Causal Relationship Between Sleep Traits and Risk of Systemic Lupus Erythematosus: A Two-Sample Mendelian Randomization Study

Analysis of the causal relationship between immune cells and rheumatoid arthritis from the perspective of genetic variation: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Immune factors are crucial in the pathogenesis of rheumatoid arthritis (RA), and immune cells play a key role in the development of RA. However, there is still disagreement regarding the specific roles of each type of immune cell in the pathological process of RA.

METHODS

This study used bidirectional two-sample Mendelian randomization (MR) analysis to determine the causal relationship between immune cell characteristics and RA. Utilizing publicly available genetic data, we initially treated immune cell characteristics as exposures to investigate their causal effects on the risk of RA. Subsequently, we performed reverse two-sample MR using the positively selected cells from the initial analysis as outcomes, aiming to identify the core immune cells involved. Finally, a comprehensive sensitivity analysis was conducted to validate the robustness, heterogeneity, and horizontal pleiotropy of the results.

RESULTS

Using data from 731 immune cells as exposures and cell SNPs as instruments, we independently conducted two-sample MR analysis for each patient with RA. The main analytical method used was the IVW method, with a significance level set at P < 0.05 for inclusion. In total, we identified 42 immune cell phenotypes that were causally associated with the onset of RA. For the reverse MR analysis, we used RA as the exposure factor and focused on 42 immune cell phenotypes as outcomes. Our analysis revealed causal relationships between the onset of RA and 7 immune cell phenotypes. Among these, 6 showed positive causal relationships, while 1 exhibited a negative causal relationship.

CONCLUSIONS

Our study emphasized the causal relationship between immune cells and RA through bidirectional two-sample MR analysis, identifying the immune cells causally associated with RA.

Study of the causal relationship between gastroesophageal reflux disease and hypertension through two-sample Mendelian randomization analysis

Objective

The purpose of this study was to investigate the causal relationship between gastroesophageal reflux disease (GERD) and hypertension using a two-sample Mendelian randomization analysis.

Methods

The associated data of GERD with hypertension were derived from the genome-wide association study (GWAS) database, and two-sample Mendelian randomization (MR) analysis was performed using methods including inverse variance weighting (IVW), MR-Egger, and weighted median (WM) to investigate the causal association between GERD and hypertension.

Results

A total of 16 single nucleotide polymorphisms (SNPs) strongly associated with GERD were screened out, and the IVW suggested a causal relationship between GERD and hypertension (OR: 1.057; 95% CI: 1.044-1.071; P < 0.05). The weighted median also showed a similar relationship (OR: 1.051, 95% CI: 1.032-1.07; P < 0.05). In addition, no heterogeneity or horizontal pleiotropy was observed, suggesting a robustness of the outcome.

Conclusion

There is a positive causal relationship between GERD and hypertension.

Causal relationship between thyroid function and multiple sclerosis: A bidirectional Mendelian randomization study

An association between thyroid function and multiple sclerosis (MS) has been reported in several observational studies, but the causal relationship between them is still unclear. Thus, this study used a bidirectional Mendelian randomization (MR) to investigate the associations between thyroid function and MS. Bidirectional MR was used to explore the causal relationship between thyroid function (thyroid-stimulating hormone [TSH], free thyroxine [FT4], hyperthyroidism, and hypothyroidism) and MS. Genome-wide association study (GWAS) data of thyroid function and MS were obtained from the ThyroidOmics Consortium and the FinnGen Consortium, respectively. Inverse-variance weighted method (IVW) was the primary analysis method to assess causality with Weighted median, MR-Egger regression, weighted mode, and simple mode as auxiliary methods. Sensitivity analyses were performed using heterogeneity tests, horizontal pleiotropy tests and leave-one-out method. There was a positive causal relationship between TSH and MS (IVW: OR = 1.202, 95% CI: 1.040-1.389, P = .013), and no strong evidence was found for an effect of FT4 (IVW: OR = 1.286, 95% CI: 0.990-1.671, P = .059), hypothyroidism (IVW: OR = 1.247, 95% CI: 0.961-1.617, P = .096), and hyperthyroidism (IVW: OR = 0.966, 95% CI: 0.907-1.030, P = .291) on the risk of MS. In the reverse MR results, there was no causal relationship between MS and TSH (IVW: β = -0.009, P = .184), FT4 (IVW: β = -0.011, P = .286), hypothyroidism (IVW: OR = 0.992, 95% CI: 0.944-1.042, P = .745), and hyperthyroidism (IVW: OR = 1.026, 95% CI: 0.943-1.117, P = .549). Cochran's Q test, MR-Egger intercept test, MR-PRESSO global test, and Leave-one-out did not observe horizontal pleiotropy and heterogeneity. In conclusion, MR analysis supported a positive causal relationship between TSH and MS.

