A number of environmental factors have been associated with the development of IBD. Alteration of the gut microbiota, or dysbiosis, is closely linked to initiation or progression of IBD, but whether dysbiosis is a primary or secondary event is unclear. Nevertheless, early-life events such as birth, breastfeeding and exposure to antibiotics, as well as later childhood events, are considered potential risk factors for IBD. Air pollution, a consequence of the progressive contamination of the environment by countless compounds, is another factor associated with IBD, as particulate matter or other components can alter the host's mucosal defences and trigger immune responses. Hypoxia associated with high altitude is also a factor under investigation as a potential new trigger of IBD flares. A key issue is how to translate environmental factors into mechanisms of IBD, and systems biology is increasingly recognized as a strategic tool to unravel the molecular alterations leading to IBD. Environmental factors add a substantial level of complexity to the understanding of IBD pathogenesis but also promote the fundamental notion that complex diseases such as IBD require complex therapies that go well beyond the current single-agent treatment approach. This Review describes the current conceptualization, evidence, progress and direction surrounding the association of environmental factors with IBD.

许多环境因素与IBD的发展有关。肠道菌群的改变或营养不良与IBD的发生或发展密切相关，但尚不清楚营养不良是原发还是继发事件。然而，早产事件如出生，母乳喂养和接触抗生素以及儿童后期事件被认为是IBD的潜在危险因素。空气污染是无数种化合物逐渐污染环境的结果，是与IBD相关的另一个因素，因为颗粒物或其他成分会改变宿主的粘膜防御能力并触发免疫反应。与高海拔相关的缺氧也是IBD耀斑潜在的新诱因，也正在研究中。关键问题是如何将环境因素转化为IBD的机制，而系统生物学已被越来越多地视为揭示导致IBD的分子变化的战略工具。环境因素大大增加了对IBD发病机理的理解的复杂性，但也提倡了以下基本观念：诸如IBD之类的复杂疾病需要复杂的疗法，远远超出了当前的单药治疗方法。这篇综述描述了围绕环境因素与IBD的关联的当前概念，证据，进展和方向。环境因素大大增加了对IBD发病机理的理解的复杂性，但也提倡了以下基本观念：诸如IBD之类的复杂疾病需要复杂的疗法，远远超出了当前的单药治疗方法。这篇综述描述了围绕环境因素与IBD的关联的当前概念，证据，进展和方向。环境因素大大增加了对IBD发病机理的理解的复杂性，但也提倡了以下基本观念：诸如IBD之类的复杂疾病需要复杂的疗法，远远超出了当前的单药治疗方法。这篇综述描述了围绕环境因素与IBD的关联的当前概念，证据，进展和方向。