Serum Lipids and Risk of Incident Psoriasis: A Prospective Cohort Study from the UK Biobank Study and Mendelian Randomization Analysis

Association between plasma odd-chain fatty acid levels and immune cell traits in psoriasis: insights from a prospective cohort study

Background/Objectives

Psoriasis is a chronic, immune-mediated skin disease frequently linked to metabolic dysregulation. Odd-chain fatty acids (OCFAs), a group of bioactive lipids, have been implicated in inflammation and metabolic health; however, their role in psoriasis remains poorly defined. This study aimed to investigate the associations between plasma OCFA levels, white blood cell (WBC) traits, and psoriasis severity.

Methods

A total of 235 patients with moderate-to-severe plaque psoriasis were enrolled from the Shanghai Psoriasis Effectiveness Evaluation CoHort. Baseline plasma OCFA concentrations were measured using gas chromatography-mass spectrometry, and routine hematologic parameters were extracted from clinical records. Psoriasis severity was assessed using the Psoriasis Area and Severity Index, Body Surface Area, Dermatology Life Quality Index, and the Hospital Anxiety and Depression Scale for Anxiety and Depression. Therapeutic response was evaluated at weeks 12 and 28 based on clinical improvement. Multivariate linear and logistic regression analyses, stratified subgroup analyses, and restricted cubic spline models were employed.

Results

Higher plasma levels of C15:0 were significantly associated with increased total WBC and neutrophil counts. C17:0 levels were positively associated with WBC counts among females and older adults, and inversely associated with eosinophil counts in females and individuals with normal BMI. Additionally, C17:1n7 levels were positively associated with lymphocyte and monocyte counts. Total OCFA levels were also positively associated with overall WBC and neutrophil counts. These associations varied by sex, age, BMI, smoking and alcohol consumption history, and the presence of comorbidities such as psoriatic arthritis, hypertension, and type 2 diabetes. While no significant associations were observed between plasma OCFA levels and psoriasis severity or treatment response in the overall cohort, stratified analyses revealed potential relationships in specific subgroups.

Conclusions

Plasma OCFAs are differentially associated with circulating immune cell profiles in patients with psoriasis, suggesting a potential immunomodulatory role. Although OCFAs were not linked to overall disease severity or short-term treatment outcomes, subgroup-specific associations indicate their relevance in particular clinical phenotypes. These findings highlight the need for further longitudinal studies to clarify the role of OCFAs in immune regulation, disease progression, and comorbidity management in psoriasis.

Causal relationship between plasma lipidome and rosacea: a Mendelian randomization analysis

Background

Rosacea is a common chronic inflammatory skin disease. Limited studies reported the association between plasma lipidome and rosacea.

Methods

We employed a two-sample Mendelian randomization (MR) study to assess the causality between plasma lipidome and rosacea. Plasma lipidome association genome-wide association study (GWAS) data were collected. The inverse variance weighted (IVW) method was utilized as the principal method in our Mendelian randomization (MR) study; we also used the MR-Egger, weighted median, simple mode, and weighted mode methods. The MR-Egger intercept test, Cochran's Q test, MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and leave-one-out analysis were conducted to identify heterogeneity and pleiotropy.

Results

A total of 179 lipid species were analyzed; among them, five lipid species were closely related to rosacea. Two species of sterol ester [sterol ester (27:1/22:6) and sterol ester (27:1/15:0)], two species of phosphatidylethanolamine [phosphatidylethanolamine (O-18:2_20:4) and phosphatidylethanolamine (18:0_20:4)], and one species of sphingomyelin [sphingomyelin (d34:0)] were causally associated with rosacea (P < 0.05). All of them play protective roles in patients with rosacea. No heterogeneity or pleiotropy was observed.

Conclusion

This study provided new evidence of the relationship between plasma lipidome and rosacea. Our MR suggested that five lipid species play protective roles in rosacea progression. These could be novel and effective ways to treat rosacea.

Associations of exposure to acrylamide and glycidamide with psoriasis among adults: Findings from a population-based study

Acrylamide (AA), a hazardous chemical prevalent in the environment and human diet, and its metabolite glycidamide (GA) are suspected contributors to psoriasis. However, the relationship between AA, GA exposure and psoriasis incidence remains unclear. Using data from the National Health and Nutrition Examination Survey (NHANES) cycles 2003-2004, 2005-2006, and 2013-2014, we conducted a cross-sectional study involving 6999 participants. While no overall association was observed between AA-hemoglobin adduct (HbAA), HbGA levels, and psoriasis risk, subgroup analyses revealed positive relationships among individuals aged 20-40 years and those with serum cotinine levels between 0.011 and 10 ng/mL. We also assessed the relationship between HbAA, HbGA exposure and various laboratory biomarkers. HbAA exposure was positively associated with high-density lipoprotein (HDL) and white blood cell counts, but negatively associated with folate. HbGA exposure was negatively associated with HDL and vitamin B12. Interaction analyses indicated that higher levels of serum HDL, folate, vitamin B12, and peripheral white blood cell and monocyte counts attenuated the detrimental effects of HbGA exposure on psoriasis risk. Sensitivity analysis based on dietary AA intake from NHANES 24-hour dietary recall data (2003-2004, 2005-2006 cycles, N = 4932) yielded results consistent with those observed for HbAA and HbGA exposure. These findings suggest that AA and GA exposure may contribute to psoriasis incidence, particularly among younger adults and smokers, and that improving nutritional intake and lifestyle factors could help mitigate this risk. Further research is needed to confirm these associations in diverse populations and elucidate the underlying mechanisms of AA/GA-related psoriasis pathogenesis.

