Family history of inflammatory bowel disease among patients with ulcerative colitis: A systematic review and meta-analysis

Background and aims: Despite numerous shared susceptibility loci between Crohn's disease and ulcerative colitis, the prevalence of family history among ulcerative colitis patients is not well-established and considered to be less prevalent. A systemic review and meta-analysis were conducted to estimate the prevalence of family history of inflammatory bowel disease in ulcerative colitis patients, and its effect on disease outcomes. Methods: PubMED was searched to identify studies reporting the prevalence of family history of inflammatory bowel disease among ulcerative colitis patients. Definitions of family history, study type, and subtypes of family history prevalence were abstracted, as were disease outcomes including age at ulcerative colitis diagnosis, disease location, surgery and extraintestinal manifestations. Pooled prevalence estimates were calculated using random effects models. Results: Seventy-one studies (86,824 patients) were included. The prevalence of a family history of inflammatory bowel disease in ulcerative colitis patients was 12% (95% confidence interval [CI] 11 to 13%; range 0-39%). Family history of ulcerative colitis (9%; 22 studies) was more prevalent than Crohn's disease (2%; 18 studies). Patients younger than 18. years of age at time of diagnosis had a greater family history of inflammatory bowel disease (prevalence 15%, 95% CI: 11-20%; 13 studies). There were no differences in disease location, need for surgery, or extraintestinal manifestations among those with a family history, although very few studies reported on these outcomes. Conclusions: Overall, 12% of ulcerative colitis patients have a family history of inflammatory bowel disease, and were more likely to have a family history of ulcerative colitis than Crohn's disease. Pediatric-onset ulcerative colitis patients were more likely to have a family history of inflammatory bowel disease.