The causal relationship between sleep characteristics and multi-site pain perception: a two-sample Mendelian randomization study

Objective

This Mendelian Randomization (MR) study aims to explore the potential causal relationships between four sleep traits and pain in 10 different body sites.

Materials and methods

The study utilizes exposure and outcome data from the GWAS database, employing the Inverse Variance Weighting Method (IVW) for primary causal estimates. Cochran Q and Rücker Q heterogeneity tests are conducted using IVW and MR-Egger methods, with the Egger-intercept method for pleiotropy testing, leave-one-out sensitivity analysis, and calculation of F-statistics to assess the presence of weak instrument bias.

Results

The study reveals that genetically predicted insomnia significantly increases the risk of unspecified pain, chest pain, gum pain, upper abdominal pain, and lower abdominal pain occurrence. Daytime napping is associated with a moderate reduction in the likelihood of joint pain but may concomitantly elevate the risk of chest pain, upper abdominal pain, and generalized abdominal pain. Neither sleep chronotype nor sleep duration demonstrated a definitive causal relationship with pain perception.

Conclusion

This study elucidates the causal relationships between four sleep characteristics and pain across 10 different body regions. Overall, the contribution of insomnia and sleep deficiency to pain in multiple body regions is more pronounced. Conversely, the association between adequate sleep and the likelihood of somatic pain is relatively lower and less significant.

Effects of antibiotic cocktail on the fecal microbiota and their potential correlation of local immune response

BACKGROUND

The guts of mammals are home to trillions of microbes, forming a complex and dynamic ecosystem. Gut microbiota is an important biological barrier for maintaining immune homeostasis. Recently, the use of antibiotics to clear gut microbiota has gained popularity as a low cost and easy-to-use alternative to germ-free animals. However, the effect of the duration of the antibiotic cocktail on the gut microbiome is unclear, and more importantly, the effect of dramatic changes in the gut microbiota on intestinal tissue morphology and local immune response is rarely reported.

RESULTS

We observed a significant reduction in fecal microbiota species and abundance after 1 week of exposure to an antibiotic cocktail, gavage twice daily by intragastric administration. In terms of composition, Bacteroidetes and Firmicutes were replaced by Proteobacteria. Extending antibiotic exposure to 2-3 weeks did not significantly improve the overall efficiency of microbiotal consumption. No significant histomorphological changes were observed in the first 2 weeks of antibiotic cocktail exposure, but the expression of inflammatory mediators in intestinal tissue was increased after 3 weeks of antibiotic cocktail exposure. Mendelian randomization analysis showed that Actinobacteria had a significant causal association with the increase of IL-1β (OR = 1.65, 95% CI = 1.23 to 2.21, P = 0.007) and TNF-α (OR = 1.81, 95% CI = 1.26 to 2.61, P = 0.001).

CONCLUSIONS

Our data suggest that treatment with an antibiotic cocktail lasting 1 week is sufficient to induce a significant reduction in gut microbes. 3 weeks of antibiotic exposure can lead to the colonization of persistant microbiota and cause changes in intestinal tissue and local immune responses.

