ABSTRACT

Background:
Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a group of chronic intestinal diseases possibly linked to genetic, environmental, and dietary factors. Recently, studies on caffeine intake and IBD risk have increased, but results remain controversial.

Objective:
To explore the relationship between caffeine intake and IBD risk through a systematic review and meta-analysis.

Methods:
This study searched multiple databases for prospective, cross-sectional and case-control studies examining caffeine intake and IBD risk, including CNKI, VIP, Wanfang, PubMed, Embase, JBI, and WOS, from database inception to May 21, 2024. Two researchers independently extracted literature data and evaluated quality using Stata 16.0 software for meta-analysis.

Results:
A total of 21 studies with 13 209 participants were included. The meta-analysis showed no significant association between caffeine intake and IBD (RR = 0.84, 95% CI = 0.68-1.04). In Americans, caffeine increased UC risk by 68% (RR = 1.68, 95% CI = 1.17-2.42). Age analysis showed caffeine increased IBD risk by 4.52 times in those ≤18 (RR = 4.52, 95% CI = 1.59-12.88) but decreased risk by 7% in those >18 (RR = 0.93, 95% CI = 0.73-1.18). Coffee reduced UC risk by 57% (RR = 0.43, 95% CI = 0.29-0.65), tea by 46% (RR = 0.54, 95% CI = 0.31-0.92). Caffeine increased CD risk by 80% in smokers (RR = 1.80, 95% CI = 1.25-2.60).

Conclusion:
The relationship between caffeine intake and IBD risk varies by region, age, caffeine source, smoking, and education level. In Asia and Europe, coffee and tea reduce UC risk, whereas in America and among adolescents, caffeine may increase UC risk. Smoking and education level also significantly influence this relationship, suggesting various factors must be considered to assess caffeine's impact on IBD risk accurately.

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