Van Ranst Marc, Joossens Marie, Joossens Sofie, Van Steen Kristel, Pierik Marieke, Vermeire Severine, Rutgeerts Paul
Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium.
Inflamm Bowel Dis. 2005 Jun;11(6):597-9. doi: 10.1097/01.mib.0000163697.34592.d4.
Environmental factors trigger the onset of inflammatory bowel disease (IBD) in genetically predisposed individuals. Exposure to seasonal external factors during the maturation of the immune system is suspected to be an inducing factor for IBD. Some studies suggested an association between the month of birth and the later development of IBD. We studied this putative relationship in a large cohort of Belgian patients with Crohn's disease (CD).
Data from 1025 patients born between 1935 and 1990 were collected. Diagnosis of CD was based on generally accepted clinical, endoscopic, and histologic criteria. As a control group, a cohort of 5125 non-IBD patients seen at the same hospital and matched for birth year and sex was used. Odds ratios were calculated using multivariate unconditional logistic regression including the matching variables and allowing for cyclic variation in risk with month of birth.
A cyclic pattern described by a 4-month periodic function was observed with peaks in April and August. Moreover, being born in June significantly reduced the risk of developing CD later in life (P = 0.012).
In this Belgian cohort, a significant association was found between the month of birth and later development of IBD; a significant reduced risk to develop CD was observed for people born in June. Moreover, environmental yearly reoccurring factors during pregnancy or postpartum might be associated with the occurrence of CD later in life.
环境因素在具有遗传易感性的个体中引发炎症性肠病（IBD）。免疫系统成熟过程中暴露于季节性外部因素被怀疑是IBD的诱发因素。一些研究表明出生月份与IBD的后期发展之间存在关联。我们在一大群比利时克罗恩病（CD）患者中研究了这种假定的关系。
收集了1935年至1990年出生的1025例患者的数据。CD的诊断基于普遍接受的临床、内镜和组织学标准。作为对照组，使用了在同一家医院就诊且出生年份和性别相匹配的5125例非IBD患者组成的队列。使用多变量无条件逻辑回归计算比值比，包括匹配变量，并考虑出生月份的风险周期性变化。
观察到由4个月周期函数描述的周期性模式，4月和8月出现峰值。此外，6月出生显著降低了日后患CD的风险（P = 0.012）。
在这个比利时队列中，发现出生月份与IBD的后期发展之间存在显著关联；观察到6月出生的人患CD的风险显著降低。此外，孕期或产后每年反复出现的环境因素可能与日后CD的发生有关。
