Alcohol consumption in relation to cardiovascular diseases and mortality: a systematic review of Mendelian randomization studies

Causal relationship between iron status and preeclampsia-eclampsia: a Mendelian randomization analysis

BACKGROUND

Preeclampsia/eclampsia is a severe pregnancy-related disorder associated with hypertension and organ damage. While observational studies have suggested a link between maternal iron status and preeclampsia/eclampsia, the causal relationship remains unclear. The aim of this study was to investigate the genetic causality between iron status and preeclampsia/eclampsia using large-scale genome-wide association study (GWAS) summary data and Mendelian randomization (MR) analysis.

METHODS

Summary data for the GWAS on preeclampsia/eclampsia and genetic markers related to iron status were obtained from the FinnGen Consortium and the IEU genetic databases. The "TwoSampleMR" software package in R was employed to test the genetic causality between these markers and preeclampsia/eclampsia. The inverse variance weighted (IVW) method was primarily used for MR analysis. Heterogeneity, horizontal pleiotropy, and potential outliers were evaluated for the MR analysis results.

RESULTS

The random-effects IVW results showed that ferritin (OR = 1.11, 95% CI: .89-1.38, p = .341), serum iron (OR = .90, 95% CI: .75-1.09, p = .275), TIBC (OR = .98, 95% CI: .89-1.07, p = .613), and TSAT (OR = .94, 95% CI: .83-1.07, p = .354) have no genetic causal relationship with preeclampsia/eclampsia. There was no evidence of heterogeneity, horizontal pleiotropy, or possible outliers in our MR analysis (p > .05).

CONCLUSIONS

Our study did not detect a genetic causal relationship between iron status and preeclampsia/eclampsia. Nonetheless, this does not rule out a relationship between the two at other mechanistic levels.

Addressing the credibility crisis in Mendelian randomization

BACKGROUND

Genome-wide association studies have enabled Mendelian randomization analyses to be performed at an industrial scale. Two-sample summary data Mendelian randomization analyses can be performed using publicly available data by anyone who has access to the internet. While this has led to many insightful papers, it has also fuelled an explosion of poor-quality Mendelian randomization publications, which threatens to undermine the credibility of the whole approach.

FINDINGS

We detail five pitfalls in conducting a reliable Mendelian randomization investigation: (1) inappropriate research question, (2) inappropriate choice of variants as instruments, (3) insufficient interrogation of findings, (4) inappropriate interpretation of findings, and (5) lack of engagement with previous work. We have provided a brief checklist of key points to consider when performing a Mendelian randomization investigation; this does not replace previous guidance, but highlights critical analysis choices. Journal editors should be able to identify many low-quality submissions and reject papers without requiring peer review. Peer reviewers should focus initially on key indicators of validity; if a paper does not satisfy these, then the paper may be meaningless even if it is technically flawless.

CONCLUSIONS

Performing an informative Mendelian randomization investigation requires critical thought and collaboration between different specialties and fields of research.

Causal factors for osteoarthritis risk revealed by mendelian randomization analysis

Osteoarthritis (OA), a prevalent chronic disease among the elderly, presents a complex pathogenesis and currently lacks effective treatment. Traditional observational studies are time-consuming, labor-intensive, susceptible to confounding factors, and cannot establish causal relationships. Mendelian randomization (MR) analysis, leveraging genetic variation to assess causal associations between exposures and outcomes, offers a cost-effective and efficient alternative. Over the past decade, large-scale genome-wide association studies have identified numerous genetic variants linked to OA risk factors, facilitating MR study design. In this review, we systematically identified 52 MR studies meeting specific criteria and evaluated their quality, exploring the impact of lifestyle, nutrition, comorbidities, circulating metabolites, plasma proteins, and other health factors on OA risk. We discuss the results and potential mechanisms of MR findings, addressing conflicting evidence based on existing literature and our prior research. With the ongoing expansion of genome-wide association data, we anticipate MR's role in future OA studies to broaden, particularly in drug development research using targeted MR approaches. We thus aim for this paper to offer valuable insights for researchers and clinicians in related fields.

Lifestyle factors and metabolomic aging biomarkers: Meta-analysis of cross-sectional and longitudinal associations in three prospective cohorts

Biological age uses biophysiological information to capture a person's age-related risk of adverse outcomes. MetaboAge and MetaboHealth are metabolomics-based biomarkers of biological age trained on chronological age and mortality risk, respectively. Lifestyle factors contribute to the extent chronological and biological age differ. The association of lifestyle factors with MetaboAge and MetaboHealth, potential sex differences in these associations, and MetaboAge's and MetaboHealth's sensitivity to lifestyle changes have not been studied yet. Linear regression analyses and mixed-effect models were used to examine the cross-sectional and longitudinal associations of scaled lifestyle factors with scaled MetaboAge and MetaboHealth in 24,332 middle-aged participants from the Doetinchem Cohort Study, Rotterdam Study, and UK Biobank. Random-effect meta-analyses were performed across cohorts. Repeated metabolomics measurements had a ten-year interval in the Doetinchem Cohort Study and a five-year interval in the UK Biobank. In the first study incorporating longitudinal information on MetaboAge and MetaboHealth, we demonstrate associations between current smoking, sleeping ≥8 hours/day, higher BMI, and larger waist circumference were associated with higher MetaboHealth, the latter two also with higher MetaboAge. Furthermore, adhering to the dietary and physical activity guidelines were inversely associated with MetaboHealth. Lastly, we observed sex differences in the associations between alcohol use and MetaboHealth.

Dairy intake and cardiovascular diseases risk factors: a cross-sectional study on Iranian obese and overweight women

OBJECTIVE

Atherosclerotic cardiovascular disease (ASCVD) is one of the leading causes of death worldwide. Dietary interventions can directly affect several ASCVD risk factors. This study aimed to assess an association between dairy consumption and the odds of ASCVD and its risk factors in women with overweight and obesity.

METHODS

The present cross-sectional study was conducted on 390 Iranian women aged 18-48 years and body mass index (BMI) ≥ 25 kg/m². Dairy consumption was assessed using a 147-item food frequency questionnaire. Participants were divided into tertiles based on their dairy consumption with 130 (33.3%) women in each category.