No genetic association between sleep traits and periodontitis: A bidirectional two-sample Mendelian randomization study

OBJECTIVE

This study aimed to investigate the potential genetic link between sleep traits and periodontitis.

METHODS

A two-sample bidirectional Mendelian randomization (MR) analysis was conducted using publicly available genome-wide association studies data on chronotype, daytime sleepiness, daytime napping frequency, insomnia, sleep duration, snoring, and the apnea-hypopnea index (AHI), along with a separate dataset on periodontitis.

RESULTS

Chronotype (OR = 0.929, 95% CI = 0.788-1.095), daytime sleepiness (OR = 0.492, 95% CI = 0.186-1.306), daytime napping frequency (OR = 1.178, 95% CI = 0.745-1.863), sleep duration (OR = 0.868, 95% CI = 0.644-1.169), AHI (OR = 1.124, 95% CI = 0.980-1.289), insomnia (OR = 0.832, 95% CI = 0.440-1.573), and snoring (OR = 0.641, 95% CI = 0.198-2.075) had no effect on periodontitis. Similarly, periodontitis demonstrated no significant effect on sleep traits.

CONCLUSIONS

There is no evidence of a bidirectional genetic relationship between sleep traits and the risk of periodontitis.

Genetic analyses of the bidirectional associations between common mental disorders and asthma

Objective

Although extensive research has explored the link between mental disorders and asthma, the characteristics and patterns of this association are still unclear. Our study aims to examine the genetic causal links between common mental disorders (specifically, anxiety and depression) and asthma.

Methods

We conducted genetic analyses including linkage disequilibrium score regression (LDSC) and bidirectional two-sample Mendelian randomization (MR) analyses, and utilized summary statistics from recent large-scale Genome-Wide Association Studies (GWASs) in European populations, covering sensation of anxiety or depression, anxiety sensation, depression sensation, anxiety disorders, major depression disorder (MDD), and asthma.

Results

LDSC revealed significant genetic correlations among sensation of anxiety or depression, MDD and asthma (P < 0.017), highlighting potential genetic correlation between anxiety disorders and asthma (P < 0.05 yet > 0.017). In bidirectional two-sample MR, inverse-variance weighted (IVW) analyses suggested that genetic liability to asthma was significantly associated with an increased risk of sensation of anxiety or depression (OR = 4.760, 95%CI: 1.645-13.777), and MDD (OR = 1.658, 95%CI: 1.477-1.860). Conversely, IVW analyses indicated that genetic liability to anxiety disorders was not associated with an increased risk of asthma (P > 0.01), nor was genetic liability to asthma associated with an increased risk of anxiety disorders (P > 0.01). Furthermore, no significant genetic causal relationships were observed for other studied traits. Multivariate MR, after adjusting for body mass index and alcohol consumption, further corroborated the independent causal effect of genetic predisposition to MDD on the risk of asthma (OR = 1.460, 95% CI: 1.285-1.660).

Conclusion

Our study establishes MDD as a predisposing factor for asthma. Meanwhile, anxiety disorders are not causal risk factors for asthma, nor is the reverse true. It is recommended to closely monitor asthma symptoms in patients with MDD.

The role of circadian clock in regulating cell functions: implications for diseases

The circadian clock system orchestrates daily behavioral and physiological rhythms, facilitating adaptation to environmental and internal oscillations. Disruptions in circadian rhythms have been linked to increased susceptibility to various diseases and can exacerbate existing conditions. This review delves into the intricate regulation of diurnal gene expression and cell function by circadian clocks across diverse tissues. . Specifically, we explore the rhythmicity of gene expressions, behaviors, and functions in both immune and non-immune cells, elucidating the regulatory effects and mechanisms imposed by circadian clocks. A detailed discussion is centered on elucidating the complex functions of circadian clocks in regulating key cellular signaling pathways. We further review the circadian regulation in diverse diseases, with a focus on inflammatory diseases, cancers, and systemic diseases. By highlighting the intimate interplay between circadian clocks and diseases, especially through clock-controlled cell function, this review contributes to the development of novel disease intervention strategies. This enhanced understanding holds significant promise for the design of targeted therapies that can exploit the circadian regulation mechanisms for improved treatment efficacy.

