No Correlation between the Month of Birth and the Likelihood of Developing Inflammatory Bowel Disease Later in Life

Background: The etiology of Crohn’s disease (CD) and Ulcerative Colitis (UC) remains unclear. It has been suggested that apart from genetic factors, prenatal or perinatal environmental factors could change the risk of developing inflammatory bowel disease (IBD) later in life. Seasonality in birth distribution over the year has been demonstrated for several immune diseases, but studies on IBD have had inconsistent results. Aim: The aim of this study was to investigate in the Netherlands the effect of the month of birth on the probability to develop IBD later in life. Methods: Birth data from CD patients and UC patients of 4 different Dutch hospitals were compared to a control group of irritable bowel syndrome (IBS) patients from the same hospitals. A chi-square test was used to test whether there was heterogeneity between the monthly and seasonal birth rates of the three groups. Results: The patient cohort consisted of 1183 CD patients and 1293 UC patients. The control group consisted of 2113 IBS patients. Data showed no difference in birth distribution over the year or over the four seasons of IBD patients as compared to the control group. P-values over the year and over the seasons respectively are 0.428 and 0.237 for CD and 0.311 and 0.812 for UC. Conclusions: There is no seasonality in the distribution of births of IBD patients as compared to controls. The hypothesis that environmental factors present at the time of birth play a role in the pathogenesis of IBD is not supported by these data.

腹部触诊筛查胎儿宫内发育迟缓在低危人群中的有效性:一项观察性研究

Objective: To evaluate the performance of abdominal palpation as a screening test for intrauterine growth retardation (IUGR) in a low risk population, under standard practice conditions. Study design: Population based observational study of 6318 consecutive low risk singleton pregnancies. The Dutch obstetric system distinguishes low from high risk pregnancies. In the low risk group abdominal palpation as a screening test is performed by midwives. If a complication, like IUGR, during prenatal care is assessed, the women is referred to a consulted obstetrician. Ultrasound is performed by the consulted obstetrician. In case of sustained suspicion the women is selected as high risk. Outcome parameters: severe small for gestational age (SGA) birthweight below 2.3rd centile, all SGA birthweight below 10th centile, operative delivery, neonatal morbidity and perinatal mortality. Screening value of abdominal palpation, abdominal palpation combined with ultrasound, and the performance of high risk selection was assessed by conventional performance measures. Results: Abdominal palpation as a screening test for IUGR is of limited value: the observed sensitivities were 28%for severe SGA and 21%for SGA p≤10, respectively. After ultrasound in case of sustained suspicion, the sensitivity in detection of severe SGA was 25%and positive predictive value (PPV) 16%. In detection of SGA p≤10 sensitivity was 15%and PPV 55%, which means 45%were false positives. The sensitivity of the Dutch obstetric system in selection of high risk pregnancies in detection of severe SGA was 53%, in detection of SGA p≤10 was 37%. Perinatal mortality was 0.9%(57/6318) and 32%of these cases were SGA. Six cases of fetal death were unrecognised during prenatal care (0.09%) and seem preventable. The prevalence of a 5 min Apgar Score≤7 was significantly higher in the SGA infants if SGA was defined as p≤10. Conclusions: The diagnostic performance of abdominal palpation as a screening test for IUGR detection in a low risk population is disappointing. However, various stratagems such as routine ultrasound do not improve detection rate or perinatal morbidity and mortality.