Section of Gastroenterology, Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK.
Gut. 2012 Mar;61(3):337-43. doi: 10.1136/gutjnl-2011-300633. Epub 2011 Aug 28.
The association between body mass index (BMI) and gastro-oesophageal pressure gradient (GOPG) is incompletely understood. We examined the association between BMI and gastro-oesophageal (GO) barrier function and the effect of mechanically increasing intra-abdominal pressure on GO physiology.
(A) 103 dyspeptic patients with normal endoscopy underwent 24 h pH-metry and upper gastrointestinal manometry. Relationships between BMI and acid reflux, intragastric pressure (IGP), GOPG and lower oesophageal sphincter (LOS) pressure were calculated using bivariate correlations. (B) In 18 healthy volunteers, the effects of increasing IGP by abdominal belt on GO manometry were studied.
(A) There was a linear correlation between BMI and oesophageal acid exposure in erect (R=0.35, p<0.001) and supine (R=0.40, p<0.001) positions. BMI was strongly associated with IGP (inspiration: R=0.66, p<0.001; expiration: R=0.78, p<0.001) and inspiratory GOPG (R=0.50, p<0.001). There were a positive correlation between BMI and inspiratory LOS pressure relative to atmospheric pressure (R=0.29, p=0.016) and a negative correlation with LOS pressure relative to IGP on expiration (R=-0.25, p=0.018). Logistic regression models using all significant manometric variables and relevant interactions revealed marked decline in the magnitude and significance of relationship between BMI and oesophageal acid exposure in supine (from OR 1.12 (95% CI 1.03 to 1.22), p=0.009, to 1.00 (0.86 to 1.17), p=0.999) and upright positions (from 1.11 (1.02 to 1.20), p=0.020, to 1.03 (0.89 to 1.18), p=0.717). (B) Application of the constricting abdominal belt produced similar manometric changes to those associated with increased BMI. However, the belt did not reproduce the reduced LOS pressure relative to IGP.
The association between reflux and BMI may be largely explained by effects of increased intra-abdominal pressure. However, the reduced LOS pressure associated with BMI may be mediated by another mechanism or effects of chronic rather than acute elevation of intra-abdominal pressure.
体质量指数（BMI）与胃食管压力梯度（GOPG）之间的关联尚不完全清楚。我们研究了 BMI 与胃食管（GO）屏障功能之间的关系，以及机械性增加腹腔内压力对 GO 生理学的影响。
（A）103 例内镜正常的消化不良患者接受了 24 小时 pH 监测和上消化道测压。使用双变量相关性计算 BMI 与酸反流、胃内压（IGP）、GOPG 和下食管括约肌（LOS）压力之间的关系。（B）在 18 名健康志愿者中，研究了通过腹部带增加 IGP 对 GO 测压的影响。
（A）BMI 与直立位（R=0.35，p<0.001）和仰卧位（R=0.40，p<0.001）时的食管酸暴露呈线性相关。BMI 与 IGP 强烈相关（吸气：R=0.66，p<0.001；呼气：R=0.78，p<0.001）和吸气性 GOPG（R=0.50，p<0.001）。BMI 与吸气时 LOS 压力相对于大气压呈正相关（R=0.29，p=0.016），与呼气时 LOS 压力相对于 IGP 呈负相关（R=-0.25，p=0.018）。使用所有显著的测压变量和相关相互作用的逻辑回归模型显示，仰卧位（从 OR 1.12（95%CI 1.03 至 1.22），p=0.009，至 1.00（0.86 至 1.17），p=0.999）和直立位（从 OR 1.11（1.02 至 1.20），p=0.020，至 1.03（0.89 至 1.18），p=0.717）时，BMI 与食管酸暴露之间的关系的幅度和显著性明显下降。（B）应用束腹带可产生与 BMI 增加相关的类似测压变化。然而，束腹带并不能复制 LOS 压力相对于 IGP 的降低。
反流与 BMI 之间的关系可能主要是由腹腔内压力升高的影响所解释。然而，与 BMI 相关的 LOS 压力降低可能通过另一种机制或慢性而不是急性腹腔内压力升高来介导。
