Tag: large-scale study

Chronic fatigue and organophosphate pesticides in sheep farming: a retrospective study amongst people reporting to a UK pharmacovigilance scheme

Abstract:

The Department of Health has recently published a report from the CFS/ME Working Group which concluded that chronic fatigue syndrome (CFS) should be recognized as a chronic illness. Symptoms consistent with CFS are often reported by people who consider their health has been affected by exposure to pesticides, but the Working Group concluded that this type of exposure is not a common trigger for the syndrome.

The Veterinary Medicines Directorate (VMD) collects self-assessed reports of ill health in humans associated with veterinary medicines under their Suspected Adverse Reaction Surveillance Scheme. The reporters have mainly been sheep farmers. These reports were used to investigate the possible relationship between chronic fatigue (CF) and exposure to organophosphate pesticides in sheep farming. The overall aim of the study was to investigate a possible association between exposure to organophosphates and the development of CF amongst people who consider their health has been affected by pesticides in sheep farming. The hypothesis investigated was that repeated exposure to organophosphate pesticides in sheep dip may increase the probability of developing CF. A group of mostly sheep farmers who had reported to the VMD surveillance scheme were identified.

We planned to use a retrospective case-control study design but the initial symptoms reports were not sufficiently reliable to enable this. The study population was asked to complete two questionnaires. The first questionnaire was designed to identify the history of exposure of subjects to organophosphate pesticides, and their exposure was then reconstructed using a metric specifically developed for this purpose. The second questionnaire collected detailed information to identify whether the subjects had CF when they originally reported to the VMD and at the time of the survey.

The questionnaire was sent to a total of 206 subjects, of whom 28 had moved home. A total of 37% of the remaining 178 subjects participated. There was a high prevalence of CF amongst those who completed the questionnaire and this has generally persisted since the subjects reported to the VMD. Higher CF scores were associated with higher exposure to organophosphate pesticides.

CF is very common amongst those who consider their health was affected by pesticides and we have shown there is limited evidence of an association between exposure to organophosphates and CF. Further research is needed to investigate the cause of this syndrome amongst farmers exposed to pesticides.

 

Source: Tahmaz N, Soutar A, Cherrie JW. Chronic fatigue and organophosphate pesticides in sheep farming: a retrospective study amongst people reporting to a UK pharmacovigilance scheme. Ann Occup Hyg. 2003 Jun;47(4):261-7. http://annhyg.oxfordjournals.org/content/47/4/261.long (Full article)

 

Clarifying the relationship between unexplained chronic fatigue and psychiatric morbidity: results from a community survey in Great Britain

Abstract:

The study examined the associations between several sociodemographic and psychosocial variables and unexplained chronic fatigue in the community before and after adjustment for psychiatric morbidity and determined the prevalence of fatigue and rate of disability resulting from fatigue in the general population. The study is a secondary analysis of 1993 data from a household survey of psychiatric morbidity conducted by the Office for Population Censuses and Surveys in Great Britain. The survey included 12,730 subjects age 16-64 years. Unexplained chronic fatigue was used as the dependent variable in a logistic regression analysis, with various sociodemographic and psychosocial variables and psychiatric morbidity as the independent variables. Psychiatric morbidity was assessed by using the Revised Clinical Interview Schedule. Fatigue was measured by using the fatigue section of the Revised Clinical Interview Schedule.

A total of 10,108 subjects agreed to cooperate (79.4% participation rate). The prevalence of unexplained chronic fatigue was 9%. Subjects with psychiatric morbidity had higher rates of fatigue. Adjustment for psychiatric morbidity had a minor effect on the associations between sociodemographic factors and chronic fatigue. After adjustment, older subjects, women, and couples with children had higher rates of fatigue. Single subjects, widowed subjects, adults living with parents, and economically inactive subjects had lower rates of fatigue. Fatigue was associated with considerable disability, but the association between fatigue and psychiatric morbidity explained most of this disability. Unexplained chronic fatigue is a common condition, strongly associated with psychiatric morbidity. The close relationship between fatigue and psychiatric morbidity should not obscure the possibility of differences as well as similarities in their aetiologies.

 

Source: Skapinakis P, Lewis G, Meltzer H. Clarifying the relationship between unexplained chronic fatigue and psychiatric morbidity: results from a community survey in Great Britain. Int Rev Psychiatry. 2003 Feb-May;15(1-2):57-64. http://www.ncbi.nlm.nih.gov/pubmed/12745311

 

Associations between bronchial hyperresponsiveness and immune cell parameters in patients with chronic fatigue syndrome

Abstract:

STUDY OBJECTIVE: To examine whether bronchial hyperresponsiveness (BHR) in patients with chronic fatigue syndrome (CFS) is caused by immune system abnormalities.

