title: Impact of vitamin A on selected gastrointestinal pathogen infections and associated diarrheal episodes among children in Mexico City, Mexico.
abstract: BACKGROUND
  The overall effect of vitamin A supplementation on diarrheal disease in community trials may result from its effect on specific diarrheal pathogens.
  
  
  METHODS
  We conducted a placebo-controlled, double-blind trial of the prophylactic effect of vitamin A on gastrointestinal pathogen infections and clinical symptoms among 188 children in Mexico City, Mexico, from January 1998 to May 1999. Children 6-15 months of age were randomly assigned to receive either a vitamin A supplement (for children <12 months of age, 20,000 international units [IU] of retinol; for children > or =12 months of age, 45,000 IU of retinol) every 2 months or a placebo and were followed for up to 15 months. Stool samples, collected semimonthly, were screened for enteropathogenic Escherichia coli (EPEC), enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), and Giardia lamblia.
  
  
  RESULTS
  Vitamin A supplementation reduced the prevalence of EPEC infections (rate ratio [RR], 0.52 [95% confidence interval {CI}, 0.23-0.86]) and led to shorter durations of both EPEC and ETEC infections. Supplementation also reduced the prevalence of EPEC-associated diarrhea (RR, 0.41 [95% CI, 0.16-1.00]), EPEC-associated fever (RR, 0.15 [95% CI, 0.02-0.98]), and G. lamblia-associated fever (RR, 0.27 [95% CI, 0.13-0.80]). Finally, children who received vitamin A supplementation had shorter durations of EPEC-associated diarrhea than did children who did not receive supplementation but had longer durations of G. lamblia-associated diarrhea.
  
  
  CONCLUSIONS
  These results suggest that the effect of vitamin A supplementation on clinical outcomes may be pathogen dependent.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA. klong@hsph.harvard.edu
authors.forename: Kurt Z
authors.initials: KZ
authors.lastname: Long
authors.forename: Jose Ignacio
authors.initials: JI
authors.lastname: Santos
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Rosado
authors.forename: Catalina
authors.initials: C
authors.lastname: Lopez-Saucedo
authors.forename: Rocio
authors.initials: R
authors.lastname: Thompson-Bonilla
authors.forename: Maricela
authors.initials: M
authors.lastname: Abonce
authors.forename: Herbert L
authors.initials: HL
authors.lastname: DuPont
authors.forename: Ellen
authors.initials: E
authors.lastname: Hertzmark
authors.forename: Teresa
authors.initials: T
authors.lastname: Estrada-Garcia
mesh_terms: D003967:Diarrhea / Q000188:drug therapy* / Q000382:microbiology / Q000517:prevention & control*; D004311:Double-Blind Method; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000517:prevention & control; D005260:Female; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*; D005873:Giardiasis / Q000188:drug therapy / Q000517:prevention & control; D006801:Humans; D007223:Infant; D008297:Male; D008800:Mexico / Q000453:epidemiology; D015995:Prevalence; D014801:Vitamin A / Q000627:therapeutic use*
chemical_list: D014801:Vitamin A