Diet-Derived Circulating Antioxidants and Risk of Coronary Heart Disease: A Mendelian Randomization Study

Levels of Asymmetric Dimethylar Ginine and Risk of Neurovascular Diseases: A Systematic Review and Meta-Analysis

SCOPE

The purpose of this study was to provide clear evidence that reliably quantifies the association of Asymmetric dimethylarginine (ADMA) levels with the risk of neurovascular diseases.

METHODS AND RESULTS

The Pubmed, Web of Science, and Embase were systematically searched to identify eligible studies published until August 2024. A total of 31 eligible studies were identified. Pooled results indicated that patients with stroke yielded a higher ADMA level than healthy controls [standardized mean difference (SMD) = 1.02, 95% CI = 0.92-1.12, P = 0.001]. Subgroup analyses showed that geographical location, sample type, number of events and the proportion of male participants were statistically significant sources of heterogeneity. Similarly, a significant association with a pooled risk ratio (RR) of 1.60 (95% CI = 1.60-1.91) was shown between ADMA exposure and the risk of stroke from seven cohort studies. There was a statistically significant difference between ADMA level and small vessel disease (SVD) (SMD = 0.33, 95% CI = 0.07-0.58, p = 0.001). In addition, migraine patients tend to have elevated ADMA levels compared to healthy controls (SMD = 0.39, 95% CI = 0.11-0.67, P = 0.001).

CONCLUSIONS

Our results indicate that ADMA levels have significant effects in patients with stroke, SVD, and migraine.

Tunable multi-enzyme activities of platinum nanoclusters for enhanced specificity and sensitivity in biosensing

Nanozymes have gained prominence for their utility in biosensing and disease diagnostics. However, challenges arise from complex sample matrices and nonspecific enzyme activities that contribute to false signals. This study introduces multifunctional platinum nanoclusters (Pt NCs) exhibiting peroxidase-like (POD-like), oxidase-like (OXD-like), and laccase-like activities tailored for enhanced biosensing capabilities. By adjusting pH, we optimized the conditions to achieve distinct POD-like and OXD-like responses, thereby reducing background signals and improving detection accuracy. The addition of ATP further amplified the POD-like activity while minimizing interference from OXD-like activity. This combined strategy substantially enhanced biomarker detection selectivity, demonstrated through glucose detection in human serum samples. Moreover, thiol inhibition of laccase-like activity in Pt NCs was leveraged for thiol-based antioxidant assessment, revealing their application in quantifying total antioxidant capacity (TAC) in human liver cancer cells, accounting for 44 % of TAC. The Pt NCs demonstrated robust sensitivity and reusability, offering a novel multi-enzyme nanomaterial with potential for precise and interference-free biosensing applications. These findings contribute to the development of advanced nanozyme-based biosensors, addressing specificity regulation challenges and expanding their practical application in biosensing and disease diagnostics.

Causal relationship between amino acids and ovarian cancer in the European population: A bidirectional Mendelian randomization study and meta-analysis

In recent years, an increasing number of observational studies have reported the impact of amino acids on ovarian cancer. However, Mendelian randomization studies have not yet been conducted to explore the causal relationship between them in the context of ovarian cancer. This study conducted Mendelian randomization (MR) analysis of 20 amino acids in relation to ovarian cancer data from 2 different sources within the European population, using a two-sample MR approach. The primary results from the inverse variance weighting analysis were then subjected to a meta-analysis, followed by multiple testing correction for the meta-analysis thresholds. Finally, reverse causality testing was performed on the positively associated amino acids and ovarian cancer. MR analyses were conducted for 20 amino acids with ovarian cancer data from both the Finngen R10 and Open genome-wide association study databases. The inverse variance weighted results from these 2 analyses were then combined through meta-analysis, with multiple corrections applied to the significance thresholds of the meta-analysis results. The findings showed that only cysteine had a significant association with ovarian cancer, with an (odds ratio) odds ratio value of 0.507 (95% confidence interval: 0.335-0.767, P = .025). The P-value of the combined MR and meta-analysis, after multiple testing correction, was 0.025, indicating statistical significance (P < .05). Additionally, cysteine did not show a reverse causal relationship with ovarian cancer in either data source. Cysteine is a protective factor for ovarian cancer, potentially reducing the risk of ovarian cancer and slowing the progression of the disease.

Association between gout and kidney stone: results from mendelian randomization and the NHANES study

Background

Kidney stones are a common urologic disease with an increasing incidence year by year, and there are similar influences between gout status and kidney stone incidence. Therefore the contribution of gout status to the incidence of kidney stones is unclear. The aim of this study was to investigate the relationship between gout status and kidney stones and to further explore the causal relationship by Mendelian randomization (MR) analysis.

Method

An epidemiologic study of 49,693 participants in the 2009-2018 National Health and Nutrition Examination Survey (NHANES) was conducted to examine the association between the two. The causal relationship between gout status and kidney stones was assessed by Mendelian randomization analysis of data from the GWAS database.

Result

A total of 28,742 participants were included in the NHANES analysis. We found that gout status was associated with an increased risk of kidney stones [odds ratio (OR) = 1.45 (95%CI, 1.243-1.692); p < 0.001]. In the MR analysis, we found a causal relationship between gout status and the risk of developing kidney stones (OR = 1.047, 95%CI, 1.011-1.085, p = 0.009).

Conclusion

There may be an association between gout status and kidney stone risk. This finding requires further large-sample studies and adequate follow-up.

Proinflammatory Diet Increases the Risk of Irritable Bowel Syndrome: A Prospective Study of 129,408 UK Biobank Participants and Mendelian Randomization Analysis

BACKGROUND

Patients with irritable bowel syndrome (IBS) often have chronic low-grade inflammation in the intestinal mucosa. Some dietary components are known to be associated with inflammation. However, there is currently limited research on the relationship between dietary inflammatory potential and the risk of IBS.

METHODS

A total of 129,408 participants in the UK Biobank were included in this study. Energy-Adjusted Dietary Inflammatory Index (E-DII) based on 26 nutrients and the Empirical Dietary Inflammatory Pattern (EDIP) based on 17 food groups were constructed, and on the basis of the tertiles, the continuous score was categorized into proinflammatory, neutral, and antiinflammatory categories. Associations between IBS and E-DII and EDIP were investigated by multivariable Cox proportional hazard models. Potential confounders including sociodemographic, lifestyle, body mass index (BMI), psychological state, type 2 diabetes, and thyroiditis were adjusted. In addition, subgroup analysis and sensitivity analysis were also performed. Finally, a two-sample Mendelian randomization (MR) analysis was employed to explore the independent causality of nutrients and dietary-derived serum antioxidants with IBS.

RESULTS

In the cohort study, over a median follow-up period of 13.26 years, 2421(1.87%) participants developed IBS. In the E-DII categories, after adjusting for the confounders, individuals in the proinflammatory diet category had a higher risk of IBS compared with the antiinflammatory category (HR 1.15, 95% CI 1.03-1.28, p = 0.015, p trend = 0.017) and neutral category (HR 1.13, 95% CI 1.01-1.26, p = 0.030, p trend = 0.017). In the EDIP categories, after adjusting for the confounders, individuals in the proinflammatory diet category had a higher risk of IBS compared with antiinflammatory category (HR 1.19, 95% CI 1.06-1.33, p = 0.002, p trend = 0.002) but no significant association compared with neutral category (HR 1.10, 95% CI 0.99-1.23, p = 0.067, p trend = 0.002). In the MR analysis, genetically determined intake levels of 16 nutrients and 6 dietary sources of circulating antioxidants did not have a causal effect on IBS.

CONCLUSIONS

Our findings indicate that proinflammatory dietary components are independent risk factors for IBS. However, there is no causal relationship between individual nutrient intake or serum antioxidants from dietary sources and IBS.

Diet-derived circulating antioxidants, periodontitis and dental caries: A Mendelian randomization study

BACKGROUND AND OBJECTIVE

Given the potential association between oxidative stress, periodontitis and dental caries, whether dietary supplementation with antioxidants is beneficial for periodontitis and dental caries has been widely reported, but remains controversial. This study aims to clarify these relationships through two-sample Mendelian randomization (MR) analysis.

METHODS

Circulating antioxidants (copper, selenium, zinc, ascorbate, β-carotene, lycopene, retinol and vitamin E) were derived from absolute circulating antioxidants and circulating antioxidant metabolites. Summary data of periodontitis and dental caries were obtained from two separate databases, respectively. We performed inverse-variance weighted (IVW) analysis separately in different databases, followed by meta-analysis. The robustness of results was examined by sensitivity analyses, including three complementary MR methods, heterogeneity and pleiotropy tests, and PhenoScanner query.

RESULTS

IVW analysis showed that elevated levels of absolute circulating retinol reduced the risk of periodontitis (GLIDE: OR = 0.41, 95% CI = 0.18-0.95, p = .038, power = 100%; FinnGen: OR = 0.15, 95% CI = 0.04-0.54, p = .004, power = 100%). The pooled OR for periodontitis risk per unit increase of retinol is 0.30 (95% CI = 0.15-0.61, p = .001, I2 = 40.3%, power = 100%). No significant associations were noted for genetically predicted circulating antioxidants and dental caries risk. The sensitivity analyses yielded similar estimates.

CONCLUSION

This study demonstrates that a negative causality between circulating retinol and periodontitis risk, and null linkage between circulating antioxidants and dental caries risk, suggesting potential strategies for the prevention and control of periodontitis.

Causal relationship between 150 skin microbiomes and prostate cancer: insights from bidirectional mendelian randomization and meta-analysis

Background

Despite relevant research, the relationship between skin microbiomes and prostate cancer remains controversial. This study utilizes bidirectional Mendelian randomization (MR) analysis combined with meta-analysis to explore the potential link between the two.

Objective

This study aims to identify the causal relationship between 150 skin microbiomes and prostate cancer (PCa) using bidirectional Mendelian randomization (MR) and meta-analysis.

