New genetic loci link adipose and insulin biology to body fat distribution

Educational attainment, body mass index, and smoking as mediators in kidney disease risk: a two-step Mendelian randomization study

BACKGROUND

Educational attainment (EA) has been linked to various health outcomes, including kidney disease (KD). However, the underlying mechanisms remain unclear. This study aims to assess the causal relationship between EA and KD and quantify the mediation effects of modifiable risk factors using a Mendelian randomization (MR) approach.

METHODS

We performed a two-sample MR analysis utilizing summary statistics from large-scale European genome-wide association studies (GWAS). EA (NGWAS = 766,345) was used as the exposure, and KD (Ncase/Ncontrol= 5,951/212,871) was the outcome. A two-step MR method was applied to identify and quantify the mediation effects of 24 candidate risk factors.

RESULTS

Each additional 4.2 years of genetically predicted EA was associated with a 32% reduced risk of KD (odds ratio [OR] 0.68; 95% confidence interval [CI] 0.56, 0.83). Among the 24 candidate risk factors, body mass index (BMI) mediated 21.8% of this protective effect, while smoking heaviness mediated 18.7%.

CONCLUSIONS

This study provides robust evidence that EA exerts a protective effect against KD, partially mediated by BMI and smoking. These findings highlight the potential for targeted public health interventions aimed at mitigating obesity and smoking-related risks to reduce KD incidence, particularly among individuals with lower educational attainment.

Sarcospan, a candidate gene of fat distribution, may affect lipid storage in adipocytes

BACKGROUND AND AIMS

Genetic and epigenetic variations in the Sarcospan (SSPN) gene are associated with parameters of fat distribution (body mass index, waist-to-hip ratio), glucose homeostasis and adipocyte size in human potentially by affecting adipogenesis. This study aims at clarifying the impact of SSPN on adipogenesis, particularly focusing on its promoter methylation.

MATERIALS AND METHODS

Immortalized murine epididymal preadipocytes were transfected with fluorescence-marked plasmids coding for DNMT3a, CRISPR/dCas9-Suntag and vectors carrying guide RNAs complementary to the transcription start site region and differentiated to mature adipocytes. We performed siRNA-mediated Sspn knockdown in epididymal preadipocytes, measured target DNA methylation using pyrosequencing and quantified transcriptional changes of Sspn and adipogenic genes by qPCR. Additionally, we correlated SSPN mRNA values and clinical characteristics from a large human adipose tissue biobank (Leipzig Obesity Biobank).

RESULTS

Epigenetic editing of the Sspn regulatory region in preadipocytes resulted in a significant increase (up to 35 %) in DNA promoter methylation throughout adipocyte differentiation but showed only minor effects on Sspn expression and fat storage. Though siRNA knockdown could also not contribute to understand the role of Sspn in a 2D adipogenesis model, large-scale correlation analyses still indicate the gene to be a key player in fat distribution and glucose homeostasis.

CONCLUSIONS

Although the epigenetic downregulation of Sspn showed only marginal effects on adipogenesis, associations of SSPN expression in human adipose tissue with parameters of fat distribution and glucose homeostasis make it a promising candidate for further studies addressing metabolic processes in adipose tissue.

Three Loci Affecting Variance of Body Mass Index in African Americans and Sub-Saharan Africans

Conventional genome-wide association studies (GWAS) are designed to assess the effect of a genetic locus on phenotypic mean by genotype. Such loci explain a proportion of phenotypic variance known as narrow-sense heritability. In contrast, variance quantitative trait loci (vQTL) are associated with the phenotypic variance by genotype. These loci explain an additional proportion of phenotypic variance and contribute to broad-sense heritability but not to narrow-sense heritability. Here, a genome-wide vQTL analysis in 22,805 African Americans yielded eight loci for body mass index (BMI). Of these loci, three were replicated in 6002 sub-Saharan Africans. No locus reached genome-wide significance using the standard additive model. Furthermore, no locus showed evidence for natural selection, haplotype effects, or gene × sex or gene × study interactions. Two loci showed evidence for an effect of locus-specific ancestry resulting from admixture and for a gene × gene interaction. One locus showed evidence for interaction with diastolic blood pressure, consistent with this vQTL capturing an unmodeled gene × covariate interaction. These analyses demonstrate that relevant BMI loci can be detected by evaluating vQTL and that these loci contribute to the underexplored broad-sense heritability for this trait.

Lipedema: Progress, Challenges, and the Road Ahead

INTRODUCTION

Lipedema is a chronic and progressive disease that predominantly affects women, characterized by a disproportionate increase in subcutaneous adipose tissue (AT), particularly in the lower limbs. It is associated with significant physical disability, chronic pain, thromboembolism, and psychosocial distress. Despite its profound impact on women's health and quality of life, lipedema remains underrecognized and insufficiently studied, with an estimated prevalence of approximately 10% among women worldwide. Although the exact etiology of lipedema remains unclear, emerging evidence suggests a multifactorial origin involving genetic predisposition, hormonal influences, and vascular dysfunction-all contributing to its development and progression. Current therapeutic options provide only partial symptom relief and remain noncurative, highlighting the urgent need for expanded research and improved management strategies.

METHODS

A systematic review was conducted to assess the current understanding of lipedema pathophysiology and current treatment options. Research articles were sourced from PubMed, Web of Science, ScienceDirect, and Scopus databases. Over 100 studies were incorporated.

