Gastroenterology Unit, Department of Internal Medicine, University of Genoa, Genoa, Italy.
J Gastrointestin Liver Dis. 2012 Jun;21(2):157-63.
Modifications of intestinal gas due to changes in microbiota may produce different symptoms. Our aim was to assess whether different patterns of hydrogen (H₂) and methane (CH₄) excretion were related to some intestinal disturbances.
Six hundred and twenty-nine consecutive patients underwent a 50 g-glucose breath test (GBT) on account of intestinal symptoms, which were evaluated by means of a questionnaire. "H₂-producers" and "CH₄-producers" were defined as with the presence of H₂ peak >12 ppm more than the basal sample and mean CH₄ excretion of 2 ppm, respectively. Forty healthy subjects were studied as controls.
A small intestinal bacterial overgrowth was found in 45 cases (7.2%) and was associated with older age (p=0.0122). Methane production occurred in 32.3% of the study population. Methane excretion was strictly related to chronic constipation (p<0.001). Median CH₄ excretion was higher in constipated patients compared with patients with normal daily stools (p=0.0406) and even more with patients complaining of diarrhea (p=0.0011). Different criteria for defining "methane-producers" provided similar results. Mean methane excretion of "methane producers" was 30.3 ppm in functional constipation and 21.5 ppm in constipation-irritable bowel syndrome (C-IBS) (p=0.0458).
Methane excretion is clearly associated with alterations in intestinal motility, particularly favouring those with constipation. Mean methane excretion was higher in subjects suffering from functional constipation than C-IBS. Mean methane excretion ≥ 2 ppm appears to be an appropriate term to define "methane-producers".
肠道菌群变化导致的肠道气体改变可能产生不同的症状。我们的目的是评估不同的氢气（H₂）和甲烷（CH₄）排泄模式是否与某些肠道紊乱有关。
629 例连续患者因肠道症状接受 50 克葡萄糖呼气试验（GBT），并通过问卷进行评估。“H₂产生者”和“CH₄产生者”的定义分别为 H₂峰值比基础样本高 12 ppm 以上和平均 CH₄排泄量为 2 ppm。40 名健康受试者作为对照进行研究。
45 例（7.2%）发现小肠细菌过度生长，与年龄较大有关（p=0.0122）。甲烷产生发生在研究人群的 32.3%。甲烷排泄与慢性便秘密切相关（p<0.001）。与每日排便正常的患者相比，便秘患者的 CH₄排泄中位数更高（p=0.0406），与腹泻患者相比更高（p=0.0011）。定义“甲烷产生者”的不同标准提供了类似的结果。功能性便秘患者的平均甲烷排泄为 30.3 ppm，便秘-肠易激综合征（C-IBS）患者为 21.5 ppm（p=0.0458）。
甲烷排泄显然与肠道运动的改变有关，特别是有利于便秘的患者。功能性便秘患者的平均甲烷排泄高于 C-IBS。甲烷排泄平均值≥2 ppm 似乎是定义“甲烷产生者”的合适术语。
