^aThe cohort consisted of the infantile colic group who had experienced infantile colic from 5 weeks to 4 months of age and the control group without infantile colic histories during the same time period.

^bAs the reference group, the control group comprises children who had not been diagnosed with infantile colic at 5 weeks to 4 months of age.

^cInfantile colic group consists of children who have been diagnosed with infantile colic at least once between 5 weeks and 4 months of age.

^dThe hazard ratios (HRs) were assessed using a Cox proportional hazards model to examine the relationship between infantile colic histories and the risk of irritable bowel syndrome (IBS) development in the cohort.

^eIBS was defined as having the diagnosis of International Classification of Diseases 10th version (ICD-10) codes K58.X (IBS) more than twice, after 4 years of age.

^fWeighted using inverse probability of exposure weighting based on the propensity score. The propensity score was estimated using multivariable logistic regression with 97 previously covariates, as defined in Supplementary Table 2. Participants in the reference group were weighted as (propensity score/[1-propensity score]). This method produces a weighted pseudo sample of participants in the reference group with the same distribution of measured covariates as the exposure group.