Tag: case-control study

Assessment of a retrovirus sequence and other possible risk factors for the chronic fatigue syndrome in adults

Abstract:

OBJECTIVE: To assess whether the human T-lymphotropic virus type II (HTLV-II) gag gene sequence, a purportedly new laboratory marker of the chronic fatigue syndrome (CFS), and other possible risk factors for CFS, particularly those associated with retroviral transmission, are associated with well-characterized CFS.

DESIGN: Two matched case-control studies.

SETTING: The metropolitan Atlanta area.

PATIENTS: Twenty-one patients with CFS who were identified by the Centers for Disease Control and Prevention CFS surveillance system; 21 CDC employee controls (laboratory study) and 42 neighborhood controls (risk-factor study) who were matched to patients by age, race, and gender.

MEASUREMENTS: Peripheral blood lymphocytes and leukocytes were assayed for the HTLV-II gag gene sequence by polymerase chain reaction and specific Southern blot hybridization. Questionnaires elicited demographic and clinical information and a history of exposures associated with retrovirus transmission (for example, blood transfusions, sexual practices, intravenous drug use).

RESULTS: All patients were white and 86% were female. The median age at illness onset was 34 years (range, 16 to 51 years). The HTLV-II gag gene sequence was not identified in the blood of any patient or control under conditions in which the appropriate assay controls were positive. No statistical differences were observed between patients and controls in frequency of blood transfusions (10% compared with 7%), median number of sex partners before illness (3 compared with 3), bisexual or homosexual behavior (14% compared with 7%), intravenous drug use (0% compared with 0%), and other factors associated with retroviral infection.

CONCLUSIONS: The HTLV-II gag gene sequence was not a marker for CFS in this small study of well-defined patients, nor did other characteristics of the patients and controls support the hypothesis that a retrovirus, transmitted by usual modes, was a cause of CFS.

 

Source: Khan AS, Heneine WM, Chapman LE, Gary HE Jr, Woods TC, Folks TM, Schonberger LB. Assessment of a retrovirus sequence and other possible risk factors for the chronic fatigue syndrome in adults. Ann Intern Med. 1993 Feb 15;118(4):241-5. http://www.ncbi.nlm.nih.gov/pubmed/8420441

 

Red blood cell magnesium and chronic fatigue syndrome

Abstract:

The hypotheses that patients with chronic fatigue syndrome (CFS) have low red blood cell magnesium and that magnesium treatment would improve the wellbeing of such patients were tested in a case-control study and a randomised, double-blind, placebo-controlled trial, respectively.

In the case-control study, 20 patients with CFS had lower red cell magnesium concentrations than did 20 healthy control subjects matched for age, sex, and social class (difference 0.1 mmol/l, 95% confidence interval [CI] 0.05 to 0.15).

In the clinical trial, 32 patients with CFS were randomly allocated either to intramuscular magnesium sulphate every week for 6 weeks (15 patients) or to placebo (17).

Patients treated with magnesium claimed to have improved energy levels, better emotional state, and less pain, as judged by changes in the Nottingham health profile. 12 of the 15 treated patients said that they had benefited from treatment, and in 7 patients energy score improved from the maximum to the minimum.

By contrast, 3 of the 17 patients on placebo said that they felt better (difference 62%, 95% CI 35 to 90), and 1 patient had a better energy score. Red cell magnesium returned to normal in all patients on magnesium but in only 1 patient on placebo. The findings show that magnesium may have a role in CFS.

Comment in:

Magnesium and chronic fatigue. [Lancet. 1991]

Magnesium and chronic fatigue syndrome. [Lancet. 1991]

Magnesium and chronic fatigue syndrome. [Lancet. 1991]

Intravenous magnesium loading in chronic fatigue syndrome. [Lancet. 1992]

 

Source: Cox IM, Campbell MJ, Dowson D. Red blood cell magnesium and chronic fatigue syndrome. Lancet. 1991 Mar 30;337(8744):757-60. http://www.ncbi.nlm.nih.gov/pubmed/1672392

 

Chronic fatigue syndrome: I. Epstein-Barr virus immune response and molecular epidemiology

Abstract:

Patients with chronic fatigue syndrome were compared to healthy seropositive control subjects in an open study and a case-control study analyzing spontaneous transformation rates of peripheral blood lymphocytes, EBV viral genome characteristics as determined by DNA restriction fragment polymorphisms, and antibody production by Western blot analysis.

Thirty percent of patients versus 8% of control subjects underwent spontaneous transformation in the two studies. Viral genome patterns were overall similar to one another, with polymorphisms frequently present in BamHI B’, K, H, and Y fragments. Only one line was found with the EBNA-2B genotype.