Methods

This study employed a comprehensive Bidirectional Two-sample MR analysis using publicly available genetic data to ascertain the relationship between 150 skin microbiomes and PCa. We conducted extensive sensitivity analyses, tests for heterogeneity, and assessments of horizontal pleiotropy to ensure the accuracy of our results. Subsequently, we conducted a meta-analysis to strengthen our conclusions' robustness further. Finally, we performed reverse causal verification on the positive skin microbiomes and PCa.

Results

After conducting a meta-analysis and multiple corrections of the MR analysis results, our findings reveal a correlation between Neisseria in dry skin and PCa risk, identifying it as a risk factor. The IVW result shows an Odds Ratio (OR) of 1.009 (95% Confidence Interval [CI]: 1.004-1.014, P = 0.027). Furthermore, the reverse MR analysis indicates the absence of an inverse causal relationship between the two. Apart from the identified skin microbiome, no significant associations were found between the other microbiomes and PCa.

Conclusions

The study identified a correlation between Neisseria in dry skin, one of the 150 skin microbiomes, and the risk of developing PCa, establishing it as a risk factor for increased susceptibility to PCa.

Exploring the causal associations between diet-derived circulating antioxidants and the risk of endometriosis: a Mendelian randomization study

Background

Numerous observational studies and randomized controlled trials have recently revealed the associations between circulating antioxidants and the risk of endometriosis, while the underlying causal relationship remains unclear. This study aimed to investigate the causal association between genetically determined circulating antioxidants and the risk of endometriosis using Mendelian randomization (MR).

Methods

A two-sample MR analysis was conducted using publicly available summary data from genome-wide association studies (GWAS) to investigate the causal impact of genetically determined absolute circulating antioxidants (such as ascorbate, retinol, β-carotene, and lycopene) and their metabolites (including α-and γ-tocopherol, ascorbate, and retinol) on the risk of endometriosis. The study used inverse variance weighted (IVW) or Wald ratio analyses as the primary estimation method and also conducted sensitivity analyses to assess heterogeneity and pleiotropy.

Results

No significant causality was observed for genetically determined circulating antioxidants and the risk of endometriosis. The pooled odds ratios (ORs) for absolute circulating antioxidants were 0.62 (95% CI: 0.32-1.18, retinol), 0.95 (95% CI: 0.79-1.15, β-carotene), 1.01 (95% CI: 0.95-1.08, lycopene), and 1.00 (95% CI: 0.99-1.02, ascorbate, expressed as a Wald ratio). The pooled ORs indicating the EM risk per unit increase in circulating antioxidant metabolites were 1.04 (95% CI: 0.82-1.33, γ-tocopherol), 0.91 (95% CI: 0.57-1.46, α-tocopherol), 1.03 (95% CI: 0.99-1.07, retinol), and 0.96 (95% CI: 0.87-1.06, ascorbate).

Conclusion

Our study demonstrated that increased levels of diet-derived circulating antioxidants were not significantly associated with a reduced risk of endometriosis.

Mendelian randomization study of childhood asthma and chronic obstructive pulmonary disease in European and East Asian population

Objective

The present study aimed to explore the potential causal relationship between childhood asthma and chronic obstructive pulmonary disease (COPD) in European and East Asian populations with Mendelian randomization (MR) analysis.

Methods

Based on summary data from genome-wide association studies, single nucleotide polymorphisms (SNPs) associated with childhood asthma were used as instrumental variables. The MR analysis employed the inverse variance weighting, MR-Egger regression and weighted median method to estimate the causal effect between childhood asthma and COPD in European and East Asian populations. Cochran's Q test, MR-PRESSO method and MR-Egger intercept were used to detect heterogeneity, outliers and horizontal pleiotropy, respectively. Leave-one-out analysis applied to assess the effect of removing individual SNP on the estimate of causal association.

Results

The MR analysis showed no genetic causal relationship between childhood asthma and COPD. The results of Cochran's Q test, MR-PRESSO and MR-Egger regression indicated the absence of heterogeneity, outliers and horizontal pleiotropy, respectively. Leave-one-out analysis showed no significant difference in the statistical results after exclusion of single SNPs.

Conclusions

The MR analysis revealed that there is no causal relationship between childhood asthma and COPD at the genetic level in both European and East Asian populations. Additionally, due to the presence of shared confounding factors and pathogenic genes, further research is needed to comprehensively assess the relationship between childhood asthma and COPD.

Effects of multiple protection model in the operating room on physiological stress and risk events in patients undergoing coronary artery stent implantation

OBJECTIVE

To analyze the impact of multiple protection model in the operating room on patients' physiological stress and risk events after coronary artery stent implantation (CASI).

METHODS

During October 2021 to October 2022, 150 patients with coronary heart disease (CHD) were picked as the research subjects, all of whom underwent CASI. The clinical data were retrospectively analyzed, and the patients were divided into two groups according to different nursing methods, with 75 cases in each group. Patients in the intervention group received multiple protection model intervention in the operating room, and the patients in the control group adopted conventional care model. The patient satisfaction with nursing, postoperative recovery, psychological stress scores, physiological stress indicators, and adverse cardiac risk events were recorded.

RESULTS

Patients in the intervention group had much higher percentage of the patient satisfaction with nursing than those in the control group (P < 0.05). The time to get out of bed and hospital stay was significantly shorter and the 6-min walking distance was markedly longer in the intervention group than the control (P < 0.05). The Hamilton Anxiety (HAMA) scale and Hamilton Depression (HAMD) scale score of patients in two groups were sharply decreased after the intervention (P < 0.05), which were strongly lower in the intervention group than the control (P < 0.001). After the intervention, the heart rate, cortisol and epinephrine of patients were all sensibly elevated in two groups (P < 0.05), which were all memorably lower in the intervention group than the control (P < 0.001). The incidence of adverse cardiac risk events in the intervention group was 5.33%, which was dramatically lower than 16.00% in the control group (P < 0.05).

CONCLUSION

The application of multiple protection model in the operating room on patients undergoing coronary stent implantation promoted postoperative recovery, reduced patients' psychological and physiological stress, maintained blood pressure and other vital signs, reduced the incidence of adverse cardiac risk events, and improved the patient satisfaction with nursing.

Isoliquiritigenin in combination with visceral adipose tissue and related markers as a predictive tool for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world. New non-invasive diagnostic tools are needed to promptly treat this disease and avoid its complications. This study aimed to find key metabolites and related variables that could be used to predict and diagnose NAFLD. Ninety-eight subjects with NAFLD and 45 controls from the Fatty Liver in Obesity (FLiO) Study (NCT03183193) were analyzed. NAFLD was diagnosed and graded by ultrasound and classified into two groups: 0 (controls) and ≥ 1 (NAFLD). Hepatic status was additionally assessed through magnetic resonance imaging (MRI), elastography, and determination of transaminases. Anthropometry, body composition (DXA), biochemical parameters, and lifestyle factors were evaluated as well. Non-targeted metabolomics of serum was performed with high-performance liquid chromatography coupled to time-of-flight mass spectrometry (HPLC-TOF-MS). Isoliquiritigenin (ISO) had the strongest association with NAFLD out of the determinant metabolites. Individuals with higher concentrations of ISO had healthier metabolic and hepatic status and were less likely to have NAFLD (OR 0.13). Receiver operating characteristic (ROC) curves demonstrated the predictive power of ISO in panel combination with other NAFLD and IR-related variables, such as visceral adipose tissue (VAT) (AUROC 0.972), adiponectin (AUROC 0.917), plasmatic glucose (AUROC 0.817), and CK18-M30 (AUROC 0.810). Individuals with lower levels of ISO have from 71 to 82% more risk of presenting NAFLD compared to individuals with higher levels. Metabolites such as ISO, in combination with visceral adipose tissue, IR, and related markers, constitute a potential non-invasive tool to predict and diagnose NAFLD.

Causal relationships between dietary antioxidant vitamin intake and atopic dermatitis: A two-sample Mendelian randomization study

OBJECTIVE

Oxidative stress is strongly associated with atopic dermatitis (AD), and increased antioxidant intake could potentially reduce the risk of or alleviate its symptoms. However, the argument is disputed. Therefore, we conducted a Mendelian randomization (MR) analysis to explore the causal relationship between dietary antioxidant vitamin intake and AD.

METHODS

We applied MR analysis to examine the causative association between dietary antioxidant vitamin intake (vitamin C, vitamin E, carotene, and retinol) and AD. The genome-wide association study (GWAS) summary data for antioxidant vitamins intake and AD were obtained from the IEU OpenGWAS database and the UK biobank. Our study consisted of two major parts, MR analysis to detect the causal relationship between exposure and outcome, and sensitivity analysis as supplemental evidence to verify the robustness of the results.

RESULT

The results revealed a suggestive causal relationship between vitamin E intake and AD (p = 0.038, OR 95% CI = 0.745-0.992). However, there was no causal relationship between the other three vitamins (vitamin C, carotene, and retinol) and AD (p = 0.507, OR 95% CI = 0.826-1.099) (p = 0.890, OR 95% CI = 0.864-1.184) (p = 0.492, OR 95% CI = 0.893-1.264). None of the single nucleotide polymorphisms (SNPs) were detected as heterogeneous and pleiotropy in the sensitivity analysis (p > 0.05).

CONCLUSION

The analysis suggested that dietary intake of vitamin E may potentially lower the risk of AD. Conversely, intake of vitamin C, retinol, and carotene is not causally related to AD. Although vitamin E intake could be protective against AD, intake of dietary antioxidant vitamins to prevent or treat AD is not necessary.

Genetically predicted inflammatory proteins and the risk of atrial fibrillation: a bidirectional Mendelian randomization study

Purpose

The causal associations between inflammatory factors and atrial fibrillation (AF) remained unclear. We aimed to investigate whether genetically predicted inflammatory proteins are related to the risk of AF, and vice versa.

Methods

A bidirectional two-sample Mendelian randomization study was performed. The genetic variation of 91 inflammatory proteins were derived from genome-wide association study (GWAS) data of European ancestry (n = 14,824). Summary statistics for AF were obtained from a published meta-analysis study (n = 1,030,836) and the FinnGen study (n = 261,395).

