Table 1.
Summary of studies that have used factor analysis in Gulf veterans.
| study | Haley et al. (1997) | Fukuda et al. (1998) | Ismail et al. (1999) | Bourdette et al. (2001) | Doebbeling et al. (2000) | Knoke et al. (2000) | Shapiro et al. (2002) | Kang et al. (2002b) |
|---|---|---|---|---|---|---|---|---|
| study population | US Seabees (active and ex-service) | US Air Force (active) | UK Military (active and ex-service) | US Military from Oregon or Washington (active and ex-service) | US Military from Iowa (active and ex-service) | US Seabees (active) | US Army/National Guard (active) | US Military (active and ex-service) |
| sample size of Gulf veterans | 249 | 1631a | 3214 | 227 | 3695 | 1459 | 1779 | 10 423 |
| no. of symptoms measured | 52 | 35 | 50 | 35 | 137 | 98 | 19 | 47 |
| percentage of common variance explained by factors reported | 71 | 39.1 | 42.1 | 34.2 | 35 | 80 | 46.7 | 44 |
| labels given to factors by authors | impaired cognition | fatigue | mood–cognition | cognitive/psychological | somatic distress | insecurity | cognitive/psychological | fatigue/ depression |
| confusion–ataxia | mood–cognition | respiratory system | mixed somatic | psychological distress | somatization | dysesthesiab | neurological | |
| arthro–myo-neuropathy | musculoskeletal | peripheral nervous system | musculoskeletal | panic | depression | vestibular dysfunction | musculoskeletal | |
| phobia–apraxia | obsessive–compulsive | gastrointestinal | ||||||
| fever–adenopathy | malaise | pulmonary | ||||||
| weakness–incontinence | upper respiratory |
a
Included non-Gulf veterans.
b
In Khamisiyah Gulf veterans only.