Causal association between systemic lupus erythematosus and the risk of migraine: A Mendelian randomization study

BACKGROUND

Numerous studies have found that patients with systemic lupus erythematosus (SLE) often have comorbid headache, especially migraine. However, the causal relationship between genetically determined SLE and migraine risk remains unclear. Therefore, we conducted a Mendelian randomization (MR) study to explore this causal association.

METHODS

Genome-wide association studies (GWAS) provided the instrumental variables. We selected summary data from GWAS of SLE as exposure (5201 SLE patients and 9066 controls). Both outcome GWAS data were from the Finnish Gene GWAS, including migraine with aura, migraine with aura and triptan purchases, and migraine without aura. The main MR approach was inverse-variance weighted. Pleiotropy and heterogeneity were detected using the MR pleiotropy residual sum and outlier, MR-Egger intercept test, leave-one-out analysis, and Cochran's Q test.

RESULTS

There was a significant association between genetically predicted SLE susceptibility and increased risk of migraine with aura [odds ratio (OR) = 1.05, 95% confidence interval (CI) = 1.02-1.08, p = .001]. The result was consistent when the outcome was migraine with aura and triptan purchases [OR = 1.05, 95% CI = 1.02-1.08, p = .001]. However, we found no association between SLE and migraine without aura. Our MR study showed no pleiotropy or heterogeneity.

CONCLUSIONS

Our study indicates that genetic susceptibility to SLE increases the incidence of migraine with aura but not migraine without aura. It is necessary for the routine evaluation and early recognition of migraine in patients with SLE in clinical settings.

Potential genetic and epigenetic mechanisms in insomnia: A systematic review

Insomnia is a stress-related sleep disorder conceptualised within a diathesis-stress framework, which it is thought to result from predisposing factors interacting with precipitating stressful events that trigger the development of insomnia. Among predisposing factors genetics and epigenetics may play a role. A systematic review of the current evidence for the genetic and epigenetic basis of insomnia was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) system. A total of 24 studies were collected for twins and family heritability, 55 for genome-wide association studies, 26 about candidate genes for insomnia, and eight for epigenetics. Data showed that insomnia is a complex polygenic stress-related disorder, and it is likely to be caused by a synergy of genetic and environmental factors, with stress-related sleep reactivity being the important trait. Even if few studies have been conducted to date on insomnia, epigenetics may be the framework to understand long-lasting consequences of the interaction between genetic and environmental factors and effects of stress on the brain in insomnia. Interestingly, polygenic risk for insomnia has been causally linked to different mental and medical disorders. Probably, by treating insomnia it would be possible to intervene on the effect of stress on the brain and prevent some medical and mental conditions.

Causal association of metformin and osteoporosis: A 2-sample Mendelian randomization study

To investigate the causal relationship between metformin use and osteoporosis and different subtypes of osteoporosis using a 2-sample Mendelian randomization method. Data from genome-wide association studies were analyzed, with the exposure factor being metformin and the outcome variables being osteoporosis and different subtypes. Mendelian randomization was performed using Inverse Variance Weighted (IVW), MR-Egger, and weight median (WM) methods, and heterogeneity tests, horizontal multivariate analyses, and sensitivity analyses were performed. The IVW method analysis with metformin and osteoporosis showed P = 1.53E-04, OR (95%CI) = 1.81E-02 (2.27E-02-1.44E-01); the IVW method analysis with metformin and postmenopausal osteoporosis with pathologic fracture showed P = 2.22E-01, OR (95%CI) = 4.89E-02 (3. 83E-04-6.23E + 00); the IVW method using metformin with osteoporosis with pathological fracture showed that P = 2.14E-01, OR (95%CI) = 1.64E + 00(5.78E-02-6.44E-04); the IVW method using metformin with pharmacological osteoporosis with pathological fracture showed that P = 9. 83E- 01, OR (95%CI) = 1.11E + 00 (3.99E-05-3.11E + 04); IVW method of metformin use and pharmacological osteoporosis showed that P = 5.99E-01, OR (95%CI) = 2.27E + 01 (2.00E-04-2.57E + 06); there is a causal relationship between metformin use and osteoporosis, but there is no causal relationship between metformin use and postmenopausal osteoporosis with pathological fracture, osteoporosis with pathological fracture, pharmacological osteoporosis, and pharmacological osteoporosis with pathological fracture, and metformin use is a protective factor for osteoporosis.

