Predisposing factors for positive D-Xylose breath test for evaluation of small intestinal bacterial overgrowth:A retrospective study of 932 patients

AIM: To investigate, in the largest cohort to date, patient characteristics and associated risk factors for developing small intestinal bacterial overgrowth(SIBO) using the D-Xylose breath test(XBT).METHODS: We performed a retrospective crosssectional study to analyze patient characteristics who underwent the XBT for evaluation of SIBO. Diagnostic testing with the XBT was performed based on a clinical suspicion for SIBO in patients with symptoms of bloating, abdominal pain, abdominal distension, weight loss, diarrhea, and/or constipation. Consecutive electronicmedical records of 932 patients who completed the XBT at the University of Florida between 2005 and 2009 were reviewed. A two-way Analysis of Variance(ANOVA) was used to test for several associations including age, gender, and body mass index(BMI) with a +XBT. A two-way ANOVA was also performed to control for the differences and interaction with age and between genders. A similar analysis was repeated for BMI. Associations between medical conditions and prior surgical histories were conducted using the Mantel-Haenszel method for 2 by 2 contingency tables, stratified for gender. Reported odds ratio estimates reflect the odds of the prevalence of a condition within the +XBT group to that of the-XBT group. P values of less than 0.05(two-sided) were considered statistically significant.RESULTS: In the 932 consecutive eligible subjects studied, 513 had a positive XBT. A positive association was found between female gender and a positive XBT(P = 0.0025), and females with a positive test were, on average, greater than 5 years older than those with a negative test(P = 0.024). The mean BMI of positive XBT subjects was normal(24.5) and significantly lower than the subjects with a negative XBT(29.5)(P = 0.0050). A positive XBT was associated with gastroesophageal reflux disease(GERD)(OR = 1.35; 95%CI: 1.02-1.80, P = 0.04), peptic ulcer disease(PUD)(OR = 2.61; 95%CI: 1.48-4.59, P < 0.01), gastroparesis(GP)(OR = 2.04; 95%CI: 1.21-3.41, P < 0.01) and steroid use(OR = 1.35; 95%CI: 1.02-1.80, P = 0.01). Irritable bowel syndrome, independent protonpump inhibitor(PPI) usage, or previous abdominal surgery was not significantly associated with a positive XBT. No single subdivision by gender or PPI use was associated with a significant difference in the odds ratios between any of the subsets. CONCLUSION: Female gender, lower BMI, steroid use, PUD, GERD(independent of PPI use), and GP were more prevalent in patients with SIBO, determined by a positive XBT. Increasing age was associated with SIBO in females, but not in males.

“双盲、安慰剂对照交叉设计研究植物药对于进食量、饱腹感、体重减轻及氧化应激的影响”的研究方案(英文)

背景:植物性治疗药物作为一种重要且尚未被完全开发的药用资源,可能有助于热量控制从而产生长期的减重功效。从藤黄果(Garcinia combogia Desr.)中提取的羟基柠檬酸可能通过影响与饱腹有关的神经通路而减少摄食量和减轻体重。方法与设计:本研究为双盲、安慰剂对照、交叉设计试验,共计划纳入48名超重或肥胖的健康受试者(体重指数25.0～39.9 kg/m^2,年龄50～70岁),研究两种剂量藤黄果来源的羟基柠檬酸对摄食量、饱腹感、体重减轻及氧化应激水平的影响。摄食量作为主要结局指标,根据受试者在测量日的早餐、午餐和晚餐的摄食量计算。与平行设计的研究相比,本研究所使用的受试者数量将大大减少。讨论:本研究选择藤黄果来源的羟基柠檬酸为研究对象是因为该药物能够安全地减少摄食量、减轻体重和降低氧化应激水平。我们将会在研究过程中探讨其可能的作用机制和安全指标。