Results

Genetically predicted fibroblast growth factor 5 (FGF5) was significantly positively associated with risk of AF [[odds ratio (OR): 1.07; 95% CI: 1.04-1.10; P < 0.01], and CD40l receptor was significantly negatively associated with risk of AF (OR: 0.95; 95% CI: 0.92-0.98; P = 0.02) in the meta-analysis study. In the FinnGen study, similar results were observed in FGF5 (OR: 1.11; 95% CI: 1.06-1.16; P < 0.01) and CD40l receptor (OR: 0.93; 95% CI: 0.89-0.97; P = 0.03) for AF. In the FinnGen study, TNF-beta was significantly positively associated with risk of AF (OR: 1.05; 95% CI: 1.02-1.09; P = 0.03) and leukemia inhibitory factor receptor was significantly negatively associated with risk of AF (OR: 0.86; 95% CI: 0.80-0.91; P = 0.001). The causal effect of AF on inflammatory proteins was not observed.

Conclusion

Our study suggested that FGF5 and CD40l receptor have a potential causal association with AF, and targeting these factors may help in the treatment of AF.

Association between circulating antioxidants and sleep disorders: comprehensive results from NHANES 2017-2018

Background: Oxidative stress plays an important role in the occurrence and pathological process of numerous human diseases. A bidirectional relationship was found between sleep disorders and oxidative stress. However, the association between circulating antioxidant levels and the risk of sleep disorders at the population-scale has yet to be determined. Methods: We used the dataset from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 data release cycle and included 3062 adult participants aged 25-75 years. The circulating antioxidants levels in serum were measured, and the sleep status was assessed by self-reported sleep disorder questionnaire tests. We investigated the association and exposure-response relationship between the 12 main circulating antioxidants and sleep disorders using a generalized additive model (GAM), multiple linear, binary logistic, and restricted cubic spline (RCS) regression models. Multiple sensitivity analyses were conducted to validate the results of our study. Results: Significantly lower serum concentrations of ten antioxidants were observed in the group which had trouble sleeping symptoms compared to the control group. After adjusting for all the covariates, the binary logistic regression models indicated that six of the circulating antioxidants including alpha-carotene, alpha-cryptoxanthin, trans-beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin, and vitamin C, showed a significant association with the risk of overall trouble sleeping symptoms, with odds ratios corresponding to 0.88 (95% CI: 0.80-0.96), 0.74 (95% CI: 0.62-0.87), 0.87 (95% CI: 0.79-0.97), 0.85 (95% CI: 0.75-0.95), 0.72 (95% CI: 0.61-0.84), and 0.83 (95% CI: 0.74-0.93), respectively. The GAM and multiple linear regression revealed similar associations whereas the RCS regression models further confirmed their significant negative exposure-response relationship. Conclusions: The circulating carotenoids and vitamin C levels were negatively correlated with the risk of sleep disorders. Higher circulating antioxidant levels were significantly associated with a lower risk of sleep disorders. The potential health risk of low circulating antioxidants levels was higher in the female population than in the male population.

Vascular Endothelial Growth Factor and Ischemic Stroke Risk: A Mendelian Randomization Study

INTRODUCTION

Previous studies have reported controversial relationships between circulating vascular endothelial growth factors (VEGF) and ischemic stroke (IS). This study aims to demonstrate the causal effect between VEGF and IS using Mendelian randomization (MR).

METHODS

Summary statistics data from two large-scale genome-wide association studies (GWAS) for 16,112 patients with measured VEGF levels and 40,585 patients with IS were downloaded from public databases and included in this study. A published calculator was adopted for MR power calculation. The primary outcome was any ischemic stroke, and the secondary outcomes were large-artery stroke, cardioembolic stroke, and small-vessel stroke. We used the inverse variance-weighted (IVW) method for primary analysis, supplemented by MR-Egger regression and the weighted median method.

RESULTS

Nine SNPs were included to represent serum VEGF levels. The IVW method revealed no strong causal association between VEGF and any ischemic stroke (odds ratio [OR] 1.01, 95% CI 0.99-1.04, p = 0.39), cardioembolic stroke (OR 1.04, 95% CI 0.97-1.12, p = 0.28), large-artery stroke (OR 1.02, 95% CI 0.95-1.09, p = 0.62), and small-vessel stroke (OR 0.98, 95% CI 0.91-1.04, p = 0.46). These findings remained robust in sensitivity analyses. MR-Egger regression suggested no horizontal pleiotropy.

CONCLUSIONS

This Mendelian randomization study found no relationship between genetically predisposed serum VEGF levels and risks of IS or its subtypes.

The association between diets and periodontitis: a bidirectional two-sample Mendelian randomization study

Background

Periodontitis, a complex inflammatory condition, has been associated with dietary habits and antioxidants. While the association between certain dietary patterns and periodontitis has been documented, the bidirectional relationship remains unclear. This study utilizes Mendelian randomization (MR) analysis to investigate the bidirectional associations between dietary factors comprising dietary antioxidants, and periodontitis.

Methods

Employing a two-sample MR approach, this study analyzed genome-wide association study (GWAS) data on diets and periodontitis from large databases and published literature. Instrumental variables (IVs) were selected and filtered based on genetic variants associated with dietary factors and periodontitis, respectively. Various MR methods, including Inverse Variance Weighted, MR-Egger, Weighted Median, Weighted Mode, and Simple Mode were applied to assess the bidirectional associations. Sensitivity analyses were conducted to validate the robustness of the findings.

Results

Our analysis revealed significant associations between certain dietary factors and the risk of periodontitis. Specifically, higher intake of filtered coffee, low-calorie drinks, and other cereals, as well as increased metabolic circulating levels of gamma-tocopherol, were associated with an elevated risk of periodontitis. Conversely, consumption of cheese, white rice, chocolate bars, unsalted peanuts, and higher absolute circulating levels of vitamin C were linked to a reduced risk. Additionally, the study suggests that periodontitis may influence dietary habits, indicating a bidirectional relationship.

Conclusion

This study provides additional evidence of a bidirectional association between dietary factors and periodontitis. It highlights the importance of dietary interventions in the prevention and management of periodontitis. The findings underscore the need for incorporating dietary counseling into periodontal disease management protocols and suggest the potential of personalized dietary strategies for periodontitis patients. Further research is warranted to explore the mechanisms underlying these associations and to confirm these findings in diverse populations.

Association between composite dietary antioxidant index and kidney stone prevalence in adults: data from National Health and Nutrition Examination Survey (NHANES, 2007-2018)

Background

The high prevalence of kidney stones in adults worldwide has prompted research into potential interventions, one of which involves exploring the consumption of antioxidants that may confer protective effects. However, the relationship between the composite dietary antioxidant index (CDAI), a crucial measure used to assess an individual's overall antioxidant capacity from daily dietary intake, and kidney stones remains unclear. Therefore, we conducted cross-sectional analysis to examine the association between CDAI and kidney stone prevalence.

Methods

The analysis was conducted utilizing data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018. Antioxidant intake was derived from two 24-h dietary recalls surveys, while CDAI, a comprehensive measure that includes antioxidants like vitamins A, C, and E, zinc, selenium, and carotenoids, was calculated. Multivariate logistic regression and restricted cubic spline (RCS) regression were utilized to examine the association between CDAI and the prevalence of kidney stones.

Results

The study included a total of 28,516 participants, with 2,748 individuals having a history of kidney stones. The median of CDAI was -0.01 (-2.02, 2.37). Individuals in the fourth quartile of CDAI exhibited a significantly lower prevalence of kidney stones compared to those in the first quartile (Odds Ratio [OR] = 0.769 [0.633-0.935]), even after adjusting for potential confounding factors (including age, sex, race, education level, poverty income ratio, smoking status, drinking status, body mass index (BMI), energy intake levels, physical activity level, serum calcium concentration, estimated glomerular filtration rate (eGFR), hypertension, diabetes and supplement use). The RCS analysis revealed a non-linear relationship between CDAI and kidney stone prevalence, with inflection points identified at 0.06 (p for non-linearity = 0.039). Subgroup analysis demonstrated consistent CDAI-kidney stone prevalence associations across all subsets. Furthermore, a significant inverse correlation was observed between CDAI and inflammatory markers.

Conclusion

This study provides evidence supporting a reciprocal correlation between adult dietary antioxidant intake, as measured by CDAI, and kidney stone prevalence. These findings emphasize the potential benefits of consuming dietary antioxidants in lowering the risk of kidney stone formation.

Correction of plasma fat-soluble vitamin levels by blood lipids in elderly patients with coronary heart disease

This study aims to investigate the correlation between plasma fat-soluble vitamin levels and blood lipid in elderly patients with coronary heart disease (CHD). A total of 120 participants were enrolled, including 60 CHD patients and 60 controls without CHD. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify plasma levels of vitamins A, D3, E, and K. Data analysis was conducted using the statistical analysis system module of MetaboAnalyst 5.0. The CHD group showed significantly higher levels of plasma total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) but not high-density lipoprotein cholesterol (HDL-C) compared to controls. The CHD group exhibited significantly higher plasma levels of VA and VE, positively correlating with TC, TG, and LDL-C. After adjusted by TG levels, the CHD group had significantly lower plasma levels of VA and VE, negatively correlating with TC, TG, and LDL-C. The CHD group also had significantly lower concentrations of VD3, independent of TG modification, compared to controls. VD3 negatively correlated with TC, TG, and LDL-C. Elderly individuals with CHD display abnormal blood lipid metabolism, and fat-soluble vitamins adjusted by TG levels can more accurately and timely response to implicit fat-soluble vitamins deficiency in CHD patients.

Causal associations of male infertility with stroke: a two-sample Mendelian randomization study

Background

Stroke is a devastating global health issue, with high mortality and disability rates. The increasing prevalence of male infertility among reproductive-aged men has become a growing concern worldwide. However, the relationship between male infertility and stroke incidence remains uncertain. This study aimed to address this knowledge gap by employing a Mendelian randomization (MR) approach.

