Lactose malabsorption in the elderly: Role of small intestinal bacterial overgrowth
Lactose malabsorption in the elderly: Role of small intestinal bacterial overgrowth
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DOI：
10.1080/00365520701676617
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发表时间：
2008-01-01
影响因子：
1.9
通讯作者：
Riordan, Stephen M.
中科院分区：
文献类型：
--
作者：
Almeida, John A.;Kim, Robert;Riordan, Stephen M.
Objective.乳糖吸收不良（LM）的患病率在老年人中增加，尽管负责的机制仍然是一个猜测的问题。本研究的目的是探讨功能性小肠吸收面积减少、乳糖酶缺乏和小肠细菌过度生长（SIBO）的可能作用。材料和方法。20名无症状、营养良好、无临床明显SIBO倾向的老年白人志愿者（中位年龄79岁，范围70-94岁）接受了50 g乳糖呼气氢试验（LBHT）和甘露醇吸收试验，后者作为功能性小肠吸收面积的指标。LM患者还进行了小肠分泌物细菌学评估和粘膜活检，以评估SIBO和乳糖酶缺乏症对个别病例LM发病机制的贡献。在无LM的老年受试者中也确定了SIBO的患病率。20名无症状的年轻受试者（中位年龄29岁，年龄范围18-35岁）作为对照。所有受试者都是对乳果糖有反应的“产氢者”。结果LM在10/20（50%）老年受试者和1/20（5%）年轻受试者中明显（p=0.003）。甘露醇吸收在老年和年轻受试者或有和无LM的老年受试者中没有显著差异。9/10例（90%）老年LM受试者记录到SIBO;根除与LM消退相关。乳糖酶缺乏症是明显的，只有一个老年人与LM。在2/10例（20%）无LM的老年受试者中，SIBO明显（与LM受试者相比，p=0.005）。乳果糖呼气氢试验仅确定2/11（18%）老年受试者患有SIBO。结论.老年人LM患病率的增加主要是由于临床上不明显的SIBO，而不是粘膜因素。不能依赖乳果糖呼气氢试验来识别患有SIBO的老年受试者，即使在那些没有解剖学倾向的受试者中也是如此。
Objective. The prevalence of lactose malabsorption (LM) is increased in the elderly, although the mechanisms responsible are still a matter of speculation. The objective of this study was to investigate the possible roles of reduced functional small intestinal absorptive area, lactase deficiency and small intestinal bacterial overgrowth (SIBO). Material and methods. Twenty Caucasian (Anglo-Celtic), asymptomatic, well-nourished, elderly volunteers (median age 79 years, range 70-94 years) with no clinically apparent predisposition to SIBO underwent a 50 g lactose breath hydrogen test (LBHT) and mannitol absorption test, the latter as an index of functional small intestinal absorptive area. Those with LM additionally underwent bacteriological assessment of small intestinal secretions and mucosal biopsy, to assess the contribution of SIBO and lactase deficiency, respectively, to the pathogenesis of LM in individual cases. The prevalence of SIBO was also determined in elderly subjects without LM. Twenty asymptomatic younger subjects (median age 29 years, age range 18-35 years) served as controls. All subjects were "hydrogen producers" in response to lactulose. Results. LM was evident in 10/20 (50%) elderly subjects and 1/20 (5%) younger subjects (p=0.003). Mannitol absorption did not differ significantly in elderly and younger subjects or in elderly subjects with and without LM. SIBO was documented in 9/10 (90%) elderly subjects with LM; eradication was associated with resolution of LM. Lactase deficiency was evident in only one elderly subject with LM. SIBO was evident in 2/10 (20%) elderly subjects without LM (p=0.005 compared to those with LM). Lactulose breath hydrogen test identified only 2/11 (18%) elderly subjects with SIBO. Conclusions. Increased prevalence of LM in the elderly is mostly due to clinically non-apparent SIBO, rather than mucosal factors. The lactulose breath hydrogen test cannot be relied upon to identify elderly subjects with SIBO, even in those without an anatomical predisposition.