title: Eosinophilia-myalgia syndrome in patients ingesting a single source of L-tryptophan.
abstract: OBJECTIVE
  To estimate the attack rate for eosinophilia-myalgia syndrome and to identify potential risk factors for illness among patients attending a New York City medical clinic, who purchased L-tryptophan containing products produced exclusively by Showa Denko K.K.
  
  
  METHODS
  A case-control design was used. Cases and controls purchased L-tryptophan containing products at the medical clinic from July 1, 1989--December 1, 1989. All case-patients identified with illness onset during the study period were included. Controls were selected by a systematic sample of the 683 purchasers of L-tryptophan attending the same clinic.
  
  
  RESULTS
  Twelve (2.2%) of an estimated 553 L-tryptophan users were case-patients. Multivariate analysis suggested that lot 2 use (adjusted odds ratio [OR] = 35.9), concomitant use of chromium (adjusted OR = 12.3), and concomitant use of pyridoxine (adjusted OR = 5.8) were associated with the development of illness. Chemical analysis of tablets corresponding to the 3 Showa Denko K.K. lots ingested by study participants showed that lot 2 had the highest concentration of ethylidenebis (L-tryptophan), a proposed causative agent or marker for a causative agent in the eosinophilia-myalgia syndrome.
  
  
  CONCLUSIONS
  Information from our study of persons exposed to implicated L-tryptophan supports the role for a contaminant as the causative agent in the eosinophilia-myalgia syndrome and identifies possible cofactors that deserve further study.
authors: Division of Field Epidemiology, Centers for Disease Control, Atlanta, GA.
authors: K J
authors: KJ
authors: Henning
authors: E
authors: E
authors: Jean-Baptiste
authors: T
authors: T
authors: Singh
authors: R H
authors: RH
authors: Hill
authors: S M
authors: SM
authors: Friedman
mesh_terms: D016022:Case-Control Studies; D002857:Chromium / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D016603:Eosinophilia-Myalgia Syndrome / Q000139:chemically induced* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009519:New York City / Q000453:epidemiology; D011736:Pyridoxine / Q000009:adverse effects; D012307:Risk Factors; D014364:Tryptophan / Q000009:adverse effects*
chemical_list: D002857:Chromium; D014364:Tryptophan; D011736:Pyridoxine