Systematic review with meta‐analysis: environmental and dietary differences of inflammatory bowel disease in Eastern and Western populations

Abstract

Summary Background While the incidence of inflammatory bowel disease (IBD) has stabilised in the West, it is still increasing in several newly industrialised countries. Aims To investigate whether the environmental and dietary risk factors for IBD differ between Eastern and Western populations Methods We systematically searched PubMed, Embase, and Web of Science for studies published from inception through June 30, 2020. Data were pooled using a random effects model. Results Overall, 255 studies were assessed. We identified 25 risk factors for IBD, seven of which were noted in both Eastern and Western populations: family history of Crohn's disease [CD] or ulcerative colitis [UC], former smoking (CD/UC), smoking (CD), appendicectomy (CD), tonsillectomy (CD), meat and meat products (CD), and vitamin D deficiency (UC). The remaining factors, including urban living, current smoking, antibiotics, oral contraceptives, caesarean section, isotretinoin, total energy, fat, cholesterol, fatty acids and their sub‐classifications, eggs, and soft drinks, were associated with an increased risk of IBD in Western or Eastern populations only. We identified 21 protective factors for IBD, among which eight were common in the East and West: farm animals (CD/UC), Helicobacter pylori infection (CD/UC), multiple births (CD), physical activity (CD), history of breastfeeding (CD), pets (UC), current smoking (UC), and coffee intake (UC). Ten factors conferred protection against IBD in Western populations only, whereas eight factors conferred protection against IBD in Eastern populations only. Conclusions Numerous environmental and dietary factors influenced the development of IBD in both Western and Eastern populations, whereas certain factors influenced IBD risk differently in these populations.

Helminth Therapy for Immune-Mediated Inflammatory Diseases: Current and Future Perspectives

“…These changes can disrupt the balance between the immune response and immune tolerance, which are associated with the increasing incidence rate of IBD. [19][20][21] Genomics has found 163 genes related to the pathogenesis of IBD, including nucleotide-binding oligomerization domain 2 (Nod2), interleukin-10 receptor (IL-10R), caspase recruitment domain family member 9 (CARD9), interleukin-23 receptor (IL-23R) and protein tyrosine phosphatase non-receptor type 2 (PTPN2). 22,23 Nod2 is an important intracellular receptor to regulate gut microbiota.…”

Does the road to primary prevention of inflammatory bowel disease start from childhood?

“…Smoking has consistently demonstrated a positive association with CD risk in West but heterogeneously so in East, with maximum studies demonstrating no association. Breastfeeding, though, is protective in both populations, the effect size is larger in Asians, and the factors related to hygiene (exposure to pets, bedroom sharing, number of household members), though heterogeneous, have demonstrated a stronger protective effect in Asians 1,2,21 . Other than the divergence between populations (West vs East), discrepant effect has also been demonstrated within populations with respect to most of the early life risk factors.…”

“…Despite this, the desultory of the disease is such that the treating physician would want to strike at the primary preventive level. Numerous studies and meta‐analysis have explored the possible factors that may trigger disease causation 1–3 . The protective umbrella is comprised of factors like vaginal delivery, breastfeeding, absence of antibiotic use, diet consisting of fruits and vegetables, and childhood pets, and clearly the common vector out here is that right from birth time each of these factors assume a very vital role.…”

“…A recent meta‐analysis that compared environmental risk factors between West and East also echoed similar findings. Antibiotic use in childhood elevated the risk of CD in West, but reduced it in studies from East 1 . In contrast to studies that have evaluated and compared the relationship between antibiotics and CD risk in native populations, an immigrant study assessed the CD risk in antibiotic‐exposed native Australians and Middle East immigrants in comparison to their respective HCs and reported similar associations 21 .…”

Helicobacter Pylori and Autoimmune Diseases: Involving Multiple Systems

“…The subtype (more protection against CD than UC) and area (more protection in East Asia than Mediterranean areas) might lead to a variation on the protective effect of H. pylori against IBD ( 42 ). Zhao Min et al included 255 clinical studies for meta-analysis and found that H. pylori infection can lower the risk of IBD in different geographical populations ( 43 ).…”