Hydrogen Breath Test - Diet and Basal H-2 Excretion: A Technical Note

Background: Hydrogen breath tests are widely used in clinical practice. For a correct evaluation of data, low basal H 2 excretion is required, thus, 12-hour fasting is usually prescribed. An additional reduction in the intake of complex carbohydrates in the preceding 24 h is suggested in some centers. The issue, however, has never been directly investigated. Aim: The aim of the present study was to analyze the effect of the pretest diet on the basal H 2 excretion and the number of subjects excluded from the test due to high basal H 2 excretion. Methods: Two cohorts of 500 consecutive patients undergoing a lactose tolerance test in the years 19971998 (when 12-hour fasting was required) and in 2007-2008 (when a low-carbohydrate diet in the preceding 24 h was also prescribed) were retrospectively reviewed. Results: The mean basal H 2 excretion was significantly lower (p < 0.0001) in the low-carbohydrate diet group (2.46 +/- 6.8 vs. 4.73 +/- 3.3 ppm). In 1997-1998, 46/500 patients (9.2%) were excluded from the test due to basal H 2 values as compared to 7/500 (1.4%) in the period 2007-2008. Discussion: To the best of our knowledge, ours is the first study to provide objective data on the advantage offered by reducing the intake of complex carbohydrates before H 2 breath tests. Copyright (C) 2010 S. Karger AG, Base

Factors affecting vitamin D deficiency in active inflammatory bowel diseases

Background: Hypovitaminosis D is prevalent in inflammatory bowel disease (IBD) and may be associated with disease activity. Aim: This study evaluated vitamin D (VitD) status in an Italian cohort of IBD patients, not taking VitD supplementation. We investigated risk factors for VitD deficiency and its correlation with disease activity. Methods: VitD levels were measured in 300 consecutive outpatients (42% with Crohn's Disease (CD) and 58% with ulcerative colitis (UC), 56% male) from a tertiary referral center. Data from the IBD cohort were compared with those of 234 healthy controls, matched by sex, age, and the month in which VitD levels were measured. Results: The mean VitD level in IBD patients was significantly lower than in controls (18.9 ng/ml vs. 25 ng/ml, p < 0.001) when accounting for gender, age, and season. VitD deficiency was present in 62% of IBD patients. Risk factors for deficiency were: age <40 and ≥60 years, winter, previous surgery, C-reactive protein (CRP) ≥0.5 mg/dl, and erythrocyte sedimentation rate ≥20 mm/h. In multivariate analysis, VitD levels were negatively influenced by disease location and CRP in UC. Conclusions: Although VitD deficiency was more prevalent than expected in healthy controls living in a Mediterranean country not at high risk of hypovitaminosis D, it was more common and severe in IBD patients. This study also found an association between VitD status and disease activit