Method

Utilizing genetic instrumental variables derived from a genome-wide association study (GWAS) on male infertility and stroke, a two-sample MR design was implemented. Five different analysis methods, with inverse-variance weighted as the primary approach, were used to examine the genetic causal associations between male infertility and various stroke subtypes. Heterogeneity analysis, pleiotropy tests, and leave-one-out validation were conducted to assess heterogeneity, evaluate pleiotropy, and ensure the robustness of the findings.

Result

The results indicate a potential lower risk of small vessel stroke associated with male infertility (odds ratio, 95% confidence interval: 0.82, 0.68 to 0.99, p=0.044), although no significant impact on other stroke subtypes was observed. The study exhibited low heterogeneity and no apparent pleiotropy; however, the stability of the results was not optimal.

Conclusion

Male infertility might potentially confer a protective effect against small vessel stroke risk. Caution is warranted due to potential confounding factors. Additional studies are necessary to confirm these findings and provide further validation.

Genetic causal relationship between immune diseases and migraine: a Mendelian randomization study

Background

Migraine has an increased prevalence in several immune disorders, but genetic cause-effect relationships remain unclear. Mendelian randomization (MR) was used in this study to explore whether immune diseases are causally associated with migraine and its subtypes.

Methods

We conducted a two-sample bidirectional multivariate Mendelian randomization study. Single-nucleotide polymorphisms (SNP) for six immune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), type 1 diabetes mellitus (T1D), allergic rhinitis (AR), asthma and psoriasis, were used as genetic instrumental variables. Summary statistics for migraine were obtained from 3 databases: the International Headache Genetics Consortium (IHGC), UK Biobank, and FinnGen study. MR analyses were performed per outcome database for each exposure and subsequently meta-analyzed. Reverse MR analysis was performed to determine whether migraine were risk factors for immune diseases. In addition, we conducted a genetic correlation to identify shared genetic variants for these two associations.

Results

No significant causal relationship was found between immune diseases and migraine and its subtypes. These results were robust with a series of sensitivity analyses. Using the linkage disequilibrium score regression method (LDSC), we detected no genetic correlation between migraine and immune diseases.

Conclusion

The evidence from our study does not support a causal relationship between immune diseases and migraine. The mechanisms underlying the frequent comorbidity of migraine and several immune diseases need to be further elucidated.

The interactions and biological pathways among metabolomics products of patients with coronary heart disease

BACKGROUND

Through bioinformatics analysis, this study explores the interactions and biological pathways involving metabolomic products in patients diagnosed with coronary heart disease (CHD).

METHODS

A comprehensive search for relevant studies focusing on metabolomics analysis in CHD patients was conducted across databases including CNKI, Wanfang, VIP, CBM, PubMed, Cochrane Library, Nature, Web of Science, Springer, and Science Direct. Metabolites reported in the literature underwent statistical analysis and summarization, with the identification of differential metabolites. The pathways associated with these metabolites were examined using the Kyoto Encyclopedia of Genes and Genomes (KEGG). Molecular annotation of metabolites and their relationships with enzymes or transporters were elucidated through analysis with the Human Metabolome Database (HMDB). Visual representation of the properties related to these metabolites was achieved using Metabolomics Pathway Analysis (metPA).

RESULTS

A total of 13 literatures satisfying the criteria for enrollment were included. A total of 91 metabolites related to CHD were preliminarily screened, and 87 effective metabolites were obtained after the unrecognized metabolites were excluded. A total of 45 pathways were involved. Through the topology analysis (TPA) of pathways, their influence values were calculated, and 13 major metabolic pathways were selected. The pathways such as Phenylalanine, tyrosine, and tryptophan biosynthesis, Citrate cycle (TCA cycle), Glyoxylate and dicarboxylate metabolism, and Glycine, serine, and threonine metabolism primarily involved the regulation of processes and metabolites related to inflammation, oxidative stress, one-carbon metabolism, energy metabolism, lipid metabolism, immune regulation, and nitric oxide expression.

CONCLUSION

Multiple pathways, including Phenylalanine, tyrosine, and tryptophan biosynthesis, Citrate cycle (TCA cycle), Glyoxylate and dicarboxylate metabolism, and Glycine, serine, and threonine metabolism, were involved in the occurrence of CHD. The occurrence of CHD is primarily associated with the regulation of processes and metabolites related to inflammation, oxidative stress, one-carbon metabolism, energy metabolism, lipid metabolism, immune regulation, and nitric oxide expression.

Exercise-based cardiac rehabilitation for patients with coronary heart disease: a systematic review and evidence mapping study

INTRODUCTION

Exercise-based cardiac rehabilitation (CR) plays a critical role in coronary heart disease (CHD) management. There is a heritage in the effect of exercise-based CR with different exercise programs or intervention settings. This study developed an evidence matrix that systematically assesses, organizes, and presents the available evidence regarding exercise-based CR in CHD management.

EVIDENCE ACQUISITION

A comprehensive literature search was conducted across six databases. Two reviewers screened the identified literature, extracted relevant data, and assessed the quality of the studies. An evidence-mapping framework was established to present the findings in a structured manner. Bubble charts were used to represent the included systematic reviews (SRs). The charts incorporated information, exercise prescriptions, outcome indicators, associated P values, research quality, and the number of original studies. A descriptive analysis summarized the types of CR, intervention settings, influential factors, and adverse events.

EVIDENCE SYNTHESIS

Sixty-two SRs were included in this analysis, focusing on six exercise types in addition to assessing major adverse cardiovascular events (MACE), cost and rehabilitation outcomes. The most commonly studied exercise types were unspecified (28 studies, 45.2%) and aerobic (11 studies, 17.7%) exercises. All-cause mortality was the most frequently reported MACE outcome (22 studies). Rehabilitation outcomes primarily centered around changes in cardiac function (135 outcomes from 39 SRs). Only 8 (12.9%) studies were rated as "high quality." No significant adverse events were observed in the intervention group. Despite some variations among the included studies, most SRs demonstrated the benefits of exercise in improving one or more MACE or rehabilitation outcomes among CHD patients.

CONCLUSIONS

The proportion of high-quality evidence remains relatively low. Limited evidence is available regarding the effectiveness of specific exercise types and specific populations, necessitating further evaluation.

Correlation Between Blood Cadmium Levels and Platelet Characteristics, As Well As Their Impact on Susceptibility to Coronary Heart Disease: Findings from NHANES 2005-2018 Data

Investigating the correlation between blood cadmium levels, platelet characteristics, and susceptibility to coronary heart disease (CHD). Utilized NHANES 2005-2018 data with covariates such as age, sex, race, marital status, and socio-economic status. Blood cadmium served as the independent variable, while platelet count (PC) and mean platelet volume (MPV) were dependent variables. The average age of the participants was 68.77 ± 11.03 years, and 67.4% of them were male. The mean values for WBC, MPV, PC, and blood cadmium were 7.53 ± 3.36 × 103 cells/µL, 11.33 ± 0.27fL, 57.61 ± 5.34 × 103 cells/µL, and 2.58 ± 0.61 µg/L, respectively. Adjusting for other variables revealed increased MPV and PC with rising blood cadmium levels in cardiac patients, indicating a higher risk of CHD in those with elevated blood cadmium. The average age of the participants was 68.77 ± 11.03 years, and 67.4% of them were male. The mean values for WBC, MPV, PC, and blood cadmium were 7.53 ± 3.36 × 103 cells/µL, 11.33 ± 0.27fL, 57.61 ± 5.34 × 103 cells/µL, and 2.58 ± 0.61 µg/L, respectively. Adjusting for other variables revealed increased MPV and PC with rising blood cadmium levels in cardiac patients, indicating a higher risk of CHD in those with elevated blood cadmium. This study enhances understanding of how cadmium impacts platelet characteristics, contributing to increased CHD risk, providing insights for primary prevention strategies.

Causal relationship between irritability and asthma: a bidirectional two-sample Mendelian randomization study

INTRODUCTION

Previous studies have suggested a relationship between bad mood and asthma. Therefore, in this study, a two-sample Mendelian randomization (MR) method was used to explore the correlation between irritability and asthma.

MATERIAL AND METHODS

Relevant instrumental variables (IVs) were extracted from the aggregated data of the genome-wide association studies (GWAS) database. Inverse-variance weighting (IVW) and weighted median (WME) were used for the MR analysis to evaluate the causal relationship between irritability and asthma using odds ratios (ORs) and the corresponding 95% confidence intervals (CIs), respectively. The "leave-one-out" method was used for sensitivity analysis.

RESULTS

The results of IVW analysis using random-effects models suggested that irritability increased the risk of asthma (OR = 1.954, 95% CI = 1.188-3.214, p = 0.008). The results of WME were consistent with this observation (OR = 1.934, 95% CI = 1.100-3.400, p = 0.021). Additionally, gastroesophageal reflux disease (GERD) might account for approximately 40% of the relationship between irritability and asthma. The sensitivity analysis revealed the stability of the results.

CONCLUSION

The causal relationship between irritability and asthma was analyzed through MR analysis. Irritability increased the risk of asthma. GERD might play an important mediating role in this relationship.

Diet-derived circulating antioxidants and risk of epilepsy: A study combining metabolomics and mendelian randomization

Background

Previous studies offer inconclusive results on the association between diet-derived circulating antioxidants and epilepsy.

Objective

This study aims to assess oxidative stress presence in epilepsy patients' circulation and investigate the causal link between diet-derived circulating antioxidants and epilepsy.

Methods

Untargeted metabolomics analysis was conducted on plasma samples from 62 epileptic patients and 20 healthy individuals to evaluate oxidative stress based on metabolite alterations in epilepsy patients' circulation. Two-sample Mendelian Randomization (MR) analysis examined the causation between diet-derived circulating antioxidants (measured by absolute levels and relative metabolite concentrations) and epilepsy, utilizing the inverse-variance weighted (IVW) method as the primary outcome, with complementary MR analysis methods (MR Egger, weighted median, weighted mode, and simple mode).

