Evidence map›Paper›PMID 42798115›Full record

ArticleMedicine2026

Genetically predicted circulating polyunsaturated fatty acids and Crohn's disease susceptibility: A two-sample mendelian randomization study.

Tingting Zhu, Qiang Hu, Kaifeng Zhu

Abstract read
In one paragraph

Article in Medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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4 · The record

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5 · Who and what money

Authors and funding

3 authors.

Tingting ZhuDepartment of Nursing, Tongde Hospital of Zhejiang Province, Hangzhou, China.
Qiang HuThe Integrated Traditional Chinese and Western Medicine School of Clinical Medicine, Zhejiang Chinese Medicine University, Hangzhou, China.
Kaifeng ZhuDepartment of general surgery, Tongde Hospital of Zhejiang Province, Hangzhou, China.ORCID 0009-0001-4101-8173

Funding

Project of Zhejiang Provincial Department of Education (Y202351378)Project of Zhejiang Traditional Chinese Medicine (No.2025ZX009,No.2024ZL345,No. GZY-ZJ-KJ-23051)
6 · The paper itself

Abstract

Crohn disease (CD) remains an increasing global health burden. Omega-3 and omega-6 polyunsaturated fatty acids participate in lipid metabolism and inflammatory regulation, but previous observational and interventional studies have produced inconsistent findings. This study aimed to assess whether genetically predicted circulating omega-3, omega-6, and the omega-6/omega-3 ratio are associated with CD susceptibility using a two-sample Mendelian randomization (MR) design. Genome-wide association study summary data for circulating omega-3, omega-6, and the omega-6/omega-3 ratio were obtained from the IEU Open GWAS project (each n = 114,999), while CD outcome data included 12,194 cases and 28,072 controls. Genome-wide significant single-nucleotide polymorphisms (P < 5 × 10-8) were clumped at r2 = 0.001 within 10,000 kb, and all retained instruments had F-statistics > 10. Multiplicative random-effects inverse-variance weighting was used as the primary analysis, supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Heterogeneity, horizontal pleiotropy, and robustness were evaluated using Cochran's Q test, the MR-Egger intercept, leave-one-out analysis, and funnel plots. A total of 46 single-nucleotide polymorphisms for omega-3, 51 for omega-6, and 34 for the omega-6/omega-3 ratio were included. Higher genetically predicted circulating omega-3 levels were associated with lower odds of CD (odds ratio [OR] = 0.823, 95% confidence interval [CI] 0.721-0.939, P =.004), whereas omega-6 showed no statistically significant association (OR = 0.885, 95% CI 0.727-1.061, P =.186). A higher genetically predicted omega-6/omega-3 ratio was associated with increased odds of CD (OR = 1.211, 95% CI 1.069-1.372, P =.003). Complementary MR methods showed generally concordant directions, and MR-Egger intercept tests provided no statistical evidence of directional horizontal pleiotropy. However, substantial between-instrument heterogeneity was observed for all three exposures. These findings suggest that genetically predicted higher circulating omega-3 levels and a lower omega-6/omega-3 ratio are associated with lower CD susceptibility, whereas omega-6 alone shows no statistically significant association. Given the substantial between-instrument heterogeneity, these results should be regarded as suggestive genetic evidence rather than definitive proof of causality and should not be interpreted as evidence that dietary omega-3 intake or supplementation prevents CD.

Indexed as

Crohn DiseaseFatty Acids, Omega-3Fatty Acids, Omega-6Fatty Acids, UnsaturatedGenetic Predisposition to DiseaseGenome-Wide Association StudyHumansMendelian Randomization AnalysisPolymorphism, Single NucleotideFatty Acids, Omega-3Fatty Acids, Omega-6Fatty Acids, UnsaturatedCrohn diseaseMendelian randomizationomega-3 fatty acidsomega-6 fatty acidsomega-6/omega-3 ratio

Identifiers

PMID42798115
PMCPMC13619288

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