Association between sarcopenia-related traits and cardiovascular diseases: a bi-directional Mendelian randomization study

Background

The two geriatric diseases, sarcopenia and cardiovascular disease (CVD), often coexist, yet the causal relationship is unclear. However, few studies focus on the effect of muscle mass on CVD. This comprehensive study is dedicated to unearthing the potential connection between sarcopenia-related traits and CVD at the genetic level.

Method

A two-sample bi-directional Mendelian randomization (MR) study was conducted. In the first stage, we performed MR analysis regarding coronary heart disease (CHD), stroke, and myocardial infarction (MI) as exposure factors to reveal their effect on appendicular lean mass (ALM) and hand grip strength. In the second stage, we reverse the position of exposures and outcomes. The inverse variance weighted (IVW) method was used as the primary approach to reveal the potential causation between the exposure and outcome.

Results

The results of the IVW method revealed a negative causal effect of ALM on CHD (OR = 0.848, 95% CI = 0.804 to 0.894, p = 8.200E-10), stroke (OR = 0.931, 95% CI = 0.890 to 0.975, p = 2.220E-03), and MI (OR = 0.810, 95% CI = 0.694 to 0.901, p = 1.266E-13). Additionally, the left-hand grip strength is a significant protective factor for CHD (OR = 0.737, 95% CI = 0.601 to 0.904, p = 3.353E-03) and MI (OR = 0.631, 95% CI = 0.515 to 0.765, p = 2.575E-06), but is not causally linked to the stroke (OR = 0.971, 95% CI =0.829 to 1.139, p = 0.720). Meanwhile, the same conclusion about the effect of right-hand grip strength on CHD (OR = 0.681, 95% CI = 0.558 to 0.832, p = 1.702E-05), MI (OR = 0.634, 95% CI = 0.518 to 0.776, p = 9.069E-06), and stroke (OR = 1.041, 95% CI = 0.896 to 1.209, p = 0.604) was obtained. However, no significant causal effect of CVD (CHD, stroke, MI) on sarcopenia-related traits (ALM, handgrip strength) was found.

Conclusion

There is a unidirectional causal relationship between sarcopenia and CVD. The loss of muscle mass and strength has a significant causal role in promoting the occurrence and development of CVD, providing a reference for the prevention and treatment of comorbidities in older people.

A Mendelian randomization-based approach to explore the relationship between leukocyte counts and breast cancer risk in European ethnic groups

Exploring the potential association between peripheral blood leukocyte counts and breast cancer risk by Mendelian randomization (MR) analysis methods. Genetic data related to peripheral blood sorting counts of leukocytes were collected from a genome-wide association study by Blood Cell Consortium (BCX). Single nucleotide polymorphic loci predicting peripheral blood sorting counts of these leukocytes were selected as instrumental variables according to the correlation assumption, independence assumption and exclusivity assumption of MR. The data on breast cancer and its subtypes were obtained from Breast Cancer Association Consortium (BCAC) and FinnGen Consortium. In this study, the Inverse-Variance Weighted (IVW), Weighted Median, MR-Egger, Maximum Likelihood (ML), MR-PRESSO and Constrained Maximum Likelihood and Model Averaging (cML-MA) methods of random effects models were used for MR analysis. Cochran's Q analysis, and MR-Egger intercept analysis were applied for sensitivity analysis. IVW and cML-MA were considered the primary analytical tools, and the results of the other 4 MRs were used as complementary and validation. The results suggest that there is no significant causal relationship between leukocyte count and breast cancer risk (IVW OR = 0.98 [95% CI: 0.93-1.03], p-value = 0.35; CML-MA OR = 1.01 [95% CI: 0.98-1.05], p-value = 0.51). In addition, we analyzed whether there was a potential correlation between the five main types of categorized leukocyte counts and different breast cancer subtypes. We did not find significant evidence to support a significant correlation between leukocyte counts and breast cancer subtypes.