Nineteen lines were found to contain viral DNA in the linear form suggesting active lytic replication. Western blot studies suggested that ill subjects made antibodies to lytic proteins more frequently than did healthy control subjects. Lack of control of EBV outgrowth in vitro is correlated with antibody evidence of active infection in vivo in some patients with chronic fatigue syndrome.

 

Source: Jones JF, Streib J, Baker S, Herberger M. Chronic fatigue syndrome: I. Epstein-Barr virus immune response and molecular epidemiology. J Med Virol. 1991 Mar;33(3):151-8. http://www.ncbi.nlm.nih.gov/pubmed/1679118

 

Antibody to Coxsackie B virus in diagnosing postviral fatigue syndrome

Abstract:

OBJECTIVE: To study the association between coxsackie B virus infection and the postviral fatigue syndrome and to assess the immunological abnormalities associated with the syndrome.

DESIGN: Case-control study of patients with the postviral fatigue syndrome referred by local general practitioners over one year.

SETTING: General practitioner referrals in Dunbartonshire, Scotland.

PATIENTS: 254 Patients referred with the postviral fatigue syndrome (exhaustion, myalgia, and other symptoms referable to postviral fatigue syndrome of fairly recent onset–that is, several months) and age and sex matched controls obtained from same general practitioner; 11 patients were rejected because of wrong diagnoses, resolution of symptoms, and refusal to participate, leaving 243 patients and matched controls.

MAIN OUTCOME MEASURES: Detailed questionnaire (patients and controls) and clinical examination (patients) and blind analysis of blood sample at entry and after six months for determination of coxsackie B virus IgM and IgG antibodies and other variables (including lymphocyte protein synthesis, lymphocyte subsets, and immune complexes).

RESULTS: Percentage positive rates for coxsackie B virus IgM at entry were 24.4% for patients and 22.6% for controls and for coxsackie B virus IgG 56.2% and 55.3% respectively; there were no significant differences between different categories of patients according to clinical likelihood of the syndrome nor any predictive value in a fourfold rise or fall in the coxsackie B virus IgG titre in patients between entry and review at six months. The rates of positive antibody test results in patients and controls showed a strong seasonal variation. Of the numerous immunological tests performed, only a few detected significant abnormalities; in particular the mean value for immune complex concentration was much higher in 35 patients and 35 controls compared with the normal range and mean value for total IgM was also raised in 227 patients and 35 controls compared with the normal range.

CONCLUSIONS: Serological tests available for detecting coxsackie B virus antibodies do not help diagnose the postviral fatigue syndrome. Percentage positive rates of the antibodies in patients simply reflect the background in the population as probably do the raised concentrations of total IgM and immune complexes.

 

Source: Miller NA, Carmichael HA, Calder BD, Behan PO, Bell EJ, McCartney RA, Hall FC. Antibody to Coxsackie B virus in diagnosing postviral fatigue syndrome. BMJ. 1991 Jan 19;302(6769):140-3. http://www.ncbi.nlm.nih.gov/pubmed/1847316

 

Reduced gait automaticity in female patients with chronic fatigue syndrome: Case-control study

Abstract:

Patients with chronic fatigue syndrome (CFS) report difficulties walking for a prolonged period of time. This study compares gait automaticity between women with CFS and nondisabled controls.

The “stops walking with eyes closed with secondary cognitive task” test is based on the classic “stops walking while talking” test but compares walking with eyes closed while performing a secondary cognitive task in a female CFS population (n = 34) and in female nondisabled controls (n = 38).

When initiating gate, 23.5% of patients with CFS looked toward the ground compared with only 2.6% of nondisabled controls. After 7 m, subjects were asked to close their eyes, and after another 7 m, they were asked, “How much is 100 minus 7?” Of the patients with CFS, 55.9% stopped walking compared with 5.3% of nondisabled controls. Less automated walking was observed in patients with CFS than in nondisabled controls (p < 0.001). The test-retest reliability is moderate for global stopping.

This simple test observed reduced gait automaticity in patients with CFS for the first time. Dual tasking could be helpful to address the functional limitations found in this particular study.

 

Source: Jan b Eyskens, Jo Nijs, Kristien Wouters, Greta Moorkens. Reduced gait automaticity in female patients with chronic fatigue syndrome: Case-control study. Journal of Rehabilitation Research & Development (JRRD), Volume 52 Number 7, 2015, Pages 805 — 814.
Note: You can read the full study HERE.