RESULTS

This review provides a comprehensive overview of lipedema, encompassing its clinical features, pathophysiological mechanisms, diagnostic challenges, and current treatment modalities. Additionally, the review discusses whether the molecular and metabolic differences between abdominal and femoral AT depots mirror those observed in classical obesity.

CONCLUSIONS

Multidisciplinary, research-informed care is essential for managing lipedema, combining conservative therapies, tailored exercise, and liposuction for advanced cases. More research to better understand the underlying pathophysiology is critical to developing targeted treatments, improving diagnostic accuracy, and informing standardized, evidence-based care.

Father's adolescent body silhouette is associated with offspring asthma, lung function and BMI through DNA methylation

Boys' pubertal overweight associates with future offspring's asthma and low lung function. To identify how paternal overweight is associated with offspring's DNA methylation (DNAm), we conducted an epigenome-wide association study of father's body silhouette (FBS) at three timepoints (age 8, voice break and 30) and change in FBS between these times, with offspring DNAm, in the RHINESSA cohort (N = 339). We identified 2005 differentially methylated cytosine-phosphate-guanine (dmCpG) sites (FDR < 0.05), including dmCpGs associated with offspring asthma (119), lung function (178) and BMI (291). Voice break FBS associated with dmCpGs in loci including KCNJ10, FERMT1, NCK2 and WWP1. Change in FBS across sexual maturation associated with DNAm at loci including NOP10, TRRAP, EFHD1, MRPL17 and NORD59A;ATP5B and showed strong correlation in reduced gene expression in loci NAP1L5, ATP5B, ZNF695, ZNF600, VTRNA2-1, SOAT2 and AGPAT2. We identified 24 imprinted genes including: VTRNA2-1, BLCAP, WT1, NAP1L5 and PTPRN2. Identified pathways relate to lipid and glucose metabolism and adipogenesis. Father's overweight at puberty and during reproductive maturation was strongly associated with offspring DNA, suggesting a key role for epigenetic mechanisms in intergenerational transfer from father to offspring in humans. The results support an important vulnerability window in male puberty for future offspring health.

Causal association between polyunsaturated fatty acids and acne: a two-sample Mendelian randomization study

BACKGROUND

Observational studies have demonstrated a close association between polyunsaturated fatty acids (PUFAs) and acne. However, the findings of clinical trials have been inconsistent, leaving the causal relationship between PUFAs and acne unclear.

OBJECTIVES

To investigate the causal association between genetically proxied PUFAs and acne risk.

METHODS

Mendelian randomization (MR) was performed using single nucleotide polymorphisms associated with PUFAs as instrumental variables. The causal associations between PUFAs and acne were estimated among 115 006 UK Biobank participants and 363 927 participants of Finnish descent.

RESULTS

Genetically predicted docosahexaenoic acid (DHA) levels [β = -0.303, 95% confidence interval (CI) -0.480 to -0.126; P = 7.74 × 10-4] and its percentage to total fatty acids (β = -0.402, 95% CI -0.651 to -0.258; P = 5.91 × 10-6) showed a significant causal association with a decreased risk of acne. Conversely, genetically predicted percentages of linoleic acid (LA) in total fatty acids (β = 0.768, 95% CI 0.411-0.126; P = 2.87 × 10-4) and omega-6 : omega-3 ratio (β = 0.373, 95% CI 0.142-0.604; P = 4.48 × 10-3) were robustly associated with an increased risk of acne. These effects were attenuated after excluding a genetic variant of rs174528 located upstream of FADS1, highlighting the biologic link between FADS1 and delta-5 desaturase activity. Multivariable MR analysis indicated that PUFAs were causally associated with acne, independent of body mass index.

CONCLUSIONS

Our study indicates that high DHA levels and their ratios to total fatty acids have causal protective effects against acne, while high LA levels and omega-6 : omega-3 ratio are associated with increased acne risk. This association was largely attributable to the influence of genetic variants related to FADS1.

Endophenotype-Informed Association Analyses for Liver Fat Accumulation and Metabolic Dysfunction in the Fels Longitudinal Study

The identification of causal genomic regions for liver fat accumulation in the context of metabolic dysfunction remains a challenging goal. This study aimed to identify potential endophenotypes for liver fat content and employ them in bivariate linkage searches for pleiotropic genetic regions where targeted association analysis is more likely to reveal significant variants. Multiple metabolic risk and adiposity distribution traits were assessed using the endophenotype ranking value. The top-ranked endophenotypes were then used in a bivariate linkage analysis, paired with liver fat content. Quantitative trait loci (QTLs) identified as significant or suggestive were targeted for measured genotype association analyses. The highest-ranked endophenotypes for liver fat accumulation were insulin resistance (IR), visceral adipose tissue (VAT), and high-density lipoprotein cholesterol (HDL-C). The univariate linkage analysis for liver fat content identified one significant QTL at chromosome 17p13.2 (Logarithm of odds score (LOD) = 2.90, p = 1.29 × 10-4). The bivariate linkage analysis pairing liver fat with IR and VAT improved the localization of two suggestive QTLs at 13q21.31 (LOD = 2.11, p = 9.03 × 10-4), and 6q21 (LOD = 2.35, p = 5.07 × 10-4), respectively. Targeted association analyses within the -1-LOD score regions of these QTLs revealed 17 marginally significant single nucleotide polymorphisms (SNPs) associated with liver fat content or its combination with the selected endophenotypes. The endophenotype-informed linkage analysis successfully identified regions suitable for the targeted association analysis of liver fat content, either alone or in combination with IR or VAT, leading to the discovery of marginally significant variants with potential for future functional studies.

