Category: Epidemiology

Prevalence and incidence of chronic fatigue syndrome in Wichita, Kansas

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is a debilitating illness with no known cause or effective therapy. Population-based epidemiologic data on CFS prevalence and incidence are critical to put CFS in a realistic context for public health officials and others responsible for allocating resources and for practicing physicians when examining and caring for patients.

METHODS: We conducted a random digit-dialing survey and clinical examination to estimate the prevalence of CFS in the general population of Wichita, Kan, and a 1-year follow-up telephone interview and clinical examination to estimate the incidence of CFS. The survey included 33 997 households representing 90 316 residents. This report focuses on 7162 respondents aged 18 to 69 years. Fatigued (n = 3528) and randomly selected nonfatigued (n = 3634) respondents completed telephone questionnaires concerning fatigue, other symptoms, and medical history. The clinical examination included the Diagnostic Interview Schedule for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, laboratory testing, and a physical examination.

RESULTS: The overall weighted point prevalence of CFS, adjusted for nonresponse, was 235 per 100,000 persons (95% confidence interval, 142-327 per 100,000 persons). The prevalence of CFS was higher among women, 373 per 100,000 persons (95% confidence interval, 210-536 per 100,000 persons), than among men, 83 per 100,000 persons (95% confidence interval, 15-150 per 100,000 persons). Among subjects nonfatigued and fatigued for less than 6 months, the 1-year incidence of CFS was 180 per 100,000 persons (95% confidence interval, 0-466 per 100,000 persons).

CONCLUSIONS: Chronic fatigue syndrome constitutes a major public health problem. Longitudinal follow-up of this cohort will be used to further evaluate the natural history of this illness.

 

Source: Reyes M, Nisenbaum R, Hoaglin DC, Unger ER, Emmons C, Randall B, Stewart JA, Abbey S, Jones JF, Gantz N, Minden S, Reeves WC. Prevalence and incidence of chronic fatigue syndrome in Wichita, Kansas. Arch Intern Med. 2003 Jul 14;163(13):1530-6. http://www.ncbi.nlm.nih.gov/pubmed/12860574

 

Differences between patients with chronic fatigue syndrome and with chronic fatigue at an infectious disease clinic in Stockholm, Sweden

Abstract:

Background data were collected from patients presenting with fatigue at the clinic of infectious diseases at Huddinge University Hospital, Stockholm. The main purpose was to look for differences as to demographic and functional status for patients fulfilling criteria for chronic fatigue syndrome (CFS) and chronic fatigue (CF).

A cross-sectional questionnaire survey was performed using a variety of instruments. A thorough medical investigation was performed. No difference was found as to social situation, occupation and illness attributions for patients in the two categories. Patients with CFS reported in general a higher degree of ‘sickness’ with more self-reported somatic symptoms, more self-reported functional impairment and more absence from work. A higher degree of psychiatric comorbidity was observed in CF than in CFS patients. A majority of CFS patients (80%) had an acute infectious onset compared to 43% in the CF group.

Presently used criteria might, according to findings presented here, define two different patient categories in a population characterized by severe, prolonged fatigue. Because CFS patients (compared to patients with CF) have more somatic symptoms, more often report an infectious, sudden onset and have less psychiatric comorbidity, and CF patients seem to have more of an emotional, burn-out-like component one could speculate about the existence of different pathogenetic backgrounds behind the two diagnoses.

 

Source: Evengård B, Jonzon E, Sandberg A, Theorell T, Lindh G. Differences between patients with chronic fatigue syndrome and with chronic fatigue at an infectious disease clinic in Stockholm, Sweden. Psychiatry Clin Neurosci. 2003 Aug;57(4):361-8. http://onlinelibrary.wiley.com/doi/10.1046/j.1440-1819.2003.01132.x/full (Full article)

 

Comparing symptoms of chronic fatigue syndrome in a community-based versus tertiary care sample

Abstract:

Chronic Fatigue Syndrome (CFS) is a debilitating condition characterized by six or more months of prolonged or relapsing, unexplained fatigue of new or definite onset and at least four of eight associated somatic and cognitive symptoms. Almost all studies of samples with patients with CFS have relied on referrals from physicians or health facilities.

