Table 1 Baseline multivariate-adjusted rate ratio (RR) of amyotrophic lateral sclerosis by class of chemical exposure in the entire cohort and excluding individuals reporting exposure to a given chemical class but no duration (restricted cohort)
ExposureCasesPerson-years (×1000)Multivariate RR* (95% CI) full cohortp ValueMultivariate RR† (95% CI) restricted cohortp Value
Pesticides/herbicides
    No109712 917RefRef
    Yes596611.07 (0.79 to 1.43)0.671.44 (0.89 to 2.31)0.14
Asbestos
    No111013 092RefRef
    Yes464851.06 (0.77 to 1.46)0.731.12 (0.60 to 2.09)0.73
Chemicals/acids/solvents
    No101412 070RefRef
    Yes14215081.05 (0.86 to 1.29)0.611.04 (0.73 to 1.49)0.82
Coal or stone dusts
    No111113 088RefRef
    Yes454901.03 (0.74 to 1.43)0.860.97 (0.48 to 1.95)0.93
Coal tar/pitch/asphalt
    No114213 358RefRef
    Yes142200.54 (0.29 to 1.02)0.060.38 (0.05 to 2.74)0.34
Diesel engine exhaust
    No107712 637RefRef
    Yes799400.95 (0.71 to 1.26)0.710.68 (0.33 to 1.40)0.30
Dyes
    No113213 230RefRef
    Yes243480.75 (0.47 to 1.20)0.230.84 (0.46 to 1.54)0.57
Formaldehyde
    No112013 218RefRef
    Yes363601.34 (0.93 to 1.92)0.11 2.47 (1.58 to 3.86) <0.0001
Gasoline exhaust
    No101811 966RefRef
    Yes13816110.90 (0.73 to 1.12)0.350.95 (0.63 to 1.42)0.79
Textile fibres/dusts
    No111313 005RefRef
    Yes435730.97 (0.70 to 1.34)0.831.23 (0.79 to 1.91)0.36
Wood dust
    No110712 980RefRef
    Yes495980.89 (0.65 to 1.20)0.440.96 (0.48 to 1.93)0.91
x Rays/radioactive material
    No111813 072RefRef
    Yes385060.90 (0.64 to 1.26)0.530.87 (0.51 to 1.50)0.62
  • Bold values indicated results significant at p<0.05.

  • *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 numbers 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 fibres/dusts, 22; wood dust, 8; x rays/radioactive material, 14.