Correlation between cardiometabolic index and psoriasis: a cross-sectional analysis using NHANES data

Background

Psoriasis is closely associated with metabolic health. The Cardiometabolic Index (CMI) is an innovative and easily obtainable metric employed to assess cardiometabolic health. This study aims to examine the possible relationship between CMI and psoriasis.

Methods

Data from four successive cycles of the National Health and Nutrition Examination Survey (NHANES) conducted between 2003-2004 and 2009-2014 were employed. This encompassed adults with self-reported psoriasis diagnoses and comprehensive information necessary for calculating the CMI. The calculation formula for CMI is Triglycerides (TG)/High-density lipoprotein cholesterol (HDL-C) × WHtR (WHtR = waist circumference/height). A multivariable logistic regression model was utilized to examine the linear relationship between CMI and psoriasis. Subgroup analyses were conducted to investigate potential contributing factors. The linear relationship was further established using smooth curve fitting.

Results

This study, utilizing NHANES data, comprised a cohort of 7,327 American adults. The multivariable logistic regression analysis indicated that in the fully adjusted model, people with the greatest CMI had a 71% increased probability of psoriasis relative to those with the lowest CMI (OR = 1.71; 95% CI, 1.11-2.61, P < 0.05). Smooth curve fitting demonstrated a linear connection between CMI and psoriasis (P < 0.05). The subgroup analysis revealed no significant interactions between CMI and specific subgroups (all interactions P > 0.05).

Conclusion

Our research indicates a substantial linear correlation between CMI and psoriasis in American adults. This method facilitates the identification of groups at increased risk for psoriasis, therefore guiding therapeutic solutions and public health activities to improve metabolic and dermatological health outcomes.

Skin Metabolic Signatures of Psoriasis and Psoriasis Concurrent with Metabolic Syndrome

Purpose

Psoriasis is a complex inflammatory skin disorder that is closely associated with metabolic syndrome (MetS). Limited information is available on skin metabolic changes in psoriasis; the effect of concurrent MetS on psoriatic skin metabolite levels is unknown. We aimed to expand this information through skin metabolomic analysis.

Patients and Methods

Untargeted metabolomics was conducted using skin samples from 38 patients with psoriasis vulgaris with MetS (PVMS), 23 patients with psoriasis vulgaris without MetS (PVNMS), and 10 healthy controls (HC). Data analyses, including multivariate statistical analysis, KEGG pathway enrichment analysis, correlation analysis, and receiver operating characteristic curve analysis, were performed.

Results

Significant discrepancies were found between skin metabolites in the HC and PVNMS groups, particularly those involved in nucleotide and glycerophospholipid metabolism. Fifteen of these metabolites were positively correlated with psoriasis severity. Furthermore, MetS was found to affect the metabolic profiles of patients with psoriasis. There were some metabolites with consistent alterations in both the PVNMS/HC and PVMS/PVNMS comparisons.

Conclusion

This study may provide new insights into the link between skin metabolism and psoriatic inflammation and the mechanism underlying the interaction between psoriasis and MetS.

Life's Essential 8, genetic susceptibility and the risk of psoriatic disease: a prospective cohort study

BACKGROUND

Psoriatic disease (PsD) is closely associated with cardiovascular (CV) disease. The Life's Essential 8 (LE8) score is a new metric to assess CV health (CVH), where a higher score indicates better CVH. However, the longitudinal association between LE8 score and the risk of PsD remains uncertain.

OBJECTIVES

To investigate, in a cohort study, the association between LE8 score, genetic susceptibility and the risk of PsD.

METHODS

This cohort study included 261 642 participants in the UK Biobank without PsD at baseline. LE8 comprises eight indicators: diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose and blood pressure. Cox proportional hazard models were used to examine the association between participants' LE8 scores, genetic risk of PsD and the risk of PsD. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

RESULTS

During an average follow-up of 12.3 years, 1501 participants developed PsD. Compared with participants with low LE8 scores, the HRs of developing PsD for those with moderate and high LE8 scores were 0.51 (95% CI 0.43-0.59) and 0.34 (95% CI 0.27-0.42) after adjustments, respectively. Dose-response analysis revealed a linear negative association between continuous LE8 score and the risk of developing PsD (P < 0.001), with no evidence of nonlinear association detected. Genetic susceptibility to PsD did not modify this association (P-interaction = 0.63). Subgroup analyses revealed that women had a more pronounced beneficial association between LE8 scores and PsD risk (P-interaction = 0.02).

CONCLUSIONS

Our study suggests that a higher LE8 score, regardless of genetic risk, is associated with a lower risk of PsD, particularly in women. Consequently, maintaining good CVH status is recommended to prevent PsD and assess associated risks.