Variant-to-function approaches for adipose tissue: Insights into cardiometabolic disorders

Genome-wide association studies (GWASs) have identified thousands of genetic loci associated with cardiometabolic disorders. However, the functional interpretation of these loci remains a daunting challenge. This is particularly true for adipose tissue, a critical organ in systemic metabolism and the pathogenesis of various cardiometabolic diseases. We discuss how variant-to-function (V2F) approaches are used to elucidate the mechanisms by which GWAS loci increase the risk of cardiometabolic disorders by directly influencing adipose tissue. We outline GWAS traits most likely to harbor adipose-related variants and summarize tools to pinpoint the putative causal variants, genes, and cell types for the associated loci. We explain how large-scale perturbation experiments, coupled with imaging and multi-omics, can be used to screen variants' effects on cellular phenotypes and how these phenotypes can be tied to physiological mechanisms. Lastly, we discuss the challenges and opportunities that lie ahead for V2F research and propose a roadmap for future studies.

Insights into modifiable risk factors of retinal vascular occlusion: A Mendelian randomization study

Understanding the etiological risk factors for retinal vascular occlusion (RVO) is critical for prevention and treatment. While the effects of cardiovascular events, hypertension, glaucoma, obesity and glycemic risk factors on RVO are still controversial. This study employed two-sample Mendelian randomization (MR) analysis to investigate these causal risk factors. Single-nucleotide polymorphisms (SNPs) were used as instrumental variables (IVs). Genetic instruments for hypertension, glaucoma, obesity, cardiovascular events and glycemic risk factors were obtained from published genome-wide association studies (GWASs). Summary-level data for RVO and hypertension were obtained from the FinnGen consortium. MR analysis primarily utilized the inverse variance weighted (IVW) method, with MR-Egger and weighted median as supplementary approaches. Multivariable MR (MVMR) adjusting for hypertension or glaucoma of RVO were conducted. Heterogeneity was assessed using Cochrane's Q test and I2, while MR-Egger intercept and MR-PRESSO tested horizontal pleiotropy. All MR analyses were performed within R software (4.1.3) using the R packages "TwoSampleMR" and "MR-PRESSO." Genetic instruments for hypertension and glaucoma were significantly associated with RVO risk. A one-standard deviation (SD) increase in hypertension was associated with a higher risk of RVO [OR = 1.577, 95% CI = (1.342, 1.854), P < .001], while a one-SD increase in the log odds of genetically predicted glaucoma was associated with a higher risk of RVO [OR = 1.24, 95% CI = (1.115, 1.379), P < .001]. Meanwhile, hypertension and glaucoma were still significant in multivariable MR. There was not sufficient evidence to suggest cardiovascular events and obesity were associated with RVO risk. This MR study provided genetic evidence supporting that hypertension and glaucoma were causally associated with the risk of RVO. It may help guide clinical decisions in the management of RVO patients with hypertension and glaucoma.

Enhancing adipose tissue plasticity: progenitor cell roles in metabolic health

Adipose tissue demonstrates considerable plasticity and heterogeneity, enabling metabolic, cellular and structural adaptations to environmental signals. This adaptability is key for maintaining metabolic homeostasis. Impaired adipose tissue plasticity can lead to abnormal adipose tissue responses to metabolic cues, which contributes to the development of cardiometabolic diseases. In chronic obesity, white adipose tissue undergoes pathological remodelling marked by adipocyte hypertrophy, chronic inflammation and fibrosis, which are linked to local and systemic insulin resistance. Research data suggest that the capacity for healthy or unhealthy white adipose tissue remodelling might depend on the intrinsic diversity of adipose progenitor cells (APCs), which sense and respond to metabolic cues. This Review highlights studies on APCs as key determinants of adipose tissue plasticity, discussing differences between subcutaneous and visceral adipose tissue depots during development, growth and obesity. Modulating APC functions could improve strategies for treating adipose tissue dysfunction and metabolic diseases in obesity.

Causal effects of obesity on estimated glomerular filtration rate: a Mendelian randomization and image data analysis study

Background

Obesity has been associated with onset and progression of chronic kidney disease (CKD) but causal relationship remains uncertain. This study investigated how obesity causally affects estimated glomerular filtration rate.

Methods

Cross-sectional and magnetic resonance imaging (MRI) data analyses were performed within the Prospective Investigation of Obesity, Energy, and Metabolism (POEM) study (502 participants, all aged 50 years). Additionally Mendelian randomization was performed using published summary data. Outcomes were creatinine- and cystatin C-based eGFR. Body mass index (BMI) and waist circumference (WC) were used as exposure variables in the cross-sectional and Mendelian randomization analyses. In the imaging data analyses, eGFR was regressed non-parametrically on tissue volume for each 3D voxel and visualized as a correlation "Imiomics" map.

Results

Negative correlations were shown between cystatin C-based eGFR and BMI [beta = -0.190 (95% CI: -0.280 to -0.100)] and WC [beta = -0.160 (95% CI: -0.250 to -0.060)] in an adjusted model. In contrast, a positive association was found for creatinine-based eGFR [BMI beta = 1.20 (95% CI: 0.030 to 0.210) and WC beta = 0.160 (95% CI: 0.070 to 0.260)]. Similar patterns were found using MRI analysis (Imiomics map). Mendelian randomization implied a negative causal effect of obesity-related measures on cystatin C-based eGFR [BMI beta = -0.031 (95% CI: -0.037 to -0.026) and WC beta = -0.038 (95% CI: -0.045 to -0.031)], but no statistically significant effect was found for creatinine-based eGFR.

