M de Vries

Radboud University Medical Centre (Radboudumc), Nymegen, Gelderland, Netherlands

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Publications (10)23.04 Total impact

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    ABSTRACT: Following their participation in a United Nations peacekeeping operation in Cambodia (1992-1993), Dutch veterans complained of symptoms similar to those reported by Gulf War veterans. The authors conducted a matched case-control study to evaluate 76 symptomatic and 32 matched asymptomatic Cambodia veterans on the basis of data collected by postal questionnaire. The number of symptomatic veterans who reported having used insect repellants that contained N,N,-diethyl-meta-toluamide (DEET) during the mission in Cambodia was significantly higher, compared with asymptomatic veterans. The percentage of veterans who reported feeling ill following brief exposures to chemicals such as paint or pesticides was equal in both groups, but the percentage was low compared with the results of other studies of Multiple Chemical Sensitivity Syndrome. The current study was limited by self-report and time delay (potential recall bias) between deployment to Cambodia and the time of survey. Nevertheless, the study results did not support the hypothesis that symptoms in the total group of Cambodia veterans could be related to Multiple Chemical Sensitivity Syndrome.
    Archives of Environmental Health An International Journal 01/2004; 58(12):740-5.
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    ABSTRACT: Post-traumatic stress disorder (PTSD) is sometimes put forward as an explanation for unexplained somatic symptoms in military personnel who have been deployed in war or peace missions. Using a cross-sectional postal survey, we investigated whether PTSD symptoms can account for fatigue in Dutch (ex-)servicemen who returned from the peace operation United Nations Transitional Authority for Cambodia and what features distinguish veterans with and without presumptive PTSD diagnoses. Increased PTSD scores were found in 1.3% of 1,698 veterans. There was no concordance between increased PTSD scores and fatigue, as defined in previous studies. Respondents with presumptive PTSD had more often left service, had more often been exposed to severe and potentially traumatic events, and more often reported a greater impact of the mission. Furthermore, they reported more mental problems that they perceived to be service related and they held a stronger causal attribution to post-traumatic stress. In conclusion, presumptive PTSD cannot offer an explanation for fatigue in Cambodia veterans.
    Military medicine 10/2002; 167(9):790-4. · 0.77 Impact Factor
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    ABSTRACT: Dutch (ex-)servicemen who encounter health problems since return from the 1992-3 peace operation UNTAC, commonly complain of reduced activity levels, decreases in physical fitness and aggravation of symptoms after strenuous exercise. To evaluate these symptoms. A prospective study of 26 symptomatic Cambodia veterans and 26 matched controls (healthy Cambodia veterans). Using an actometer and diaries, both groups were followed for a 12-day baseline period prior to an incremental maximal exercise test on a bicycle ergometer, followed by 7 days of post-ergometer data. During baseline, symptomatic Cambodia veterans reported more symptoms, had lower levels of physical activity and took longer periods of rest after high activity periods. Symptomatic veterans did not perceive the exercise test needing more exertion than healthy veterans did, although their physical fitness was decreased. Post-ergometer, daily observed symptoms did not aggravate in symptomatic veterans. Four days post-ergometer, actometer and daily observed activity scores were lowered in both groups. As compared to baseline, one day post-ergometer, levels of physical activity were changed in healthy veterans, but not in controls. Complaints about reduced activity levels and decreases in physical fitness in symptomatic Cambodia veterans were confirmed. Post-exertion malaise was not found. The observed post-exertion effects were traced back to weekday patterns.
    QJM: monthly journal of the Association of Physicians 03/2002; 95(2):99-105. · 2.36 Impact Factor