Results

Untargeted metabolomics analysis revealed elevated circulating oxidizing metabolites (palmitic acid, oleic acid, linoleic acid, and myristic acid) and reduced reducing metabolites (glutamine) in epilepsy patients, providing robust evidence of oxidative stress. The IVW analysis indicated significantly reduced epilepsy risk (odds ratio: 0.552; 95% confidence interval: 0.335-0.905, P = 0.018) with genetically determined higher absolute circulating β-carotene. However, other diet-derived circulating antioxidants (lycopene, retinol, ascorbic acid, and selenium) and antioxidant metabolites (α-tocopherol, γ-tocopherol, ascorbic acid, and retinol) did not significantly associate with epilepsy risk. Additional MR analysis methods and heterogeneity assessments confirmed the results' robustness.

Conclusion

This study provides compelling evidence of oxidative stress in epilepsy patients' circulation. However, the majority of diet-derived circulating antioxidants (lycopene, retinol, ascorbic acid, vitamin E, and selenium) are unlikely to causally associate with reduced epilepsy risk, except for β-carotene.

Effects of menstrual disorders and dysmenorrhea on cardiovascular disease: a Mendelian randomization study

Background

Observational studies have demonstrated associations between menstrual disorders, dysmenorrhea, and cardiovascular disease (CVD). However, it remains unclear whether these associations are causal. This study is to investigate whether menstrual disorders and dysmenorrhea causally affect the risk of CVD.

Methods

The summary data for menstrual disorders (excessive menstruation and irregular menses) and dysmenorrhea were obtained from FinnGen study, summary data for CVD were obtained from UK Biobank and meta-analysis. The inverse-variance-weighted method was mainly used in the Mendelian randomization for causality analysis. Sensitivity analyses were performed by several methods under different model assumptions.

Results

Genetic liability to excessive menstruation was associated with higher risk of atrial fibrillation (odds ratio (OR), 1.078 [95% confidence interval (CI), 1.015-1.145]; P=0.014), but a lower risk of hypertension (OR, 0.994 [95% CI: 0.989-0.999]; P=0.016). Irregular menses was associated with higher risk of atrial fibrillation (OR, 1.095 [95% CI: 1.015-1.182]; P=0.02), hypertension (OR, 1.007 [95% CI: 1.000-1.013]; P=0.047), myocardial infarction (OR, 1.172 [95% CI: 1.060-1.295]; P=0.02), ischemic heart disease, (OR, 1.005 [95% CI: 1.000-1.010]; P=0.037) and coronary heart disease (OR, 1.004 [95% CI: 1.001-1.008]; P=0.026). Dysmenorrhea was associated with higher risk of atrial fibrillation (OR, 1.052 [95% CI: 1.014-1.092]; P=0.008) and Ischemic stroke (cardioembolic) (OR, 1.122 [95% CI: 1.002-1.257]; P=0.046). After Benjamini-Hochberg correction, irregular menses was associated with higher risk of myocardial infarction.

Conclusion

We confirmed a causal relationship of excessive menstruation, irregular menses and dysmenorrhea on cardiovascular outcomes independent of sex hormone levels, with an emphasis on the link between irregular menses and myocardial infarction. These clinical features can be utilized as markers to identify women at higher risk of developing CVD in the future, recommending early clinical intervention of menstrual diseases.

Assessment of Causality Between Diet-Derived Antioxidants and Primary Open-Angle Glaucoma: A Mendelian Randomization Study

Purpose

This study aimed to investigate the genetic causal relationships among diet-derived circulating antioxidants, primary open-angle glaucoma (POAG), and glaucoma-related traits using two-sample Mendelian randomization (MR).

Methods

Genetic variants associated with diet-derived circulating antioxidants (retinol, ascorbate, β-carotene, lycopene, α-tocopherol, and γ-tocopherol) were assessed as absolute and metabolic instrumental variables. POAG and glaucoma-related traits data were derived from a large, recently published genome-wide association study database; these traits included intraocular pressure (IOP), macular retinal nerve fiber layer (mRNFL) thickness, macular ganglion cell-inner plexiform layer (mGCIPL) thickness, and vertical cup-to-disc ratio (vCDR). MR analyses were performed per outcome for each exposure.

Results

We found no causal association between six diet-derived antioxidants and POAG using the International Glaucoma Genetics Consortium data. For absolute antioxidants, the odds ratios (ORs) ranged from 1.011 (95% confidence interval [CI], 0.854-1.199; P = 0.895) per natural log-transformed β-carotene to 1.052 (95% CI, 0.911-1.215; P = 0.490) for 1 µmol/L of ascorbate. For antioxidant metabolites, the OR ranged from 0.998 (95% CI, 0.801-1.244; P = 0.989) for ascorbate to 1.210 (95% CI, 0.870-1.682; P = 0.257) for γ-tocopherol, using log-transformed levels. A similar result was obtained with the FinnGen Biobank. Furthermore, our results showed no significant genetic association between six diet-derived antioxidants and glaucoma-related traits.

Conclusions

Our study did not support a causal association among six diet-derived circulating antioxidants, POAG, and glaucoma-related traits. This suggests that the intake of antioxidants may not have a preventive effect on POAG and offers no protection to retinal nerve cells.

Translational Relevance

This study provides valid evidence regarding the use of diet-derived antioxidants for glaucoma patients.

The causal effect of Helicobacter pylori infection on coronary heart disease is mediated by the body mass index: a Mendelian randomization study

The association between Helicobacter pylori (H. pylori) infection and coronary heart disease (CHD) remains controversial, with an unclear causal link. This study employed bidirectional Mendelian randomization (MR) method, using H. pylori infection as the exposure, to investigate its causal relationship with CHD diagnosis, prognosis, and potential pathogenesis. H. pylori infection exhibited a causal association with body mass index (BMI) (β = 0.022; 95% CI 0.008-0.036; p = 0.001). Conversely, there was no discernible connection between H. pylori infection and the diagnosis of CHD (OR = 0.991; 95% CI 0.904-1.078; p = 0.842; IEU database; OR = 1.049; 95% CI 0.980-1.118; p = 0.178; FinnGen database) or CHD prognosis (OR = 0.999; 95% CI 0.997-1.001; p = 0.391; IEU database; OR = 1.022; 95% CI 0.922-1.123; p = 0.663; FinnGen database). Reverse MR analysis showed no causal effect of CHD on H. pylori infection. Our findings further support that H. pylori infection exerts a causal effect on CHD incidence, mediated by BMI. Consequently, eradicating or preventing H. pylori infection may provide an indirect clinical benefit for patients with CHD.

A bidirectional Mendelian randomization study investigating the relationship between genetically predicted systemic inflammatory regulators and chronic obstructive pulmonary disease

Research has shown a connection between inflammation and chronic obstructive pulmonary disease (COPD), however the relationship between inflammation mediators and COPD causation remains unknown. To investigate the causal relationship of mediators of inflammation and COPD, we conducted a two-sample Mendelian randomization (MR) study. In our study, we incorporated 41 regulators of inflammation from 8293 Finnish individuals from genome-wide association studies (GWASs) of COPD corresponding to GWAS summary data for 2115 cases and 454,233 healthy individuals in Europe. Our research validated that higher levels of interleukin 8 (IL-8) are related with a decrease occurrence of COPD (OR = 0.795, 95 % CI = 0.642-0.984, p = 0.035) but that elevated levels of interleukin 18(IL-18) and interleukin 2 (IL-2) may be connected to an amplified risk of COPD (OR = 1.247, 95 % CI = 1.011-1.538; p = 0.039; OR = 1.257, 95 % CI = 1.037-1.523, p = 0.020, respectively). According to our research, cytokines play a crucial role in the development of COPD, and further investigation is necessary to explore the potential of utilizing these cytokines as targets for treatment and prevention of COPD.

Recent Advances in the Synthesis of Antioxidant Derivatives: Pharmacological Insights for Neurological Disorders

Neurological disorders, characterized by oxidative stress (OS) and inflammation, have become a major global health concern. Redox reactions play a vital role in regulating the balance of the neuronal microenvironment. Specifically, the imbalance leads to a significant weakening of the organism's natural defensive mechanisms. This, in turn, causes the development of harmful oxidative stress, which plays a crucial role in the onset and progression of neurodegenerative diseases. The quest for effective therapeutic agents has led to significant advancements in the synthesis of antioxidant derivatives. This review provides a comprehensive overview of the recent developments in the use of novel antioxidant compounds with potential pharmacological applications in the management of neurological disorders. The discussed compounds encompass a diverse range of chemical structures, including polyphenols, vitamins, flavonoids, and hybrid molecules, highlighting their varied mechanisms of action. This review also focuses on the mechanism of oxidative stress in developing neurodegenerative disease. The neuroprotective effects of these antioxidant derivatives are explored in the context of specific neurological disorders, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. The ultimate goal is to provide effective treatments for these debilitating conditions and improve the quality of life for patients.

Tea consumption and risk of lung diseases: a two‑sample Mendelian randomization study

BACKGROUND

Numerous studies have reported the association between tea intake and lung diseases. However, the probable relationship between tea consumption on lung diseases still remain controversial and it is unclear whether these findings are due to reverse causality or confounding factor.

METHODS

In order to systematically investigate the causal connection between tea intake on respiratory system disorders, we employed a two-sample Mendelian randomized (MR) study. Genetic instruments for tea intake were identified from a genome-wide association study (GWAS) involving 447,385 individuals. Data on lung diseases were collected from a variety of publicly available genome-wide association studies. The main method used for MR analysis is the inverse variance weighting (IVW) method. To ensure the accuracy of the findings, further sensitivity analysis was conducted.

RESULTS

The IVW method in our MR analysis revealed no evidence to support a causal relationship between tea intake and lung diseases (IPF: OR = 0.997, 95% CI = 0.994-1.000, p = 0.065; Lung cancer: OR = 1.003, 95% CI = 0.998-1.008, P = 0.261; COPD: OR = 1.001, 95% CI = 0.993-1.006, p = 0.552; acute bronchitis: OR = 0.919, 95% CI = 0.536-1.576, p = 0.759; tuberculosis: OR = 1.002, 95% CI = 0.998-1.008, p = 0.301; pneumonia: OR = 0.789, 95% CI = 0.583-1.068, p = 0.125). The reliability of the results was further demonstrated by four additional MR analysis techniques and additional sensitivity testing.