Conclusion

This study suggests a causal negative effect of obesity on cystatin C-based, but not creatinine-based eGFR. These findings warrant further research regarding estimations of kidney function when assessing obesity and CKD.

Modifiable risk factors and inflammation-related proteins in polymyalgia rheumatica: genome-wide meta-analysis and Mendelian randomization

OBJECTIVE

PMR is an age-related inflammatory disease of unknown cause. We aimed to identify potentially modifiable risk factors and therapeutic targets for preventing or treating PMR.

METHODS

We meta-analysed genetic association data from 8156 cases of PMR (defined using diagnostic codes and self-report) and 416 495 controls of European ancestry from the UK Biobank and FinnGen. We then performed Mendelian randomization analyses to estimate the association between eight modifiable risk factors (using data from up to 1.2 million individuals) and 65 inflammation-related circulating proteins (up to 55 792 individuals), using the inverse variance weighted and pleiotropy robust methods.

RESULTS

We identified three novel genome-wide significant loci in the IL1R1, NEK6 and CCDC88B genes and confirmation of previously described associations with HLA-DRB1 and ANKRD55. Genetically predicted smoking intensity (OR 1.32; 95%CI 1.08-1.60; P = 0.006) and visceral adiposity (OR 1.22; 95%CI 1.10-1.37; P = 3.10 × 10-4) were associated with PMR susceptibility. Multiple circulating proteins related to IL-1 family signalling were associated with PMR. IL-1 receptor-like 2, also known as IL-36 receptor (OR 1.25; P = 1.89 × 10-32), serum amyloid A2 (OR 1.06, 9.91 × 10-10) and CXCL6 (OR 1.09, P = 4.85 × 10-7) retained significance after correction for multiple testing.

CONCLUSION

Reducing smoking and visceral adiposity at a population level might reduce incidence of PMR. We identified proteins that may play causal roles in PMR, potentially suggesting new therapeutic opportunities. Further research is needed before these findings are applied to clinical practice.

Genetic predisposition to adiposity, and type 2 diabetes: the role of lifestyle and phenotypic adiposity

AIMS

Genetic predisposition to adiposity is associated with type 2 diabetes (T2D), even in the absence of phenotypic adiposity (obesity and central obesity). We aimed to quantify the overall contribution of obesity and modifiable lifestyle factors to the association between genetic predisposition to adiposity and the development of T2D.

METHODS

This prospective cohort study involved 220 703 White British participants from the UK Biobank. It examined the associations between genetic predisposition to adiposity [body mass index polygenic risk (BMI-PRS) and waist-hip ratio polygenic risk (WHR-PRS)] and incident T2D, as well as interactions and mediation via lifestyle factors (diet quality, physical activity levels, total energy intake, sleep duration, and smoking and alcohol intake) and phenotypic adiposity.

RESULTS

People with high phenotypic adiposity and high adiposity PRS values (>1 SD above the mean) had the highest risk of incident T2D (versus non-obese/central obese and non-high PRS). This was the case for BMI-PRS [hazard ratio (HR) = 3.72] and WHR-PRS (HR = 4.17). Lifestyle factors explained 30.5% of the BMI-PRS/T2D association (2.0% mediation; 28.5% effect modification), and lifestyle and obesity together explained 92.1% (78.8% mediation; 13.3% effect modification). Lifestyle factors explained 20.4% of the WHR-PRS/T2D association (3.4% mediation; 17.0% effect modification), and lifestyle and central obesity together explained 72.8% (41.1% mediation; 31.7% effect modification).

CONCLUSIONS

Whilst phenotypic adiposity explains a large proportion of the association between BMI-PRS/WHR-PRS and T2D, modifiable lifestyle factors also make contributions. Promoting healthy lifestyles among people prone to adiposity is important in reducing the global burden of T2D.

Association of Genetically Predicted Obesity and Stool Frequency: Evidence From an Observational and Mendelian Randomization Study

Background/Aims

Obesity is associated with several gastrointestinal (GI) disorders and has been identified as a potential risk factor for various GI symptoms. Bowel frequency is an important indicator of bowel function. However, the causal link between obesity and gastrointestinal motility remains uncertain. This study aims to determine the causal effect of overall and central obesity on stool frequency.

Methods

Four obesity-related anthropometric indicators-body mass index, body fat percentage, waist circumference (WC), and waist-to-hip ratio (WHR)-were investigated. Individual-level baseline information from the UK Biobank was used to explore observational associations between obesity and stool frequency. Additionally, summary-level data from published genome-wide association studies were subjected to two-sample Mendelian randomization (MR) analyses to examine causal associations.

Results

For all 4 indicators of obesity, higher levels of obesity were associated with more frequent bowel movements after adjusting for demographic characteristics, lifestyle, and dietary factors. After rigorous screening, 482 body mass index single nucleotide polymorphisms (SNPs), 7 body fat percentage SNPs, 48 WC SNPs, and 287 WHR SNPs were identified as instrument variables for MR analysis. The MR results were generally consistent with observational findings, proving that the associations observed in the overall obesity indicators were causal. For central obesity, the association between WHR and stool frequency remained consistent in both analysis phases, whereas WC showed a multidirectional association.

Conclusions

Obesity-related anthropometric indicators were causally associated with increased stool frequency in the overall and central obesity groups. Weight loss could be a potential approach to improve gastrointestinal regularity in individuals with obesity.