RESULTS

The participants had an average age of 36.73 ± 9.18 years, and the mean BMI was 31.28 ± 4.30 kg/m2. In the unadjusted model, individuals in the third tertile of dairy consumption had 0.79 times lower odds of ASCVD compared to those in the first tertile (OR: 0.21; 95% Confidence Interval (CI): 0.11, 0.41; P-value = 0.001). Additionally, we observed a significant inverse relationship between higher dairy intake and adiposity markers, blood pressure, and Triglyceride glucose-body mass index (TyG-BMI).

CONCLUSION

The study revealed a negative association between dairy intake and the risk of ASCVD but this association diminished after adjusting for confounding factors. It also found a negative association between dairy consumption with BMI, fat mass index, body fat, blood pressure, and TyG-BMI.

The association between alcohol consumption and all-cause mortality: An umbrella review of systematic reviews using lifetime abstainers or low-volume drinkers as a reference group

BACKGROUND AND AIMS

Systematic reviews of the relationship between alcohol consumption and all-cause mortality have reported different relative risk (RR) curves, possibly due to the choice of reference group. Results have varied from 'J-shaped' curves, where low-volume consumption is associated with reduced risk, to monotonically increased risk with increasing consumption. We summarised the evidence on alcohol consumption and all-cause mortality exclusively from systematic reviews using lifetime abstainers or low-volume/occasional drinkers as the reference group.

METHODS

We conducted a systematic umbrella review of systematic reviews of the relationship between alcohol consumption and all-cause mortality in prospective cohort studies using a reference group of lifetime abstainers or low-volume/occasional drinkers. Several databases (PubMed/Medline/Embase/PsycINFO/Cochrane Library) were searched to March 2022. Reviews were assessed for risk of bias, and those with reference groups containing former drinkers were excluded.

RESULTS

From 2149 articles retrieved, 25 systematic reviews were identified, and five did not include former drinkers in the reference group. Four of the five included reviews had high risk of bias. Three reviews reported a J-shaped relationship between alcohol consumption and all-cause mortality with significant decreased risk for low-volume drinking (RR range 0.84 to 0.95), while two reviews did not. The one review at low risk of bias reported monotonically increased risk with greater consumption (RRs = 1.02, 1.13, 1.33 and 1.52 for low-, medium-, high- and higher-volume drinking, respectively, compared with occasional drinking). All five reviews reported significantly increased risk with higher levels of alcohol consumption (RR range 1.28 to 3.70). Sub-group analyses were reported by sex and age; however, there were evidence gaps for many important factors. Conversely, 17 of 20 excluded systematic reviews reported decreased mortality risk for low-volume drinking.

CONCLUSIONS

Over 70% of systematic reviews and meta-analyses published to March 2022 of all-cause mortality risk associated with alcohol consumption did not exclude former drinkers from the reference group and may therefore be biased by the 'sick-quitter effect'.

Using Negative Control Populations to Assess Unmeasured Confounding and Direct Effects

Sometimes treatment effects are absent in a subgroup of the population. For example, penicillin has no effect on severe symptoms in individuals infected by resistant Staphylococcus aureus , and codeine has no effect on pain in individuals with certain polymorphisms in the CYP2D6 enzyme. Subgroups where a treatment is ineffective are often called negative control populations or placebo groups. They are leveraged to detect bias in different disciplines. Here we present formal criteria that justify the use of negative control populations to rule out unmeasured confounding and mechanistic (direct) causal effects. We further argue that negative control populations, satisfying our formal conditions, are available in many settings, spanning from clinical studies of infectious diseases to epidemiologic studies of public health interventions. Negative control populations can also be used to rule out placebo effects in unblinded randomized experiments. As a case study, we evaluate the effect of mobile stroke unit dispatches on functional outcomes at discharge in individuals with suspected stroke, using data from a large trial. Our analysis supports the hypothesis that mobile stroke units improve functional outcomes in these individuals.

Causal relationship between gestational diabetes and preeclampsia: A bidirectional mendelian randomization analysis

AIMS

The study aimed to explore the potential causal link between gestational diabetes mellitus (GDM) and preeclampsia (PE) using a bidirectional mendelian randomization (MR) analysis.

MATERIALS

We conducted a bidirectional MR analysis to investigate the causal relationship between GDM and PE. Data from public genome-wide association studies (GWAS) for GDM and PE were obtained from the FinnGen consortium. Various MR methods were employed, including inverse-variance weighted (IVW), MR-Egger, and sensitivity analyses. Additionally, a knowledge-based approach identified genes underlying this potential connection.

RESULTS

The IVW method revealed a lack of significant association between GDM and PE (OR: 1.04, 95 % CI: 0.96-1.14; p = 0.275). Conversely, IVW analysis indicated a causal connection from PE to GDM (OR: 1.14, 95 % CI: 1.06-1.23; p < 0.001). Molecular pathway analysis identified 20 key genes, including ASAP2, central to the PE-GDM relationship. Tissue enrichment analysis showed pertinent gene expression in significant tissues. Moreover, lower ASAP2 expression was detected in PE patients' placentas.

CONCLUSIONS

Our bidirectional MR analysis offers evidence supporting a causal link between PE and GDM, elucidating their interconnected pathogenesis. Genetic and knowledge-based insights facilitate a deeper comprehension of these complex pregnancy complications.

Risk of diabetes and hypertension in a population with alcohol use disorders

BACKGROUND

A population-based follow-up study assessing the risk of developing hypertension and diabetes associated with alcohol use disorder (AUD) is crucial. We investigated this relationship by using insurance claims data from Taiwan.

