Yanna Ko

OBJECTIVE: The rising incidence of inflammatory bowel disease in Asia supports the importance of environmental risk factors in disease aetiology. This prospective population-based case-control study in Asia-Pacific examined risk factors prior to patients developing IBD. DESIGN: 442 incident cases (186 Crohn's disease (CD); 256 UC; 374 Asians) diagnosed between 2011 and 2013 from eight countries in Asia and Australia and 940 controls (frequency-matched by sex, age and geographical location; 789 Asians) completed an environmental factor questionnaire at diagnosis. Unconditional logistic regression models were used to estimate adjusted ORs (aOR) and 95% CIs. RESULTS: In multivariate model, being breast fed >12 months (aOR 0.10; 95% CI 0.04 to 0.30), antibiotic use (aOR 0.19; 0.07 to 0.52), having dogs (aOR 0.54; 0.35 to 0.83), daily tea consumption (aOR 0.62; 0.43 to 0.91) and daily physical activity (aOR 0.58; 0.35 to 0.96) decreased the odds for CD in Asians. In UC, being breast fed >12 months (aOR 0.16; 0.08 to 0.31), antibiotic use (aOR 0.48; 0.27 to 0.87), daily tea (aOR 0.63; 0.46 to 0.86) or coffee consumption (aOR 0.51; 0.36 to 0.72), presence of hot water tap (aOR 0.65; 0.46 to 0.91) and flush toilet in childhood (aOR 0.71; 0.51 to 0.98) were protective for UC development whereas ex-smoking (aOR 2.02; 1.22 to 3.35) increased the risk of UC. CONCLUSIONS: This first population-based study of IBD risk factors in Asia-Pacific supports the importance of childhood immunological, hygiene and dietary factors in the development of IBD, suggesting that markers of altered intestinal microbiota may modulate risk of IBD later in life.

BACKGROUND: Breastfeeding is a modifiable factor that may influence development of inflammatory bowel diseases. However, literature on this has been inconsistent and not accounted for heterogeneity in populations and exposure. AIM: To conduct a meta-analysis to examine the association between breastfeeding in infancy and risk of Crohn's disease (CD) and ulcerative colitis (UC). METHODS: A systematic search of Medline/PubMed and Embase was performed for full text, English-language literature through November 2016. Studies were included if they described breastfeeding in infancy in patients with CD or UC, and healthy controls. Data were pooled using a random effects model for analysis. RESULTS: A total of 35 studies were included in the final analysis, comprising 7536 individuals with CD, 7353 with UC and 330 222 controls. Ever being breastfed was associated with a lower risk of CD (OR 0.71, 95% CI 0.59-0.85) and UC (OR 0.78, 95% CI 0.67-0.91). While this inverse association was observed in all ethnicity groups, the magnitude of protection was significantly greater among Asians (OR 0.31, 95% CI 0.20-0.48) compared to Caucasians (OR 0.78, 95% CI 0.66-0.93; P = .0001) in CD. Breastfeeding duration showed a dose-dependent association, with strongest decrease in risk when breastfed for at least 12 months for CD (OR 0.20, 95% CI 0.08-0.50) and UC (OR 0.21, 95% CI 0.10-0.43) as compared to 3 or 6 months. CONCLUSION: Breastfeeding in infancy protects against the development of CD and ulcerative colitis.

BACKGROUND: Medication persistence contributes real-world evidence about treatment effectiveness, tolerability and prescriber and patient acceptability. AIMS: To evaluate persistence of biological agents in Crohn's disease (CD) and ulcerative colitis (UC) and the effects of immunomodulator use and treatment lines. METHODS: Retrospective national population-based data on treatment persistence for adalimumab, infliximab vedolizumab and ustekinumab for CD and UC were analysed from the Australian Pharmaceutical Benefits Scheme using Kaplan-Meier analysis and Cox proportional hazards models. RESULTS: There were 2499 patients included with 8219 person-years of follow-up. In CD patients ustekinumab had increased persistence compared to anti-TNF agents (HR: 1.79, 95%CI: 1.32-2.38, P < 0.01). Twelve-month CD persistence rates were ustekinumab 80.0%, vedolizumab 73.5%, infliximab 68.1% and adalimumab 64.2% (P = 0.01). In moderate-severe UC vedolizumab had increased persistence compared to anti-TNF agents (HR: 1.67, 95% CI: 1.27-2.18 P < 0.001). Twelve-month UC persistence rates were vedolizumab 73.4%, infliximab 61.1% and adalimumab 45.5% (P < 0.001). Immunomodulator co-therapy did not significantly increase persistence in non-anti-TNF therapy (P > 0.05). Thiopurines increased persistence of anti-TNF agents in CD (P < 0.001) and UC (P = 0.03). Methotrexate co-therapy increased persistence of anti-TNF agents in CD (P = 0.001) only. First-line therapy was superior to non-first line in persistence (P < 0.001). In fistulising CD, the persistence of infliximab and adalimumab was not significantly different (P = 0.11). CONCLUSION: Persistence was highest in ustekinumab in CD and vedolizumab in UC. Factors which increased the persistence of biological agents are first-line therapy, and immunomodulator co-therapy in anti-TNF agent use.

Inflammatory bowel diseases (IBD) are idiopathic chronic diseases of the gastrointestinal tract well known to be associated with both genetic and environmental risk factors. Permissive genotypes may manifest into clinical phenotypes under certain environmental influences and these may be best studied from migratory studies. Exploring differences between first and second generation migrants may further highlight the contribution of environmental factors towards the development of IBD. There are few opportunities that have been offered so far. We aim to review the available migration studies on IBD, evaluate the known environmental factors associated with IBD, and explore modern migration patterns to identify new opportunities and candidate migrant groups in IBD migration research.