Underserved minorities, who not only tend to manifest higher levels of chronic illness, but are also less likely to seek and receive adequate medical care, have not been adequately represented in these studies. The present study compared two groups of individuals with CFS, one from a community-based sample and another from a tertiary-based sample. Findings indicate that patients with CFS from tertiary care settings have a higher frequency of symptoms than those in the general population who have CFS.

 

Source: Jason LA, Plioplys AV, Torres-Harding S, Corradi K. Comparing symptoms of chronic fatigue syndrome in a community-based versus tertiary care sample. J Health Psychol. 2003 Jul;8(4):459-64. http://www.ncbi.nlm.nih.gov/pubmed/19127712

 

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

 

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)

 

Prognosis of chronic fatigue in a community-based sample

Abstract:

OBJECTIVE: This study examined predictors of fatigue severity and predictors of continued chronic fatigue status at wave 2 follow-up within a random, community-based sample of individuals previously evaluated in a wave 1 prevalence study of chronic fatigue and chronic fatigue syndrome that originally took place between 1995 and 1997.

METHODS: Wave 1 data were from a larger community-based prevalence study of chronic fatigue syndrome. In the present study, a second wave of data were collected by randomly selecting a sample of participants from the wave 1 sample of 18,675 adults and readministering a telephone screening questionnaire designed to assess symptoms of chronic fatigue syndrome.

RESULTS: Findings revealed that wave 1 fatigue severity was a predictor of fatigue severity at wave 2 in the overall sample of individuals with and without chronic fatigue. In the smaller sample of individuals with chronic fatigue, wave 1 fatigue severity, worsening of fatigue with physical exertion, and feeling worse for 24 hours or more after exercise significantly predicted continued chronic fatigue status (vs. improvement) at wave 2 follow-up.

CONCLUSIONS: These findings underscore the prognostic validity of postexertional malaise in predicting long-term chronic fatigue and also highlight the importance of using population-based, representative random samples when attempting to identify long-term predictors of chronic fatigue at follow-up.

 

Source: Taylor RR, Jason LA, Curie CJ. Prognosis of chronic fatigue in a community-based sample. Psychosom Med. 2002 Mar-Apr;64(2):319-27. http://www.ncbi.nlm.nih.gov/pubmed/11914449

 

Predictions and associations of fatigue syndromes and mood disorders that occur after infectious mononucleosis

Abstract:

BACKGROUND: Certain infections can trigger chronic fatigue syndromes (CFS) in a minority of people infected, but the reason is unknown. We describe some factors that predict or are associated with prolonged fatigue after infectious mononucleosis and contrast these factors with those that predicted mood disorders after the same infection.

METHODS: We prospectively studied a cohort of 250 primary-care patients with infectious mononucleosis or ordinary upper-respiratory-tract infections until 6 months after clinical onset. We sought predictors of both acute and chronic fatigue syndromes and mood disorders from clinical, laboratory, and psychosocial measures.

FINDINGS: An empirically defined fatigue syndrome 6 months after onset, which excluded comorbid psychiatric disorders, was most reliably predicted by a positive Monospot test at onset (odds ratio 2.1 [95% CI 1.4-3.3]) and lower physical fitness (0.35 [0.15-0.8]). Cervical lymphadenopathy and initial bed rest were associated with, or predicted, a fatigue syndrome up to 2 months after onset. By contrast, mood disorders were predicted by a premorbid psychiatric history (2.3 [1.4-3.9]), an emotional personality score (1.21 [1.11-1.35]), and social adversity (1.7 [1.0-2.9]). Definitions of CFS that included comorbid mood disorders were predicted by a mixture of those factors that predicted either the empirically defined fatigue syndrome or mood disorders.

