Table 1

Baseline demographic and clinical characteristics of participants

CharacteristicALS patients (n=636)Controls (n=2166)p Value
Male (n (%))395 (62.1)1259 (58.1)0.17
Age (years) (median (range))*63 (23 to 87)62 (20 to 91)0.91
Site of onset (n (%))
 Bulbar204 (32.3)
 Spinal427 (67.7)
El Escorial classification (n (%))
 Definite112 (17.8)
 Probable280 (44.6)
 Probable lab supported111 (17.7)
 Possible119 (18.9)
Education (n (%))
 No education2 (0.3)3 (0.1)
 Primary school54 (8.5)131 (6.1)
 Junior vocational education127 (20.0)356 (16.5)
 Lower general secondary education149 (23.4)474 (21.9)0.02
 Intermediate vocational education106 (16.7)410 (18.9)
 Higher general secondary education45 (7.1)186 (8.6)
 College/university153 (24.1)604 (27.9)
BMI (kg/m2) (median (range))24.1 (12 to 48)25.6 (16 to 53)<0.001
Current smoking (n (%))133 (20.9)288 (13.3)<0.001
Current alcohol consumption (n (%))475 (74.7)1846 (85.3)<0.001
  • *Age at onset in patients and age at which the questionnaire was completed in controls.

  • ALS, amyotrophic lateral sclerosis; BMI, body mass index.