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    ABSTRACT: The aim of this study was to assess the effects of 2 weeks of supplementation with (−)-hydroxycitrate (HCA) and HCA combined with medium-chain triglycerides (MCT) on satiety and energy intake. The experimental design consisted of three intervention periods of 2 weeks separated by washout periods of 2 or 6 weeks in a double-blind, placebo-controlled, randomized, and crossover design. Seven male and 14 female normal to moderately obese subjects (mean±S.D.; age, 43±10 years; body mass index, 27.6±2.0 kg/m2) participated in this study. Subjects consumed three self-selected meals and four isoenergetic snacks daily with either no supplementation (PLA), with 500 mg HCA (HCA), or 500 mg HCA and 3 g MCT (HCA+MCT). Each intervention period ended with a test day, consisting of a standardized breakfast and ad libitum a lunch and a dinner. There was a significant body weight (BW) loss during the 2 weeks of intervention (PLA, −0.5±0.3 kg, P<.05; HCA, −0.4±0.2 kg, P<.05; HCA+MCT, −0.7±0.2 kg, P<.01), but this reduction was not different between treatments. Twenty-four-hour energy intake (PLA, 8.1±0.3 MJ; HCA, 8.3±0.3 MJ; HCA+MCT, 8.4±0.3 MJ) and the area under the curve of the appetite-related parameters during the test day were similar for all treatments. Two weeks of supplementation with HCA and HCA combined with MCT did not result in increased satiety or decreased energy intake compared to placebo in subjects losing BW.
    Physiology & Behavior 11/2001; · 3.16 Impact Factor
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    ABSTRACT: Dutch (ex-)servicemen were deployed in the 1992-3-peace operation UNTAC in Cambodia. Since their return, they have voiced concerns about the health consequences of their service and they have reported symptoms such as fatigue and cognitive problems. The natural course of symptoms in Dutch Cambodia veterans was evaluated in a prospective study. At 18-months follow-up, a questionnaire was sent to 354 veterans who met a set case definition for symptoms in Cambodia veterans or who had sub-threshold scores. Initial measurement of fatigue severity, psychological well-being, depression, post-traumatic stress disorder, trait-anxiety, self-efficacy and causal attributions, was used to evaluate predictors for self-reported improvement and low levels of fatigue at follow-up. At follow-up, 19% of the respondents reported complete recovery, 20% felt much better, 57% had the same complaints and 4% had become worse compared with their initial assessment. Self-reported improvement and less severe fatigue at follow-up were predicted by less severe fatigue at initial assessment and more perceived control over symptoms. Self-reported improvement was reported in a considerable percentage of Cambodia veterans, whereas another substantial percentage of Cambodia veterans continued to suffer with severe levels of fatigue and related symptoms. Predictors of improvement in Cambodia veterans and patients with chronic fatigue syndrome show similarities and also seem to bear importance for Gulf War veterans.
    Psychological Medicine 03/2001; 31(2):331-8. · 5.59 Impact Factor
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    ABSTRACT: In the Netherlands, a large-scale prospective cohort study was started on prolonged fatigue in the working population. The 1st issue that had to be addressed was the determination of a cutoff point for fatigue for use in the working population. Fatigue is measured with the Checklist Individual Strength (CIS), a 20-item self-report questionnaire. This article demonstrates the process of decision making in the determination of the cutoff point. Total CIS scores were calculated, sensitivity and specificity were compared for potential cutoff points, and a receiver operating characteristics analysis was conducted. A CIS total cutoff point for fatigue of >76 was determined, with a specificity of 90% and a sensitivity of 73%. Limitations regarding the use of cutoff points are discussed. It is concluded that the defined cutoff point seems to be appropriate for use in the working population.
    Journal of Occupational Health Psychology 11/2000; 5(4):411-6. · 2.07 Impact Factor
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    ABSTRACT: Since the end of the American Civil War, unexplained symptoms in military personnel arising after a war or peace mission have frequently been described. The pattern of symptoms is highly similar for all of the various war syndromes although the conditions of each war or peace mission are widely different. Many somatic hypotheses have been formulated to explain these syndromes; a considerable proportion of them are already outdated. In the last few years much attention has been given to Gulf War Syndrome and to unexplained symptoms of military personnel who were sent to Cambodia, Rwanda, Burundi, Zaire, or the former Yugoslavia. In this review the symptoms of war syndromes will be considered in more detail and the suggested somatic explanations will be discussed. During the last decade the following somatic causes have been suggested as possible explanations for these symptoms: (persistent) infection, abnormal immune response, administration of multiple vaccinations within a short period of time, use of malaria chemoprophylaxis, neurological abnormalities, exposure to toxicological substances and environmental factors. The various investigations performed to study these hypotheses are discussed. The fact that bias regularly occurs in the course of these investigations is pointed out. For the future, a reliable investigation of a war syndrome should be a prospective multidisciplinary study and should distinguish between causative and sustaining factors.