Causal association between B cell count and psoriasis using two-sample Mendelian randomization

To investigate the causality between B cell count and psoriasis by Mendelian randomization (MR). Collected B cell count and psoriasis data from IEU Open GWAS Project. Employed inverse variance weighting (IVW), MR-Egger, WM, weighted mode for analysis, ensuring result robustness. Assessed horizontal pleiotropy with MR-Egger, detected outliers using MR-PRESSO and examined instrumental variables heterogeneity with Cochran's Q-test. The IVW method suggested an association between a genetically predicted memory B cell count and the risk of psoriasis vulgaris. IVW results also showed no causality between other exposure factors and the corresponding outcomes. Also, the global test of MR-PRESSO analysis showed a significant association between a genetically predicted transitional absolute B cell count and the lower risk of psoriasis vulgaris. MR-Egger regression showed that horizontal pleiotropy did not influence the analysis results. We found that memory B cell absolute counts are associated with a lower risk of psoriasis. These data further elucidate the role of memory B cells in psoriasis and provide new options for psoriasis treatment.

Epidemiology of lipid disturbances in psoriasis: An analysis of trends from 2006 to 2023

INTRODUCTION

A strong link has been established between psoriasis and lipid disturbances; however, no study has systematically examined their global epidemiology.

METHODS

We searched six databases from their inception up to October 1, 2023. Data analysis was conducted using Stata SE 15.1. We performed subgroup, meta-regression, and sensitivity analyses to assess the heterogeneity of the pooled studies.

RESULTS

Our review included 239 studies comprising 15,519,570 participants. The pooled prevalence rate of dyslipidemia among individuals with psoriasis was 38%.

CONCLUSION

Patients with severe psoriasis should undergo screening for lipid abnormalities. This can facilitate the early detection of lipid dysfunction and associated cardiovascular comorbidities.

Assessing the genetic associations between plasma lipidomic profiles and psoriasis vulgaris

Several studies have indicated a potential causal relationship between plasma standard lipids, such as high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and total cholesterol (TC), and psoriasis. However, few studies have offered causal evidence of lipid species beyond these standard lipids. We conducted an analysis using a genome-wide association study (GWAS) dataset comprising 179 lipid species, including 13 types across four major categories, to identify instrumental variables (IVs) associated with plasma lipids. We utilized two GWAS datasets from the IEU and Finngen for psoriasis vulgaris as the outcome. A two-sample Mendelian randomization (MR) analysis was used to explore the causal relationship between 179 lipid species and psoriasis vulgaris in two datasets. Lipid species showing causal association in both psoriasis datasets were compared for overlap. Our study identified potential causal relationships between six lipid species and psoriasis vulgaris: phosphatidylcholine (16:1_18:2), phosphatidylcholine (18:0_18:2), phosphatidylcholine (18:1_20:4), phosphatidylethanolamine (16:0_18:2), phosphatidylinositol (18:0_20:3), and triacylglycerol (50:1). In summary, elevated plasma levels of phosphatidylcholine (16:1_18:2), phosphatidylcholine (18:0_18:2), phosphatidylethanolamine (16:0_18:2), phosphatidylinositol (18:0_20:3), and triacylglycerol (50:1) may increase the risk of psoriasis vulgaris. Conversely, plasma phosphatidylcholine (18:1_20:4) may play a protective role against psoriasis vulgaris.

Elevated plasma triglycerides increase the risk of psoriasis: a cohort and Mendelian randomization study

BACKGROUND

It is increasingly clear that triglyceride-rich lipoproteins are proinflammatory and cause low-grade systemic inflammation. However, it is currently unknown whether elevated plasma triglycerides are causally related to the development of psoriasis, a skin disorder driven by chronic inflammation.

OBJECTIVES

To determine if elevated plasma triglycerides are associated with increased risk of psoriasis in observational and Mendelian randomization analysis.

METHODS

Consecutive individuals from the Copenhagen General Population Study were included. We used plasma triglycerides (n = 108 043) and a weighted triglyceride allele score (n = 92 579) on nine known triglyceride-altering genetic variants. Genetic results were replicated in 337 159 individuals from the UK Biobank. Psoriasis was defined using the International Classification of Diseases, version 10 (ICD-10) code for hospital contact in the main analyses, and prescription of topical antipsoriatics for mild psoriasis in the sensitivity analysis.

RESULTS

During a follow-up of median (range) 9.3 (0.1-15.1) years from 2003 to 2015 through 2018, 855 (1%) individuals were diagnosed with psoriasis by ICD-10 in the observational analysis and 772 (1%) in the Mendelian randomization analysis. In the observational analysis, the multivariable adjusted hazard ratio for psoriasis by ICD-10 was 1.26 [95% confidence interval (CI) 1.15-1.39] per doubling in plasma triglycerides with a corresponding causal odds ratio of incident psoriasis of 2.10 (95% CI 1.30-3.38). Causality was confirmed from data from the UK Biobank. Results were similar but slightly attenuated when we used topical antipsoriatic prescriptions for mild psoriasis.

CONCLUSIONS

Elevated plasma triglycerides are associated with an increased risk of psoriasis in observational and Mendelian randomization analysis.

Adding salt to foods and risk of psoriasis: A prospective cohort study

BACKGROUND

High salt intake may play a critical role in the etiology of psoriasis. Yet, evidence on the association of high salt intake with risk of psoriasis is limited.

OBJECTIVE

To estimate the association between frequency of adding salt to foods and risk of psoriasis.

METHODS

We conducted a prospective cohort study of 433,788 participants from the UK Biobank. Hazard ratios (HRs) and their 95 % confidence intervals (CIs) for risk of psoriasis in relation to frequency of adding salt to foods were estimated using multivariable Cox proportional hazards models. We further evaluated the joint association of adding salt to foods and genetic susceptibility with risk of psoriasis. We conducted a mediation analysis to assess how much of the effect of adding salt to foods on risk of psoriasis was mediated through several selected mediators.

