Association Between Inflammatory Bowel Disease and Both Psoriasis and Psoriatic Arthritis

Abstract

ImportancePsoriasis, psoriatic arthritis, and inflammatory bowel disease, ie, Crohn disease and ulcerative colitis, are chronic systemic immune-mediated disorders affecting an increasing proportion of adults and children worldwide. Observational studies have suggested an association between inflammatory bowel disease and psoriasis and vice versa. So far, however, it remains unclear whether and in which direction causal relationships exist.ObjectiveTo investigate the association between inflammatory bowel disease, particularly Crohn disease and ulcerative colitis, and psoriasis or psoriatic arthritis.Design, Setting, and ParticipantsA bidirectional 2-sample mendelian randomization study was conducted using summary statistics from genome-wide association studies including up to 463 372 European individuals. Total and direct effects were derived performing an iterative radial and robust inverse-variance weighted method within the univariable and multivariable mendelian randomization setting, respectively. Causal estimates were verified using a validation inflammatory bowel disease sample, a series of pleiotropy-robust mendelian randomization methods, and sensitivity analyses based on a PhenoScanner search in conjunction with network analysis. Data analysis was performed from April to May 2022.Main Outcomes and MeasuresInflammatory bowel disease, Crohn disease, ulcerative colitis, psoriasis, and psoriatic arthritis were used as both exposures and outcomes.ResultsThe European samples included 12 882 cases of inflammatory bowel disease and 5621 cases of psoriasis. The proportion of women ranged between 48% and 56%. Genetically predicted inflammatory bowel disease was associated with higher risk of psoriasis (pooled odds ratio [OR], 1.10; 95% CI, 1.05-1.15; P < .001) and psoriatic arthritis (pooled OR, 1.10; 95% CI, 1.04-1.18; P = .003). In contrast with ulcerative colitis, the Crohn disease subentity was associated with psoriasis (OR, 1.16; 95% CI, 1.12-1.20; P < .001) and psoriatic arthritis (OR, 1.13; 95% CI, 1.06-1.20; P < .001). Regarding the reverse directions, no notable associations could be found.Conclusions and RelevanceFindings of this mendelian randomization study support a causal effect between inflammatory bowel disease and psoriasis as well as psoriatic arthritis, but not vice versa. It seems that especially Crohn disease and not ulcerative colitis is responsible for the causal effect of inflammatory bowel disease on both psoriasis outcomes. These findings have implications for the management of inflammatory bowel disease and psoriasis in clinical practice.

Genetic study of psoriasis highlights its close link with socio-economic status and affective symptoms

“…This is in line with previous knowledge about psoriasis risk factors and two previous MR studies 53,54 reporting causality between psoriasis and BMI. Additionally, our results confirm the previously detected 55 causal relationship between inflammatory bowel disease (IBD) and psoriasis.…”

The causal relationship between psoriasis, psoriatic arthritis, and inflammatory bowel diseases

“…Yajia et al have presented another MR analysis which confirms the bidirectional relationship between psoriasis, psoriatic arthritis, and CD 50 . However, findings of Dennis' study only support a unidirectional causal effect between CD and psoriasis as well as psoriatic arthritis 51 . There are some discrepancies between these reported estimates and our results.…”

The role of nutrition, food allergies, and gut dysbiosis in immune-mediated inflammatory skin disease: a narrative review

“…Thirty-two studies were eligible and therefore included: 13 narrative reviews [1,3,4 ▪ ,5,6 ▪ ,7 ▪ ,8–10,11 ▪ ,12,13 ▪ ,14 ▪ ], 4 meta-analyses (MA) [15,16 ▪▪ ,17 ▪▪ ,18], 3 randomized controlled trials (RCTs) [19,20 ▪▪ ,21], 2 retrospective case control studies [22,23], 2 retrospective cohort studies [24 ▪▪ ,25], 2 prospective cohort studies [26 ▪▪ ,27 ▪▪ ], 2 animal studies [28,29], 1 prospective cross-sectional study [30 ▪▪ ], 1 systematic review [31], 1 case control study [32 ▪ ], and 1 genome-wide association study (GWAS) [33 ▪▪ ]. The data found that nutrition, microbiome, and gut dysbiosis play a significant role in the development and progression of various inflammatory and immune-related skin conditions, such as psoriasis, AD, HS, and alopecia areata (AA).…”

“…IBD and psoriasis both involve an epithelial barrier dysfunction and increased epithelial cellular turnover rate, leading to increased permeability of the epidermal skin and intestinal barrier. Both also involve similar immune responses and involve dysbiosis in the microbiome composition [23,24 ▪▪ ,33 ▪▪ ]. Microbial-associated molecular patterns are sampled by dendritic cells (DCs), which produce interleukin (IL)-17 and IL-22.…”