The role of small intestinal bacterial overgrowth and false positive diagnosis of lactose intolerance in southwest Hungary-A retrospective observational study

PLoS One. 2020 May 8;15(5):e0230784. doi: 10.1371/journal.pone.0230784. eCollection 2020.

Abstract

Background: Lactose intolerance is a frequent gastrointestinal disease affecting 47% of the Eastern European population. Small intestinal bacterial overgrowth (SIBO) leads to carbohydrate malabsorption and therefore to false results during lactose breath and tolerance tests.

Objectives: We aimed to assess the prevalence of lactose maldigestion and intolerance in Hungary and to investigate the role of combined diagnostic method and testing for SIBO in reducing false results.

Methods: We retrospectively analyzed data from 264 adult symptomatic patients who underwent 50g lactose breath and tolerance tests in parallel over a one-year period at our center. A ≥20 ppm elevation of H2 or less than 1.1 mmol/l rise of blood glucose was diagnostic for lactose maldigestion. Patients with maldigestion who had symptoms during the test were defined as lactose intolerant. Patients with an early (≤90 min) significant (≥20 ppm) rise of H2 during lactose and/or lactulose breath tests were determined to have SIBO. Patients with slow/rapid oro-cecal transit and inappropriate preparation before the test were excluded.

Results: 49.6% of the 264 patients had lactose maldigestion, and 29.5% had lactose intolerance. The most frequent symptom was bloating (22.7%), while 34.8% of the study population and 60% of the symptomatic patients had SIBO. In 9.1% and 9.8% of the patients, the lactose breath and tolerance test alone gave false positive result compared with the combined method. SIBO was present in 75% of the false positives diagnosed with breath test only.

Conclusions: The prevalence of lactose intolerance is lower in Hungary compared to the Eastern European value (29.5% vs 47%), so it is worth performing a population-based prospective analysis in this area. A combination of lactose breath and tolerance tests and the careful monitoring of results (with early H2 rise, lactulose breath test, etc.) can decrease the false cases caused by e.g. SIBO.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bacterial Infections / diagnosis*
  • Bacterial Infections / epidemiology
  • Bacterial Infections / microbiology
  • Bacterial Infections / pathology
  • Breath Tests
  • False Positive Reactions
  • Female
  • Gastrointestinal Tract / microbiology
  • Humans
  • Hungary / epidemiology
  • Hydrogen
  • Intestine, Small / microbiology*
  • Irritable Bowel Syndrome / diagnosis*
  • Irritable Bowel Syndrome / epidemiology
  • Irritable Bowel Syndrome / microbiology
  • Irritable Bowel Syndrome / pathology
  • Lactose / administration & dosage
  • Lactose Intolerance / diagnosis*
  • Lactose Intolerance / epidemiology
  • Lactose Intolerance / microbiology
  • Lactose Intolerance / pathology
  • Male
  • Middle Aged
  • Prospective Studies

Substances

  • Hydrogen
  • Lactose

Grants and funding

This work was funded by: Emberi Erőforrás Fejlesztési Operatív Program (EFOP), EFOP-3.6.2-16-2017-0006 and EFOP-3.6.3-VEKOP (Versenyképes Közép-Magyarország Operatív Program) -16-2017-00009. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.