METHODS

From the claims data, an AUD cohort (N = 60,590) diagnosed between 2000 and 2006 and a non-AUD comparison cohort (N = 60,590) without the diagnosis of hypertension or diabetes at baseline were established and matched by propensity scores estimated by baseline demographic status and the Charlson comorbidity index (CCI). We assessed the incidence rates of hypertension and/or diabetes at the end of 2016 and used Cox's method to estimate the related hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Relative to the comparison cohort, the AUD cohort had an approximately 1.70-fold higher incidence of hypertension (35.1 vs. 20.7 per 1,000 person-years), with an adjusted HR (aHR) of 1.72 (95% CI: 1.68-1.76), 2.16-fold higher incidence of diabetes (20.2 vs. 9.36 per 1,000 person-years), with an aHR of 2.18 (95% CI: 2.11-2.24), and 1.91-fold higher incidence of both diabetes and hypertension (10.3 vs. 5.38 per 1,000 person-years) with an aHR of 2.02 (95% CI: 1.94-2.10). The incidence rates of all outcomes were greater in men than in women, whereas the HRs were greater for AUD in women than for AUD in men relative to the respective comparison patients. The risk increased further for subjects with CCI ≥ 1, which was higher in the AUD cohort.

CONCLUSIONS

The increased risk of developing diabetes and hypertension in patients with AUD, especially the differences noted according to gender, indicates that clinicians should address potential comorbidities in these patients.

Bidirectional associations between alcohol drinking and depressive symptom scores among US older adults

BACKGROUND

This study examines the bidirectional associations between alcohol drinking and depression in which low to moderate alcohol drinking may reduce the risk of depression, while the occurrence of depression may increase the amount of alcohol drinking as a coping strategy.

METHOD

Data for the community-dwelling older adults from the Medicare Current Beneficiary Survey (MCBS) 2016 to 2019 were analyzed using random intercept cross-lagged panel models to explore the within-individual causal associations for males and females separately. Socioeconomic status (SES), smoking and comorbidities were adjusted in the models.

RESULTS

Among 3388 older adults with three measures for the number of alcohol drinks and Patient Health Questionnaire (PHQ) depression scores, a prior increase in the number of drinks was related to a moderate non-significant decrease in PHQ scores in the follow-up, but a previous increase in the PHQ scores was significantly associated with a decrease in the number of drinks at the follow-up visit in the adjusted models (regression coefficient = -0.144, p = 0.017 for males; and coefficient = -0.11, p < 0.001 for females).

CONCLUSION

Prior depression may lead to reduced drinking in the follow up visits, but no bidirectional association was found among US older adults.

Causal Factors for Osteoarthritis: A Scoping Review of Mendelian Randomization Studies

OBJECTIVE

Mendelian randomization (MR) has increasingly been utilized as a tool for establishing causal relations between modifiable exposures and osteoarthritis (OA). The goal of this review was to summarize available MR studies of OA that evaluate the causal role of modifiable risk factors on OA.

METHODS

This review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Extension for Scoping Reviews model. We performed a literature search for relevant studies published before December 2021 across multiple databases using the search terms "osteoarthritis" and ("Mendelian randomization" or "polygenic risk score"). We reported the MR estimates of causal associations between exposures and OA and then assessed methodologic quality of abstracted studies according to their efforts to validate the three key MR assumptions.

RESULTS

Our search identified 45 studies reporting on 141 exposure-association analyses. All studies performed a formal instrumental variable analysis to estimate the causal effect of exposure on OA. Causal associations (P < 0.05) were reported in 60 of these analyses representing 36 unique publications, and MR-Egger sensitivity analyses were performed in 45 of these analyses. MR studies provided support for causal associations of OA with increased levels of adiposity, coffee consumption, bone mineral density, and sleep disturbance, and decreased levels of serum calcium and low-density lipoprotein cholesterol.

CONCLUSION

These results highlight the potential benefits of weight reduction and improvement of sleep quality to reduce the risk of OA and call for a better understanding of the relations of coffee consumption and serum calcium to OA risk.

Alcohol consumption and the risk of all-cause and cause-specific mortality-a linear and nonlinear Mendelian randomization study

BACKGROUND

Many observational studies support light-to-moderate alcohol intake as potentially protective against premature death. We used a genetic approach to evaluate the linear and nonlinear relationships between alcohol consumption and mortality from different underlying causes.

METHODS

We used data from 278 093 white-British UK Biobank participants, aged 37-73 years at recruitment and with data on alcohol intake, genetic variants, and mortality. Habitual alcohol consumption was instrumented by 94 variants. Linear Mendelian randomization (MR) analyses were conducted using five complementary approaches, and nonlinear MR analyses by the doubly-ranked method.

RESULTS

There were 20 834 deaths during the follow-up (median 12.6 years). In conventional analysis, the association between alcohol consumption and mortality outcomes was 'J-shaped'. In contrast, MR analyses supported a positive linear association with premature mortality, with no evidence for curvature (Pnonlinearity ≥ 0.21 for all outcomes). The odds ratio [OR] for each standard unit increase in alcohol intake was 1.27 (95% confidence interval [CI] 1.16-1.39) for all-cause mortality, 1.30 (95% CI 1.10-1.53) for cardiovascular disease, 1.20 (95% CI 1.08-1.33) for cancer, and 2.06 (95% CI 1.36-3.12) for digestive disease mortality. These results were consistent across pleiotropy-robust methods. There was no clear evidence for an association between alcohol consumption and mortality from respiratory diseases or COVID-19 (1.32, 95% CI 0.96-1.83 and 1.46, 95% CI 0.99-2.16, respectively; Pnonlinearity ≥ 0.21).

CONCLUSION

Higher levels of genetically predicted alcohol consumption had a strong linear association with an increased risk of premature mortality with no evidence for any protective benefit at modest intake levels.