RESULTS

During a median of 14.0 years of follow-up, 4279 incident cases of psoriasis were identified. In the multivariable-adjusted model, a higher frequency of adding salt to foods was significantly associated with an increased risk of psoriasis ("always" versus "never/rarely" adding salt to foods, HR = 1.25, 95 % CI: 1.10, 1.41). The observed positive association was generally similar across subgroups. In the joint association analysis, we observed that participants with a high genetic risk (above the second tertile) and the highest frequency of adding salt to foods experienced 149 % higher risk of psoriasis, when compared with participants with a low genetic risk (below the first tertile) and the lowest frequency of adding salt to foods (HR = 2.49, 95 % CI: 2.05, 3.02). Mediation analysis revealed that 1.8 %-3.2 % of the positive association between frequency of adding salt and risk of psoriasis was statistically significantly mediated by obesity and inflammatory biomarkers such as C-reactive protein and systemic immune-inflammation index (all P values < 0.004).

CONCLUSIONS

Our study demonstrated a positive association between frequency of adding salt to foods and risk of psoriasis. The positive association was independent of multiple other risk factors, and may be partially mediated through obesity and inflammation.

Genetic causality and metabolite pathway identifying the relationship of blood metabolites and psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory disease that causes significant disability. However, little is known about the underlying metabolic mechanisms of psoriasis. Our study aims to investigate the causality of 975 blood metabolites with the risk of psoriasis.

MATERIALS AND METHODS

We mainly applied genetic analysis to explore the possible associations between 975 blood metabolites and psoriasis. The inverse variance weighted (IVW) method was used as the primary analysis to assess the possible association of blood metabolites with psoriasis. Moreover, generalized summary-data-based Mendelian randomization (GSMR) was used as a supplementary analysis. In addition, linkage disequilibrium score regression (LDSC) was used to investigate their genetic correction further. Metabolic pathway analysis of the most suggested metabolites was also performed using MetaboAnalyst 5.0.

RESULTS

In our primary analysis, 17 metabolites, including unsaturated fatty acids, phospholipids, and triglycerides traits, were selected as potential factors in psoriasis, with odd ratios (OR) ranging from 0.986 to 1.01. The GSMR method confirmed the above results (β = 0.001, p < 0.05). LDSC analysis mainly suggested the genetic correlation of psoriasis with genetic correlations (rg) from 0.088 to 0.155. Based on the selected metabolites, metabolic pathway analysis suggested seven metabolic pathways including ketone body that may be prominent pathways for metabolites in psoriasis.

CONCLUSION

Our study supports the causal role of unsaturated fatty acid properties and lipid traits with psoriasis. These properties may be regulated by the ketone body metabolic pathway.

Advance in Multi-omics Research Strategies on Cholesterol Metabolism in Psoriasis

The skin is a complex and dynamic organ where homeostasis is maintained through the intricate interplay between the immune system and metabolism, particularly cholesterol metabolism. Various factors such as cytokines, inflammatory mediators, cholesterol metabolites, and metabolic enzymes play crucial roles in facilitating these interactions. Dysregulation of this delicate balance contributes to the pathogenic pathways of inflammatory skin conditions, notably psoriasis. In this article, we provide an overview of omics biomarkers associated with psoriasis in relation to cholesterol metabolism. We explore multi-omics approaches that reveal the communication between immunometabolism and psoriatic inflammation. Additionally, we summarize the use of multi-omics strategies to uncover the complexities of multifactorial and heterogeneous inflammatory diseases. Finally, we highlight potential future perspectives related to targeted drug therapies and research areas that can advance precise medicine. This review aims to serve as a valuable resource for those investigating the role of cholesterol metabolism in psoriasis.

Cholesterol and low-density lipoprotein as a cause of psoriasis: Results from bidirectional Mendelian randomization

BACKGROUND

Psoriasis is an inflammatory disease that affects many people. However, the causal effect of lipid metabolism on psoriasis has not yet been verified. This study aimed to identify the genetic relationship between serum lipid levels and psoriasis.

METHODS

Bidirectional two-sample Mendelian randomization (MR) was used to analyse the causal relationship between cholesterol and psoriasis. The outcome of the forward causality test was psoriasis. In the analysis of reverse causality, psoriasis was exposed, and 79 single-nucleotide polymorphisms were detected in the genome-wide association study (GWASs) database from the IEU GWASs Project. MR-Egger regression, inverse variance-weighted, weighted median, weighted mode and simple mode were used for the MR analyses.

RESULTS

The level of triglyceride, lipase member N, chylomicrons, extremely large very low-density lipoprotein (VLDL) particles, high-density lipoprotein (HDL) cholesterol levels, cholesterol esters in large HDL, cholesterol esters in medium HDL and cholesterol esters in medium VLDL have not affected the development of psoriasis. However, total cholesterol, total free cholesterol, low-density lipoprotein (LDL) cholesterol levels, cholesterol esters in large VLDL and cholesterol esters in medium LDL were unidirectional causal effects on psoriasis.

CONCLUSION

Bidirectional two-sample MR analysis indicated that high levels of total cholesterol, total free cholesterol, LDL cholesterol, cholesterol esters in large VLDL and cholesterol esters in medium LDL are genetic risk factors for psoriasis.

