Intoduction Paediatric inflammatory bowel disease (PIBD) is considered to be a multifactorial disease with both genetic and acquired factors involved in its aetiology. The acquired factors include lifestyles and environmental factors of both patients in paediatric period and their mothers in perinatal period. Parental smoking, not breast-feeding (human milk substitute), mental stress, lack of sleeping time, low body activity, appendectomy, preterm delivery, and some genetic variants concerning pathways of immune responses such as CARD15/NOD2, DLG5, TLR4, OCTN1/2, MYO9B, IL23R, ATG16L, have reported to be possible risk factors for PIBD. However, to date, there has been no study analysing these factors simultaneously and clarifying their confoundings. The present study tries to elucidate genetic and acquired risk factors for PIBD and their confounding.

Methods PIBD cases and controls were recruited from affiliated hospitals of the Japan workshop for paediatric inflammatory bowel disease. Saliva sample of patients for genotyping and self-administrated questionnaire for their mothers were obtained with written informed-consent.

Result and conclusion This paper will report interim results of the study starting from 2011. The present study is expected to develop early and individualised measures to prevent PIBD, intervention for lifestyles and environmental factors of expectant mothers possessing genetic risk factors for baby‘s future PIBD manifestation. Further, the results may contribute to clarify new pathogenesis of PIBD manifestation and more useful disease classification.