Assessing the causal effects of type 2 diabetes and obesity-related traits on COVID-19 severity

BACKGROUND

Type 2 diabetes (T2D) and obesity-related traits are highly comorbid with coronavirus disease 2019 (COVID-19), but their causal relationships with disease severity remain unclear. While recent Mendelian randomization (MR) studies suggest a causal link between obesity-related traits and COVID-19 severity, findings regarding T2D are inconsistent, particularly when adjusting for body mass index (BMI). This study aims to clarify these relationships.

METHODS

We applied various MR methods to assess the causal effects of BMI-adjusted T2D (T2DadjBMI) and obesity-related traits (BMI, waist circumference, and waist-hip ratio) on COVID-19 severity. Genetic instruments were obtained from large-scale genome-wide association studies (GWAS), including 898K participants for T2D and 2M for COVID-19 severity. To address potential bias from sample overlap, we conducted large-scale simulations comparing MR results from overlapping and independent samples.

RESULTS

Our MR analysis identified a significant causal relationship between T2DadjBMI and increased COVID-19 severity (OR = 1.057, 95% CI = 1.012-1.105). Obesity-related traits were also causally associated with COVID-19 severity. Simulations confirmed that MR results remained robust to sample overlap, demonstrating consistency between overlapping and independent datasets.

CONCLUSIONS

These findings highlight the causal role of T2D and obesity-related traits in COVID-19 severity, emphasizing the need for targeted prevention and management strategies for high-risk populations. The robustness of our MR analysis, even in the presence of sample overlap, strengthens the reliability of these causal inferences.

New insights into causal relationship between serum lipids, obesity, and asthma: a Mendelian randomization study

OBJECTIVE

To identify causal risk factors for asthma using a Mendelian randomization (MR) approach.

METHODS

Genetic variants associated with the exposures at the genome-wide significance level (p < 5 × 10 - 8) were obtained from corresponding genome-wide association studies. Summary-level statistical data for asthma were obtained from the UK Biobank (UKB) and the FinnGen Consortia. Univariate and multivariate MR analyses were performed to clarify causal relationships among obesity, serum lipids, and asthma. Meta-analyses were performed to combine UKB and FinnGen results using a fixed-effects model.

RESULTS

In FinnGen, the odds for asthma increased for every 1-SD increase in body mass index (BMI; odds ratio [OR] 1.292, p = 1.34 × 10-7), together with body fat percentage (BF%; OR 1.449, p = 4.90×10-3), and total cholesterol level (OR = 0.949, p = 0.027). However, higher BMI and BF% were found to increase the risk for asthma in the multivariate MR analysis. In the UKB, the BMI results were replicated. Meta-analysis revealed that high-density lipoprotein cholesterol could also increase the risk for asthma, although there were no associations with other risk factors included in this study.

CONCLUSION

This MR study found that genetically predicted higher BF% and BMI could increase the risk for asthma and corroborated some risk factors for asthma from previous MR studies. Moreover, the results suggest that higher BMI and BF% could serve as independent risk factors for asthma.

Gene clusters linked to insulin resistance identified in a genome-wide study of the Taiwan Biobank population

This pioneering genome-wide association study examined surrogate markers for insulin resistance (IR) in 147,880 Taiwanese individuals using data from the Taiwan Biobank. The study focused on two IR surrogate markers: the triglyceride to high-density lipoprotein cholesterol (TG:HDL-C) ratio and the TyG index (the product of fasting plasma glucose and triglycerides). We identified genome-wide significance loci within four gene clusters: GCKR, MLXIPL, APOA5, and APOC1, uncovering 197 genes associated with IR. Transcriptome-wide association analysis revealed significant associations between these clusters and TyG, primarily in adipose tissue. Gene ontology analysis highlighted pathways related to Alzheimer's disease, glucose homeostasis, insulin resistance, and lipoprotein dynamics. The study identified sex-specific genes associated with TyG. Polygenic risk score analysis linked both IR markers to gout and hyperlipidemia. Our findings elucidate the complex relationships between IR surrogate markers, genetic predisposition, and disease phenotypes in the Taiwanese population, contributing valuable insights to the field of metabolic research.

Pitfalls in performing genome-wide association studies on ratio traits

Genome-wide association studies (GWASs) are often performed on ratios composed of a numerator trait divided by a denominator trait. Examples include body mass index (BMI) and the waist-to-hip ratio, among many others. Explicitly or implicitly, the goal of forming the ratio is typically to adjust for an association between the numerator and denominator. While forming ratios may be clinically expedient, there are several important issues with performing GWAS on ratios. Forming a ratio does not "adjust" for the denominator in the sense of conditioning on it, and it is unclear whether associations with ratios are attributable to the numerator, the denominator, or both. Here we demonstrate that associations arising in ratio GWAS can be entirely denominator driven, implying that at least some associations uncovered by ratio GWAS may be due solely to a putative adjustment variable. In a survey of 10 common ratio traits, we find that the ratio model disagrees with the adjusted model (performing GWAS on the numerator while conditioning on the denominator) at around 1/3 of loci. Using BMI as an example, we show that variants detected by only the ratio model are more strongly associated with the denominator (height), while variants detected by only the adjusted model are more strongly associated with the numerator (weight). Although the adjusted model provides effect sizes with a clearer interpretation, it is susceptible to collider bias. We propose and validate a simple method of correcting for the genetic component of collider bias via leave-one-chromosome-out polygenic scoring.