Causal Effects of Gut Microbiota on Sleep-Related Phenotypes: A Two-Sample Mendelian Randomization Study

Increasing evidence suggests a correlation between changes in the composition of gut microbiota and sleep-related phenotypes. However, it remains uncertain whether these associations indicate a causal relationship. The genome-wide association study summary statistics data of gut microbiota (n = 18,340) was downloaded from the MiBioGen consortium and the data of sleep-related phenotypes were derived from the UK Biobank, the Medical Research Council-Integrative Epidemiology Unit, Jones SE, the FinnGen consortium. To test and estimate the causal effect of gut microbiota on sleep traits, a two-sample Mendelian randomization (MR) approach using multiple methods was conducted. A series of sensitive analyses, such as horizontal pleiotropy analysis, heterogeneity test, MR Steiger directionality test and "leave-one-out" analysis as well as reverse MR analysis, were conducted to assess the robustness of MR results. The genus Anaerofilum has a negative causal effect on getting up in the morning (odd ratio = 0.977, 95% confidence interval: 0.965-0.988, p = 7.28 × 10-5). A higher abundance of order Enterobacteriales and family Enterobacteriaceae contributed to becoming an "evening person". Six and two taxa were causally associated with longer and shorter sleep duration, respectively. Specifically, two SCFA-produced genera including Lachnospiraceae UCG004 (odd ratio = 1.029, 95% confidence interval = 1.012-1.046, p = 6.11 × 10-4) and Odoribacter contribute to extending sleep duration. Two obesity-related genera such as Ruminococcus torques (odd ratio = 1.024, 95% confidence interval: 1.011-1.036, p = 1.74 × 10-4) and Senegalimassilia were found to be increased and decreased risk of snoring, respectively. In addition, we found two risk taxa of insomnia such as the order Selenomonadales and one of its classes called Negativicutes. All of the sensitive analysis and reverse MR analysis results indicated that our MR results were robust. Our study revealed the causal effect of gut microbiota on sleep and identified causal risk and protective taxa for chronotype, sleep duration, snoring and insomnia, which has the potential to provide new perspectives for future mechanistic and clinical investigations of microbiota-mediated sleep abnormal patterns and provide clues for developing potential microbiota-based intervention strategies for sleep-related conditions.

Environmental and occupational risk factors for COPD and its prevalence among miners worldwide: a Mendelian randomization and meta-analysis study

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death after cardiovascular disease and stroke, and its incidence is associated with genetic, environmental, and occupational factors. Miner is high-risk population for COPD, but the global prevalence of COPD in this group is inaccurate. In this study, the environmental and occupational risk factors for COPD were explored comprehensively with a two-sample Mendelian randomization study by combining genome-wide association data from two large global sample sizes of publicly available databases, UK Biobank (n = 503,317) and FinnGen (n = 193,638), as well as the prevalence of COPD among miners was investigated with meta-analysis followed a random-effects model including seven studies (16,033 miners in total). This study found that asthma, smoking, shift work, and workplace dust exposure may increase an individual's risk of COPD. The pooled prevalence of COPD among miners globally was 12% (95% CI: 8%, 18%), with higher prevalence of COPD among ex-smokers and dust-exposed individuals, and was significantly influenced by the method of diagnosis. Our findings suggest that there is currently a lack of practical criteria for diagnosing COPD in the physical examination and screening of miners. The actual prevalence of COPD may be underestimated due to the healthy worker effect and the phenomenon of job switching, and appropriate policies should be favored in the future to reduce the risk of COPD in miner.