INTERPRETATION: The predictors of a prolonged fatigue syndrome after an infection differ with both definition and time, depending particularly on the presence or absence of comorbid mood disorders. The particular infection and its consequent immune reaction may have an early role, but physical deconditioning may also be important. By contrast, mood disorders are predicted by factors that predict mood disorders in general.

 

Source: White PD, Thomas JM, Kangro HO, Bruce-Jones WD, Amess J, Crawford DH, Grover SA, Clare AW. Predictions and associations of fatigue syndromes and mood disorders that occur after infectious mononucleosis. Lancet. 2001 Dec 8;358(9297):1946-54. http://www.ncbi.nlm.nih.gov/pubmed/11747919

 

Sexual abuse, physical abuse, chronic fatigue, and chronic fatigue syndrome: a community-based study

Abstract:

Using a randomly selected community-based sample, this investigation examined whether histories of childhood sexual, physical, and death threat abuse predicted adulthood outcomes of specific medical and psychiatric conditions involving chronic fatigue. This study also tested prior suggestions that most individuals with chronic fatigue syndrome report a past history of interpersonal abuse.

Multinomial logistic regression was used to examine the relationship between abuse history and chronic fatigue group outcomes while controlling for the effects of sociodemographics. Compared with healthy controls, childhood sexual abuse was significantly more likely to be associated with outcomes of idiopathic chronic fatigue, chronic fatigue explained by a psychiatric condition, and chronic fatigue explained by a medical condition. None of the abuse history types were significant predictors of chronic fatigue syndrome.

A closer examination of individuals in the chronic fatigue syndrome group revealed that significantly fewer individuals with CFS reported abuse as compared with those who did not. The implications of these findings are discussed.

 

Source: Taylor RR, Jason LA. Sexual abuse, physical abuse, chronic fatigue, and chronic fatigue syndrome: a community-based study. J Nerv Ment Dis. 2001 Oct;189(10):709-15. http://www.ncbi.nlm.nih.gov/pubmed/11708672

 

A community-based study of seasonal variation in the onset of chronic fatigue syndrome and idiopathic chronic fatigue

Abstract:

One proposed hypothesis regarding the etiology of chronic fatigue syndrome (CFS) is that there is a subgroup of patients in which symptom onset is precipitated by a viral infection. If this is indeed true, then one would anticipate a greater incidence of the emergence of CFS symptoms during months when viral infections occur with the greatest frequency. The current community-based epidemiology study examined the month of symptom onset for 31 patients with CFS and 44 others with idiopathic chronic fatigue (ICF). It was determined that the distribution of the month of illness onset for the CFS and ICF groups was nonrandom, with greater numbers of participants than expected reporting an onset of CFS and ICF during January.

 

Source: Jason LA, Taylor RR, Carrico AW. A community-based study of seasonal variation in the onset of chronic fatigue syndrome and idiopathic chronic fatigue. Chronobiol Int. 2001 Mar;18(2):315-9. http://www.ncbi.nlm.nih.gov/pubmed/11379670

 

On the epidemiology of ‘mysterious’ phenomena

Abstract:

In the field of epidemiology, research topics are favored or dismissed depending on whether respective variables under investigation are believed to exist according to current scientific theories. Unconventional independent variables or exposures, such as religiousness and spirituality, and controversial dependent variables or outcomes, such as chronic fatigue syndrome, may be considered unacceptable topics for researchers because they do not fit comfortably into the consensus clinical perspectives of mainstream medical scientists or physicians.

Disapproval of research in these and other taboo areas is generally masked by claims that such studies are “pseudoscientific,” despite hundreds or thousands of peer-reviewed publications on these topics. In reality, seemingly “mysterious” variables are equally as amenable to epidemiologic research as any other exposure or disease. Similarly, alternative therapies are able to be investigated using existing methods, despite claims to the contrary. Such research is vital for scientific understanding to be expanded into new areas of inquiry.

 

Source: Levin J, Steele L. On the epidemiology of ‘mysterious’ phenomena. Altern Ther Health Med. 2001 Jan;7(1):64-6. http://www.ncbi.nlm.nih.gov/pubmed/11191044