Table 1.

Proportion of cases and controls reporting exposure to each phenotypic variables. Individual exposures were tested using Fishers Exact Test. The difference in means of the first principal component of each cluster were tested using a two-sided student's t-test. HP: herbicide/pesticide, OR: odds ratio, PC1: principal component 1.

	Control (n = 417)			ALS (n = 438)				95% CI
	n	%	Mean	n	%	Mean	p	OR	Low	High
Metal PC1			− 0.17			0.16	0.002		− 0.55	− 0.12
Cadmium	13	3.1		27	6.2		0.036	2.04	1	4.37
Metallurgy	22	5.3		40	9.1		0.034	1.8	1.02	3.25
Lead	40	9.6		78	17.8		< 0.001	2.04	1.34	3.15
Mercury	21	5		30	6.8		0.312	1.39	0.75	2.59
Copper	45	10.8		67	15.3		0.054	1.49	0.98	2.29
Chemical PC1			− 0.27			0.26	< 0.001		− 0.71	− 0.35
Chemicals/solvents	146	35		238	54.3		< 0.001	2.21	1.66	2.94
Any HP use	224	53.7		290	66.2		< 0.001	1.69	1.27	2.25
Regular HP use	24	5.8		47	10.7		0.009	1.97	1.15	3.43
Industrial HP use	43	10.3		83	18.9		< 0.001	2.03	1.35	3.1
Farm PC1			− 0.2			0.19	< 0.001		-0.57	-0.2
Bore water	57	13.7		80	18.3		0.076	1.41	0.96	2.08
Rural ≥ 24 months	62	14.9		110	25.1		< 0.001	1.92	1.34	2.76
Farm ≥ 12 months	93	22.3		130	29.7		0.016	1.47	1.07	2.03
Non-city ≥ 12 months	202	48.4		260	59.4		0.002	1.55	1.18	2.06
Blue Collar PC1			− 0.21			0.2	< 0.001		− 0.56	− 0.24
Diesel	98	23.5		157	35.8		< 0.001	1.82	1.33	2.48
Manual labor	170	40.8		244	55.7		< 0.001	1.83	1.38	2.42
Smoker	50	12		32	7.3		0.027	0.58	0.35	0.94