TY - JOUR
T1 - Gulf War unexplained illnesses
T2 - Persistence and unexplained nature of self-reported symptoms
AU - McCauley, Linda A.
AU - Joos, Sandra K.
AU - Lasarev, Michael R.
AU - Storzbach, Daniel
AU - Bourdette, Dennis N.
N1 - Funding Information:
1This research was funded by the Department of Veterans Affairs to the Portland Environmental Hazards Research Center, a joint project of the Portland Veterans Affairs Medical Center and the Center for Research on Occupational and Environmental Toxicology, Oregon Health Sciences University, Portland, Oregon. All protocols in this study were conducted in accordance with national, Department of Veterans Affairs, and Oregon Health Sciences University institutional guidelines for the protection of human subjects.
PY - 1999/10
Y1 - 1999/10
N2 - Most published reports of health symptoms among Gulf War (GW) veterans have been based on self-reported questionnaire data. The presence of these symptoms at the time of a clinical evaluation and the unexplained nature of the symptoms have not been described. We report the findings of a sample of symptomatic veterans that were examined as part of a population-based case- control study of GW unexplained illnesses. Participants in the case-control study were selected from responders to a cross- sectional survey of a random sample of GW veterans residing in the northwestern United States. The initial survey questionnaire solicited information on the presence of fatigue and psychological/cognitive, gastrointestinal, musculoskeletal, and dermatological problems. The persistence of the symptoms and possible explanatory diagnoses were explored at the time of the clinical evaluation. Findings from the first 225 participants who completed clinical examinations indicate significant differences between self-reported symptoms on the survey questionnaire and those confirmed at the time of clinical exam. The agreement between symptoms reported both on the survey and at the time of examination varies across the symptom groups. While self-reported unexplained fatigue was confirmed at the time of clinical encounter in 79% of participants, self-reported gastrointestinal symptoms were confirmed at the clinical encounter in only 20% of participants. Differences between symptoms reported on the survey questionnaire and those confirmed at the time of clinical encounter were attributable to finding a clinical diagnosis for the symptom, resolution of symptom(s) between time of questionnaire and clinical exam, and inadvertent endorsement of the symptom on the questionnaire. These findings suggest that due to the possibility of outcome misclassification, inappropriate conclusions may be drawn about the association between exposures and unexplained illnesses in GW veterans from data derived solely from self-administered questionnaires.
AB - Most published reports of health symptoms among Gulf War (GW) veterans have been based on self-reported questionnaire data. The presence of these symptoms at the time of a clinical evaluation and the unexplained nature of the symptoms have not been described. We report the findings of a sample of symptomatic veterans that were examined as part of a population-based case- control study of GW unexplained illnesses. Participants in the case-control study were selected from responders to a cross- sectional survey of a random sample of GW veterans residing in the northwestern United States. The initial survey questionnaire solicited information on the presence of fatigue and psychological/cognitive, gastrointestinal, musculoskeletal, and dermatological problems. The persistence of the symptoms and possible explanatory diagnoses were explored at the time of the clinical evaluation. Findings from the first 225 participants who completed clinical examinations indicate significant differences between self-reported symptoms on the survey questionnaire and those confirmed at the time of clinical exam. The agreement between symptoms reported both on the survey and at the time of examination varies across the symptom groups. While self-reported unexplained fatigue was confirmed at the time of clinical encounter in 79% of participants, self-reported gastrointestinal symptoms were confirmed at the clinical encounter in only 20% of participants. Differences between symptoms reported on the survey questionnaire and those confirmed at the time of clinical encounter were attributable to finding a clinical diagnosis for the symptom, resolution of symptom(s) between time of questionnaire and clinical exam, and inadvertent endorsement of the symptom on the questionnaire. These findings suggest that due to the possibility of outcome misclassification, inappropriate conclusions may be drawn about the association between exposures and unexplained illnesses in GW veterans from data derived solely from self-administered questionnaires.
KW - Case-control studies
KW - Clinical evaluation
KW - Gulf War
KW - Health symptoms
KW - Survey questionnaires
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U2 - 10.1006/enrs.1999.3973
DO - 10.1006/enrs.1999.3973
M3 - Article
C2 - 10585017
AN - SCOPUS:0032857960
SN - 0013-9351
VL - 81
SP - 215
EP - 223
JO - Environmental Research
JF - Environmental Research
IS - 3
ER -