Waist Circumference, a Body Shape Index, and Molecular Subtypes of Colorectal Cancer: A Pooled Analysis of Four Cohort Studies

BACKGROUND

Waist circumference (WC) and its allometric counterpart, "a body shape index" (ABSI), are risk factors for colorectal cancer; however, it is uncertain whether associations with these body measurements are limited to specific molecular subtypes of the disease.

METHODS

Data from 2,772 colorectal cancer cases and 3,521 controls were pooled from four cohort studies within the Genetics and Epidemiology of Colorectal Cancer Consortium. Four molecular markers (BRAF mutation, KRAS mutation, CpG island methylator phenotype, and microsatellite instability) were analyzed individually and in combination (Jass types). Multivariable logistic and multinomial logistic models were used to assess the associations of WC and ABSI with overall colorectal cancer risk and, in case-only analyses, to evaluate heterogeneity by molecular subtype, respectively.

RESULTS

Higher WC (ORper 5 cm = 1.06, 95% confidence interval, 1.04-1.09) and ABSI (ORper 1-SD = 1.07, 95% confidence interval, 1.00-1.14) were associated with elevated colorectal cancer risk. There was no evidence of heterogeneity between the molecular subtypes. No difference was observed regarding the influence of WC and ABSI on the four major molecular markers in proximal colon, distal colon, and rectal cancers, as well as in early- and late-onset colorectal cancers. Associations did not differ in the Jass-type analysis.

CONCLUSIONS

Higher WC and ABSI were associated with elevated colorectal cancer risk; however, they do not differentially influence all four major molecular mutations involved in colorectal carcinogenesis but underscore the importance of maintaining a healthy body weight in colorectal cancer prevention.

IMPACT

The proposed results have potential utility in colorectal cancer prevention.

Genetic causal effects of multi-site chronic pain on post-traumatic stress disorder: Evidence from a two-sample, two-step Mendelian randomization study

BACKGROUND

Existing evidence supports a correlation between multi-site chronic pain and post-traumatic stress disorder (PTSD), but it is yet to be determined if this correlation is causal and in what direction the causation works.

METHODS

Applying two-sample Mendelian randomization (MR) analysis to data from available genome-wide association studies in populations of European ancestry, we estimated the causal association between multi-site chronic pain and no pain versus PTSD. Moreover, we used multivariable and mediation MR analysis to assess the mediating effects of 13 lifestyle factors or diseases on the causal relationship between multi-site chronic pain and PTSD. The MR analyses were mainly conducted with the inverse variance weighted (IVW) method, followed by various sensitivity and validation analyses.

RESULTS

Multi-site chronic pain dramatically increases the risk of developing PTSD (odds ratio [OR]IVW = 2.39, 95 % confidence interval [CI] = 1.72-3.31, p = 2.10 × 10-7), and no pain significantly reduces the risk of developing PTSD (ORIVW = 0.12, 95 % CI = 0.05-0.30, p = 3.14 × 10-6). Multivariable MR found that 13 potential confounding factors do not influence the causal effect of multi-site chronic pain on PTSD. Moreover, body mass index (BMI) (6.98 %), educational attainment (8.79 %), major depressive disorder (MDD) (36.98 %) and insomnia (27.25 %) mediate the causal connection between multi-site chronic pain and PTSD.

CONCLUSION

Overall, individuals with multi-site chronic pain may be at a higher risk of developing PTSD, and this risk is partially influenced by the pathways involving BMI, educational attainment, MDD, and insomnia. These factors offer potential targets for therapeutic interventions.

Obesity, Visceral Adipose Tissue, and Essential Hypertension: Evidence From a Mendelian Randomization Study and Mediation Analysis

This study aims to investigate the causal relationship between obesity and essential hypertension, and evaluate the mediation effect of visceral adipose tissue (VAT) by Mendelian randomization (MR) analysis. We included body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), WC adjusted for BMI (WCadjbmi), and WHR adjusted for BMI (WHRadjbmi) as obesity-related anthropometric traits. In the bidirectional MR analyses, we found that higher BMI (OR, 1.638; p = 3.97 × 10-19), WC (OR, 1.702; p = 1.45 × 10-12), and WHR (OR, 1.863; p = 1.84 × 10-8) were significantly associated with increased risk of essential hypertension, while no evidence of reverse causality was observed. Then, in the two-step MR analyses, all five anthropometric traits had a positive and significant association with VAT mass, especially WC (OR, 2.315; p = 1.00 × 10-210). Meanwhile, higher predicted VAT mass was significantly associated with increased risk of essential hypertension (OR, 1.713; p = 1.18 × 10-38). Furthermore, the mediation analyses revealed that VAT had a significant mediation effect on the causal relationship between obesity-related anthropometric traits and essential hypertension, and mediated proportions in BMI, WC, and WHR were 77.8%, 80.1%, and 41.4%, respectively. Finally, the sensitivity analyses using two other datasets showed a similar result. In conclusion, our results showed that BMI, WC, and WHR have a positive and significant association with increased risk of essential hypertension. Moreover, VAT has a significant mediation effect on the causal relationship between obesity-related anthropometric traits and essential hypertension. Our study provided important statistical evidence suggesting that VAT may play a crucial meditation role in the occurrence and development of obesity-related hypertension.