CONCLUSION

We found no evidence of a link between tea intake on lung diseases in our MR results based on genetic information.

Appraising the Causal Role of Risk Factors in Coronary Artery Disease and Stroke: A Systematic Review of Mendelian Randomization Studies

BACKGROUND Mendelian randomization (MR) offers a powerful approach to study potential causal associations between exposures and health outcomes by using genetic variants associated with an exposure as instrumental variables. In this systematic review, we aimed to summarize previous MR studies and to evaluate the evidence for causality for a broad range of exposures in relation to coronary artery disease and stroke. METHODS AND RESULTS MR studies investigating the association of any genetically predicted exposure with coronary artery disease or stroke were identified. Studies were classified into 4 categories built on the significance of the main MR analysis results and its concordance with sensitivity analyses, namely, robust, probable, suggestive, and insufficient. Studies reporting associations that did not perform any sensitivity analysis were classified as nonevaluable. We identified 2725 associations eligible for evaluation, examining 535 distinct exposures. Of them, 141 were classified as robust, 353 as probable, 110 as suggestive, and 926 had insufficient evidence. The most robust associations were observed for anthropometric traits, lipids, and lipoproteins and type 2 diabetes with coronary artery; disease and clinical measurements with coronary artery disease and stroke; and thrombotic factors with stroke. CONCLUSIONS Despite the large number of studies that have been conducted, only a limited number of associations were supported by robust evidence. Approximately half of the studies reporting associations presented an MR sensitivity analysis along with the main analysis that further supported the causality of associations. Future research should focus on more thorough assessments of sensitivity MR analyses and further assessments of mediation effects or nonlinearity of associations.

The causal effect of metabolic syndrome and its components on benign prostatic hyperplasia: A univariable and multivariable Mendelian randomization study

BACKGROUND

Previous observational studies have indicated that metabolic abnormalities are associated with benign prostatic hyperplasia (BPH). The limitations of the research methodology of observational studies do not allow causal inference to be drawn; however, Mendelian randomization (MR) can clarify this.

METHODS

Using summary-level data from genome-wide association studies, we conducted a two-sample MR study to examine the causality of the metabolic syndrome (MetS) and its components on BPH (26,358 BPH cases and 110,070 controls). The random-effects inverse-variance weighted was employed as the primary method for MR analyses.

RESULTS

We observed that genetically predicted waist circumference (WC) (odds ratio [OR] = 1.236, 95% confidence interval [CI]: 1.034-1.478, p = 0.020) and diastolic blood pressure (DBP) (OR = 1.011, 95% CI: 1.002-1.020, p = 0.020) were significantly positively associated with BPH risk. We did not identify a causal effect of MetS (OR = 0.975, 95% CI: 0.922-1.031, p = 0.375), systolic blood pressure (OR = 1.004, 95% CI: 0.999-1.008, p = 0.115), triglycerides (OR = 1.016, 95% CI: 0.932-1.109, p = 0.712), high-density lipoprotein (OR = 1.005, 95% CI: 0.930-1.086, p = 0.907), and fasting blood glucose (OR = 1.037, 95% CI: 0.874-1.322, p = 0.678) on BPH. In the multivariable MR analysis, we observed that the risk effect of DBP (OR = 1.013, 95% CI: 1.000-1.026, p = 0.047) on BPH persisted after conditioning with WC (OR = 1.132, 95% CI: 0.946-1.356, p = 0.177).

CONCLUSIONS

Our study provides genetic evidence supporting the causal effect of DBP on BPH, although the effect of WC needs to be further validated.

Relationship between food-derived antioxidant vitamin intake and breast cancer risk: a mendelian randomized study

BACKGROUND

In previous observational studies, food-derived antioxidant vitamins have been suggested to be associated with breast cancer. However, the findings were inconsistent and the causal relationship could not be clearly elucidated. To confirm the potential causal relationship between food-derived antioxidants (retinol, carotene, vitamin C and vitamin E) and the risk of breast cancer, we conducted a two-sample Mendelian randomization (MR) study.

METHODS

The instrumental variables (IVs) as proxies of genetic liability to food-derived antioxidant vitamins were obtained from the UK Biobank Database. We extracted breast cancer data (122,977 cases and 105,974 controls) from the Breast Cancer Consortium (BCAC). In addition, we studied estrogen expression status categorically, including estrogen receptor positive (ER+) breast cancer (69,501 cases and 105,974 controls) and versus estrogen receptor (ER-) negative breast cancer (21,468 cases and 105,974 controls). We performed two-sample Mendelian randomization study, and inverse variance-weighted (IVW) test was regarded as main analysis. Sensitivity analyses were further conducted to assess heterogeneity and horizontal pleiotropy.

RESULTS

The results of IVW showed that among the four food-derived antioxidants, only vitamin E had protective effect on the risk of overall breast cancer (OR = 0.837, 95% CI 0.757-0.926, P = 0.001) and ER+ breast cancer (OR = 0.823, 95% CI 0.693-0.977, P = 0.026). However, we found no association between food-derived vitamin E and ER- breast cancer.

CONCLUSIONS

Our study suggested food-derived vitamin E can decrease the risk of breast cancer overall and ER+ breast cancer, and the robustness of our results was confirmed by sensitivity analyses.

Genetically Predicted Vegetable Intake and Cardiovascular Diseases and Risk Factors: An Investigation with Mendelian Randomization

BACKGROUND

The associations between vegetable intake and cardiovascular diseases have been demonstrated in observational studies, but less sufficiently in randomized trials. Mendelian randomization has been considered a promising alternative in causal inference. The separate effects of cooked and raw vegetable intake remain unclear. This study aimed to investigate the associations between cooked and raw vegetable intake with cardiovascular outcomes using MR.

METHODS

We identified 15 and 28 genetic variants statistically and biologically associated with cooked and raw vegetable intake, respectively, from previous genome-wide association studies, which were used as instrumental variables to estimate associations with coronary heart disease (CHD), stroke, heart failure (HF), and atrial fibrillation (AF). The independent effects of genetically predicted cooked and raw vegetable intake were examined using multivariable MR analysis. We performed one-sample and two-sample MR analyses and combined their results using meta-analysis. Bonferroni correction was applied for multiple comparisons. We performed two-sample MR analysis for cardiometabolic risk factors (serum lipids, blood pressure, body mass index, and glycemic traits) to explore the potential mechanisms.

RESULTS

In the MR meta-analysis of 1.2 million participants, we found null evidence for associations between genetically predicted cooked and raw vegetable intake with CHD, HF, or AF. Raw vegetable intake was nominally associated with stroke (odds ratio [95% confidence interval] 0.82 [0.69-0.98] per 1 daily serving increase, p = 0.03), but this association did not pass the corrected significance level. We found consistently null evidence for associations with serum lipids, blood pressure, body mass index, or glycemic traits.

CONCLUSIONS

We found null evidence for associations between genetically predicted vegetable intake with CHD, AF, HF, or cardiometabolic risk factors in this MR study. Raw vegetable intake may reduce risk of stroke, but this warrants more research. True associations between vegetable intake and CVDs cannot be completely ruled out, and future investigations are required for causal inference in nutritional research.

Retinol Saturase Mediates Retinoid Metabolism to Impair a Ferroptosis Defense System in Cancer Cells

Ferroptosis is an iron-dependent form of regulated cell death induced by the lethal overload of lipid peroxides in cellular membranes. In recent years, modulating ferroptosis has gained attention as a potential therapeutic approach for tumor suppression. In the current study, retinol saturase (RETSAT) was identified as a significant ferroptosis mediator using a publicly accessible CRISPR/Cas9 screening dataset. RETSAT depletion protected tumor cells from lipid peroxidation and subsequent cell death triggered by various ferroptosis inducers. Furthermore, exogenous supplementation with retinoids, including retinol (the substrate of RETSAT) and its derivatives retinal and retinoic acid, also suppressed ferroptosis, whereas the product of RETSAT, 13, 14-dihydroretinol, failed to do so. As effective radical-trapping antioxidant, retinoids protected the lipid membrane from autoxidation and subsequent fragmentation, thus terminating the cascade of ferroptosis. Pseudotargeted lipidomic analysis identified an association between retinoid regulation of ferroptosis and lipid metabolism. Retinoic acid, but not 13, 14-dihydroretinoic acid, interacted with its nuclear receptor and activated transcription of stearoyl-CoA desaturase, which introduces the first double bond into saturated fatty acid and thus catalyzes the generation of monounsaturated fatty acid, a known ferroptosis suppressor. Therefore, RETSAT promotes ferroptosis by transforming retinol to 13, 14-dihydroretinol, thereby turning a strong anti-ferroptosis regulator into a relatively weak one.

SIGNIFICANCE

Retinoids have ferroptosis-protective properties and can be metabolized by RETSAT to promote ferroptosis, suggesting the possibility of targeting retinoid metabolism in cancer as a treatment strategy to trigger ferroptosis.

Diet-derived circulating antioxidants and risk of knee osteoarthritis, hip osteoarthritis and rheumatoid arthritis: a two-sample Mendelian randomization study

Objective

To examine the causal associations of diet-derived circulating antioxidants with knee osteoarthritis (OA), hip OA, and rheumatoid arthritis (RA) within the two-sample Mendelian randomization (MR) framework.

Method

Independent single-nucleotide polymorphisms (SNPs) significantly associated with circulating levels of diet-derived antioxidants (retinol, β-carotene, lycopene, vitamin C and vitamin E) were extracted as genetic instruments. Summary statistics of genetic instruments associated with knee OA, hip OA, and RA were obtained from corresponding genome-wide association studies (GWASs). The inverse-variance weighted (IVW) was applied as the primary analysis method, with four sensitivity analysis approaches employed to evaluate the robustness of the primary results.