A genome-wide cross-trait analysis identifies shared loci and causal relationships of obesity and lipidemic traits with psoriasis

Background

Obesity and dyslipidemia, major global health concerns, have been linked to psoriasis, but previous studies faced methodological limitations and their shared genetic basis remains unclear. This study examines various obesity-related and lipidemic traits as potential contributors to psoriasis development, aiming to clarify their genetic associations and potential causal links.

Methods

Summary statistics from genome-wide association studies (GWAS) conducted for obesity-related traits (body mass index (BMI), waist-to-hip ratio (WHR), and waist-to-hip ratio adjusted for the body mass index (WHRadjBMI)) and lipidemic traits (high-density lipoprotein (HDL), LDL, triglyceride (TG), total Cholesterol (TC), apolipoprotein A1 (apoA1), apolipoprotein B (apoB), and apolipoprotein E (apoE)) and psoriasis, all in populations of European ancestry, were used. We quantified genetic correlations, identified shared loci and explored causal relationship across traits.

Results

We found positive genetic correlation between BMI and psoriasis (rg=0.22, p=2.44×10-18), and between WHR and psoriasis (rg=0.19, p=1.41×10-12). We further found the positive genetic correlation between psoriasis and WHRadjBMI(rg=0.07, p=1.81×10-2) the genetic correlation, in while the effect of BMI was controlled for. We identified 14 shared loci underlying psoriasis and obesity-related traits and 43 shared loci between psoriasis and lipidemic traits via cross-trait meta-analysis. Mendelian randomization (MR) supported the causal roles of BMI (IVW OR=1.483, 95%CI=1.333-1.649), WHR (IVW OR=1.393, 95%CI=1.207-1.608) and WHRadjBMI (IVW OR=1.18, 95%CI=1.047-1.329) in psoriasis, but not observe any significant association between lipidemic traits and the risk of psoriasis. Genetic predisposition to psoriasis did not appear to affect the risk of obesity and lipidemic traits.

Conclusions

An intrinsic link between obesity-related traits and psoriasis has been demonstrated. The genetic correlation and causal role of obesity-related traits in psoriasis highlight the significance of weight management in both the prevention and treatment of this condition.

Causal association between psoriasis vulgaris and bullous pemphigoid: a two-sample bidirectional Mendelian randomization study

Background

The association between psoriasis vulgaris and bullous pemphigoid (BP) remains largely unknown.

Objectives

To investigate whether there is a causal effect between psoriasis vulgaris and BP.

Methods

Two-sample bidirectional Mendelian randomization (MR) analyses were conducted using publicly released genome-wide association studies (GWAS) summary statistics. The GWAS summary statistics for BP were downloaded online from FinnGen Biobank Documentation of the R12 release, which includes 219 BP cases and 218,066 controls. The GWAS data for psoriasis vulgaris were extracted from Sakaue et al., which comprises 5072 cases and 478,102 controls. Single-nucleotide polymorphisms (SNPs) associated with exposure were selected as instrumental variables by performing additional quality control steps. The inverse-variance-weighted (IVW) method was used for the primary MR analyses, and the MR-Egger regression, weighted mode method, weighted median method, and simple mode were employed for sensitivity analyses. The MR-Egger intercept test and "leave-one-out" sensitivity analysis were performed to evaluate the horizontal pleiotropy and the potentially influential SNPs, respectively.

Results

Genetically determined log odds of psoriasis vulgaris were associated with an increased risk of BP (IVW: odds ratio (OR) = 1.263, 95% confidence interval (CI): 1.013-1.575, P=0.038). Sensitivity analyses by the weighted mode (OR=1.255, 95%CI: 0.973-1.618, P=0.106), MR Egger (OR=1.315, 95%CI: 0.951-1.817, P=0.126), simple mode (OR=1.414, 95%CI: 0.823-2.429, P=0.234) and weighted median method (OR=1.177, 95%CI: 0.889-1.559, P=0.254) derived directionally consistent relationship between the genetically predicted log odds of psoriasis vulgaris and risks of developing BP. On the contrary, we found that genetically predicted BP had no significant effect on psoriasis vulgaris (IVW: OR=0.996, P= 0.707), indicating the unidirectionality of the relationship. MR-Egger intercept tests showed no evidence of horizontal pleiotropy. No influential SNP driving the results was detected by the leave-one-out sensitivity analysis.

Conclusions

Our results suggested that psoriasis vulgaris causally increases the risk of BP, highlighting the need for potential strategies for the prevention and early diagnosis of comorbid BP in patients with psoriasis vulgaris. Further researches into this association and underlying mechanisms are warranted.

Causality of unsaturated fatty acids and psoriasis a Mendelian randomization study

Background

Many observational studies have identified a link between unsaturated fatty acids and psoriasis. However, they contain reverse causality and confounding factors, and there is no definite causal study between unsaturated fatty acids and psoriasis.

Objectives

Analysis of causality between unsaturated fatty acids and psoriasis by Mendelian randomization.

Methods

We used IEU Open GWAS Project, omega-3 PUFA and omega-6 PUFA data from 114,999 subjects, MUFA data from 13,535 subjects, and psoriasis data from 4,510 cases and 212,242 controls were included. We employed the inverse-variance weighted (IVW) method as the primary analytical approach and four additional MR methods. Moreover, we performed heterogeneity and horizontal pleiotropy assessments using Cochrane's Q and MR-Egger intercept tests, respectively. Finally, we performed sensitivity analyses to enhance our findings' precision and veracity.

