Vernia P, Camillo M Di, Marinaro V, Caprilli R
Cattedra di Gastroenterologia 1, Dipartimento Scienze Cliniche, Università di Roma 'La Sapienza', Rome, Italy.
Eur J Clin Nutr. 2003 Sep;57(9):1116-9. doi: 10.1038/sj.ejcn.1601651.
The relationship between hydrogen and methane production is a possible confounding factor in the interpretation of H(2) breath tests (HBT), but is usually disregarded for the interpretation of HBT and, in most instances, only H(2) excretion is measured. The present study was designed to evaluate the effect of predominant fasting methane CH(4) or H(2) production on the outcome of lactose HBT, in a large, homogeneous series of adult patients with irritable bowel syndrome (IBS).
A lactose HBT was performed in 237 IBS patients with predominant fasting methane production (CH(4)>H(2)), recording the outcome of the test, amount of gas excreted and occurrence of clinical symptoms. Data were compared to those of 237 age- and sex-matched IBS patients with low fasting CH(4) excretion.
The test was positive in 124 predominant CH(4) producers (52.3%) (PMP), as compared to 201 (84.8%) low methane producers (LMP) (P<0.0001). Peak hydrogen concentration and area under the curve of H(2) were significantly (P<0.001) lower, and the occurrence of symptoms during the test less frequent, in PMP vs LMP patients. During the test, CH(4) excretion doubled in 57/113 (50.4%) patients with negative HBT, and in 49/124 (39.5%) with positive HBT.
Patients with predominant fasting methane production excrete less H(2) than LMP, after an oral load of lactose. The lower prevalence of severe lactose intolerance in PMP, as well as lower incidence of symptoms during the test, is, indeed, related to lower and slower H(2) excretion. The assumption that H(2) excretion is an effective means of quantifying the amount of malabsorbed carbohydrates is questionable in PMP. Methane-producing patients likely have a higher 'false negative' rate as compared to LMP after an oral load of lactose. Nonetheless, as symptoms are related to the amount of gas produced in the colon, HBT identifies patients with 'lactose intolerance', irrespective of the presence of lactose malabsorption, and helps in predicting the effect of lactose-restricted diet.
氢气与甲烷产生之间的关系是氢呼气试验（HBT）解读中一个可能的混杂因素，但在HBT解读中通常被忽视，而且在大多数情况下，仅测量氢气排泄量。本研究旨在评估在大量、同质的成年肠易激综合征（IBS）患者中，空腹时主要产生甲烷（CH₄）或氢气对乳糖HBT结果的影响。
对237例空腹时主要产生甲烷（CH₄＞H₂）的IBS患者进行乳糖HBT，记录试验结果、气体排泄量及临床症状的发生情况。将数据与237例年龄和性别匹配、空腹CH₄排泄量低的IBS患者的数据进行比较。
124例主要产生CH₄的患者（52.3%）（PMP）试验呈阳性，而201例低甲烷产生者（LMP）（84.8%）试验呈阳性（P＜0.0001）。与LMP患者相比，PMP患者的氢气峰值浓度和氢气曲线下面积显著更低（P＜0.001），且试验期间症状出现频率更低。在试验期间，113例HBT阴性患者中有57例（50.4%）CH₄排泄量翻倍，124例HBT阳性患者中有49例（39.5%）CH₄排泄量翻倍。
口服乳糖后，空腹时主要产生甲烷的患者比LMP患者排泄的氢气更少。PMP中严重乳糖不耐受的患病率较低，以及试验期间症状发生率较低，确实与氢气排泄量较低和排泄速度较慢有关。在PMP中，认为氢气排泄是量化碳水化合物吸收不良量的有效方法这一假设值得怀疑。口服乳糖后，与LMP相比，产甲烷患者可能有更高的“假阴性”率。尽管如此，由于症状与结肠中产生的气体量有关，HBT可识别出“乳糖不耐受”患者，而不论是否存在乳糖吸收不良，并有助于预测限制乳糖饮食的效果。