Results

Genetically determined per unit increment of absolute circulating levels of retinol was significantly associated with a reduced risk of hip OA [odds ratio (OR) = 0.45, 95% confidence interval (CI) 0.26-0.78, p = 4.43 × 10^-3], while genetically determined per unit increase in absolute circulating levels of β-carotene was suggestively associated with increased risk of RA (OR = 1.32, 95% CI 1.07-1.62, p = 9.10 × 10^-3). No other causal association was found. Significant evidence for heterogeneity and pleiotropic outlier was only identified when absolute circulating vitamin C was evaluated as the exposure, whereas all sensitive analysis provided consistently non-significant results.

Conclusion

Our results demonstrated that genetically determined lifelong higher exposure to absolute circulating levels of retinol is associated with a decreased risk of hip OA. Further MR study with more genetic instruments for absolute circulating levels of antioxidants are needed to confirm our results.

Associations of composite dietary antioxidant index with cardiovascular disease mortality among patients with type 2 diabetes

To investigate the associations of composite dietary antioxidant index (CDAI) with risk of cardiovascular disease (CVD) mortality among individuals with type 2 diabetes (T2D). This prospective cohort study included 7551 patients with T2D who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2018. Death statistics were gathered by connecting the cohort database to the National Death Index through December 31, 2019. Multivariable Cox proportional hazards regression models were utilized to calculate hazard ratios and 95% CIs for the relationship of CDAI with risks of CVD and all-cause mortality. Three multivariable models were built. Restricted cubic spline analyses were utilized to explore the nonlinear association of CDAI with CVD mortality, and nonlinearity was tested by the likelihood ratio test. This cohort study included data from 7551 participants with T2D (mean [SE] age, 61.4 (0.2) years; 3811 male [weighted, 50.5%] and 3740 female [weighted, 49.5%]; median CDAI level, - 2.19 [IQR, - 2.19 ~ - 0.22]). A total of 2227 all-cause deaths and 746 CVD deaths were identified during an average of 98 months of follow-up. Nonlinear associations were observed for CDAI (P < 0.05 for nonlinearity) with risk of CVD mortality among patients with T2D. Compared with participants in the first quartile of CDAI levels (< - 2.19), the hazard ratios for CVD mortality were 0.47 (95% CI 0.30-0.75) for participants in the highest CDAI level quartile. This cohort study found that higher CDAI levels were significantly associated with lower risk of CVD mortality among individuals with T2D.

Irritability and risk of lung cancer: a Mendelian randomization and mediation analysis

BACKGROUND

There is no research to prove the association between irritability and lung cancer, our study performed a Mendelian randomization (MR) approach to elucidate the causal relationship of irritability with lung cancer risk.

METHODS

Genome-wide association studies (GWAS) data of irritability, lung cancer and gastroesophageal reflux disease (GERD) were downloaded from a public database for two-sample MR analysis. Independent single-nucleotide polymorphisms (SNPs) associated with irritability and GERD were selected as instrumental variables (IVs). Inverse variance weighting (IVW) and weighted median method were used to analyze causality.

RESULTS

There is an association between irritability and lung cancer risk (OR_IVW = 1.01, 95% CI = [1.00, 1.02], P = 0.018; OR_{weighted median} = 1.01, 95% CI = [1.00, 1.02], P = 0.046), and GERD might account for about 37.5% of the association between irritability and lung cancer.

CONCLUSIONS

This study confirmed the causal effect between irritability and lung cancer through MR analysis, and found that GERD played an essential mediating role in this relationship, which can partly indicate the role of the "inflammation-cancer transformation" process in lung cancer.

Ovarian Cancer and Parkinson's Disease: A Bidirectional Mendelian Randomization Study

(1) Background: Ovarian cancer (OC) and Parkinson's disease (PD) represent a huge public health burden. The relationship of these two diseases is suggested in the literature while not fully understood. To better understand this relationship, we conducted a bidirectional Mendelian ran-domization analysis using genetic markers as a proxy. (2) Methods: Utilizing single nucleotide polymorphisms associated with PD risk, we assessed the association between genetically predicted PD and OC risk, overall and by histotypes, using summary statistics from previously conducted genome-wide association studies of OC within the Ovarian Cancer Association Consortium. Similarly, we assessed the association between genetically predicted OC and PD risk. The inverse variance weighted method was used as the main method to estimate odds ratios (OR) and 95% confidence intervals (CI) for the associations of interest. (3) Results: There was no significant association between genetically predicted PD and OC risk: OR = 0.95 (95% CI: 0.88-1.03), or between genetically predicted OC and PD risk: OR = 0.80 (95% CI: 0.61-1.06). On the other hand, when examined by histotypes, a suggestive inverse association was observed between genetically predicted high grade serous OC and PD risk: OR = 0.91 (95% CI: 0.84-0.99). (4) Conclusions: Overall, our study did not observe a strong genetic association between PD and OC, but the observed potential association between high grade serous OC and reduced PD risk warrants further investigation.

Associations between diet and incidence risk of lung cancer: A Mendelian randomization study

Background

Observational studies have revealed associations between diet and lung cancer. However, it is unclear whether the association is disturbed by confounding factors. We used a two-sample Mendelian randomization (MR) method to characterize the associations between diet and the lung cancer risk (including 3 subtypes: lung adenocarcinoma (LA), squamous cell lung carcinoma (SqCLC), and small cell lung cancer (SCLC)).

Materials and methods

Data on 20 diets were screened from the UK Biobank. Lung cancer data came from a large meta-analysis of 85,716 individuals. The inverse-variance weighted method was used as the main analysis. Sensitivity analysis was also used to explain the different multiplicity patterns of the final model.

Results

Our results showed significant evidence that 3 diets were associated with lung cancer [odds ratio (OR): 0.271, 95% confidence interval (CI): 0.150–0.488, p = 1.46 × 10−4, dried fruit; OR: 3.010, 95% CI: 1.608–5.632, p = 5.70 × 10−4, beer] and SqCLC (OR: 0.135, 95% CI: 0.062–0.293, p = 2.33 × 10−5, dried fruit; OR: 0.485, 95% CI: 0.328–0.717, p = 2.9 × 10−4, cheese). There were also suggestive correlations between 5 dietary intakes and lung cancer (OR: 0.441, 95% CI: 0.250–0.778, p = 0.008, cereal; OR: 2.267, 95% CI: 1.126–4.564, p = 0.022, beef), LA (OR: 0.494, 95% CI: 0.285–0.858, p = 0.012, dried fruit; OR: 3.536, 95% CI: 1.546–8.085, p = 0.003, beer) and SCLC (OR: 0.006, 95% CI: 0.000–0.222, p = 0.039, non-oily fish; OR: 0.239, 95% CI: 0.086–0.664, p = 0.006, dried fruit). No other association between diet and lung cancer was observed.

Conclusion

Our study preliminary found that cheese, dried fruit, and beer intake were significantly associated with the risk of lung cancer or its subtypes, while cereal, beef, and non-oily fish intake were suggestively associated with the risk of lung cancer or its subtypes. Well-designed prospective studies are still needed to confirm our findings in the future.

Causal association between cardiovascular diseases and erectile dysfunction, a Mendelian randomization study

Background

Cardiovascular diseases (CVD), including coronary heart disease (CHD), heart failure, ischemic heart disease (IHD), and atrial fibrillation, are prevalent in the aged. However, the influence of CVD on ED is less investigated. This study was performed to clarify the causal association between CVD and ED.

Materials and methods

Genome-wide association studies (GWAS) datasets targeting CHD, heart failure, IHD, and atrial fibrillation were downloaded to retrieve single nucleotide polymorphisms (SNPs). Further, single-variable Mendelian randomization and multivariable Mendelian randomization (MVMR) were adopted to explore the causal association between CVD and ED.

Results

Genetically predicted CHD and heart failure were found to increase the risks of ED (OR = 1.09, P < 0.05 and OR = 1.36, P < 0.05, respectively). However, no causal association was disclosed among IHD, atrial fibrillation and ED (all P > 0.05). These findings remained consistent in sensitivity analyses. After controlling for body mass index, alcohol, low density lipoprotein, smoking and total cholesterol levels, the results of MVMR support the causal role of CHD on ED (P < 0.05). Similarly, the direct causal effect estimates of heart failure on ED were significant in MVMR analyses (P < 0.05).

Conclusion

Using genetic data, this study revealed that genetically predicted CHD and heart failure may predict better ED compared with atrial fibrillation and IHD. The results should be interpreted with caution and the insignificant causal inference of IHD still needs further verification in future studies.

White blood cells and coronary heart disease: A mendelian randomization study

Background: The causal direction and magnitude of the associations between blood cell count and coronary heart disease (CHD) remain uncertain due to susceptibility of reverse causation and confounding. This study aimed to investigate the associations between blood cell count and CHD using Mendelian randomization (MR). Methods: In this two-sample MR study, we identified independent blood cell count associated genetic variants from a genome-wide association studies (GWAS) among European ancestry individuals. Summary level data of CHD was obtained from a GWAS consisting of 547261 subjects. Methods of inverse variance weighted (IVW), Mendelian Randomization-Egger (MR-Egger), weighted median, and outlier test (MR-PRESSO) were conducted to investigate the associations between blood cell and CHD. Results: Among all cardiovascular outcomes of interest, blood cell counts were only associated with CHD. Our findings indicated that white blood cell count and neutrophil cell count were significantly associated with increased risk of CHD [odds ratio (OR) = 1.07, 95% confidence interval (CI), 1.01-1.14; OR = 1.09, 1.02-1.16). However, there was no significant association between monocyte cell count, basophil cell count, lymphocyte cell count, eosinophil cell count, and CHD (p > 0.05). The results after excluding outliers were consistent with main results and the sensitivity analyses showed no evidence of pleiotropy (MR-Egger intercept, p > 0.05). Conclusion: Our MR study suggested that greater white blood cell count and neutrophil cell count were associated with a higher risk of CHD. Future studies are still warranted to validate the results and investigate the mechanisms underlying these associations.