Results

IVW results showed no causal effect of omega-3 PUFA on psoriasis (p = 0.334; OR, 0.909; 95% CI, 0.748-1.104), omega-6 PUFA cause psoriasis (p = 0.046; OR, 1.174; 95% CI, 1.003-1.374), MUFA cause psoriasis (p = 0.032; OR, 1.218; 95% CI, 1.018-1.457), no causal effect of omega-3 PUFA in psoriasis (p = 0.695; OR, 0.989; 95% CI, 0.937-1.044), no causal effect of omega-6 PUFA in psoriasis (p = 0.643; OR, 1.013; 95% CI, 0.960-1.068), psoriasis is not causal to MUFA (p = 0.986; OR, 1.000; 95% CI, 0.949-1.055). Heterogeneity, horizontal pleiotropy, and sensitivity analyses showed reliable results.

Conclusion

We found that circulating omega-6 PUFA and MUFA cause psoriasis, while omega-3 PUFA do not. Treatments that lower circulating omega-6 PUFA and MUFA are effective in psoriasis. After a better understanding of fatty acid intake and circulation, the population can be advised to regulate their diet.

IL-17A Orchestrates Reactive Oxygen Species/HIF1α-Mediated Metabolic Reprogramming in Psoriasis

Immune cell-derived IL-17A is one of the key pathogenic cytokines in psoriasis, an immunometabolic disorder. Although IL-17A is an established regulator of cutaneous immune cell biology, its functional and metabolic effects on nonimmune cells of the skin, particularly keratinocytes, have not been comprehensively explored. Using multiomics profiling and systems biology-based approaches, we systematically uncover significant roles for IL-17A in the metabolic reprogramming of human primary keratinocytes (HPKs). High-throughput liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy revealed IL-17A-dependent regulation of multiple HPK proteins and metabolites of carbohydrate and lipid metabolism. Systems-level MitoCore modeling using flux-balance analysis identified IL-17A-mediated increases in HPK glycolysis, glutaminolysis, and lipid uptake, which were validated using biochemical cell-based assays and stable isotope-resolved metabolomics. IL-17A treatment triggered downstream mitochondrial reactive oxygen species and HIF1α expression and resultant HPK proliferation, consistent with the observed elevation of these downstream effectors in the epidermis of patients with psoriasis. Pharmacological inhibition of HIF1α or reactive oxygen species reversed IL-17A-mediated glycolysis, glutaminolysis, lipid uptake, and HPK hyperproliferation. These results identify keratinocytes as important target cells of IL-17A and reveal its involvement in multiple downstream metabolic reprogramming pathways in human skin.

Assessment of relationships between bullous pemphigoid and neurological diseases: A bidirectional two-sample Mendelian randomization study

Bullous pemphigoid (BP) is the most prevalent autoimmune vesiculobullous skin illness that tends to affect the elderly. Growing evidence has hinted a correlation between BP and neurological diseases. However, existing observational studies contained inconsistent results, and the causality and direction of their relationship remain poorly understood. To assess the causal relationship between BP and neurological disorders, including Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD), and stroke. A bidirectional two-sample Mendelian randomization (MR) adopted independent top genetic variants as instruments from the largest accessible genome-wide association studies (GWASs), with BP (n = 218 348), PD (n = 482 730), AD (n = 63 926), stroke (n = 446 696), and MS (n = 115 803). Inverse variance weighted (IVW), MR-Egger, weighted mode methods, weighted median, and simple mode were performed to explore the causal association. Multiple sensitivity analyses, MR-Pleiotropy Residual Sum and Outlier (PRESSO) was used to evaluate horizontal pleiotropy and remove outliers. With close-to-zero effect estimates, no causal impact of BP on the risk of the four neurological diseases was discovered. However, we found that MS was positively correlated with higher odds of BP (OR = 1.220, 95% CI: 1.058-1.408, p = 0.006), while no causal associations were observed between PD (OR = 0.821, 95% CI: 0.616-1.093, p = 0.176), AD (OR = 1.066, 95% CI: 0.873-1.358, p = 0.603), stroke (OR = 0.911, 95% CI: 0.485-1.713, p = 0.773) and odds of BP. In summary, no causal impact of BP on the risk of PD, AD, MS and stroke was detected in our MR analysis. However, reverse MR analysis identified that only MS was positively correlated with higher odds of BP, but not PD, AD and stroke.

No causal effect of genetically determined circulating homocysteine levels on psoriasis in the European population: evidence from a Mendelian randomization study

Background

Although numerous studies demonstrated a link between plasma homocysteine (Hcy) levels and psoriasis, there still exists a certain level of controversy. Therefore, we conducted a Mendelian randomization study to investigate whether homocysteine plays a causative role in the development or exacerbation of psoriasis.

