Childhood abdominal pain in primary care: design and patient selection of the HONEUR abdominal pain cohort

Background: Abdominal pain in children is a common complaint presented to the GP. However, the prognosis and prognostic factors of childhood abdominal pain are almost exclusively studied in referred children. This cohort study aims at describing prognosis and prognostic factors of childhood abdominal pain in primary care. In this paper we describe methods used for data-collection and determine possible selective recruitment. Methods/Design: We conducted an observational, prospective cohort study with a 1-year follow-up. From May 2004 to March 2006, 53 Dutch GPs recruited consecutive children aged 4-17 years with a new episode of abdominal pain not preceded by a consultation for this complaint in the previous 3 months. Participants filled in standardized questionnaires, and faeces and urine were sampled. To evaluate selective recruitment, the electronic medical records of participating GPs were retrospectively searched for eligible non-included children. Discussion: This study allows us to describe prognosis and prognostic factors of childhood abdominal pain in primary care. A total of 305 children were included of whom 142 (46.6%) met predefined criteria for chronic/recurrent abdominal pain at presentation; from the total group of eligible children identified from the electronic medical record, 27% were included. The included children were significantly younger than non-included children (mean age 8.49 and 9.20 years). In proportion to identified eligible children, significantly less children diagnosed with "gastroenteritis" (6.8%) and significantly more children with "generalized abdominal pain" (39%) were included compared to the 27% that was expected. This cohort represents young school-aged children consulting GPs for a new episode of abdominal pain, not diagnosed as gastroenteritis. Almost half of them fulfil the criteria for chronic abdominal pain at presentation

Gene-Gene and Gene-Environmental Interactions of Childhood Asthma: A Multifactor Dimension Reduction Approach

Background: The importance of gene-gene and gene-environment interactions on asthma is well documented in literature, but a systematic analysis on the interaction between various genetic and environmental factors is still lacking. Methodology/Principal Findings: We conducted a population-based, case-control study comprised of seventh-grade children from 14 Taiwanese communities. A total of 235 asthmatic cases and 1,310 non-asthmatic controls were selected for DNA collection and genotyping. We examined the gene-gene and gene-environment interactions between 17 singlenucleotide polymorphisms in antioxidative, inflammatory and obesity-related genes, and childhood asthma. Environmental exposures and disease status were obtained from parental questionnaires. The model-free and non-parametrical multifactor dimensionality reduction (MDR) method was used for the analysis. A three-way gene-gene interaction was elucidated between the gene coding glutathione S-transferase P (GSTP1), the gene coding interleukin-4 receptor alpha chain (IL4Ra) and the gene coding insulin induced gene 2 (INSIG2) on the risk of lifetime asthma. The testing-balanced accuracy on asthma was 57.83 % with a cross-validation consistency of 10 out of 10. The interaction of preterm birth and indoor dampness had the highest training-balanced accuracy at 59.09%. Indoor dampness also interacted with many genes, including IL13, beta-2 adrenergic receptor (ADRB2), signal transducer and activator of transcription 6 (STAT6). We also used likelihood ratio tests for interaction and chi-square tests to validate our results and all tests showed statistical significance