Table 1.
Demographic characteristics of 2018 and 2017 survey cohorts, all individuals with SMA types I, II, and III
| Characteristics | 2018 Survey | 2017 Survey | ||||
| Type I | Type II | Type III | Type I | Type II | Type III | |
| (n = 268) | (n = 290) | (n = 173) | (n = 213) | (n = 270) | (n = 187) | |
| Sex, n (%) | ||||||
| Male | 129 (48.1) | 127 (43.8) | 80 (46.2) | 109 (51.2) | 115 (42.6) | 72 (38.5) |
| Female | 139 (51.9) | 150 (51.7) | 90 (52.0) | 96 (45.1) | 142 (52.6) | 106 (56.7) |
| Unknown | 0 | 13 (4.5) | 3 (1.7) | 8 (3.8) | 13 (4.8) | 9 (4.8) |
| Age at survey | ||||||
| n* | 157 | 275 | 171 | 104 | 243 | 176 |
| Mean (SD), years | 6.4 (7.8) | 15.8 (14.0) | 30.1 (19.0) | 8.2 (9.0) | 15.0 (12.6) | 30.7 (18.2) |
| Median (range), years | 3 (0–43) | 11 (1–76) | 29 (2–78) | 5 (0–52) | 11 (0–64) | 29.2 (1–77) |
| Age at survey categories, in years, n (%) | ||||||
| n* | 157 | 275 | 171 | 104 | 243 | 176 |
| ≤4 | 96 (61.2) | 58 (21.1) | 10 (5.9) | 50 (48.1) | 53 (21.8) | 7 (4.0) |
| 5–10 | 26 (16.6) | 73 (26.5) | 24 (14.0) | 19 (18.3) | 61 (25.1) | 26 (14.8) |
| 11–17 | 21 (13.4) | 44 (16.0) | 25 (14.6) | 23 (22.1) | 47 (19.3) | 23 (13.1) |
| ≥18 | 14 (8.9) | 100 (36.4) | 112 (65.5) | 12 (11.5) | 82 (33.7) | 120 (68.2) |
| Deceased, n (%) | 111 (41.4) | 15 (5.2) | 2 (1.2) | 108 (50.7) | 5 (1.9) | 0 |
| Age at death | ||||||
| N | 110 | 15 | 2 | 99 | 4 | 0 |
| Mean (SD), months | 27.8 (54.3) | 124.8 (128.4) | 243 (239.0) | 22.8 (48.1) | 138.3 (102.8) | N/A |
| Median (range), months | 9 (0–348) | 67 (14–407) | 243 (74–412) | 8 (0–348) | 121.5 (32–278) | N/A |
| Highest level of education for adults (≥18), n (%)† | ||||||
| N | 14 | 100 | 112 | 12 | 82 | 120 |
| No schooling completed | 1 (7.1) | 1 (1.0) | 0 | 0 | 0 | 0 |
| Some high school, no diploma | 1 (7.1) | 3 (3.0) | 2 (1.8) | 4 (33.3) | 2 (2.4) | 1 (0.8) |
| High school graduate | 4 (28.6) | 11 (11.0) | 15 (13.4) | 2 (16.7) | 16 (19.5) | 12 (10.0) |
| Trade/technical/voca-tional training | 0 | 3 (3.0) | 3 (2.7) | 0 | 1 (1.2) | 4 (3.4) |
| Some college credit, no degree | 3 (21.4) | 17 (17.0) | 13 (11.6) | 3 (25.9) | 18 (22.0) | 15 (12.5) |
| Associate or professional degree | 0 | 5 (5.0) | 17 (15.1) | 1 (8.3) | 6 (7.3) | 18 (15.0) |
| Bachelor’s degree | 3 (20.0) | 31 (31.0) | 41 (36.6) | 0 | 25 (30.5) | 41 (34.2) |
| Master’s or Doctorate degree | 2 (14.2) | 24 (24.0) | 20 (17.9) | 2 (16.7) | 13 (15.8) | 27 (22.5) |
| Unknown/missing | 0 | 5 (5.0) | 1 (0.9) | 0 | 1 (1.2) | 2 (1.7) |
| Currently employed or attending school, n (%) | ||||||
| n‡ | 54 | 206 | 152 | 51 | 198 | 162 |
| Employed full-time | 0 | 26 (12.6) | 37 (24.3) | 1 (2.0) | 18 (9.1) | 44 (27.2) |
| Employed part-time | 2 (3.7) | 17 (8.3) | 9 (5.9) | 0 | 16 (8.1) | 9 (5.6) |
| Attend school full-time | 28 (51.9) | 118 (57.3) | 49 (32.2) | 32 (62.8) | 119 (60.1) | 54 (33.3) |
| Attend school and employed | 0 | 1 (0.5) | 7 (4.6) | 1 (2.0) | 6 (3.0) | 1 (0.6) |
| Not employed nor attending school | 15 (27.8) | 32 (15.5) | 41 (27.0) | 7 (13.7) | 35 (17.7) | 48 (29.6) |
| Not applicable (N/A) | 9 (16.7) | 12 (5.8) | 9 (5.9) | 10 (19.6) | 4 (2.0) | 6 (3.7) |
N/A, not applicable; SMA, spinal muscular atrophy. Note: Percentages may not add up to 100 due to rounding. *Sample size is for age at survey among living individuals with valid responses. †If homeschooled, respondent is asked to select the grade equivalent. ‡Sample size is for living individuals who are at least school-aged (i.e., ≥5 years).