Table 2

Bladder cancer risk by duration of employment and time since first employment in the departments with definite exposure to o-toluidine and aniline, in the original and updated studies

Study	Characteristic	Number of workers^‡	Bladder cancer		SIR	95% CI^§	SRR	95% CI
Study	Characteristic	Number of workers^‡	Observed	Expected	SIR	95% CI^§	SRR	95% CI
Ward et al (1991)2	Duration of employment
	<5 years	584	0	0.75	–	–
	5–<10 years	51	1	0.11	8.8	0.22 to 49.0
	≥10 years	73	6	0.22	27.2^*	9.98 to 59.2
	Time since first employment
	<10 years	196	0	0.22	–	–
	10–<20 years	364	1	0.49	2.03	0.05 to 11.3
	≥20 years	148	6	0.37	16.4^*	6.02 to 35.7
Current update	Duration of employment
	<5 years	678	1	0.80	1.25	0.03 to 6.97	1.0	–
	5–<10 years	95	1	0.27	3.67	0.09 to 20.44	2.0	0.13 to 32.05
	≥10 years	189	9	0.81	11.09^*	5.07 to 21.05	6.07^†	0.77 to 48.17
	Time since first employment
	<10 years	78	1	0.28	3.63	0.09 to 20.23	1.0	–
	10–<20 years	250	2	0.72	2.77	0.34 to 10.02	1.05	0.09 to 12.38
	≥20 years	634	8	0.89	9.02^*	3.89 to 17.76	3.39^†	0.40 to 29.03

↵* p<0.001.
↵† Tests for trend: p<0.0001 for duration of employment and p=0.12 for time since first employment.
↵‡ Number of workers whose duration of employment or time since first employment (as of the study end date, the date of diagnosis, date of death, or date last observed) was in the category stated.
↵§ Original study reported 90% CI; 95% CI were calculated based on the estimates reported in the manuscript.
SIR, standardised incidence ratio; SRR, standardised rate ratio.