DESIGN: Prospective comparative study.

SETTING: A university-based outpatient clinic (Vrije Universiteit; Brussels, Belgium).

PARTICIPANTS: One hundred thirty-seven CFS patients and 27 healthy volunteers.

MEASUREMENTS: Pulmonary function testing, histamine bronchoprovocation test, immunophenotyping, and ribonuclease (RNase) latent determination.

RESULTS: Seventy-three of 137 patients presented with BHR, of whom 64 had normal results of the histamine bronchoprovocation test. No significant differences were found in age or sex characteristics between the groups. There were no differences in the RNase L ratio, total lung capacity, or FEV(1)/FVC ratio between CFS patients with or without BHR. The group of patients in whom BHR was present (BHR+) differs most significantly from the control group with eight differences in the immunophenotype profile in the cell count analysis and seven differences in the percentage distribution profile. The group of patients in whom no BHR was detected (BHR-) only differed from the control subjects in CD25+ count and in the percentage of CD25+ cells. We observed a significant increase in cytotoxic T-cell count and in the percentage of BHR+ patients compared to BHR- patients, which is consistent with the significant reduction in percentage naïve T cells.

CONCLUSIONS: These results refute any association between the cleaving of 80 kd RNase L and BHR. Immunophenotyping of our sample confirmed earlier reports on (chronic) immune activation in patients with CFS, compared to healthy control subjects. BHR+ CFS patients have more evidence of immune activation compared to BHR- patients. Inflammation and the consequent IgE-mediated activation of mast cells and eosinophils, as seen in asthma patients, is unlikely to be responsible for the presence of BHR in patients with CFS.

 

Source: Nijs J, De Becker P, De Meirleir K, Demanet C, Vincken W, Schuermans D, McGregor N. Associations between bronchial hyperresponsiveness and immune cell parameters in patients with chronic fatigue syndrome. Chest. 2003 Apr;123(4):998-1007. http://www.ncbi.nlm.nih.gov/pubmed/12684286

 

Financial, occupational, and personal consequences of disability in patients with chronic fatigue syndrome and fibromyalgia compared to other fatiguing conditions

Abstract:

OBJECTIVE: To examine the nature and degree of self-reported disability in patients with chronic fatigue syndrome (CFS) and its associated conditions, fibromyalgia (FM) and subsyndromal fatigue (CF), compared with a chronically fatiguing but unrelated medical condition (MED).

METHODS: Six hundred and thirty patients evaluated at the University of Washington Chronic Fatigue Clinic were sent questionnaires asking them to identify the financial, occupational, and personal consequences of their fatiguing illness. Thorough medical evaluations had previously applied accepted criteria for defining CFS, FM, and CF.

RESULTS: The FM groups (those with and without CFS) were among the least employed. Likewise, the FM and CFS groups, more frequently than the other groups, endorsed loss of material possessions (such as car), loss of job, and loss of support by friends and family, as well as recreational activities as a result of their fatiguing illness. There were no reliable differences between groups in use of disability benefits.

CONCLUSION: There is substantial illness-related disability among those evaluated at a specialized chronic fatigue clinic. Those reporting the most pervasive disability met criteria for FM either alone or in conjunction with CFS. Employers and personal relations of patients with chronic fatigue should make a greater effort to accommodate the illness-related limitations of these conditions, especially for those with FM and CFS.

 

Source: Assefi NP, Coy TV, Uslan D, Smith WR, Buchwald D. Financial, occupational, and personal consequences of disability in patients with chronic fatigue syndrome and fibromyalgia compared to other fatiguing conditions. J Rheumatol. 2003 Apr;30(4):804-8. http://www.ncbi.nlm.nih.gov/pubmed/12672203

 

Unexplained fatigue syndromes in a multinational primary care sample: specificity of definition and prevalence and distinctiveness from depression and generalized anxiety

Abstract:

OBJECTIVE: The authors investigated whether narrow definitions of unexplained fatigue syndromes that require additional minor somatic symptoms are more strongly associated with psychiatric morbidity than wider ones.

METHOD: This was a secondary analysis of the World Health Organization Collaborative Project on Psychological Problems in General Health Care. A total of 5,438 primary care patients from 14 countries were assessed with the Composite International Diagnostic Interview.

