title: Varicella, ephemeral breastfeeding and eczema as risk factors for multiple sclerosis in Mexicans.
abstract: OBJECTIVE
  It has been suggested that the incidence of multiple sclerosis (MS) in Mexico and other countries of Latin America has increased steadily for the last two decades. We made a thorough search of antecedents on MS patients that could be potential risk factors.
  
  
  METHODS
  A case-control study was conducted using a questionnaire that included demographic, nutritional, infectious and personal antecedents previously identified in other reports as possible risk factors for MS.
  
  
  RESULTS
  The frequency of varicella, ephemeral breastfeeding and eczema in the medical history of MS patients were significant when compared with controls; all appeared to be mutually additive. However, they were unrelated with clinical characteristics or disease severity.
  
  
  CONCLUSIONS
  During the last decades, breastfeeding has been abandoned in large segments of society and the incidence of varicella and childhood eczema keeps a north-south gradient similar to that described for MS. These factors may participate in the sharp increase of MS in countries like Mexico traditionally considered as an area of very low incidence.
authors.affiliation: Neuroimmunology Unit, National Institute of Neurology and Neurosurgery of Mexico, Mexico City, Mexico.
authors.forename: R
authors.initials: R
authors.lastname: Tarrats
authors.forename: G
authors.initials: G
authors.lastname: Ordoñez
authors.forename: C
authors.initials: C
authors.lastname: Rios
authors.forename: J
authors.initials: J
authors.lastname: Sotelo
mesh_terms: D000818:Animals; D001942:Breast Feeding / Q000009:adverse effects*; D016022:Case-Control Studies; D002417:Cattle; D002644:Chickenpox / Q000150:complications*; D004485:Eczema / Q000150:complications*; D004810:Ephemeral Fever / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000209:etiology*; D012307:Risk Factors; D012720:Severity of Illness Index; D012959:Socioeconomic Factors