title: Methane production and small intestinal bacterial overgrowth in children living in a slum.
abstract: OBJECTIVE
  To analyze small intestinal bacterial overgrowth in school-aged children and the relationship between hydrogen and methane production in breath tests.
  
  
  METHODS
  This transversal study included 85 children residing in a slum and 43 children from a private school, all aged between 6 and 10 years, in Osasco, Brazil. For characterization of the groups, data regarding the socioeconomic status and basic housing sanitary conditions were collected. Anthropometric data was obtained in children from both groups. All children completed the hydrogen (H(2)) and methane (CH(4)) breath test in order to assess small intestinal bacterial overgrowth (SIBO). SIBO was diagnosed when there was an increase in H(2) ≥ 20 ppm or CH(4) ≥ 10 ppm with regard to the fasting value until 60 min after lactulose ingestion.
  
  
  RESULTS
  Children from the slum group had worse living conditions and lower nutritional indices than children from the private school. SIBO was found in 30.9% (26/84) of the children from the slum group and in 2.4% (1/41) from the private school group (P = 0.0007). Greater hydrogen production in the small intestine was observed in children from the slum group when compared to children from the private school (P = 0.007). A higher concentration of hydrogen in the small intestine (P < 0.001) and in the colon (P < 0.001) was observed among the children from the slum group with SIBO when compared to children from the slum group without SIBO. Methane production was observed in 63.1% (53/84) of the children from the slum group and in 19.5% (8/41) of the children from the private school group (P < 0.0001). Methane production was observed in 38/58 (65.5%) of the children without SIBO and in 15/26 (57.7%) of the children with SIBO from the slum. Colonic production of hydrogen was lower in methane-producing children (P = 0.017).
  
  
  CONCLUSIONS
  Children who live in inadequate environmental conditions are at risk of bacterial overgrowth and methane production. Hydrogen is a substrate for methane production in the colon.
authors.affiliation: Pediatric Gastroenterology Division, Federal University of Sao Paulo, 04039-031 Sao Paulo, Brazil.
authors.forename: Carolina Santos
authors.initials: CS
authors.lastname: Mello
authors.forename: Soraia
authors.initials: S
authors.lastname: Tahan
authors.forename: Lígia Cristina F L
authors.initials: LC
authors.lastname: Melli
authors.forename: Mirian Silva do Carmo
authors.initials: MS
authors.lastname: Rodrigues
authors.forename: Ricardo Martin Pereira
authors.initials: RM
authors.lastname: de Mello
authors.forename: Isabel Cristina Affonso
authors.initials: IC
authors.lastname: Scaletsky
authors.forename: Mauro Batista
authors.initials: MB
authors.lastname: de Morais
mesh_terms: D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001765:Blind Loop Syndrome / Q000175:diagnosis / Q000378:metabolism / Q000382:microbiology*; D001938:Brazil; D001944:Breath Tests; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D007421:Intestine, Small / Q000382:microbiology*; D007792:Lactulose; D008297:Male; D008697:Methane / Q000378:metabolism*; D009752:Nutritional Status; D011204:Poverty Areas; D012924:Social Conditions
chemical_list: D015415:Biomarkers; D007792:Lactulose; D006859:Hydrogen; D008697:Methane
keywords: Bacterial overgrowth; Breath test; Children; Colon; Hydrogen; Methane; Small intestine