Methods

A two-sample Mendelian randomization (MR) analysis was conducted. Summary-level data for psoriasis were acquired from the latest R9 release results from the FinnGen consortium (9,267 cases and 364,071 controls). Single nucleotide polymorphisms (SNPs) robustly linked with plasma Hcy levels at the genome-wide significance threshold (p < 5 × 10-8) (18 SNPs) were recognized from the genome-wide meta-analysis on total Hcy concentrations (n = 44,147 participants) in individuals of European ancestry. MR analyses were performed utilizing the random-effect inverse variance-weighted (IVW), weighted median, and MR-Egger regression methods to estimate the associations between the ultimately filtrated SNPs and psoriasis. Sensitivity analyses were conducted to evaluate heterogeneity and pleiotropy.

Results

MR analyses revealed no causal effects of plasma Hcy levels on psoriasis [IVW: odds ratio (OR) = 0.995 (0.863-1.146), p = 0.941; weighed median method: OR = 0.985 (0.834-1.164), p = 0.862; MR-Egger regression method: OR = 0.959 (0.704-1.305), p = 0.795]. The sensitivity analyses displayed no evidence of heterogeneity and directional pleiotropy, and the causal estimates of Hcy levels were not influenced by any individual SNP.

Conclusion

Our study findings did not demonstrate a causal effect of genetically determined circulating Hcy levels on psoriasis.

The Cross Talk Between Psoriasis, Obesity, and Dyslipidemia: A Meta-Analysis

Although psoriasis is a multi-organ disease, it is usually managed as a skin disease, ignoring its associated serious comorbidities. This meta-analysis aimed to investigate the relationship between psoriasis, dyslipidemia, and obesity. Two authors independently searched three databases (PubMed, Medical Literature Analysis and Retrieval System Online (MEDLINE), The Cochrane Library, and Google Scholar). The search was set for articles published in the English language during the period from January 2013 to August 2023. The keywords "psoriasis", "hypercholesterolemia", "dyslipidemia", "low-density lipoproteins", "high body mass index", and "obesity", were used. Out of the 145 full texts reviewed, only seven studies fulfilled the inclusion and exclusion criteria (773,761 participants and 196,593 events). Psoriasis was associated with dyslipidemia and obesity (odds ratio (OR)=1.63, 95% CI: 1.42-1.88 and OR=1.70, 95% CI: 1.43-2.02), respectively, with significant heterogeneity (98% and 97%, respectively). Dyslipidemia and obesity were significant psoriasis comorbidities; a broader approach, viewing psoriasis as a multi-organ disease, is recommended for optimal treatment and outcomes.

A Holistic View of Psoriasis: Examining Its Association With Dyslipidemia and Obesity in a Decade-Long Systematic Review and Meta-Analysis

Psoriasis is a multifaceted inflammatory condition with systemic implications, impacting not only the skin but also various organs and overall health. It is associated with mood disorders, malignancy, infections, and components of metabolic syndrome, including diabetes, atherogenic dyslipidemia, and obesity. The coexistence of psoriasis with obesity poses additional challenges, as obesity worsens psoriasis severity and reduces treatment effectiveness. This systematic review and meta-analysis aim to further understand the associations between psoriasis, dyslipidemia, and obesity. Our systematic review of six studies revealed significant links between psoriasis and both dyslipidemia and obesity. Individuals with psoriasis exhibited a 1.40-fold higher likelihood of dyslipidemia (odds ratio (OR) 1.40, 95% confidence interval (CI) 1.24-1.58) and a 1.37-fold higher likelihood of obesity (OR 1.37, 95% CI 1.23-1.53) compared to those without psoriasis. These findings emphasize the systemic nature of psoriasis and its implications for metabolic health. In conclusion, this review underscores the importance of holistic management for psoriasis patients. Further research is warranted to explore underlying mechanisms and develop targeted therapeutic strategies. These findings contribute valuable insights to promote the overall well-being of individuals with psoriasis.

Association between psoriasis and serum apolipoprotein A1 and B: A systematic review and meta-analysis

Background

Psoriasis has been linked to dyslipidemia. However, the magnitude of the association between psoriasis and serum apolipoproteins A1 and B remains unclear.

Methods

We systematically searched PubMed, Embase, and Cochrane Library databases for eligible studies published before August 10, 2023. Data were pooled using Stata software. We adopted a random-effects model for the meta-analysis. Additionally, we conducted subgroup analyses of the studies according to the psoriasis type and matched body mass index (BMI).

Results

Seventeen studies involving 2467 participants were included. Psoriasis was associated with decreased serum apolipoprotein A1 (weighted mean difference [WMD] = -9.05, P < 0.001) and increased serum apolipoprotein B (WMD = 11.68, P < 0.001). In subgroup analysis after matching BMI, the findings showing an association of psoriasis with serum apolipoprotein A1 (WMD = -14.07, P < 0.001) and serum apolipoprotein B (WMD = 13.07, P < 0.001) were consistent with the overall results. The subgroup analysis for the presence or absence of psoriatic arthritis showed that serum apolipoprotein A1 was significantly decreased in psoriasis with (WMD = -11.29, P < 0.001) and without arthritis (WMD = -8.69, P = 0.039); whereas serum apolipoprotein B was significantly increased in psoriasis with (WMD = 13.57, P < 0.001) and without arthritis (WMD = 9.21, P < 0.001).

Conclusions

Our study revealed that psoriasis is associated with decreased serum apolipoprotein A1 and increased serum apolipoprotein B levels compared with healthy controls.

