Table 2

Associations between ever/never occupationally exposed to selected agents and ALS mortality in men*

	Exposure level	Cases	Person-years in subcohort	HR	95% CI
Extremely low frequency magnetic fields	Background	28	13 968	1.00	Reference
	Only ever low	39	12 979	1.57	(0.4 to 2.63)
	Ever high	9	2185	2.19	(1,02 to 4.73)
	Test for trend	76	29 132		p=0.02
Electrical shocks	No exposure	41	17 575	1.00	Reference
	Only ever low	17	4423	1.47	(0.80 to2.71)
	Ever high	18	7133	1.04	(0.57 to 1.92)
	Test for trend	76	29 132		p=0.73
Total solvents	No exposure	46	18 547	1.00	Reference
	Only ever low	13	5850	0.84	(0.44 to 1.63)
	Ever high	17	4734	1.46	(0.81 to 2.61)
	Test for trend	76	29 132		p=0.35
Aromatic solvents	No exposure	51	19 902	1.00	Reference
	Only ever low	19	8222	0.85	(0.49 to 1.47)
	Ever high	6	1008	1.99	(0.81 to 4.92)
	Test for trend	76	29 132		p=0.59
Chlorinated solvents	No exposure	52	22 211	1.00	Reference
	Only ever low	14	3283	1.80	(0.97 to 3.36)
	Ever high	10	3640	1.23	(0.63 to 2.39)
	Test for trend	76	29 132		p=0.21
Metals	No exposure	56	22 932	1.00	Reference
	Only ever low	8	2541	1.25	(0.57 to 2.75)
	Ever high	12	3660	1.47	(0.79 to 2.76)
	Test for trend	76	29 132		p=0.33
Pesticides†	No exposure	69	25 618	1.00	Reference
	Ever low or high	7	3515	0.60	(0.27 to 1.35)
Insecticides†	No exposure	70	25 762	1.00	Reference
	Ever low or high	6	3371	0.54	0.23 to 1.26
Herbicides†	No exposure	73	26 738	1.00	Reference
	Ever low or high	3	2395	0.36	(0.11 to 1.18)
Fungicides†	No exposure	70	26 243	1.00	Reference
	Ever low or high	6	2890	0.62	(0.26 to 1.47)

*Cox proportional hazard regression using age as the time-axis, single occupational exposure adjusted for attained level of education.
†Due to the low number of exposed subjects, exposure categories were merged.
ALS, amyotrophic lateral sclerosis.