IngentaConnect Correlation between Symptoms and Gas Production in Lactose Intole...

Abstract:

Purpose: To correlate intestinal gas production with the intensity of symptoms experienced during a lactose breath test (LBT) and to evaluate the value of different symptoms in lactose malabsorption diagnosis as assessed by LBT, considered as the gold standard.

Design: A statistical correlation between symptoms and gas production, and the prevalence of symptoms in consecutive patients screened for lactose malabsorption.

Materials and Methods: All symptoms and their intensity during a 5 hour breath test after a 20 g oral lactose dose were recorded in 214 patients. A symptom score was calculated and correlated to the gases measured in expired air.

Results: The most frequently experienced symptoms were: bloating in 70.3% of patients with a pathological breath test and in 22.3% of patients with a normal breath test (p < 0.0005, odds ratio = 7.7); abdominal pain in 34.7% of patients with a pathological breath test and in 18.7% of patients with a normal breath test (p = 0.009, odds ratio = 2.7); headache in 11.9% of patients with a pathological breath test and in 9.4% of patients with a normal breath test (p = 0.3); nausea in 8.5% of patients with a pathological breath test and in 5.2% of patients with a normal breath test (p = 0.3); diarrhoea in 9.3% of patients with a pathological breath test and in 5.2% of patients with a normal breath test (p = 0.2). There was a low but significant correlation between hydrogen (H₂) production and symptoms (r = 0.37, p < 0.000005), but we found no correlation between methane (CH₄) production and symptoms. Bloating appearing within 5 hours after an oral lactose dose had a positive predictive value of 79% and a negative predictive value of 68% in breath test results.

Conclusions: Our results show that only H₂ but not CH₄ production correlates with symptoms after a 20 g lactose dose. A possible interpretation of these results is that the generation of symptoms is a complex process that involves not only gases but other bacterial fermentation products linked to H₂ but not to CH₄. Bloating within 5 hours of an oral lactose dose is a good predictor of LBT results.

Keywords: Lactose intolerance; colonic bacterial flora; intestinal gas; CO2; H2; CH4; breath test; abdominal symptoms

Document Type: Research article

DOI: 10.1080/135908403764731874

Affiliations: 1: Department of Gastroenterology and Internal Medicine, A.C.O. San Filippo Neri, Rome, Italy

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Correlation between Symptoms and Gas Production in Lactose Intolerant Subjects. Can Symptoms Predict a Diagnosis of Lactose Intolerance?