Document Detail

Lactose malabsorption in the elderly: role of small intestinal bacterial overgrowth.
MedLine Citation:
PMID:  18224561     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: The prevalence of lactose malabsorption (LM) is increased in the elderly, although the mechanisms responsible are still a matter of speculation. The objective of this study was to investigate the possible roles of reduced functional small intestinal absorptive area, lactase deficiency and small intestinal bacterial overgrowth (SIBO). MATERIAL AND METHODS: Twenty Caucasian (Anglo-Celtic), asymptomatic, well-nourished, elderly volunteers (median age 79 years, range 70-94 years) with no clinically apparent predisposition to SIBO underwent a 50 g lactose breath hydrogen test (LBHT) and mannitol absorption test, the latter as an index of functional small intestinal absorptive area. Those with LM additionally underwent bacteriological assessment of small intestinal secretions and mucosal biopsy, to assess the contribution of SIBO and lactase deficiency, respectively, to the pathogenesis of LM in individual cases. The prevalence of SIBO was also determined in elderly subjects without LM. Twenty asymptomatic younger subjects (median age 29 years, age range 18-35 years) served as controls. All subjects were "hydrogen producers" in response to lactulose. RESULTS: LM was evident in 10/20 (50%) elderly subjects and 1/20 (5%) younger subjects (p=0.003). Mannitol absorption did not differ significantly in elderly and younger subjects or in elderly subjects with and without LM. SIBO was documented in 9/10 (90%) elderly subjects with LM; eradication was associated with resolution of LM. Lactase deficiency was evident in only one elderly subject with LM. SIBO was evident in 2/10 (20%) elderly subjects without LM (p=0.005 compared to those with LM). Lactulose breath hydrogen test identified only 2/11 (18%) elderly subjects with SIBO. CONCLUSIONS: Increased prevalence of LM in the elderly is mostly due to clinically non-apparent SIBO, rather than mucosal factors. The lactulose breath hydrogen test cannot be relied upon to identify elderly subjects with SIBO, even in those without an anatomical predisposition.
John A Almeida; Robert Kim; Alina Stoita; Christopher J McIver; Jelica Kurtovic; Stephen M Riordan
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Scandinavian journal of gastroenterology     Volume:  43     ISSN:  0036-5521     ISO Abbreviation:  Scand. J. Gastroenterol.     Publication Date:  2008  
Date Detail:
Created Date:  2008-01-28     Completed Date:  2008-05-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0060105     Medline TA:  Scand J Gastroenterol     Country:  Norway    
Other Details:
Languages:  eng     Pagination:  146-54     Citation Subset:  IM    
Gastrointestinal and Liver Unit, The Prince of Wales Hospital and University of New South Wales, Sydney, Australia.
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MeSH Terms
Age Distribution
Aged, 80 and over
Breath Tests
Hydrogen / metabolism
Intestinal Mucosa / metabolism,  microbiology
Intestine, Small / metabolism,  microbiology*
Lactase / deficiency
Lactose / diagnostic use*,  pharmacokinetics
Lactulose / diagnostic use
Malabsorption Syndromes / diagnosis,  epidemiology,  metabolism*,  microbiology*
Mannitol / pharmacokinetics
Reproducibility of Results
Reg. No./Substance:
1333-74-0/Hydrogen; 4618-18-2/Lactulose; 63-42-3/Lactose; 69-65-8/Mannitol; EC

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