Circadian rhythm in systemic autoimmune conditions: Potential of chrono-immunology in clinical practice: A narrative review

The circadian rhythm (CR) is a fundamental biological process regulated by the Earth's rotation and solar cycles. It plays a critical role in various bodily functions, and its dysregulation can have systemic effects. These effects impact metabolism, redox homeostasis, cell cycle regulation, gut microbiota, cognition, and immune response. Immune mediators, cycle proteins, and hormones exhibit circadian oscillations, supporting optimal immune function and defence against pathogens. Sleep deprivation and disruptions challenge the regulatory mechanisms, making immune responses vulnerable. Altered CR pathways have been implicated in diseases such as diabetes, neurological conditions, and systemic autoimmune diseases (SADs). SADs involve abnormal immune responses to self-antigens, with genetic and environmental factors disrupting self-tolerance and contributing to conditions like Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Inflammatory Myositis. Dysregulated CR may lead to increased production of pro-inflammatory cytokines, contributing to the systemic responses observed in SADs. Sleep disturbances significantly impact the quality of life of patients with SADs; however, they are often overlooked. The relationship between sleep and autoimmune conditions, whether causal or consequential to CR dysregulation, remains unclear. Chrono-immunology investigates the role of CR in immunity, offering potential for targeted therapies in autoimmune conditions. This paper provides an overview of the connections between sleep and autoimmune conditions, highlighting the importance of recognizing sleep disturbances in SADs and the need for further research into the complex relationship between the CR and autoimmune diseases.

The role of inflammatory biomarkers in the association between rheumatoid arthritis and depression: a Mendelian randomization study

BACKGROUND

Inflammation may mediate the co-pathogenesis of rheumatoid arthritis (RA) and depression because inflammatory cytokines are associated with RA and depression. However, traditional observational research was not able to address problems with residual confusion and reverse causality.

METHODS

We summarized and retrieved 28 inflammatory cytokines associated with RA, depression, or RA with depression through a literature search. The summary statistics from genome-wide association studies for RA, inflammatory biomarkers, broad depression, and major depression disease phenotypes were used. Mendelian randomization was performed to assess the causal association between RA and inflammatory biomarkers, as well as the effects of inflammatory biomarkers on depression. Bonferroni correction was used to reduce the possibility of false positive results.

RESULTS

The study found that evidence for associations of genetically predicted RA was associated with higher levels of interleukin (IL)-9 (OR = 1.035, 95%CI = 1.002-1.068, P = 0.027), IL-12 (OR = 1.045, 95%CI = 1.045-1.014, P = 0.004), IL-13 (OR = 1.060, 95%CI = 1.028-1.092, P = 0.0001), IL-20 (OR = 1.037, 95%CI = 1.001-1.074, P = 0.047), and IL-27 (OR = 1.017, 95%CI = 1.003-1.032, P = 0.021). The level of IL-7 (OR = 1.029, 95%CI = 1.018-1.436, P = 0.030) was significantly related to RA. Only the analysis results between RA and IL-13 were satisfied with the statistical significance threshold corrected by Bonferroni (P < 0.002). However, a causal effect was not found between inflammatory biomarkers and depression.

CONCLUSIONS

In the current study the inflammatory cytokines associated with RA comorbid depression may not be the mediators that directly lead to the co-pathogenesis of RA and depression.