Should we remove wine from the Mediterranean diet?: a narrative review

Moderate alcohol intake (or, more specifically, red wine) represents one of the postulated beneficial components of the traditional Mediterranean diet. Many well-conducted nonrandomized studies have reported that light-to-moderate alcohol intake is not only associated with reduced risk of cardiovascular disease, but also of all-cause mortality. Nonetheless, alcohol is an addictive substance imposing huge threats for public health. Alcohol consumption is associated with increased risks of cancer, neurological harms, injuries, and other adverse outcomes. Both the Global Burden of Disease (2016) and Mendelian randomization studies recently supported that the healthiest level of alcohol intake should be 0. Therefore, despite findings of conventional observational epidemiologic studies supporting a potential beneficial role of wine in the context of a healthy Mediterranean dietary pattern, a strong controversy remains on this issue. Age, sex, and drinking patterns are likely to be strong effect modifiers. In this context, a new 4-y noninferiority pragmatic trial in Spain (University of Navarra Alumni Trialist Initiative or "UNATI"), publicly funded by the European Research Council, will randomly assign >10,000 current drinkers (males, 50-70 y; females, 55-75 y) to repeatedly receive advice on either abstention or moderation in alcohol consumption. The recruitment will begin in mid-2024. The primary endpoint is a composite of the main clinical outcomes potentially related to alcohol intake including all-cause mortality. Clinical trial registry number: PREDIMED, ISRCTN35739639, www.predimed.es; SUN, clinicaltrials.gov identifier: NCT02669602, https://medpreventiva.es/i2CmeL.

Alcohol use and the pain system

The World Health Organization's epidemiological data from 2016 revealed that while 57% of the global population aged 15 years or older had abstained from drinking alcohol in the previous year, more than half of the population in the Americas, Europe, and Western Pacific consumed alcohol. The spectrum of alcohol use behavior is broad: low-risk use (sensible and in moderation), at-risk use (e.g., binge drinking), harmful use (misuse) and dependence (alcoholism; addiction; alcohol use disorder). The at-risk use and misuse of alcohol is associated with the transition to dependence, as well as many damaging health outcomes and preventable causes of premature death. Recent conceptualizations of alcohol dependence posit that the subjective experience of pain may be a significant contributing factor in the transition across the spectrum of alcohol use behavior. This narrative review summarizes the effects of alcohol at all levels of the pain system. The pain system includes nociceptors as sensory indicators of potentially dangerous stimuli and tissue damage (nociception), spinal circuits mediating defensive reflexes, and most importantly, the supraspinal circuits mediating nocifensive behaviors and the perception of pain. Although the functional importance of pain is to protect from injury and further or future damage, chronic pain may emerge despite the recovery from, and absence of, biological damage (i.e., in the absence of nociception). Like other biological perceptual systems, pain is a construction contingent on sensory information and a history of individual experiences (i.e., learning and memory). Neuroadaptations and brain plasticity underlying learning and memory and other basic physiological functions can also result in pathological conditions such as chronic pain and addiction. Moreover, the negative affective/emotional aspect of pain perception provides embodied and motivational components that may play a substantial role in the transition from alcohol use to dependence.

The impact of estimation methods for alcohol-attributable mortality on long-term trends for the general population and by educational level in Finland and Italy (Turin)

BACKGROUND AND AIMS

This paper assesses the impact of estimation methods for general and education-specific trends in alcohol-attributable mortality (AAM), and develops an alternative method that can be used when the data available for study is limited.

METHODS

We calculated yearly adult (30+) age-standardised and age-specific AAM rates by sex for the general population and by educational level (low, middle, high) in Finland and Turin (Italy) from 1972 to 2017. Furthermore the slope index of inequality and relative inequality index were computed by country and sex. We compared trends, levels, age distributions, and educational inequalities in AAM according to three existing estimation methods: (1) Underlying COD (UCOD), (2) Multiple COD (MCOD) method, and (3) the population attributable fractions (PAF)-method. An alternative method is developed based on the pros and cons of these methods and the outcomes of the comparison.

RESULTS

The UCOD and MCOD approaches revealed mainly increasing trends in AAM compared to the declining trends according to the PAF approach. These differences are more pronounced when examining AAM trends by educational groups, particularly for Finnish men. Until age 65, age patterns are similar for all methods, and levels nearly identical for MCOD and PAF in Finland. Our novel method assumes a similar trend and age pattern as observed in UCOD, but adjusts its level upwards so that it matches the level of the PAF approach for ages 30-64. Our new method yields levels in-between UCOD and PAF for Turin (Italy), and resembles the MCOD rates in Finland for females. Relative inequalities deviate for the PAF-method (lower levels) compared to other methods, whereas absolute inequalities are generally lower for UCOD than all three methods that combine wholly and partly AAM.

CONCLUSIONS

The choice of method to estimate AAM affects not only levels, but also general and education-specific trends and inequalities. Our newly developed method constitutes a better alternative for multiple-country studies by educational level than the currently used UCOD-method when the data available for study is limited to underlying causes of death.

Association of age at first sexual intercourse and lifetime number of sexual partners with cardiovascular diseases: a bi-directional Mendelian randomization study

Background

Limited studies have explored the association between sexual factors [age at first sexual intercourse (AFS) and lifetime number of sexual partners (LNSP)] and cardiovascular diseases (CVDs), leaving the causality inconclusive.

Methods

We performed a bi-directional Mendelian randomization (MR) study to investigate the causality between sexual factors and CVDs, including coronary artery disease, myocardial infarction, atrial fibrillation (AF), heart failure (HF), and ischemic stroke (IS). Single-nucleotide polymorphisms (SNPs) for sexual factors were extracted from the UK Biobank. Statistics for each CVD were derived from two different databases. MR estimates were calculated per outcome database and were combined through meta-analysis. Several complementary sensitivity analyses were also performed.

Results

The primary analysis suggested that AFS was causally associated with the risk of CVDs; the odds ratios (ORs) ranged from 0.686 [95% confidence interval (CI), 0.611-0.770] for HF to 0.798 (95% CI, 0.719-0.886) for AF. However, the association between AFS and IS (OR, 0.844; 95% CI, 0.632-1.126) was not consistent in the meta-analysis after excluding SNPs related to confounders. Moreover, non-significant associations were found between LNSP and CVDs. Reverse direction MR analysis showed that CVDs were not associated with sexual factors.

Conclusions

Genetic evidence suggested that AFS was causally associated with the risk of CVDs except for IS, whereas non-significant association of LNSP with CVDs was detected. Further investigation into AFS could be warranted in preventing the progression of CVDs.

