Dietary, lifestyle, and environmental factors associated with ulcerative colitis: a systematic review and meta-analysis of observational studies
Related Experiment Video
Updated: Aug 9, 2026
Analyzing Beneficial Effects of Nutritional Supplements on Intestinal Epithelial Barrier Functions During Experimental Colitis
Published on: January 5, 2017
Yahui Wang1, Tianru Xie1, Ziwen Liao1
1Guangxi University of Chinese Medicine, Nanning, Guangxi, China.
Background And Aims:
Ulcerative colitis (UC) is increasing worldwide, and dietary, lifestyle, and environmental exposures may contribute to disease susceptibility. This systematic review and meta-analysis evaluated the associations between these exposures and the risk of incident UC.
Methods:
PubMed, Embase, and the Cochrane Library were searched for observational studies examining dietary, lifestyle, medication-related, surgical, early-life, sociodemographic, and other environmental exposures in relation to UC risk through November 12, 2025. Random-effects models were used to pool effect estimates. Study quality was assessed using the Newcastle-Ottawa Scale, and the certainty of evidence was evaluated using GRADE.
Results:
Thirty observational studies involving 148,468 patients with UC were included, covering 17 factors and 27 comparisons. Daily egg consumption, family history of inflammatory bowel disease, the highest reported category of antibiotic exposure, ever smoking, and former smoking were associated with increased UC risk. Pet exposure, coffee consumption, appendectomy, higher educational attainment, light alcohol consumption, and fruit intake were associated with reduced UC risk. Current smoking was associated with a lower risk of UC in case-control studies, whereas the association was not statistically significant in cohort studies. Adjusted estimates suggested that breastfeeding might be associated with a lower risk of UC, although the evidence was limited. No clear associations were observed for body mass index, oral contraceptive use, tonsillectomy, previous gastrointestinal infection, place of residence, any antibiotic use, tea consumption, or heavy alcohol consumption.
Conclusion:
Dietary, lifestyle, and broader environmental factors showed different directions of association with UC risk, although the overall certainty of evidence was low. These findings support further prospective and mechanistic studies to clarify causal pathways and identify potentially modifiable exposures relevant to UC prevention.
Systematic Review Registration:
PROSPERO, CRD420261343412.
Related Concept Videos
01:30Inflammatory Bowel Disease III: Diagnostic Studies and Management I-Nutritional Therapy
Diagnostic studies
A colonoscopy is the definitive screening test, distinguishing ulcerative colitis from other colon diseases with similar symptoms. During a colonoscopy test, inflamed mucosa with exudate ulcerations can be observed, and biopsies are taken to determine the histologic characteristics of the colonic...
01:27Inflammatory Bowel Disease I: Ulcerative Colitis
Inflammatory bowel disease, or IBD, encompasses a group of disorders characterized by chronic inflammation or ulceration of the gastrointestinal tract.
Risk Factors
The exact cause of IBD remains unclear, although it is believed to be due to a mix of genetic, environmental, microbial, and immune factors. Genetic factors are significant in determining susceptibility to IBD, with family history being a critical risk factor. Individuals with a first-degree relative who has IBD are at...
01:20Inflammatory Bowel Disease II: Ulcerative Colitis
01:29Drugs for Treatment of Ulcerative Colitis in IBD
01:17Chronic Bowel Disorders: Introduction
Irritable Bowel Syndrome (IBS) is a common disorder affecting the gastrointestinal tract. The distinctive feature is recurrent abdominal pain associated with altered bowel movements, manifesting as constipation, diarrhea, or fluctuating between both. The...
01:20Inflammatory Bowel Disease IV: Clinical Manifestations