Assessment of Bidirectional Relationships between Mental Illness and Rheumatoid Arthritis: A Two-Sample Mendelian Randomization Study

A correlation between mental illness and systemic rheumatoid arthritis (RA) has been observed in several prior investigations. However, little is known about the causative relationship between them. The present study aimed to systematically investigate the potential association between genetically determined mental illness and RA. Two-sample bidirectional Mendelian randomization (MR) analysis was performed using publicly released genome-wide association studies (GWAS). We selected independent genetic variants associated with four mental illnesses (bipolar disorder, broad depression, major depression, and anxiety) as instrumental variables. The inverse variance weighted (IVW) method was used as the primary analysis to assess the causal relationship between mental illness and RA. Results of the IVW analysis suggested that genetic predisposition to bipolar disorder was associated with a decreased risk of RA (odds ratio [OR] = 0.825, 95% CI = 0.716 to 0.95, p = 0.007). Furthermore, we did not find a significant causal effect of RA on bipolar disorder in the reverse MR analysis (p > 0.05). In addition, our study found no evidence of a bidirectional causal relationship between genetically predicted broad depression, major depression, anxiety, and RA (p > 0.05). The genetically proxied bipolar disorder population has a lower RA risk, which may indicate that there is a hidden mechanism for inhibiting the pathogenesis of RA in bipolar disorder. However, results do not support a causal connection between depression, anxiety, and RA.

Bidirectional two-sample Mendelian randomization study of causality between rheumatoid arthritis and myocardial infarction

Background

Epidemiological evidence suggests an association between rheumatoid arthritis (RA) and myocardial infarction (MI). However, causality remains uncertain. Therefore, this study aimed to explore the causal association between RA and MI.

Methods

Using publicly available genome-wide association study summary datasets, bidirectional two-sample Mendelian randomization (TSMR) was performed using inverse-variance weighted (IVW), weighted median, MR-Egger regression, simple mode, and weighted mode methods.

Results

The MR results for the causal effect of RA on MI (IVW, odds ratio [OR] = 1.041, 95% confidence interval [CI]: 1.007-1.076, P = 0.017; weighted median, OR = 1.027, 95% CI: 1.006-1.049, P = 0.012) supported a causal association between genetic susceptibility to RA and an increased risk of MI. MR results for the causal effect of MI on RA (IVW, OR = 1.012, 95% CI: 0.807-1.268, P = 0.921; weighted median, OR = 1.069, 95% CI: 0.855-1.338, P = 0.556) indicated that there was no causal association between genetic susceptibility to MI and an increased risk of RA.

Conclusion

Bidirectional TSMR analysis supports a causal association between genetic susceptibility to RA and an increased risk of MI but does not support a causal association between genetic susceptibility to MI and an increased risk of RA.

Post-traumatic growth in adult patients with systemic lupus erythematosus: a cross-sectional study in China

This cross-sectional study aims to evaluate the post-traumatic growth (PTG) level and explores its predictors among adult patients with SLE in China. From April 2020 to April 2021, 135 hospitalized adult SLE patients completed the questionnaire including sociodemographic and disease-related data, Post-traumatic Growth Inventory (PTGI), Medical Coping Modes Questionnaire (MCMQ), Social Support Rating Scale (SSRS), Pittsburgh Sleep Quality Index (PSQI), Hospital Anxiety and Depression Scale (HADS), and Self-Perceived Burden Scale (SPBS). Descriptive analysis, pearson's correlation analysis, and forward multiple line regression analysis were used for analysis by SPSS 22.0. Results showed that, the mean PTGI score was 57.52 ± 20.82. Pearson correlation analysis showed that, complicated autoimmune hemolytic anemia (r = - 0.185), CD4 +/CD8 + (r = - 0.383), acceptance-resignation (r = - 0.185), poor PSQI (r = - 0.215), and depression (r = - 0.322) were negatively associated with total PTGI score; while the relationship with lupus nephritis (r = 0.247), confrontation (r = 0.313), avoidance (r = 0.379), and SSRS (r = 0.242) were positive (all P < 0.05). The total score of PTGI and its five sub-dimensions were not correlated with anxiety and self-perceived burden. Further, CD4 +/CD8 +, confrontation of MCMQ, and SSRS could explain 30.3% of the variance in total PTGI (F = 6.646, P < 0.01). In summary, Chinese adults with SLE experience moderate levels of PTG. Clinical nurses need pay attention to the current disease status and individual characteristics of patients, as well as their mental health, to promote their growth experience, so that they can cope with the future life in a better state and coexist well with SLE.