Identifying Cardiovascular Disease Risk Factors in Adults with Explainable Artificial Intelligence

BACKGROUND

The aim of this study was to evaluate the relationship between risk factors causing cardiovascular diseases and their importance with explainable machine learning models.

METHODS

In this retrospective study, multiple databases were searched, and data on 11 risk factors of 70 000 patients were obtained. Data included risk factors highly associated with cardiovascular disease and having/not having any cardiovascular disease. The explainable prediction model was constructed using 7 machine learning algorithms: Random Forest Classifier, Extreme Gradient Boost Classifier, Decision Tree Classifier, KNeighbors Classifier, Support Vector Machine Classifier, and GaussianNB. Receiver operating characteristic curve, Brier scores, and mean accuracy were used to assess the model's performance. The interpretability of the predicted results was examined using Shapley additive description values.

RESULTS

The accuracy, area under the curve values, and Brier scores of the Extreme Gradient Boost model (the best prediction model for cardiovascular disease risk factors) were calculated as 0.739, 0.803, and 0.260, respectively. The most important risk factors in the permutation feature importance method and explainable artificial intelligence-Shapley's explanations method are systolic blood pressure (ap_hi) [0.1335 ± 0.0045 w (weight)], cholesterol (0.0341 ± 0.0022 w), and age (0.0211 ± 0.0036 w).

CONCLUSION

The created explainable machine learning model has become a successful clinical model that can predict cardiovascular patients and explain the impact of risk factors. Especially in the clinical setting, this model, which has an accurate, explainable, and transparent algorithm, will help encourage early diagnosis of patients with cardiovascular diseases, risk factors, and possible treatment options.

Association between periodontitis and temporomandibular joint disorders

BACKGROUND

Periodontitis (PD) may affect temporomandibular joint disorders (TMD) and TMD may influence PD in previous observational studies. Nevertheless, these studies were prone to confounders and reverse causation, leading to incorrect conclusions about causality and direction of association. This research investigates the associations between PD and TMD employing bidirectional two-sample Mendelian randomization (MR) analysis.

METHODS

Single-nucleotide polymorphisms (SNPs) related to PD (p < 5 × 10-6) were selected from a genome-wide association study (GWAS) from the Gene-Lifestyle Interaction in the Dental Endpoints (GLIDE) consortium, and related these to SNPs from FinnGen and UK Biobank (UKB) consortia, and vice versa. We implemented the standard inverse variance weighted (IVW), weighted median (WM), MR-Egger regression, and MR-PRESSO methods to estimate the potential causality between PD and TMD. Sensitive tests were conducted using robust MR methods. Results from FinnGen and UKB were combined using the fixed model.

RESULTS

PD did not appear to causally affect TMD. Additionally, the reverse MR analysis did not reveal a significant causal effect of TMD on PD. The results of other MR methods were similar to those of the IVW method. Sensitivity analyses addressed no potential pleiotropy in MR estimations. Results from the meta-analysis were consistent with the above-mentioned consequences.

CONCLUSION

This research does not support a causal relationship between PD and TMD. PD does not appear to worsen TMD directly, and vice versa.

Drinking alcohol in moderation is associated with lower rate of all-cause mortality in individuals with higher rather than lower educational level: findings from the MORGAM project

The association between socioeconomic status (SES) and alcohol-related diseases has been widely explored. Less is known, however, on whether the association of moderate drinking with all-cause mortality is modified by educational level (EL). Using harmonized data from 16 cohorts in the MORGAM Project (N = 142,066) the association of pattern of alcohol intake with hazard of all-cause mortality across EL (lower = primary-school; middle = secondary-school; higher = university/college degree) was assessed using multivariable Cox-regression and spline curves. A total of 16,695 deaths occurred in 11.8 years (median). In comparison with life-long abstainers, participants drinking 0.1-10 g/d of ethanol had 13% (HR = 0.87; 95%CI: 0.74-1.02), 11% (HR = 0.89; 0.84-0.95) and 5% (HR = 0.95; 0.89-1.02) lower rate of death in higher, middle and lower EL, respectively. Conversely, drinkers > 20 g/d had 1% (HR = 1.01; 0.82-1.25), 10% (HR = 1.10; 1.02-1.19) and 17% (HR = 1.17; 1.09-1.26) higher rate of death. The association of alcohol consumption with all-cause mortality was nonlinear, with a different J-shape by EL levels. It was consistent across both sexes and in various approaches of measuring alcohol consumption, including combining quantity and frequency and it was more evident when the beverage of preference was wine. We observed that drinking in moderation (≤ 10 g/d) is associated with lower mortality rate more evidently in individuals with higher EL than in people with lower EL, while heavy drinking is associated with higher mortality rate more evidently in individuals with lower EL than in people with higher EL, suggesting that advice on reducing alcohol intake should especially target individuals of low EL.

A systematic review of relative risks for the relationships between chronic alcohol use and the occurrence of disease

Alcohol use is causally linked to the development of and mortality from numerous diseases. The aim of this study is to provide an update to a previous systematic review of meta-analyses that quantify the sex-specific dose-response risk relationships between chronic alcohol use and disease occurrence and/or mortality. An updated systematic search of multiple databases was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria to identify meta-analyses published from January 1, 2017, to March 8, 2021, which quantified the risk relationships between chronic alcohol use and the risk of disease occurrence and/or mortality. This systematic review was not preregistered. The comparator was people who have never consumed at least one standard drink of alcohol. Measurements included relative risks, odds ratios, and hazard ratios of disease occurrence and/or mortality based on long-term alcohol intake measured in grams per day. The systematic search yielded 5953 articles, of which 14 were included in the narrative review. All diseases showed an increased risk of occurrence as alcohol use increased. At all doses examined, alcohol had a significant detrimental effect on tuberculosis, lower respiratory infections, oral cavity and pharyngeal cancers, esophageal cancer, colorectal cancer, liver cancer, laryngeal cancer, epilepsy, hypertension, liver cirrhosis, and pancreatitis (among men). For ischemic heart disease, ischemic stroke, and intracerebral hemorrhage, protective effects from low-dose chronic alcohol use among both men and women were observed. Low-dose alcohol consumption also had a protective effect for diabetes mellitus and pancreatitis among women (approximately to 50 g/day and 30 g/day, respectively). Alcohol use increases the risk of numerous infectious and noncommunicable diseases in a dose-response manner. Higher levels of alcohol use have a clear detrimental impact on health; however, at lower levels of use, alcohol can have both disease-specific protective and detrimental effects.

