Title: Results From the Follow-Up Study of a National Cohort of Gulf War and Gulf Era Veterans
Abstract: To the Editor: The authors of a recent article published in the journal noted that the study had a response rate of 50%.1 It would be helpful to know the response rates for important subgroups (eg, Gulf War veterans, non-deployed Gulf Era veterans) and whether the nonresponse analyses mentioned in the discussion section were done separately for deployed and nondeployed groups. The survey questionnaire used in this follow-up study included a question about whether the veteran had experienced a medically unexplained chronic multisymptom illness (CMI) and, in addition, numerous questions about medical conditions and symptoms.1 Based upon scientific input from the Research Advisory Committee on Gulf War Illness (RAC), the number of questions in the survey questionnaire was increased so that it would be possible to examine the frequency of Gulf War Illness using the Centers for Disease Control and Prevention (CDC) definition of CMI.2 Although the authors correctly note that there is no universally accepted definition of CMI, the Institute of Medicine recommended “that the Department of Veterans Affairs consider the use of the [CDC] and Kansas definitions because they capture the most commonly reported symptoms.”3 It would be helpful to know the frequency of CMI in this study population when the CDC criteria are used so that the results can be compared with other studies. A further issue is that the authors state that they reported the “frequency of [CMI] presenting as Gulf War Illness,” among Gulf War and nondeployed Gulf Era veterans, yet Gulf War Illness is by definition a condition that occurs among veterans who were deployed to the Persian Gulf theatre. The authors reported mean body mass index but did not report the frequency of underweight, normal weight, overweight, obesity, or severe obesity by deployment status, and they did not report the 95% confidence interval or standard error of mean BMI. As mean BMI was essentially the same in Gulf War and Gulf Era veterans, it is not clear why their analyses summarized in Tables 2 and 3 are adjusted for BMI, in addition to certain other variables. Adjusting for BMI unnecessarily could obscure associations with hypertension, diabetes, etc. Although BMI was based upon height and weight reported by the veterans at the time of the survey, people suffering from life-threatening illnesses such as amyotrophic lateral sclerosis and certain types of cancer often experience substantial weight loss as a result of their illness. In an article based upon an earlier survey of this same cohort, there was a suggestion of an interaction between underweight and CMI.4 The authors of the current article did not mention effect modifications or whether they looked for them in their analysis. A further concern is that gender-specific results were not reported, not even for “pelvic organ disease.” Rather, the results are adjusted for sex and certain other variables. There is a pressing need for more research on the health of Gulf War women veterans.5 Much of the article is focused on post-traumatic stress disorder (PTSD), major depression, and other psychiatric conditions. The authors did not mention whether they view Gulf War Illness as a psychiatric condition or a neurological condition. In the methods section, they provide references about the reliability and validity of measures of PTSD and major depression. However, in epidemiologic studies of GWI, a neurological condition that is often manifested by several symptoms including depression and anxiety, the reliability and validity of screening questions about probable PTSD and major depression are uncertain. In Table 3 summarizing psychiatric conditions, the authors included somatic symptoms. Scientific theories that Gulf War Illness is psychosomatic or a somatic symptom disorder have been discredited. The authors note that the respondents were provided with the telephone number of the VA Crisis Line and that institutional review board (IRB) approval was obtained, but they did not mention that special IRB-approved patient safety procedures were followed to ensure that respondents who reported that they were having thoughts of being better off dead were followed-up by clinical psychologists or social workers.6 Enhanced patient safety procedures are essential, as severely depressed individuals often do not have hope that they will get better and may not reach out for help or call a suicide crisis line. The survey questionnaire included questions about whether the respondents had served in Operation Iraqi Freedom, Operation Enduring Freedom, or Operation New Dawn (OIF/OEF/OND). The authors did not report how many of the Gulf War and Gulf Era respondents served in OIF/OEF/OND and did not take that source of misclassification bias into account in their analysis. The high frequency of PTSD and major depression could be partly due to respondent having been deployed to Iraq or Afghanistan during the more recent, prolonged conflicts.
Publication Year: 2016
Publication Date: 2016-05-01
Language: en
Type: letter
Indexed In: ['crossref', 'pubmed']
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