Antioxidants, minerals and vitamins in relation to Crohn's disease and ulcerative colitis: A Mendelian randomization study

BACKGROUND

Evidence for antioxidants, minerals and vitamins in relation to the risk of Crohn's disease (CD) and ulcerative colitis (UC) is limited and inconsistent. This mendelian randomization (MR) study aimed to examine the causal associations of circulating levels of antioxidants, minerals and vitamins with CD and UC.

METHODS

Single-nucleotide polymorphisms associated with antioxidants (beta-carotene, lycopene and uric acid), minerals (copper, calcium, iron, magnesium, phosphorus, zinc and selenium), and vitamins (folate, vitamins A, B6, B12, C, D, E and K1) were employed as instrumental variables. Genetic associations with CD and UC were extracted from the UK Biobank, the FinnGen study and the International Inflammatory Bowel Disease Genetics Consortium. The inverse variance weighted method and sensitivity analyses were performed.

RESULTS

Genetically predicted higher lycopene (OR = 0.94, 95% CI: 0.91-0.97), vitamins D (OR = 0.65, 95% CI: 0.54-0.79) and K1 (OR = 0.93, 95% CI: 0.90-0.97) levels were inversely associated with CD risk, whereas genetically predicted higher magnesium (OR = 1.53, 95% CI: 1.23-1.90) levels were positively associated with CD risk. Higher levels of genetically predicted lycopene (OR = 0.91, 95% CI: 0.88-0.95), phosphorus (OR = 0.69, 95% CI: 0.58-0.82), selenium (OR = 0.91, 95% CI: 0.85-0.97), zinc (OR = 0.91, 95% CI: 0.89-0.94), folate (OR = 0.71, 95% CI: 0.56-0.92) and vitamin E (OR = 0.78, 95% CI: 0.69-0.88) were associated with reduced UC risk, whereas genetically predicted high levels of calcium (OR = 1.46, 95% CI: 1.22-1.76) and magnesium (OR = 1.24, 95% CI: 1.03-1.49) were associated with increased risk of UC.

CONCLUSIONS

Our study provided evidence that circulating levels of antioxidants, minerals and vitamins might be causally linked to the development of IBD.

Genetically determined serum bilirubin level and the risk of heart failure: A mendelian randomization study

Background: The association between serum bilirubin level and heart failure (HF) was controversial in previous observational studies and the causal effects of bilirubin on HF have not been investigated. Here, we conducted a Mendelian randomization (MR) study to investigate the associations between genetically determined bilirubin level and HF. Methods: Summary data on the association of single nucleotide polymorphisms (SNPs) with serum bilirubin levels were obtained from genome-wide association study (GWAS) for individuals of European descent and East Asian descent separately. Statistical data for gene-HF associations were extracted from three databases: the HERMES Consortium (47,309 cases and 930,014 controls), FinnGen study (30,098 cases and 229,612 controls) for European population and Biobank Japan (2,820 HF cases and 192,383 controls) for East Asian population. We applied a two-sample Mendelian randomization framework to investigate the causal association between serum bilirubin and HF. Results: Findings from our MR analyses showed that genetically determined serum bilirubin levels were not causally associated with HF risk in either European or East Asian population (odds ratio [OR] = 1.01 and 95% confidence interval [CI] = .97-1.05 for HERMES Consortium; OR = 1.01 and 95% CI = .98-1.04 for FinnGen Study; OR = .82, 95% CI: .61-1.10 for Biobank Japan). These results remained unchanged using different Mendelian randomization methods and in sensitivity analyses. Conclusion: Our study did not find any evidence to support a causal association between serum bilirubin and HF.

Dissecting Causal Associations of Diet-Derived Circulating Antioxidants with Six Major Mental Disorders: A Mendelian Randomization Study

Although observational studies have suggested associations between circulating antioxidants and many mental disorders, causal inferences have not been confirmed. Mendelian randomization (MR) analyses were conducted using summary-level statistics from genome-wide association studies (GWASs) to explore whether genetically determined absolute circulating antioxidants (i.e., ascorbate, retinol, β-carotene, and lycopene) and metabolites (i.e., α- and γ-tocopherol, ascorbate, and retinol) were causally associated with the risk of six major mental disorders, including anxiety disorders (AD), major depressive disorder (MDD), bipolar disorder (BIP), schizophrenia (SCZ), post-traumatic stress disorder (PTSD), and obsessive-compulsive disorder (OCD). MR analyses were performed per specific-outcome databases, including the largest GWAS published to date (from 9725 for OCD to 413,466 for BIP participants), UK Biobank (over 370,000 participants), and FinnGen (over 270,000 participants), followed by meta-analyses. We found no significant evidence that genetically determined diet-derived circulating antioxidants were significantly causally associated with the risk of the six above-mentioned major mental disorders. For absolute antioxidant levels, the odds ratios (ORs) ranged from 0.91 (95% CI, 0.67-1.23) for the effect of β-carotene on OCD to 1.18 (95% CI, 0.90-1.54) for the effect of ascorbate on OCD. Similarly, for antioxidant metabolites, ORs ranged from 0.87 (95% CI, 0.55-1.38) for the effect of ascorbate on MDD to 1.08 (95% CI, 0.88-1.33) for the effect of ascorbate on OCD. Our study does not support significant causal associations of genetically determined diet-derived circulating antioxidants with the risk of major mental disorders.

Antioxidant Supplementation in Oxidative Stress-Related Diseases: What Have We Learned from Studies on Alpha-Tocopherol?

Oxidative stress has been proposed as a key contributor to lifestyle- and age-related diseases. Because free radicals play an important role in various processes such as immune responses and cellular signaling, the body possesses an arsenal of different enzymatic and non-enzymatic antioxidant defense mechanisms. Oxidative stress is, among others, the result of an imbalance between the production of various reactive oxygen species (ROS) and antioxidant defense mechanisms including vitamin E (α-tocopherol) as a non-enzymatic antioxidant. Dietary vitamins, such as vitamin C and E, can also be taken in as supplements. It has been postulated that increasing antioxidant levels through supplementation may delay and/or ameliorate outcomes of lifestyle- and age-related diseases that have been linked to oxidative stress. Although supported by many animal experiments and observational studies, randomized clinical trials in humans have failed to demonstrate any clinical benefit from antioxidant supplementation. Nevertheless, possible explanations for this discrepancy remain underreported. This review aims to provide an overview of recent developments and novel research techniques used to clarify the existing controversy on the benefits of antioxidant supplementation in health and disease, focusing on α-tocopherol as antioxidant. Based on the currently available literature, we propose that examining the difference between antioxidant activity and capacity, by considering the catabolism of antioxidants, will provide crucial knowledge on the preventative and therapeutical use of antioxidant supplementation in oxidative stress-related diseases.

Diet-derived antioxidants and nonalcoholic fatty liver disease: a Mendelian randomization study

BACKGROUND

Whether supplementation with diet-derived antioxidants is beneficial for nonalcoholic fatty liver disease (NAFLD) is still controversial and we hope to answer this question using population-based genetic data.

METHODS

A total of 8485 NAFLD cases and 658,849 healthy controls from four independent NAFLD genome-wide association studies were enrolled in this study. Genetic variants closely associated with the diet-derived antioxidants were selected to predict their circulating levels. A bi-directional Mendelian randomization (MR) design was employed to assess their causations.

RESULTS

Genetic correlation analyses suggested inverse associations between diet-derived antioxidants and NAFLD. MR analyses indicated that the odds ratio (OR) of per standard deviation increase in genetically predicted toenail and blood selenium was 1.179 for NAFLD (95% confidence interval [1.083-1.284]). Also, the genetically elevated selenium level was causally associated with increased levels of C-reactive protein, fibrinogen, alkaline phosphatase and glycated hemoglobin. The OR of 1 µg/dL increase in genetically predicted serum lycopene was 1.082 (95%CI [1.051-1.113]). No other causal associations were found for NAFLD. However, we observed protective effects of genetically predicted β-carotene (OR = 0.929[0.911-0.947]) and retinol (OR = 0.483[0.460-0.508]) on type 2 diabetes (T2D), and further they could reduce the serum levels of blood lipids and glucose. Reverse MR analysis suggested genetically predicated NAFLD status would not affect the levels of diet-derived antioxidants.

CONCLUSION

Overall, we observed the positive associations of genetically predicted selenium and lycopene with NAFLD. However, the genetically predicted β-carotene and retinol levels were inversely associated with the risk of T2D.

Effects of Hyperthyroidism on Venous Thromboembolism: A Mendelian Randomization Study

Objective

Observational studies show the correlation between thyroid dysfunction and risk of venous thromboembolism. However, the causal effects remain uncertain. Our study was conducted to evaluate whether thyroid function and dysfunction were causally linked to the risk of venous thromboembolism.

Methods

Publicly available summary data of thyrotropin (TSH) and free thyroxine (FT4), hypothyroidism, and hyperthyroidism were obtained from the ThyroidOmics Consortium and the UK Biobank. With single nucleotide polymorphisms (SNPs) as instrumental variables, the casual effects of genetically predicted TSH and FT4 and hypo- and hyperthyroidism on venous thromboembolism outcome were estimated through Mendelian randomization analysis methods (inverse variance weighted (IVW), MR-Egger, weighted median, simple mode, and weighted mode). Cochran's Q test was performed to evaluate the heterogeneity and horizontal pleiotropy.

Results

Our study selected 15 FT4-, 36 TSH-, 3 hyperthyroidism-, and 79 hypothyroidism-associated SNPs as instrumental variables. The IVW analysis results showed that the odds ratio of venous thromboembolism for hyperthyroidism was 1.124 (95% confidence interval: 1.019-1.240; p = 0.019), demonstrating the casual effect of hyperthyroidism not FT4, TSH, and hypothyroidism on venous thromboembolism. No heterogeneity or horizontal pleiotropy was observed according to Cochran's Q test.

Conclusion

Our Mendelian randomization analysis supports the causal effect of hypothyroidism on risk of venous thromboembolism. There is no evidence that genetically predicted TSH, FT4, and hypothyroidism have casual effects on venous thromboembolism. Future studies should be conducted to elucidate the underlying pathophysiological mechanisms.