Perinatal and familial risk factors for irritable bowel syndrome in a Swedish national cohort

Objective: Studies of the importance of perinatal factors for the development of irritable bowel syndrome (IBS) are sparse. We conducted a large national cohort study to examine perinatal and familial risk factors for IBS. Material and methods: A national cohort of 1,963,685 persons who were born in Sweden in 1973–1992 (identified from the Swedish Birth Registry) were followed up for adult (18 years and older) IBS incidence in the Swedish Patient Register through 2010 (maximum age 38 years). There were 24,633 IBS cases in 46,784,296 person-years of follow-up. Results: After adjusting for potential confounders, significant risk factors for IBS included caesarean (HR = 1.10, 95% confidence interval [CI] 1.05–1.11, p < .001), low birth weight (<2500g) (HR = 1.11, 95%CI 1.01–1.22, p = .02), being second in birth order (HR = 1.04, 95%CI 1.01–1.08, p = .01), foetal growth ≥1 SD (HR = 1.06, 95%CI 1.00–1.11, p = .05), young maternal age (<20 years) (HR= 1.09, 95%CI 1.02–1.17, p = .02), maternal marital status (divorced/widowed) (HR = 1.12, 95%CI 1.08–1.17, p < .001), maternal education of 10–11 years (HR = 1.04, 95%CI 1.01–1.08, p = .01), maternal education of 12–14 years (HR = 1.06, 95%CI 1.01–1.11, p = .03), parental history of IBS (HR = 1.54, 95%CI 1.42–1.66, p < .001), parental history of anxiety (HR = 1.21, 95%CI 1.17–1.26, p < .001) and parental history of depression (HR = 1.09, 95%CI 1.02–1.17, p = .02). Protective factors were male sex (HR = 0.36, 95%CI 0.35–0.37, p < .001) and old maternal at delivery (≥35 years) (HR = 0.95, 95%CI 0.90–1.00, p = .03). Conclusions: In this large cohort study, several perinatal and familial factors were associated with an increased risk of IBS independently, suggesting that perinatal and familial factors may play an important long-term role in the aetiology of IBS