RESULTS: The prevalence of fatigue syndromes fell from 7.99 to 1.69 as somatic criteria were added. Patients with depression or anxiety were more likely to report unexplained fatigue, but this association was stronger for definitions of unexplained fatigue with more somatic criteria.

CONCLUSIONS: Definitions of unexplained fatigue syndromes that require more somatic criteria selected more patients with psychiatric disorders in this culturally diverse sample. These findings might have implications for the revision of existing international diagnostic criteria for neurasthenia or chronic fatigue syndrome.

 

Source: Skapinakis P, Lewis G, Mavreas V. Unexplained fatigue syndromes in a multinational primary care sample: specificity of definition and prevalence and distinctiveness from depression and generalized anxiety. Am J Psychiatry. 2003 Apr;160(4):785-7. http://www.ncbi.nlm.nih.gov/pubmed/12668371

 

Chronic fatigue syndrome: symptom subtypes in a community based sample

Abstract:

Most studies of Chronic Fatigue Syndrome (CFS) have been based on patients recruited from primary or tertiary care settings. Patients from such settings might not be typical of patients in the general population. The present investigation involved examining individuals with CFS from a community-based study. A random sample of 18,675 respondents in Chicago were first interviewed by telephone. A group of individuals with chronic fatigue accompanied by at least four Fukuda et al. (1994) symptoms associated with CFS were given medical and psychiatric examinations. From this sample, a physician review group diagnosed individuals with CFS. Those diagnosed with CFS were subclassified based on frequency of symptoms. Important differences emerged on measures of sociodemographics and disability. The implications of these findings and others are discussed.

 

Source: Jason LA, Taylor RR, Kennedy CL, Jordan KM, Song S, Johnson D, Torres-Harding S. Chronic fatigue syndrome: symptom subtypes in a community based sample. Women Health. 2003;37(1):1-13. http://www.ncbi.nlm.nih.gov/pubmed/12627607

 

Chronic fatigue in a population-based study of Gulf War veterans

Abstract:

Fatigue has been associated with illness in veterans of the Gulf War; however, few studies have confirmed self-reported fatigue by using clinical evaluation, and symptomatic veterans have not been evaluated with established criteria for Chronic Fatigue Syndrome (CFS). The authors describe the frequency and clinical characteristics of CFS in a sample of veterans residing in the northwestern United States. The sample was selected randomly from U.S. Department of Defense databases of troops deployed to southwest Asia during the Gulf War. The selected individuals were invited to participate in a clinical case-control study of unexplained illness.

Of 799 survey respondents eligible for clinical evaluation, 178 had fatigue symptoms. Of the 130 veterans who were evaluated clinically, 103 had unexplained fatigue, and 44 veterans met the 1994 U.S. Centers for Disease Control criteria for CFS. In this population, the authors estimated a minimum prevalence of any unexplained fatigue to be 5.1%, and of CFS to be 2.2%. The estimated prevalence was greater among females than among males. Cases were similar to healthy controls, as determined by laboratory tests and physical findings. In comparison to several clinical studies of CFS patients, the authors of this study found a lower proportion of veterans who reported a sudden onset of symptoms (19%) vs. a gradual onset (50%).

Although it has previously been suggested that veterans of the Gulf War suffer from higher rates of chronic fatigue than the general population, the study results described herein–on the basis of clinical examination of a population-based sample of veterans-actually indicate that an increased rate may indeed exist. Gulf War veterans with unexplained fatigue should be encouraged to seek treatment so that the impact of these symptoms on overall quality of life can be reduced.

 

Source: McCauley LA, Joos SK, Barkhuizen A, Shuell T, Tyree WA, Bourdette DN. Chronic fatigue in a population-based study of Gulf War veterans. Arch Environ Health. 2002 Jul-Aug;57(4):340-8. http://www.ncbi.nlm.nih.gov/pubmed/12530602

 

High prevalence of Mycoplasma infections among European chronic fatigue syndrome patients. Examination of four Mycoplasma species in blood of chronic fatigue syndrome patients

Abstract:

Prevalence of Mycoplasma species infections in chronic fatigue syndrome (CFS) has been extensively reported in the scientific literature. However, all previous reports highlighted the presence of Mycoplasmas in American patients. In this prospective study, the presence of Mycoplasma fermentans, M. penetrans, M. pneumoniae and M. hominis in the blood of 261 European CFS patients and 36 healthy volunteers was examined using forensic polymerase chain reaction.