Milk consumption and the risk of type 2 diabetes: A systematic review of Mendelian randomization studies

AIMS

Previously, no relationship between milk consumption and the risk of type 2 diabetes has been found in prospective cohorts. However, Mendelian randomization allows researchers to almost bypass much residual confounding, providing a more precise effect estimate. This systematic review aims to investigate the risk of type 2 diabetes and levels of HbA1c by assessing all Mendelian Randomization studies investigating this subject matter.

DATA SYNTHESIS

PubMed and EMBASE were searched from October 2021 through February 2023. Inclusion and exclusion criteria were formulated to filter out irrelevant studies. Studies were qualitatively assessed with STROBE-MR together with a list of five MR criteria. Six studies were identified, containing several thousand participants. All studies used the SNP rs4988235 as the main exposure and type 2 diabetes and/or HbA1c as the main outcome. Five studies were graded as "good" with STROBE-MR, with one graded as "fair". For the six MR criteria, five studies were graded "good" in four criteria, while two studies were graded "good" in two criteria. Overall, genetically predicted milk consumption did not seem to be associated with an increased risk of type 2 diabetes.

CONCLUSIONS

This systematic review found that genetically predicted milk consumption did not seem to increase the risk of type 2 diabetes. Future Mendelian randomization studies concerning this topic should consider conducting two-sample Mendelian Randomization studies, in order to derive a more valid effect estimate.

Alcohol and the vasculature: a love-hate relationship?

Alcohol consumption is a leading risk factor and increases the risk of liver diseases, cancers, tuberculosis, and injuries. The relationship between alcohol use and cardiovascular risk is complex. While it is well established that heavy alcohol use and binge drinking harm cardiovascular health, the effect of light-to-moderate alcohol consumption remains controversial. Observational studies have repeatedly confirmed the U- or J-shaped relationship between alcohol consumption and cardiovascular disease risk, with the lowest risk observed in the light-to-moderate drinking group. However, the protective effect of low-level alcohol has been challenged by recent genetic epidemiological studies with Mendelian randomization. Such studies have their own limitations, and the application of this methodology in studying alcohol has been questioned. Results from the latest Global Burden of Diseases, Injuries, and Risk Factors Study suggest that the impact of alcohol consumption on health depends on the age structure and the distribution of disease burden and underlying causes in a given population. For young adults, even small amounts of alcohol cause heath loss. For older adults facing a high burden of cardiovascular diseases, light-to-moderate alcohol consumption may improve cardiovascular health outcomes. Mechanistically, all types of alcoholic beverages, including wine, spirits, and beer, have been shown to increase the levels of high-density lipoprotein cholesterol and adiponectin, and reduce the level of fibrinogen. Nonalcoholic components of wine, especially polyphenolic compounds like resveratrol, may additionally enhance endothelial nitric oxide production, and provide antioxidant and anti-inflammatory effects.

Alcohol consumption and socioeconomic status associated with the risk of kidney cancer in a large Australian cohort study

PURPOSE

Studies have shown an inverse association between alcohol consumption and kidney cancer risk. We postulate that this inverse association may be further influenced by other risk factors.

METHODS

We used an Australian cohort, the 45 and Up Study recruited between 2005-2009 to investigate the association between alcohol consumption, and other potential risk factors and kidney cancer incidence. The median follow up was 5.4 years.

RESULTS

Of the 267 357 participants aged ≥45 years living in New South Wales, 497 were diagnosed with kidney cancer. There was a significant inverse association between alcohol consumption and risk of kidney cancer (p = 0.027), and a significant inverse dose-response relationship (p=0.011). There was significant interaction between alcohol consumption and socioeconomic status (p interaction = 0.001). Participants residing in higher socioeconomic areas (the two most advantaged quintiles) who consumed 8-10 drinks or >10 drinks per week, respectively, had a lower risk of kidney cancer compared to the group who consumed 1-4 drinks per week (HR 0.34, 95% CI 0.15-0.76, HR 0.51, 95% CI 0.31-0.83) with a dose-response trend of HR 0.62 (95% CI 0.42-0.93) per 7 drink increase in weekly alcohol consumption.

CONCLUSION

There could be an inverse association between alcohol consumption and risk in those residents in higher socioeconomic areas.

DATA AVAILABILITY

The data that support the findings of this study are available from the Sax Institute (https://www.saxinstitute.org.au/our-work/45-up-study/).

Causal association between vitamin D and diabetic neuropathy: a Mendelian randomization analysis

OBJECTIVES

Vitamin D has been linked to diabetic neuropathy (DN) in previous epidemiological observational studies, however, their findings are inconsistent. The causal relationship between vitamin D and DN remains unknown. In this study we aim to investigate the causal association of serum 25-hydroxyvitamin D (25OHD) and DN.

METHODS

Based on summary statistics from publicly available genome-wide association studies (GWAS) database, we detected the genetic correlation between serum 25OHD levels and DN by a two-sample Mendelian randomization (MR) analysis. The inverse-variance weighted (IVW) method was used as the primary analysis, weighted median and MR-Egger were applied as complementary methods for MR estimates. In addition, we took sensitivity analyses including Cochran's Q test, MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO) and leave-one-out analysis to ensure that we obtained stable and reliable results.

RESULTS

Our MR study showed no significant genetic association between serum 25OHD levels and DN (OR = 1.13, 95% CI = 0.81-1.57, P = 0.46). Furthermore, in the reverse direction analysis, we did not find a significant causal effect of DN and serum 25OHD levels (OR = 0.99, 95% CI = 0.98-1.00, P = 0.09). Results of MR-Egger, Weighted Median were consistent with those of the IVW method. The sensitivity analysis suggesting that no significant heterogeneity and genetic pleiotropy was observed.