Interaction between genetic risk score and dietary carbohydrate intake on high-density lipoprotein cholesterol levels: Findings from the study of obesity, nutrition, genes and social factors (SONGS)

BACKGROUND & AIMS

Cardiometabolic traits are complex interrelated traits that result from a combination of genetic and lifestyle factors. This study aimed to assess the interaction between genetic variants and dietary macronutrient intake on cardiometabolic traits [body mass index, waist circumference, total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, triacylglycerol, systolic blood pressure, diastolic blood pressure, fasting serum glucose, fasting serum insulin, and glycated haemoglobin].

METHODS

This cross-sectional study consisted of 468 urban young adults aged 20 ± 1 years, and it was conducted as part of the Study of Obesity, Nutrition, Genes and Social factors (SONGS) project, a sub-study of the Young Lives study. Thirty-nine single nucleotide polymorphisms (SNPs) known to be associated with cardiometabolic traits at a genome-wide significance level (P < 5 × 10-8) were used to construct a genetic risk score (GRS).

RESULTS

There were no significant associations between the GRS and any of the cardiometabolic traits. However, a significant interaction was observed between the GRS and carbohydrate intake on HDL-C concentration (Pinteraction = 0.0007). In the first tertile of carbohydrate intake (≤327 g/day), participants with a high GRS (>37 risk alleles) had a higher concentration of HDL-C than those with a low GRS (≤37 risk alleles) [Beta = 0.06 mmol/L, 95 % confidence interval (CI), 0.01-0.10; P = 0.018]. In the third tertile of carbohydrate intake (>452 g/day), participants with a high GRS had a lower concentration of HDL-C than those with a low GRS (Beta = -0.04 mmol/L, 95 % CI -0.01 to -0.09; P = 0.027). A significant interaction was also observed between the GRS and glycaemic load (GL) on the concentration of HDL-C (Pinteraction = 0.002). For participants with a high GRS, there were lower concentrations of HDL-C across tertiles of GL (Ptrend = 0.017). There was no significant interaction between the GRS and glycaemic index on the concentration of HDL-C, and none of the other GRS∗macronutrient interactions were significant.

CONCLUSIONS

Our results suggest that young adults who consume a higher carbohydrate diet and have a higher GRS have a lower HDL-C concentration, which in turn is linked to cardiovascular diseases, and indicate that personalised nutrition strategies targeting a reduction in carbohydrate intake might be beneficial for these individuals.

Genome Wide Association Study (GWAS) Identifies Novel Genetic Loci for Second-Generation Antipsychotics (SGA)-Induced Metabolic Syndrome (MetS)

Second-generation antipsychotics (SGA) are widely used for treating psychiatric disorders; however, their use is associated with an increased risk of metabolic syndrome (MetS). To identify common genetic associations of SGA-induced metabolic syndrome (SGA-MetS), we conducted a genome-wide association study (GWAS) in a diverse patient population within the BioVU and BioMe electronic health records (EHRs)-linked biobanks. Additionally, we performed Mendelian Randomization (MR) analysis to investigate the association between the individual metabolic parameters comprising MetS (body mass index [BMI], fasting glucose, blood pressure, HDL, and triglycerides) and SGA-MetS. The meta-analysis of European ancestry GWAS from BioVU and BioMe (N = 9248) identified a genome-wide signal (rs61900075, β = -0.27, SE = 0.05, p = 1.6 × 10-8) on chromosome 11. Multiple associated variants met the suggestive level of association (p ≤ 10-5) in the PELO-ITGA1 locus on chromosome 5 and were associated among the Hispanic Ancestry within BioMe. The meta-analysis of the African Ancestry patients of BioVU and BioMe (N = 2018) identified multiple genome-wide signals that were functionally mapped to NPPC-DIS3L2 in chromosome 2. Finally, the inverse-variance weighted average MR (BMI: OR = 1.2, 95% CI: 1.1-1.4, p = 0.002) showed that genetically predicted, higher BMI was associated with an increased risk of SGA-MetS. Similar results were seen in the sensitivity analyses using the weighted median and Egger MR. This study identified novel variants for SGA-MetS and suggested a role of BMI in increasing the risk of SGA-MetS. The findings highlight the value of EHR biobanks for identifying the genetics underlying SGA-MetS. The associations in chromosome 2 and 5 will need further replication.

Association between different obesity metrics and risk of inguinal hernia

PURPOSE

Obesity is closely associated with a lower risk of inguinal hernia, but the association between different obesity metrics and the risk of inguinal hernia is still unclear.

METHODS

In our study, we categorized obesity measurement indicators into three groups based on the difficulty of measurement: (1) indicators easily available, such as body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR); (2) indicators accessible with moderate difficulty, such as body fat percentage and body fat mass; (3) indicators difficultly accessible, such as the volume of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Mendelian randomization (MR) analysis was used to investigate the causal relationship between various adiposity measures and the risk of inguinal hernia in both European ancestry and East Asians.

RESULTS

We identified a total of 17,096 patients with inguinal hernia in the FinnGen cohort and 1664 cases in the Japan Biobank cohort. For European ancestry, MR analysis reported a significant causal association between one standard deviation increase of BMI, WC, HC, body fat percentage, and body fat mass and the lower risk of inguinal hernia, rather than WHR, VAT, and SAT. After the adjustment of BMI, increased WC is still causally associated with a lower risk of inguinal hernia (OR: 0.52; 95% CI: 0.33-0.80; P < 0.01). Among East Asians, only body fat mass is causally associated with a reduced risk of inguinal hernia, rather than BMI, WC, and HC.

CONCLUSION

Obesity is causally associated with a relatively lower risk of inguinal hernia. The association between different obesity measures and the risk of inguinal hernia has ethnic specificity. These findings help us deepen our understanding of the intrinsic causal relationship between fat distribution and the risk of inguinal hernias at the genetic level.