Metabolic Syndrome Screening and Nutritional Status of Patients with Psoriasis: A Scoping Review

Background: Patients with plaque psoriasis have an increased risk of metabolic syndrome. However, no studies have assessed the nutritional status or screening methods of this population. Aims: This review aimed to identify and summarise metabolic syndrome screening criteria and the tools/methods used in nutrition assessment in patients with plaque psoriasis. Data synthesis: PubMed, Web of Science, Ovid and Scopus were searched from inception to March 2023, following the Arkensey and O'Malley framework, to identify articles that report nutritional assessment methods/tools and metabolic screening criteria. Twenty-one studies were identified. Overall, these studies used four different screening criteria to define metabolic syndrome. Patients with psoriasis had a high prevalence of metabolic syndrome and had a poor nutritional status compared to controls. However, only anthropometric measures such as weight, height and waist circumference were employed to determine the nutritional status. Only two studies assessed the vitamin D status. Conclusions: Patients with psoriasis have a poor nutritional status, and they are at risk of nutrient deficiencies. However, these health aspects are not routinely assessed and may increase the risk of malnutrition among these patients. Therefore, additional assessments, such as body composition and dietary assessment, are needed to determine the nutritional status to provide a suitable intervention.

Mendelian Randomization Studies in Psoriasis and Psoriatic Arthritis: A Systematic Review

Psoriasis (PSO) and psoriatic arthritis (PSA) are inflammatory diseases with complex genetic and environmental contributions. Although studies have identified environmental and clinical associations with PSO/PSA, causality is difficult to establish. Mendelian randomization (MR) employs the random assortment of genetic alleles at birth to evaluate the causal impact of exposures. We systematically reviewed 27 MR studies in PSO/PSA examining health behaviors, comorbidities, and biomarkers. Exposures, including smoking, obesity, cardiovascular disease, and Crohn's disease, were causal for PSO and PSA, whereas PSO was causally associated with several comorbidities. These findings provide insights that can guide preventive counseling and precision medicine.

Smoking is an independent but not a causal risk factor for moderate to severe psoriasis: A Mendelian randomization study of 105,912 individuals

Background

Smoking is strongly associated with higher risk of psoriasis in several observational studies; however, whether this association is causal or can be explained by confounding or reverse causation is not fully understood. Randomized controlled trials are the gold standard when examining causality; however, when this method is not feasible, the Mendelian randomization design is an alternative. Herein genetic variants can be used as robust proxies for modifiable exposures and thereby avoiding confounding and reverse causation.In this study, we hypothesized that smoking is an independent and causal risk factor for psoriasis and tested this using a Mendelian randomization design.

Methods

We used data from the Copenhagen General Population Study including 105,912 individuals with full information on lifestyle factors, biochemistry, and genotype data. In total, 1,240 cases of moderate to severe psoriasis were included to investigate the association between smoking and psoriasis. To assess causality of the association, we used the genetic variant CHRNA3 rs1051730, where the T-allele is strongly associated with high lifelong cumulative smoking, as a proxy for smoking.

Results

In observational analyses, the multivariable adjusted hazard ratio of developing moderate to severe psoriasis was 1.64 (95% confidence interval: 1.35-2.00) in ever smokers with ≤ 20 pack-years and 2.23 (1.82-2.73) in ever smokers with > 20 pack-years compared to never smokers. In genetic analyses, the odds ratio of developing moderate to severe psoriasis was 1.05 (0.95-1.16) per CHRNA3 rs10511730 T-allele in ever smokers.

Conclusion

Smoking was an independent risk factor for moderate to severe psoriasis in observational analyses. However, using a genetic variant as a robust proxy for smoking, we did not find this association to be causal.

Non-alcoholic fatty liver disease is not a causal risk factor for psoriasis: A Mendelian randomization study of 108,835 individuals

Background

Psoriasis is observationally associated with a higher risk of non-alcoholic fatty liver disease (NAFLD); however, the causal relationship between the two diseases remains unclear.

Objective

We hypothesized that individuals with NAFLD or elevated liver fat content have higher risk of psoriasis and that NAFLD is a causal risk factor for psoriasis. We tested this using a Mendelian randomization approach.

Methods

We included 108,835 individuals from the Danish general population, including 1,277 individuals with psoriasis and 802 individuals with NAFLD according to ICD codes. To estimate liver fat content, a subset of the participants (N = 7,416) also had a CT scan performed. First, we tested whether a diagnosis of NAFLD or elevated liver fat content was observationally associated with risk of psoriasis. Subsequently, we used the genetic variants PNPLA3 and TM6SF2, both strongly associated with NAFLD and high liver fat content, to test whether NAFLD was causally associated with increased risk of psoriasis.

Results

Observationally, individuals with vs. without a diagnosis of NAFLD had higher risk of psoriasis with an odds ratio of 2.03 (95% confidence interval 1.28-3.21). The risk of psoriasis increased in a stepwise manner with increasing liver fat content with an odds ratio of 5.00 (2.63-9.46) in individuals in the highest quartile of liver fat content compared to individuals in the lowest quartile. In genetic analyses, PNPLA3 and TM6SF2 were both associated with increased risk of NAFLD but not with increased risk of psoriasis.

Conclusion

Observationally, a diagnosis of NAFLD or elevated liver fat content was associated with higher risk of psoriasis. However, using genetic variants as a proxy for NAFLD, we did not find evidence of a causal relationship between NAFLD and psoriasis. Thus, the observational association between NAFLD and psoriasis is presumably a result of shared confounding factors or reverse causation.