Notes on the kelp shell, Cantharidus irisodontes

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Risk factors for chronic fatigue syndrome: A case-control study

Objective: To study various risk factors previously reported to be associated with chronic fatigue syndrome (CFS). Design: Case-control study. Setting: Metropolitan Atlanta CFS surveillance registry consisting of physicians and clinics that evaluate patients with fatiguing illness. Patients: Twenty-five CFS patients identified from the Centers for Disease Control and Prevention, Atlanta CFS study site, were matched by race, sex, and age to two randomly selected controls. Cases were further subgrouped by type of illness onset-sudden, occurring within a few days, or gradual, occurring over a longer time period. Main outcome measures: A broad panel of risk factors previously associated with CFS. Results: CFS patients were significantly more likely than controls to report a history of stress, persistent nasal symptoms, ear infections, and ingestion of B-complex vitamins during the year prior to the case's onset of illness. In addition, women patients were significantly more likely to have had a hysterectomy. The subset of patients (n = 17) who reported a gradual onset were significantly more likely than patients reporting a sudden onset of illness or controls to report stressful events in the year prior to onset, certain dental procedures, sinusitis, exposures to herbicides, pesticides, or insecticides, and a history of hysterectomy. We could not confirm previously reported associations of CFS with a history of asthma or eczema; exposure to sick animals; exposure to solvents, paint, or other chemicals; ingestion of raw- milk; or travel, occupation, or recreational activity. Conclusions: While no risk factors were identified that effectively distinguish CFS cases from controls, the data do suggest that gradual and sudden onset CFS constitute distinct subclasses of the syndrome. Future studies should subgroup patients based on type of illness onset and further evaluate risk factors of interest, focusing on the role of stress, exposure to herbicides, pesticides, insecticides, and dental and medical histories.Link_to_subscribed_fulltex

Surveillance for Chronic Fatigue Syndrome - Four U.S. Cities, September 1989 Through August 1993

Problem/Condition: Although chronic fatigue syndrome (CFS) has been recognized as a cause of morbidity in the United States, the etiology of CFS is unknown. In addition, information is incomplete concerning the clinical spectrum and prevalence of CFS in the United States. Reporting Period Covered: This report summarizes CFS surveillance data collected in four U.S. cities from September 1989 through August 1993. Description of System: A physician-based surveillance system for CFS was established in four U.S. metropolitan areas: Atlanta, Georgia; Wichita, Kansas; Grand Rapids, Michigan; and Reno, Nevada. The objectives of this surveillance system were to collect descriptive epidemiologic information from patients who had unexplained chronic fatigue, estimate the prevalence and incidence of CFS in defined populations, and describe the clinical course of CFS. Patients aged ≥18 years who had had unexplained, debilitating fatigue or chronic unwellness for at least 6 months were referred by their physicians to a designated health professional(s) in their area. Those patients who participated in the surveillance system a) were interviewed by the health professional(s); b) completed a self-administered questionnaire that included their demographic information, medical history, and responses to the Beck Depression Inventory, the Diagnostic Interview Schedule, and the Sickness Impact Profile; c) submitted blood and urine samples for laboratory testing; and d) agreed to a review of their medical records. On the basis of this information, patients were assigned to one of four groups: those whose illnesses met the criteria of the 1988 CFS case definition (Group I); those whose fatigue or symptoms did not meet the criteria for CFS (Group II); those who had had an identifiable psychological disorder before onset of fatigue (Group III); and those who had evidence of other medical conditions that could have caused fatigue (Group IV). Patients assigned to Group III were further evaluated to determine the group to which they would have been assigned had psychological illness not been present. The epidemiologic characteristics of the illness and the frequency of symptoms among patients were evaluated, and the prevalence and incidence of CFS were estimated for each of the areas. Results: Of the 648 patients referred to the CFS surveillance system, 565 (87%) agreed to participate. Of these, 130 (23%) were assigned to Group I; 99 (18%), Group II; 235 (42%), Group III; and 101 (18%), Group IV. Of the 130 CFS patients, 125 (96%) were white and 111 (85%) were women. The mean age of CFS patients at the onset of illness was 30 years, and the mean duration of illness at the time of the interview was 6.7 years Most (96%) CFS patients had completed high school, and 38% had graduated from college. The median annual household income for CFS patients was $40,000. In the four cities, the age-, sex-, and race-adjusted prevalences of CFS for the 4-year surveillance period ranged from 4.0 to 8.7 per 100,000 population. The age-adjusted 4-year prevalences of CFS among white women ranged from 8.8 to 19.5 per 100,000 population. Interpretation: The results of this surveillance system were similar to those in previously published reports of CFS. Additional studies should be directed toward determining whether the data collected in this surveillance system were subject to selection bias (e.g., education and income levels might have influenced usage of the health-care system, and the populations of these four surveillance sites might not be representative of the U.S. population). Actions Taken: In February 1997, CDC began a large-scale, cross-sectional study at one surveillance site (Wichita) to describe more completely the magnitude and epidemiology of unexplained chronic fatigue and CFS.Link_to_subscribed_fulltex