ORIGINAL ARTICLE

The health of Australian veterans of the 1991 Gulf War: factor analysis of self-reported symptoms

A B Forbes¹, D P McKenzie¹, A J Mackinnon², H L Kelsall¹, A C McFarlane³, J F Ikin¹, D C Glass¹, M R Sim¹

¹ Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
² Department of Psychological Medicine, Monash University, and Biostatistics and Psychometrics Unit, Mental Health Research Institute, Melbourne, Victoria, Australia
³ Department of Psychiatry, University of Adelaide, South Australia, Australia

Correspondence to:
Correspondence to:
Associate Professor Andrew Forbes
Department of Epidemiology and Preventive Medicine, Central and Eastern Clinical School, Monash University, The Alfred Hospital, Commercial Road, Melbourne, VIC 3004, Australia; andrew.forbes{at}med.monash.edu.au

Background: A recent report showed that Australian veterans of the 1991 Gulf War displayed a greater prevalence of a multitude of self-reported symptoms than a randomly sampled comparison group of military personnel who were eligible for deployment but were not deployed to the Gulf.

Aims: To investigate whether the pattern, rather than frequency, of symptom reporting in these Australian Gulf War veterans differed from that of the comparison group personnel.

Methods: Factor analysis was used to determine whether the co-occurrence of 62 symptoms in 1322 male Gulf War veterans can be explained by a number of underlying dimensions, called factors. The methodology was also applied to 1459 male comparison group subjects and the factor solutions of the two groups were compared.

Results: For the Gulf War veterans, a three factor solution displayed replicability and construct validity. The three factors were labelled as psycho-physiological distress, somatic distress, and arthro-neuromuscular distress, and were broadly similar to those described in previous studies of Gulf War veterans. A concordant three factor solution was also found for the comparison group subjects, with strong convergence of the factor loadings and factor scores across the two groups being displayed.

Conclusion: Results did not display evidence of a unique pattern of self-reported symptoms among Gulf War veterans. Results also indicated that the differences between the groups lie in the degrees of expression of the three underlying factors, consistent with the well documented evidence of increased self-reported symptom prevalence in Gulf War veterans.

Abbreviations: SF-12, 12-item version of the Short-Form Health Survey; PCS-12, Physical Component Summary scale of the SF-12; MCS-12, Mental Component Summary scale of the SF-12; TLI, Tucker-Lewis Index; CFI, comparative fit index; RMSEA, root mean squared error of approximation; SRMR, standardised root mean squared residual

Keywords: Gulf War; symptoms; factor analysis; ordinal scales; Pearson correlations; polychoric correlations

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• Kelsall, H. L., McKenzie, D. P., Sim, M. R., Leder, K., Forbes, A. B., Dwyer, T. (2009). Physical, Psychological, and Functional Comorbidities of Multisymptom Illness in Australian Male Veterans of the 1991 Gulf War. Am J Epidemiol 170: 1048-1056 [Abstract] [Full Text]  
• Sim, M., Kelsall, H. (2006). Gulf War illness: a view from Australia. Phil Trans R Soc B 361: 619-626 [Abstract] [Full Text]