Table 1.
Characteristics of study population
| All subjects (n = 2717) | Very short sleepa (n = 1169) | Short sleepb (n = 777) | ≥ 7 hours of sleep (n = 771) | P-valuec | |
|---|---|---|---|---|---|
| Mean age (SD) | 25.6 (5.7) | 27.2 (5.9) | 27.0 (5.6) | 27.2 (5.5) | 0.14 |
| Sex | 0.08 | ||||
| Male | 2617 (96%) | 97% | 96% | 96% | |
| Female | 34 (4%) | 3% | 4% | 4% | |
| Average weight in pounds (SD) | 183 (36) | 185 (38) | 180 (35) | 182 (35) | 0.03 |
| Average BMI in kg/m2 (SD) | 26.3 (4.8) | 26.5 (5.0) | 26.1 (4.8) | 26.2 (4.4) | 0.10 |
| Rank | < 0.001 | ||||
| Junior enlisted | 1333 (49%) | 45% | 27% | 28% | |
| Noncommissioned officers | 1185 (44%) | 43% | 29% | 27% | |
| Warrant and commissioned officers | 198 (7%) | 27% | 35% | 38% | |
| Symptoms of insufficient sleep | 444 (16%) | 75% | 18% | 7% | < 0.001 |
| Any combat exposure | 2111 (78%) | 48% | 28% | 24% | < 0.001 |
| Killed | 1131 (42%) | 51% | 27% | 22% | < 0.001 |
| Wounded | 419 (15%) | 59% | 21% | 20% | < 0.001 |
| Saw killing | 1451 (53%) | 50% | 26% | 24% | < 0.001 |
| Saw dead bodies | 2054 (76%) | 48% | 28% | 24% | < 0.001 |
| Mean number of combat exposures (SD) | 0.78 (41%) | 0.86 (0.34) | 0.76 (0.43) | 0.68 (0.47) | < 0.001 |
| Mean number of GWOT deployments (SD) | 1.74 (0.90) | 1.80 (0.98) | 1.70 (0.84) | 1.69 (0.83) | 0.01 |
| Any medical comorbidity | 1387 (51%) | 55% | 25% | 19% | < 0.001 |
| PTSD | 422 (16%) | 75% | 17% | 8% | < 0.001 |
| Mild TBI | 940 (35%) | 57% | 24% | 19% | < 0.001 |
| Depression | 94 (4%) | 84% | 13% | 3% | < 0.001 |
| Panic syndrome | 86 (3%) | 73% | 20% | 7% | < 0.001 |
| Obesity | 471 (17%) | 50% | 28% | 23% | < 0.001 |
| Any high-risk health behaviors | 1790 (65%) | 48% | 27% | 24% | |
| Tobacco use | 1600 (59%) | 48% | 28% | 25% | < 0.001 |
| Alcohol use | 739 (27%) | 55% | 24% | 21% | < 0.001 |
| Suicide attempt | 70 (3%) | 70% | 20% | 10% | < 0.001 |
| None | 931 (34%) | 34% | 32% | 34% | < 0.001 |
a
Self reported < 6 h sleep duration.
b
Self reported < 7 h sleep duration.
c
Student's T-test was used for weight and BMI; Chi-square analysis was used for all other categorical variables.