Association between demographic and military characteristics and mental disorders attributed to deployment in support of the Afghanistan mission
| Characteristic | Crude HR (95% CI) | Adjusted HR (95% CI) from selected model* |
|---|---|---|
| Sex | ||
| Male | 1.00 (ref) | 1.00 (ref) |
| Female | 1.23 (0.87–1.74) | 1.35 (0.96–1.91) |
| Age, yr | ||
| < 30 | 1.46 (1.03–2.06) | – |
| 30–39 | 1.11 (0.79–1.56) | – |
| ≥ 40 | 1.00 (ref) | – |
| Component | ||
| Regular Forces | 1.00 (ref) | – |
| Reserve Forces | 1.15 (0.69–1.90) | – |
| Element | ||
| Land | 1.00 (ref) | 1.00 (ref) |
| Sea | 0.47 (0.29–0.75) | 0.92 (0.54–1.57) |
| Air | 0.38 (0.26–0.55) | 0.60 (0.40–0.87) |
| Rank | ||
| Officer | 0.59 (0.39–0.90) | 0.60 (0.40–0.92) |
| Senior NCM | 0.88 (0.64–1.21) | 0.89 (0.64–1.22) |
| Junior NCM | 1.00 (ref) | 1.00 (ref) |
| Deployment location | ||
| Kandahar | 1.00 (ref) | 1.00 (ref) |
| Kabul | 0.48 (0.35–0.66) | 0.48 (0.35–0.66) |
| United Arab Emirates | 0.15 (0.07–0.30) | 0.18 (0.08–0.38) |
| Arabian Gulf | 0.25 (0.14–0.46) | 0.23 (0.11–0.48) |
| Multiple locations† | 0.46 (0.35–0.59) | 0.49 (0.33–0.72) |
| Unspecified | 0.36 (0.23–0.56) | 0.33 (0.21–0.52) |
| No. of deployments | ||
| 1 | 1.00 (ref) | 1.00 (ref) |
| 2 | 1.02 (0.78–1.33) | 1.16 (0.77–1.72) |
| ≥ 3 | 0.58 (0.35–0.98) | 0.74 (0.40–1.37) |
| Duration of first deployment, d | ||
| < 180 | 1.00 (ref) | – |
| 180–365 | 1.26 (0.99–1.61) | – |
| > 365 | 0.51 (0.12–2.18) | – |
| Total duration of all deployments, d | ||
| < 180 | 1.00 (ref) | 1.00 (ref) |
| 180–365 | 1.25 (0.96–1.61) | 0.82 (0.62–1.06) |
| > 365 | 0.92 (0.63–1.34) | 0.66 (0.41–1.07) |
Note: CI = confidence interval, deployment = deployment in support of the Afghanistan mission, HR = hazard ratio, NCM = noncommissioned officer, ref = reference group.
↵* Selected model included the variables sex, element, rank, deployment location, number of deployments and total duration of deployments.
↵† The hazard function for the “multiple locations” category represented a blending of the hazards for other locations and appears to be nonproportional to the hazard function for the Kandahar location at later time points; as such, care is warranted when comparing these 2 deployment location categories.