Table 2

Observed deaths (O) from selected causes, and corresponding standardised mortality ratios (SMR), according to various characteristics of exposure in a cohort of asbestos miners in Balangero, Italy

	Laryngeal cancer		Lung cancer		Pleural and peritoneal cancer		All cancers		All causes		Man-years
	O	SMR	O	SMR	O	SMR	O	SMR	O	SMR	Man-years
Duration of exposure (years)
<10	2	1.06	15	1.02	1	1.55	47	0.87	262	1.41*	17774
10–19	1	1.12	11	1.57	0	0	32	1.22	131	1.48*	9106
⩾20	5	3.07	19	1.37	4	6.64*	63	1.37*	197	1.43*	7552
Age at first exposure (years)
<30	5	1.99	27	1.22	3	3.01	80	1.09	321	1.47*	23619
⩾30	3	1.59	18	1.34	2	3.42	62	1.17	269	1.38*	10814
Time since first exposure (years)
<20	2	3.81	5	1.66	0	0	16	1.08	107	1.61*	16209
20–29	2	1.98	7	1.01	0	0	27	1.02	129	1.41*	8721
⩾30	4	1.40	33	1.29	5	4.45*	99	1.16	354	1.39*	9502
Time since last exposure (years)
During exposure	1	1.74	2	0.56	1	6.19	10	0.69	69	1.23	13097
1–<10	3	3.44	12	1.84	2	7.22	37	1.61*	125	1.69*	7557
⩾10	4	1.36	31	1.22	2	1.75	95	1.07	396	1.40*	13778
Period at first exposure
Before 1946	7	2.26	26	1.14	4	4.19*	89	1.04	408	1.36*	18298
1946–1959	1	1.23	11	1.60	1	3.35	32	1.42	122	1.81*	6188
1960 or after	0	0	8	1.38	0	0	21	1.17	60	1.32*	9946
Cumulative dust exposure (fibre-years)
<100	1	0.83	9	0.83	0	0	30	0.81	141	1.23*	12892
100–<400	2	1.48	17	1.57	1	2.09	49	1.27	212	1.66*	10254
⩾400	5	2.73	19	1.37	4	6.80*	63	1.25	237	1.39*	11286

Deaths and man-years beyond age 80 are excluded.
*95% confidence interval does not include unity.