CONCLUSIONS

Our results provided no evidence to support the causal association of serum 25OHD levels with DN.

Smoking, alcohol consumption, and frailty: A Mendelian randomization study

Background: Tobacco smoking and alcohol consumption have been associated with frailty in observational studies. We sought to examine whether these associations reflect causality using the two-sample Mendelian randomization (MR) design. Methods: We used summary genome-wide association statistics for smoking initiation (N = 2,669,029), alcohol consumption (N = 2,428,851), and the frailty index (FI, N = 175,226) in participants of European ancestry. Both univariable and multivariable MR were performed to comprehensively evaluate the independent effects of smoking and alcohol consumption on the FI, accompanied by multiple sensitivity analyses. Results were verified using lifetime smoking and alcohol use disorder. Reverse direction MR was undertaken to assess the potential for reverse causation. Results: Genetic predisposition to smoking initiation was significantly associated with increased FI (univariable MR: β = 0.345; 95% confidence interval [CI] = 0.316 to 0.374; p = 1.36E-113; multivariable MR: β = 0.219; 95% CI = 0.197 to 0.241; p = 2.44E-83). Genetically predicted alcohol consumption showed a suggestive association with the FI (univariable MR: β = -0.090; 95% CI = -0.151 to -0.029; p = 0.003; multivariable MR β = -0.153; 95% CI = -0.212 to -0.094; p = 2.03E-07), with inconsistent results in sensitivity analyses. In complementary analysis, genetic predicted lifetime smoking, but not alcohol use disorder was associated with the FI. There is no convincing evidence for reverse causation. Conclusion: The present MR study supported smoking as a causal risk factor of frailty. Further research is warranted to investigate whether alcohol consumption has a causal role in frailty.

Causality of genetically determined metabolites on anxiety disorders: a two-sample Mendelian randomization study

BACKGROUND

Although anxiety disorders are one of the most prevalent mental disorders, their underlying biological mechanisms have not yet been fully elucidated. In recent years, genetically determined metabolites (GDMs) have been used to reveal the biological mechanisms of mental disorders. However, this strategy has not been applied to anxiety disorders. Herein, we explored the causality of GDMs on anxiety disorders through Mendelian randomization study, with the overarching goal of unraveling the biological mechanisms.

METHODS

A two-sample Mendelian randomization (MR) analysis was implemented to assess the causality of GDMs on anxiety disorders. A genome-wide association study (GWAS) of 486 metabolites was used as the exposure, whereas four different GWAS datasets of anxiety disorders were the outcomes. Notably, all datasets were acquired from publicly available databases. A genetic instrumental variable (IV) was used to explore the causality between the metabolite and anxiety disorders for each metabolite. The MR Steiger filtering method was implemented to examine the causality between metabolites and anxiety disorders. The standard inverse variance weighted (IVW) method was first used for the causality analysis, followed by three additional MR methods (the MR-Egger, weighted median, and MR-PRESSO (pleiotropy residual sum and outlier) methods) for sensitivity analyses in MR analysis. MR-Egger intercept, and Cochran's Q statistical analysis were used to evaluate possible heterogeneity and pleiotropy. Bonferroni correction was used to determine the causative association features (P < 1.03 × 10^-4). Furthermore, metabolic pathways analysis was performed using the web-based MetaboAnalyst 5.0 software. All statistical analysis were performed in R software. The STROBE-MR checklist for the reporting of MR studies was used in this study.

RESULTS

In MR analysis, 85 significant causative relationship GDMs were identified. Among them, 11 metabolites were overlapped in the four different datasets of anxiety disorders. Bonferroni correction showing1-linoleoylglycerophosphoethanolamine (OR_{fixed-effect IVW} = 1.04; 95% CI 1.021-1.06; P_{fixed-effect IVW} = 4.3 × 10^-5) was the most reliable causal metabolite. Our results were robust even without a single SNP because of a "leave-one-out" analysis. The MR-Egger intercept test indicated that genetic pleiotropy had no effect on the results (intercept = - 0.0013, SE = 0.0006, P = 0.06). No heterogeneity was detected by Cochran's Q test (MR-Egger. Q = 7.68, P = 0.742; IVW. Q = 12.12, P = 0.436). A directionality test conducted by MR Steiger confirmed our estimation of potential causal direction (P < 0.001). In addition, two significant pathways, the "primary bile acid biosynthesis" pathway (P = 0.008) and the "valine, leucine, and isoleucine biosynthesis" pathway (P = 0.03), were identified through metabolic pathway analysis.

CONCLUSION

This study provides new insights into the causal effects of GDMs on anxiety disorders by integrating genomics and metabolomics. The metabolites that drive anxiety disorders may be suited to serve as biomarkers and also will help to unravel the biological mechanisms of anxiety disorders.

The role of the gut microbiota in health and cardiovascular diseases

The gut microbiota is critical to human health, such as digesting nutrients, forming the intestinal epithelial barrier, regulating immune function, producing vitamins and hormones, and producing metabolites to interact with the host. Meanwhile, increasing evidence indicates that the gut microbiota has a strong correlation with the occurrence, progression and treatment of cardiovascular diseases (CVDs). In patients with CVDs and corresponding risk factors, the composition and ratio of gut microbiota have significant differences compared with their healthy counterparts. Therefore, gut microbiota dysbiosis, gut microbiota-generated metabolites, and the related signaling pathway may serve as explanations for some of the mechanisms about the occurrence and development of CVDs. Several studies have also demonstrated that many traditional and latest therapeutic treatments of CVDs are associated with the gut microbiota and its generated metabolites and related signaling pathways. Given that information, we summarized the latest advances in the current research regarding the effect of gut microbiota on health, the main cardiovascular risk factors, and CVDs, highlighted the roles and mechanisms of several metabolites, and introduced corresponding promising treatments for CVDs regarding the gut microbiota. Therefore, this review mainly focuses on exploring the role of gut microbiota related metabolites and their therapeutic potential in CVDs, which may eventually provide better solutions in the development of therapeutic treatment as well as the prevention of CVDs.

