.11	0.22–3.25
x	14	22.4	0.63	0.34–1.05	17	18.2	0.93	0.54–1.49
Sensitivity analysis based on 20-year latency period
Total	189	121.4	1.56	1.34–1.80	133	92.2	1.44	1.21–1.71
1	7	14.3	0.49	0.20–1.01	10	11.3	0.89	0.43–1.63
2	125	58.8	2.12	1.77–2.53	73	43.9	1.66	1.30–2.09
3	38	23.4	1.62	1.15–2.23	31	17.7	1.75	1.19–2.49
4	5	3.2	1.57	0.51–3.67	3	2.4	1.25	0.25–3.65
x	14	21.6	0.65	0.35–1.09	16	16.9	0.95	0.54–1.54

95% CI: 95% confidence interval; SIR: Standardized incidence rate