    European Journal of Clinical Investigation 08/2000; 30(7):630-41. · 3.37 Impact Factor
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    ABSTRACT: In 1992 and 1993, Dutch military personnel were deployed in the peace operation UNTAC in Cambodia. Since returning, Cambodia veterans have reported health complaints which they perceive to be related to their service. Their symptoms strikingly resemble health problems reported by Gulf War veterans. Four years post-return, a cross-sectional survey on health symptoms in Cambodia veterans was initiated. Questionnaires were sent to all Cambodia veterans and four comparison groups. Forgetfulness, difficulty concentrating and fatigue were the symptoms most commonly endorsed. An operational case definition was constructed using a validated fatigue severity questionnaire. Cases were not uniquely found in Cambodia veterans (17%). In Rwanda and Bosnia veterans, respectively, 28% and 11% also met our case definition. Fatigue severity level was predicted by pre-mission, during-mission and post-mission variables, of which retrospective recollection of side-effects of vaccines and causal attributions also have been shown to be relevant in studies on Gulf-related illness.
    QJM: monthly journal of the Association of Physicians 06/2000; 93(5):283-9. · 2.36 Impact Factor
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    ABSTRACT: Dutch soldiers who have participated in the peace keeping operation United Nations Transitional Authority in Cambodia (UNTAC) have reported various somatic and psychological symptoms since their return. Their symptoms show similarities to the Gulf War Syndrome. The question arises whether Gulf War Syndrome, symptoms in UNTAC soldiers and other symptoms after acts of war and peace operations are unique syndromes or comparable complaints? From an historical overview it is not plausible that new and unique syndromes will occur with each war or peace operation. On the other hand it also seems unlikely that war syndromes can be reduced to one diagnostic category. The post-Cambodia complaints may be described in four hypothetical models: the somatic start model, the psychotrauma start model, the premorbidity model and the complaints-not-related-to-Cambodia model. These models are expected to be applicable, after further validation, to other symptoms after acts of war and peace operations. Also they will provide points of application for prevention and treatment of symptoms after future wars and peace operations.
    Nederlands tijdschrift voor geneeskunde 01/2000; 143(51):2557-62.
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    ABSTRACT: The pathogenesis of post-combat syndromes, such as Gulf War syndrome, is poorly understood. Recently, it has been postulated that the symptoms of veterans with such syndromes are due to a disturbed cytokine balance shifted towards a T-helper (Th) 2 profile. We investigated this hypothesis in 21 symptomatic former UNTAC soldiers and compared their results with those obtained in 21 healthy former UNTAC soldiers matched for age, sex and military force. The numbers of intracellular interleukin 4 (IL-4) and interferon gamma- (IFN-gamma) producing CD4+ and CD8+ T lymphocytes (CD3+) were determined after in vitro stimulation with phorbol myristate acetate and calcium ionophore in the presence of brefeldin to block secretion of induced cytokines. Circulating concentrations and lipopolysaccharide- (LPS) or phytohaemagglutinin- (PHA) stimulated whole-blood production of the proinflammatory cytokines IL-1beta, IL-1ra, tumour necrosis factor alpha (TNF-alpha) and IL-10 and IFN-gamma were measured. The numbers of CD4+ and CD8+ T lymphocytes positive for IL-4 or IFN-gamma production were not significantly different in patients and control subjects. After stimulation with LPS or PHA, the in vivo circulating concentration and concentration of IL-10 and IFN-gamma were also similar. The present study demonstrates that there is no shift in cytokine balance towards a Th2 profile in former UNTAC soldiers with symptoms similar to those of the Gulf War syndrome.
    European Journal of Clinical Investigation 12/1999; 29(11):960-3. · 3.37 Impact Factor

Publication Stats

194 Citations
23.04 Total Impact Points

Institutions

  • 2002
    • Radboud University Medical Centre (Radboudumc)
      • Department of Human Genetics
      Nymegen, Gelderland, Netherlands
  • 2001–2002
    • Radboud University Nijmegen
      • Department of Medical Psychology
      Nijmegen, Provincie Gelderland, Netherlands