Association between total number of self-reported symptoms and service type, rank, and age
| Total number of symptoms | ||||
|---|---|---|---|---|
| Gulf War veterans Mean (SD) | Comparison group Mean (SD) | Adjusted ratio of means (95% CI)* | p value | |
| *Ratios of means are adjusted for service type, rank, age (<20, 20–24, 25–34, ⩾35 years), education, and marital status by negative binomial regression. | ||||
| †p values shown for service type, rank, and age result from a test of whether the ratio of the mean total number of symptoms between Gulf War veterans and the comparison group are the same at each level of service type, rank, or age. | ||||
| ‡“Other ranks—supervisory” includes all non-commissioned officer ranks. These ranks were considered to hold supervisory positions, with the lowest rank being Leading Seamen in the Navy and Corporal in the Army and Air Force. | ||||
| Total study population | 14.7 (11.1) | 11.3 (9.2) | 1.3 (1.2 to 1.4) | <0.001 |
| Subgroup (at Gulf War) | ||||
| Service type | ||||
| Navy | 14.9 (11.2) | 11.2 (9.3) | 1.3 (1.3 to 1.4) | 0.164† |
| Army | 16.6 (11.6) | 14.1 (9.8) | 1.1 (1.0 to 1.4) | |
| Air Force | 11.4 (9.7) | 9.5 (8.0) | 1.2 (1.0 to 1.5) | |
| Rank | ||||
| Officer | 11.0 (8.5) | 8.8 (7.9) | 1.3 (1.1 to 1.5) | 0.087† |
| Other ranks—supervisory‡ | 15.1 (11.2) | 12.5 (9.4) | 1.3 (1.2 to 1.4) | |
| Other ranks—non-supervisory | 16.3 (11.9) | 11.4 (9.6) | 1.5 (1.3 to 1.6) | |
| Age | ||||
| <20 years | 16.2 (11.7) | 9.8 (8.6) | 1.6 (1.4 to 2.0) | 0.063† |
| 20–24 years | 14.5 (11.1) | 10.8 (9.1) | 1.3 (1.2 to 1.5) | |
| 25–34 years | 14.9 (10.9) | 11.2 (8.7) | 1.3 (1.2 to 1.4) | |
| ⩾35 years | 14.9 (11.5) | 13.0 (10.9) | 1.2 (1.0 to 1.4) | |