Causal relationship between insomnia and tuberculosis: A bi-directional Mendelian randomization analysis

Previous observational studies appear to have established a bi-directional association between sleep disorders and tuberculosis. However, their conclusions are prone to be biased by confounding effects and reverse causation due to the nature of observational studies. Mendelian randomization (MR) approach provides unconfounded estimates of causal effects and overcomes the limitations of observational studies. We performed a bi-directional MR analysis to clarify whether there existed a causal effect of insomnia on tuberculosis, or tuberculosis on insomnia. In forward-direction MR, we chose genome-wide significant (P < .5 × 10-8) and independent (r2 < 0.001) single-nucleotide polymorphisms (SNPs) as instrumental variants (IVs), then extracted effect estimates of these IVs in tuberculosis genome-wide association study (GWAS) dataset to explore causal effect of genetically proxied insomnia on tuberculosis using inverse variance-weighted (IVW), MR-Egger, and weighted median methods. Additionally, we examined robustness and pleiotropy of effect estimates by heterogeneity and sensitivity analysis. Similarly, we investigated causal effect of genetically proxied tuberculosis on insomnia in reverse-direction MR. We revealed no causal relationship between genetically proxied insomnia and tuberculosis using 15 SNPs in forward-direction MR (IVW OR 5.305 [0.100-281.341], P = .410) and reverse-direction MR analysis (ORs and P values were not applicable due to no eligible SNPs in GWAS), with insignificant heterogeneity (Q = 22.6, I2 < 0.001, P = .066) and pleiotropy (intercept = 0.032, SE = 0.057, P = .592) in effect estimates. Our bi-directional MR analysis affirms no causal effect of insomnia on tuberculosis, or tuberculosis on insomnia.

Associations between sleep duration and cardiovascular diseases: A meta-review and meta-analysis of observational and Mendelian randomization studies

The associations between sleep duration and cardiovascular diseases (CVDs) have been explored in many observational studies. However, the causality of sleep duration and many CVDs, such as coronary artery disease (CAD), heart failure (HF), and stroke, remains unclear. In this study, we conducted a systematic meta-review and meta-analysis of the results of observational and Mendelian randomization (MR) studies to examine how sleep duration impacts the risk of CVDs. We searched articles published in English and before 10 September 2021 in PubMed, Web of Science, and Embase. The articles were screened independently by two reviewers to minimize potential bias. We combined the meta-analyses of observational studies and 11 MR studies and summarized evidence of the effect of sleep duration on the risk of CAD, HF, stroke, and cardiovascular and all-cause mortality. Results showed that (a) evidence is accumulating that short sleep duration is a causal risk factor for CAD and HF; (b) abundant evidence from observational studies supports that long sleep duration is associated with the risk of CAD, stroke, and mortality, and long sleep duration has no causal associations with stroke and CAD in the MR studies; the causation of long sleep duration and other CVDs should be further studied; and (c) emerging evidence indicates that an increase in hours of sleep is associated with a decreased risk of CAD. Finally, we discussed the underlying pathophysiological mechanisms underlying short sleep duration and CVDs and suggested that increasing sleep duration benefits cardiovascular health.

Population-level risks of alcohol consumption by amount, geography, age, sex, and year: a systematic analysis for the Global Burden of Disease Study 2020

BACKGROUND

The health risks associated with moderate alcohol consumption continue to be debated. Small amounts of alcohol might lower the risk of some health outcomes but increase the risk of others, suggesting that the overall risk depends, in part, on background disease rates, which vary by region, age, sex, and year.

METHODS

For this analysis, we constructed burden-weighted dose-response relative risk curves across 22 health outcomes to estimate the theoretical minimum risk exposure level (TMREL) and non-drinker equivalence (NDE), the consumption level at which the health risk is equivalent to that of a non-drinker, using disease rates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020 for 21 regions, including 204 countries and territories, by 5-year age group, sex, and year for individuals aged 15-95 years and older from 1990 to 2020. Based on the NDE, we quantified the population consuming harmful amounts of alcohol.

FINDINGS

The burden-weighted relative risk curves for alcohol use varied by region and age. Among individuals aged 15-39 years in 2020, the TMREL varied between 0 (95% uncertainty interval 0-0) and 0·603 (0·400-1·00) standard drinks per day, and the NDE varied between 0·002 (0-0) and 1·75 (0·698-4·30) standard drinks per day. Among individuals aged 40 years and older, the burden-weighted relative risk curve was J-shaped for all regions, with a 2020 TMREL that ranged from 0·114 (0-0·403) to 1·87 (0·500-3·30) standard drinks per day and an NDE that ranged between 0·193 (0-0·900) and 6·94 (3·40-8·30) standard drinks per day. Among individuals consuming harmful amounts of alcohol in 2020, 59·1% (54·3-65·4) were aged 15-39 years and 76·9% (73·0-81·3) were male.

INTERPRETATION

There is strong evidence to support recommendations on alcohol consumption varying by age and location. Stronger interventions, particularly those tailored towards younger individuals, are needed to reduce the substantial global health loss attributable to alcohol.

FUNDING

Bill & Melinda Gates Foundation.

Alcohol Consumption and Cardiovascular Disease Risk: Placing New Data in Context

PURPOSE OF REVIEW

A clear link between excessive alcohol consumption and cardiovascular disease (CVD) has been established, but no consensus exists on the effects of moderate alcohol consumption on CVD.

RECENT FINDINGS

A lower risk of coronary heart disease and myocardial infarction among moderate drinkers compared to abstainers has been consistently observed in epidemiological studies and meta-analyses of these studies. However, ambiguity remains on the effect of alcohol on other CVDs and all-cause mortality. Short-term randomized controlled trials (RCT) have identified potentially beneficial effects of alcohol consumption on cardiovascular risk factors, but studies investigating genetic polymorphisms that influence alcohol consumption (i.e., Mendelian randomization) have yielded inconclusive results. To date, a long-term RCT providing causal evidence is lacking but urgently needed. Triangulation of evidence from different study designs, including long-term RCTs, pragmatic trials and the evaluation of policy measures, combined will lead to the best available evidence.