One hundred and seventy-nine (68.6%) patients were infected by at least one species of Mycoplasma, compared to two out of 36 (5.6%) in the control sample (P<0.001). Among Mycoplasma-infected patients, M. hominis was the most frequently observed infection (n=96; 36.8% of the overall sample), followed by M. pneumoniae and M. fermentans infections (equal frequencies; n=67; 25.7%). M. penetrans infections were not found. Multiple mycoplasmal infections were detected in 45 patients (17.2%). Compared to American CFS patients (M. pneumoniae>M. hominis>M. penetrans), a slightly different pattern of mycoplasmal infections was found in European CFS patients (M. hominis>M. pneumoniae, M. fermentansz.Gt;M. penetrans).

 

Source: Nijs J, Nicolson GL, De Becker P, Coomans D, De Meirleir K. High prevalence of Mycoplasma infections among European chronic fatigue syndrome patients. Examination of four Mycoplasma species in blood of chronic fatigue syndrome patients. FEMS Immunol Med Microbiol. 2002 Nov 15;34(3):209-14. http://femsim.oxfordjournals.org/content/34/3/209.long (Full article)

 

Treatment with staphylococcus toxoid in fibromyalgia/chronic fatigue syndrome–a randomised controlled trial

Abstract:

We have previously conducted a small treatment study on staphylococcus toxoid in fibromyalgia (FM) and chronic fatigue syndrome (CFS). The aim of the present study was to further assess the efficacy of the staphylococcus toxoid preparation Staphypan Berna (SB) during 6 months in FM/CFS patients.

One hundred consecutively referred patients fulfilling the ACR criteria for FM and the 1994 CDC criteria for CFS were randomised to receive active drug or placebo. Treatment included weekly injections containing 0.1 ml, 0.2 ml, 0.3 ml, 0.4 ml, 0.6 ml, 0.8 ml, 0.9 ml, and 1.0 ml SB or coloured sterile water, followed by booster doses given 4-weekly until endpoint.

Main outcome measures were the proportion of responders according to global ratings and the proportion of patients with a symptom reduction of > or =50% on a 15-item subscale derived from the comprehensive psychopathological rating scale (CPRS). The treatment was well tolerated. Intention-to-treat analysis showed 32/49 (65%) responders in the SB group compared to 9/49 (18%) in the placebo group (P<0.001). Sixteen patients (33%) in the SB group reduced their CPRS scores by at least 50% compared to five patients (10%) in the placebo group (P< 0.01). Mean change score on the CPRS (95% confidence interval) was 10.0 (6.7-13.3) in the SB group and 3.9 (1.1-6.6) in the placebo group (P<0.01). An increase in CPRS symptoms at withdrawal was noted in the SB group.

In conclusion, treatment with staphylococcus toxoid injections over 6 months led to significant improvement in patients with FM and CFS. Maintenance treatment is required to prevent relapse.

 

Source: Zachrisson O, Regland B, Jahreskog M, Jonsson M, Kron M, Gottfries CG. Treatment with staphylococcus toxoid in fibromyalgia/chronic fatigue syndrome–a randomised controlled trial. Eur J Pain. 2002;6(6):455-66. http://www.ncbi.nlm.nih.gov/pubmed/12413434

 

A factor analysis of chronic fatigue symptoms in a community-based sample

Abstract:

BACKGROUND: This study examined characteristics of fatigue in individuals with chronic fatigue from a community-based study. Most studies of chronic fatigue have been based on patients recruited from primary or tertiary care settings. Samples such as these might not be representative of patients within the general population. The purpose of this study was to determine the factor structure of participants’ symptoms in a random community sample of individuals with chronic fatigue.

METHOD: A random sample of 18,675 respondents in Chicago received a brief telephone questionnaire designed to identify individuals with chronic fatigue. A group of 780 (4.2%) with chronic fatigue received further interview via telephone questionnaire involving characteristics of their fatigue. The analyses for this study were based on those people identified with having chronic fatigue. A factor analysis was conducted on responses to questionnaire items, and a four-factor solution emerged. Mean factor scores were derived and analyzed in relation to sociodemographic characteristics and sample subgroups.

RESULTS: The four factors were labeled: Lack of Energy, Physical Exertion, Cognitive Functioning, and Fatigue and Rest.

CONCLUSIONS: Results indicated that individuals with chronic fatigue have symptoms that can be differentiated into theoretically distinct factors.

 

Source: Jason LA, Taylor RR, Kennedy CL, Jordan K, Huang CF, Torres-Harding S, Song S, Johnson D. A factor analysis of chronic fatigue symptoms in a community-based sample.  Soc Psychiatry Psychiatr Epidemiol. 2002 Apr;37(4):183-9. http://www.ncbi.nlm.nih.gov/pubmed/12027245