Evidence-Based Medicine
Copyright ©The Author(s) 2016.
World J Gastroenterol. Jul 21, 2016; 22(27): 6296-6317
Published online Jul 21, 2016. doi: 10.3748/wjg.v22.i27.6296
Table 4 Effect of environmental factors on ulcerative colitis and impact of interventional studies to modify specific environmental factors
Ref.Disease onset (incident UC)Disease ActivityStudy population and designIntervention and comparison groupOutcome
Lifestyle
Smoking[11,20,24] (LOE 2b, 3b, 2a)Current smoking ↓Mild-moderate UC Systematic review (n = 233)[205] (LOE 1a) (n = 81)[205] (LOE 1a)Nicotine or placeboNo evidence for efficacy for nicotine preparations in inducing remission in UC
Smoking cessation ↑Nicotine or corticosteroids
Sleep[176,179] (LOE 2b)No dataNoneNoneNo data
Stress[158,159] (LOE 5, 2b)No data↑?Adult and adolescent patients with IBDMulti-modality psychotherapyNo evidence for efficacy of psychological therapy in adult patients with IBD
Systematic review of RCTs and quasi-RCTs (n = 1745)[162] (LOE 1a)In adolescents, psychological interventions may be beneficial, but the evidence is limited
Diet
Dietary fat[118] (LOE 3a)n-3 PUFA ↓n-3 PUFA ↓UC in remission Systematic review of RCTs (n = 148)[208] (LOE 1a)fish oil (n-3 PUFA) or placeboNo difference in risk of relapse between n-3 PUFA compared with placebo
n-6 PUFA ↑
Dietary milk[116,117] (LOE 5)No dataActive UCMilk-free diet or sham dietFewer relapses on milk-free diet than on sham diet
RCT (n = 77)[209] (LOE 2b)
Dietary protein[118] (LOE 3a)NoneNoneNo data
Dietary fiber[118,120] (LOE 2b)UC in remission Open label RCT (n = 59)[200](LOE 2b)Germinated barley food stuff (GBF) + conventional therapy or conventional therapyProlonged maintenance of remission in GBF group[200]
UC in remission Open label RCT (n = 105)[122] (LOE 2b)Plantago ovata or MesalaminePlantago ovata as effective as Mesalamine in maintenance of remission[122]
Food antigens[128] (LOE 4)↑?No dataNoneNoneNo data
Food additives[131,132] (LOE 5)↑?No dataNoneNoneNo data
Breastfeeding[187,189] (LOE 3a, 3b, 2b)No dataNoneNoneNo data
Medication
Nsaids[139,140] (LOE 2b)↑?Quiescent to mildRofecoxib 25 mg or 12.5 mg × 20 d41% responded with reduction in arthralgia scores. P < 0.05. No IBD flares 9% developed GI side effects
UC and CD with arthralgia
Prospective Open label trial (n = 32)
Oral contraceptives[150,151,153,155] (LOE 3a, 2b)NoneNoneNo data
Antibiotics[145,147] (LOE 3b, 3a)Early exposure ↔Active UC Systematic review of RCTs (n = 9 studies)[71] (LOE 1a)Antibiotic or placeboAntibiotics superior to placebo at inducing remission
Vaccination[183] (LOE 3a)No effectNo dataNoneNoneNo data
Gut microbiome
Dysbiosis[80,83,84] (LOE 4)Mild-moderate UC Systematic review of RCTs (n = 650)[199] (LOE 1a)Probiotics + conventional treatment or placeboProbiotics effective for induction and maintenance of remission in UC and pouchitis[199]
Active UC RCT (n = 70)[204] (LOE 1b)Fecal microbiota transplant (FMT) or PlaceboFMT induced remission in a significantly greater percentage of patients with active UC than placebo (24% vs 5%)[204]
Active UC, RCT (n = 100)[206] (LOE1b)Ciprofloxacin + E-coli Nissle or placebo + E-coli NissleNo benefit in the use of E. coli Nissle as an add-on treatment to conventional therapies for active UC
Ecological (Abiotic)
Air pollution[33,34] (LOE 2c, 3b)NoneNoneNo data
Water pollution[36-38] (LOE 5)NoneNoneNo data
Low Vitamin D[44,57] (LOE 2a, 2b)Active UC Cohort study (n = 368)[59] (LOE 2b)Vitamin D3 or No treatmentReduction in health-care utilization in the vitamin D treatment group
Surgery
Appendectomy[195-196] (LOE 2b, 3b)No dataNoneNoneNo data