ALS and control participant demographics
| Covariate | Cases (n=164) | Controls (n=105) | P value |
| Age at sample collection (years) | 65.3 (57.2–72.1) | 62.4 (55.2–68.5) | 0.016 |
| Body mass index (kg/m2)* | 26.3 (23.2–30.1) | 26.5 (23.4–29.7) | 0.747 |
| Sex | 0.001 | ||
| Female | 82 (50.0) | 74 (70.5) | |
| Male | 82 (50.0) | 31 (29.5) | |
| Military service | 0.414 | ||
| No | 148 (90.2) | 93 (88.6) | |
| Yes | 14 (8.5) | 5 (4.8) | |
| Missing | 2 (1.2) | 7 (6.7) | |
| Education | <0.001 | ||
| High school or less | 54 (32.9) | 8 (7.6) | |
| Some postsecondary | 58 (35.4) | 24 (22.9) | |
| Bachelor’s degree | 29 (17.7) | 36 (34.3) | |
| Graduate degree | 19 (11.6) | 30 (28.6) | |
| Missing | 4 (2.4) | 7 (6.7) | |
| Race | NA | ||
| American Indian/Alaska Native | 1 (0.6) | 0 (0.0) | |
| Asian | 3 (1.8) | 3 (2.9) | |
| Black or African American | 3 (1.8) | 5 (4.8) | |
| White | 157 (95.7) | 97 (92.4) | |
| ALSFRS-R† | 36 (31–41) | ||
| Time between symptom onset and diagnosis (years)‡ | 1.02 (0.59–1.67) | ||
| Time between diagnosis and sample acquisition (years) | 0.48 (0.26–0.94) | ||
| Observed death | |||
| Yes | 147 (89.6) | ||
| No | 17 (10.4) | ||
| El Escorial criteria | |||
| Possible/suspected | 28 (17.1) | ||
| Probable, lab supported | 32 (19.5) | ||
| Probable | 47 (28.7) | ||
| Definite | 57 (34.8) | ||
| Onset segment | |||
| Bulbar | 55 (33.5) | ||
| Cervical | 49 (29.9) | ||
| Lumbar | 59 (36.0) | ||
| Cannot be determined | 1 (0.6) |
Table of descriptive statistics for the study population. For continuous variables, median (25th–75th percentile), and for categorical variables, N (%). P values for continuous and categorical variables correspond to t-tests and χ2 tests, respectively.
*Body mass index is observed for 157 cases and 93 controls.
†ALSFRS-R is observed for 162 cases.
‡Time between symptom onset and diagnosis is observed for 163 cases.
ALS, amyotrophic lateral sclerosis; ALSFRS-R, revised amyotrophic lateral sclerosis functional rating scale.