Document Detail

Diagnosis of lactose intolerance and the "nocebo" effect: the role of negative expectations.
MedLine Citation:
PMID:  20227928     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Diagnosis of lactose intolerance is based on a "positive" H(2) breath test associated with abdominal symptoms. The present study established to what extent the occurrence of symptoms during a "negative" H(2) breath test may result from a "nocebo effect" instead of lack of sensitivity of the procedure.
METHODS: Between 2005 and 2007, 636 outpatients performed a standard 4-h 25g lactose tolerance test. The test was positive in 254, negative in 325, and 57 patients were H(2) "non-producers". Twenty-seven patients reporting symptoms despite a negative H(2) breath test underwent a "sham" breath test following ingestion of 1g of glucose. Fifty-four patients presenting with documented lactose intolerance were used as controls.
RESULTS: Twelve out of 27 patients (44.4%), and unexpectedly also 14 (25.9%) controls presented abdominal symptoms during the sham test. The difference between the two groups was not significant (P<0.15) OR 2.28; C.I. 0.77-6.78.
CONCLUSION: In most instances, symptoms reported by patients during a negative lactose H(2)BT cannot be attributed to a false-negative test. Instead, a non-organic component, resulting from negative expectations ("nocebo effect") is likely implicated. Moreover, also in patients diagnosed as lactose intolerant, the need for restricting the primary source of dietary calcium should be critically reconsidered.
Piero Vernia; Mauro Di Camillo; Tiziana Foglietta; Veronica E Avallone; Aurora De Carolis
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Publication Detail:
Type:  Journal Article     Date:  2010-03-15
Journal Detail:
Title:  Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver     Volume:  42     ISSN:  1878-3562     ISO Abbreviation:  Dig Liver Dis     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-08-03     Completed Date:  2010-11-29     Revised Date:  2010-12-28    
Medline Journal Info:
Nlm Unique ID:  100958385     Medline TA:  Dig Liver Dis     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  616-9     Citation Subset:  IM    
Copyright Information:
Copyright (c) 2010 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.
Gastroenterologia A, Dipartimento di Scienze Cliniche, Sapienza Università di Roma, Viale del Policlinico, 00161 Roma, Italy.
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MeSH Terms
Breath Tests / methods
Case-Control Studies
Hydrogen / analysis*
Lactose Intolerance / diagnosis*
Middle Aged
Young Adult
Reg. No./Substance:
Comment In:
Dig Liver Dis. 2011 Jan;43(1):86; author reply 86-7   [PMID:  20620123 ]

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