Table 2. Baseline Characteristics of Participants in the Marine Resiliency Study a .
| Characteristic | Battalion 1 | Battalion 2 | Battalion 3 | Battalion 4 | Total |
|---|---|---|---|---|---|
|
| |||||
| n = 315 | n = 721 | n = 671 | n = 886 | n = 2,593 | |
| Age, yb | |||||
| Mean (SD) | 21.4 (3.1) | 21.9 (3.4) | 22.7 (3.5) | 22.7 (3.7) | 22.3 (3.5) |
| Range | 18–42 | 18–47 | 18–47 | 18–43 | 18–47 |
| Marital status, %b | |||||
| Not married | 71.7 | 68.0 | 57.7 | 54.4 | 61.1 |
| Married | 26.3 | 28.6 | 38.7 | 40.4 | 35.0 |
| Divorced/separated | 1.9 | 3.2 | 3.6 | 4.2 | 3.5 |
| Deployments, %b | |||||
| Never deployed | 46.0 | 44.5 | 53.9 | 48.1 | 48.4 |
| Previously deployed | 54.0 | 55.3 | 46.1 | 51.1 | 51.3 |
| Rank, %b | |||||
| E1-E3 | 75.9 | 75.5 | 68.9 | 58.5 | 68.0 |
| E4-E9 | 21.0 | 22.6 | 27.4 | 38.4 | 29.0 |
| O1-O9 | 3.2 | 1.7 | 3.1 | 2.3 | 2.4 |
| Race, % | |||||
| European American | 84.4 | 87.4 | 78.5 | 81.6 | 82.8 |
| African American | 2.9 | 3.7 | 5.5 | 5.5 | 4.7 |
| Asian | 3.5 | 2.5 | 2.4 | 2.8 | 2.7 |
| American Indian | 0.6 | 1.4 | 1.6 | 1.5 | 1.4 |
| Pacific Islander | 1.6 | 1.2 | 0.9 | 2.0 | 1.5 |
| Mixed/other | 7.0 | 3.5 | 5.8 | 5.1 | 5.1 |
| Ethnicity, % | |||||
| Not Hispanic | 77.8 | 79.9 | 73.8 | 74.7 | 76.3 |
| Hispanic/Latino | 22.2 | 19.7 | 25.2 | 24.7 | 23.1 |
| Childhood trauma | |||||
| Total score, mean (SD) | 40.8 (13.1) | 39.4 (13.4) | 38.5 (12.5) | 42.0 (14.9) | 40.3 (13.7) |
| Total score, range | 25–95.5 | 25–106.5 | 25–105.3 | 25–103.3 | 25–106.5 |
| Head injury, % | 67.9 | 65.7 | 58.4 | 55.1 | 60.5 |
| TBI with LOC and AMSc | 54.2 | 60.5 | 54.7 | 56.4 | 56.9 |
| Duration of LOC, %d | |||||
| ≤15 min | 63.8 | 62.6 | 60.3 | 59.0 | 61.1 |
| 16–30 min | 12.9 | 14.0 | 18.7 | 16.5 | 15.7 |
| ≥30 min | 10.3 | 14.0 | 11.2 | 10.6 | 11.8 |
| Unknown | 12.9 | 9.4 | 9.8 | 13.9 | 11.4 |
| SF-12 – NEMC mean, (SD) | |||||
| Physical | 54.9 (5.7) | 53.5 (6.3) | 54.0 (6.0) | 53.3 (6.2) | 53.7 (6.2) |
| Mental | 49.0 (8.4) | 49.3 (8.3) | 50.7 (7.6) | 50.7 (7.8) | 50.2 (8.1) |
Abbreviations: SD, standard deviation; E1-E9, enlisted; O1-O9, officer; TBI, traumatic brain injury; LOC, loss of consciousness; AMS, altered mental state; SF-12, Health and Well-Being Questionnaire; NEMC, New England Medical Center.
a Percentages based on predeployment N (visit 1) and may not sum to 100% due to missing data.
b Very small but significant differences in age (F3 = 16.01; P < .001, ηp2 = .02), marital status (χ2 3 = 48.20; P < .001; φ = .14), rank (χ2 6 = 69.17; P < .001; φ = .16), and percentage of previously deployment Marines (N = 2,585; χ2 3 = 1.17; P < .005; φ = .07) were detected between cohorts.
c Percentages based on number of Marines who reported TBI at visit 1. Small but significant variations in rates of TBI were found in LOC and AMS with deployment history (N = 1,560; χ2 2 = 6.12; P = .013; φ = .06).
d Percentages based on number of Marines who reported TBI with LOC and AMS at visit 1.