Table 1.
Baseline multivariate-adjusted rate ratio (RR) of ALS by class of chemical exposure in the entire cohort and excluding individuals reporting exposure to a given chemical class but no duration (restricted cohort).
| Exposure | Cases | Person-Years (×1000) | Multivariate RRa (95% CI) Full Cohort | p-value | Multivariate RRb (95% CI) Restricted Cohort | p-value |
|---|---|---|---|---|---|---|
| Pesticides/Herbicides | ||||||
| No | 1097 | 12,917 | Ref | Ref | ||
| Yes | 59 | 661 | 1.07 (0.79, 1.43) | 0.67 | 1.44 (0.89, 2.31) | 0.14 |
| Asbestos | ||||||
| No | 1110 | 13,092 | Ref | Ref | ||
| Yes | 46 | 485 | 1.06 (0.77, 1.46) | 0.73 | 1.12 (0.60, 2.09) | 0.73 |
| Chemicals/Acids/Solvents | ||||||
| No | 1014 | 12,070 | Ref | Ref | ||
| Yes | 142 | 1,508 | 1.05 (0.86, 1.29) | 0.61 | 1.04 (0.73, 1.49) | 0.82 |
| Coal or Stone Dusts | ||||||
| No | 1111 | 13,088 | Ref | Ref | ||
| Yes | 45 | 490 | 1.03 (0.74, 1.43) | 0.86 | 0.97 (0.48, 1.95) | 0.93 |
| Coal Tar/Pitch/Asphalt | ||||||
| No | 1142 | 13,358 | Ref | Ref | ||
| Yes | 14 | 220 | 0.54 (0.29, 1.02) | 0.06 | 0.38 (0.05, 2.74) | 0.34 |
| Diesel Engine Exhaust | ||||||
| No | 1077 | 12,637 | Ref | Ref | ||
| Yes | 79 | 940 | 0.95 (0.71, 1.26) | 0.71 | 0.68 (0.33, 1.40) | 0.30 |
| Dyes | ||||||
| No | 1132 | 13,230 | Ref | Ref | ||
| Yes | 24 | 348 | 0.75 (0.47, 1.20) | 0.23 | 0.84 (0.46, 1.54) | 0.57 |
| Formaldehyde | ||||||
| No | 1120 | 13,218 | Ref | Ref | ||
| Yes | 36 | 360 | 1.34 (0.93, 1.92) | 0.11 | 2.47 (1.58, 3.86) | <0.0001 |
| Gasoline Exhaust | ||||||
| No | 1018 | 11,966 | Ref | Ref | ||
| Yes | 138 | 1,611 | 0.90 (0.73, 1.12) | 0.35 | 0.95 (0.63, 1.42) | 0.79 |
| Textile Fibers/ Dusts | ||||||
| No | 1113 | 13,005 | Ref | Ref | ||
| Yes | 43 | 573 | 0.97 (0.70, 1.34) | 0.83 | 1.23 (0.79, 1.91) | 0.36 |
| Wood Dust | ||||||
| No | 1107 | 12,980 | Ref | Ref | ||
| Yes | 49 | 598 | 0.89 (0.65, 1.20) | 0.44 | 0.96 (0.48, 1.93) | 0.91 |
| X-rays/Radioactive Material | ||||||
| No | 1118 | 13,072 | Ref | Ref | ||
| Yes | 38 | 506 | 0.90 (0.64, 1.26) | 0.53 | 0.87 (0.51, 1.50) | 0.62 |
Adjusted for age, sex, smoking (never, former, current), military service (yes/no; all women were coded as “no” because they were not asked this question), education (some high school, completed high school, vocational/trade, some college, completed college/graduate school), alcohol intake (non-drinkers and quartiles of grams per day), occupation (farmer, laboratory technician, machine assembler, programmer), vitamin E use (never, occasional, regular <10 years, regular >10 years), and all other chemical classes.
The number of cases among the exposed in these analyses were: pesticides/herbicides, 18; asbestos, 10; chemicals/acids/solvents, 36; coal or stone dusts, 8; coal tar/pitch/asphalt, 1; diesel engine exhaust, 9; dyes, 13; formaldehyde, 22; gasoline exhaust, 30; textile fibers/dusts, 22; wood dust, 8; X-rays/radioactive material, 14.