Table 4.

Analyses of cumulative estimated exposure to lead and ALS case status in women

	Controls N (%)	Cases N (%)	OR (95% CI)*	aOR (95% CI)†
No lag (n=60 105)
No exposure	44 867 (75.47)	495 (75.80)	1.00 (Ref)	1.00 (Ref)
Ever exposure (μmol/L)‡	14 585 (24.53)	158 (24.20)	0.99 (0.82 to 1.18)	1.01 (0.83 to 1.21)
<17.40	3566 (6.00)	37 (5.67)	0.95 (0.68 to 1.33)	0.94 (0.66 to 1.34)
17.40–72.89	3663 (6.16)	39 (5.97)	0.97 (0.70 to 1.34)	1.03 (0.74 to 1.31)
>72.89	7356 (12.37)	82 (12.56)	1.01 (0.80 to 1.28)	1.03 (0.80 to 1.31)
Test for trend			1.00 (0.97 to 1.04)	1.00 (0.97 to 1.04)
5-year lag
No exposure	46 938 (78.95)	514 (78.71)	1.00 (Ref)	1.00 (Ref)
Ever exposure (μmol/L)‡	12 514 (21.05)	139 (21.29)	1.00 (0.84 to 1.20)	1.02 (0.85 to 1.24)
<17.40	3675 (6.18)	40 (6.13)	1.00 (0.73 to 1.39)	0.99 (0.70 to 1.39)
17.40–72.89	3678 (6.19)	44 (6.74)	1.10 (0.81 to 1.50)	1.14 (0.83 to 1.56)
>72.89	5161 (8.68)	55 (8.42)	0.98 (0.74 to 1.30)	1.00 (0.75 to 1.34)
Test for trend			1.01 (0.95 to 1.07)	1.02 (0.95 to 1.08)
10-year lag
No exposure	47 637 (80.13)	520 (79.63)	1.00 (Ref)	1.00 (Ref)
Ever exposure (μmol/L)‡	11 815 (19.87)	133 (20.37)	1.04 (0.86 to 1.26)	1.04 (0.85 to 1.27)
<17.40	3544 (5.96)	39 (6.73)	1.02 (0.74 to 1.36)	1.00 (0.71 to 1.41)
17.40–72.89	3545 (5.96)	44 (6.74)	1.15 (0.84 to 1.56)	1.17 (0.85 to 1.61)
>72.89	4726 (7.95)	50 (7.66)	0.98 (0.73 to 1.31)	0.98 (0.72 to 1.32)
Test for trend			1.00 (0.93 to 1.07)	1.01 (0.94 to 1.08)

^*Controls were individually matched to cases on age and sex.

^†Models adjusted for SES and residential location.

^‡Cumulative estimated exposure=[(level of exposure)*(probability of exposure)/100]*(days employed).

ALS, amyotrophic lateral sclerosis; aOR, adjusted OR; SES, socioeconomic status.