The hypothalamic estrogen receptor α pathway is involved in high-intensity interval training-induced visceral fat loss in premenopausal rats

BACKGROUND

Visceral adipose tissue (VAT) is strongly associated with metabolic diseases. Both high-intensity interval training (HIT) and moderate-intensity training (MIT) reduce VAT effectively; however, HIT might mediate greater VAT loss in females. The estrogen receptor α (ERα) pathway may play a key role. The aim of the present study was to confirm the role of adipose/hypothalamic ERα in HIT/MIT-mediated VAT loss, as well as the associated hypothalamic electrophysiology and body catabolism changes in pre- and post-menopausal animal models.

METHODS

Ovariectomy (OVX) or sham surgeries were conducted to establish pre/postmenopausal female rat models. After distance-matched long-term HIT and MIT interventions, ERα expression in hypothalamic/VAT, as well as food intake, spontaneous physical activity (SPA), VAT mass and morphology, local field potential (LFPs) in paraventricular nuclei (PVN) and excessive post-exercise oxygen consumption (EPOC), were observed. A target chemical block during the post-exercise recovery period was executed to further verify the role of the hypothalamic ERα pathway.

RESULTS

HIT enhanced the expression of ERα in the hypothalamus rather than VAT in the pre-, but not the postmenopausal group, which was accompanied by elevated LFP power density in α and β bands, enhanced EPOC and larger VAT loss than MIT. Chemical blockade of ERα suppressed EPOC and VAT catabolism mediated by HIT.

CONCLUSION

During the post-exercise recovery period, the hypothalamic ERα pathway involved in HIT induced EPOC elevation and VAT reduction in premenopausal female rats.

Druggable genome-wide Mendelian randomization identifies therapeutic targets for metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects > 25% of the global population, potentially leading to severe hepatic and extrahepatic complications, including metabolic dysfunction-associated steatohepatitis. Given that the pathophysiology of MASLD is incompletely understood, identifying therapeutic targets and optimizing treatment strategies are crucial for addressing this severe condition.

METHODS

Mendelian randomization (MR) analysis was conducted using two genome-wide association study datasets: a European meta-analysis (8,434 cases; 770,180 controls) and an additional study (3,954 cases; 355,942 controls), identifying therapeutic targets for MASLD. Of 4302 drug-target genes, 2,664 genetic instrument variables were derived from cis-expression quantitative trait loci (cis-eQTLs). Colocalization analyses assessed shared causal variants between MASLD-associated single nucleotide polymorphisms and eQTLs. Using the drug target gene cis-eQTL of liver tissue from the genotype-tissue expression project, we performed MR and summary MR to validate the significance of the gene results of the blood eQTL MR. RNA-sequencing data from liver biopsies were validated using immunohistochemistry and quantitative polymerase chain reaction (qPCR) tests to confirm gene expression findings.

RESULT

MR analysis across both datasets identified significant MR associations between MASLD and two drug targets-milk fat globule-EGF factor 8 (MFGE8) (odds ratio [OR] 0.89, 95% confidence interval [CI] 0.85-0.94; P = 2.15 × 10-6) and cluster of differentiation 33 (CD33) (OR 1.17, 95% CI 1.10-1.25; P = 1.39 × 10-6). Both targets exhibited strong colocalization with MASLD. Genetic manipulation indicating MFGE8 activation and CD33 inhibition did not increase the risk for other metabolic disorders. RNA-sequencing, qPCR, and immunohistochemistry validation demonstrated consistent differential expressions of MFGE8 and CD33 in MASLD.

CONCLUSION

CD33 inhibition can reduce MASLD risk, while MFGE8 activation may offer therapeutic benefits for MASLD treatment.

The mediating roles of anthropo-metabolic biomarkers on the association between beverage consumption and breast cancer risk

BACKGROUND

Breast cancer (BC) is the most common malignancy in women, yet the role of beverage consumption in BC risk remains unclear. Additionally, the contribution of anthropo-metabolic biomarkers as mediators is unknown, limiting the development of effective prevention strategies.

METHODS

This study included 13,567 participants from the Guangzhou Biobank Cohort Study (GBCS), where beverage consumption was assessed at baseline using a food frequency questionnaire. BC cases were identified through cancer registry linkage over a mean follow-up of 14.8 years. Mendelian randomization (MR) analyses were performed to evaluate the causal effects of beverage consumption on BC risk, with a two-step MR approach used to estimate mediation effects.

RESULTS

During follow-up, 243 BC cases were identified. Weekly consumption of ≥ 1 portion of sugar sweetened beverages (SSB), versus < 1 portion, was significantly associated with a higher risk of BC (hazard ratio [HR] 1.58, 95% confidence interval [CI] 1.12-2.23). This association was partly mediated by body mass index (proportion mediated [PM] 4.2%, 95% CI 0.9-17.1%) and uric acid (PM 18.8%, 95% CI 1.5-77.5%). Weekly consumption of > 6 portions of dairy-based milk was associated with a non-significantly higher BC risk (HR 1.41, 95% CI 0.99-2.03), while 3-6 portions of soy milk were associated with a lower BC risk (HR 0.31, 95% CI 0.10-0.98). No significant associations were found for pure fruit juice, coffee, tea, or alcoholic drinks. MR analyses supported the detrimental effect of SSB on BC risk, with high-density lipoprotein cholesterol, polyunsaturated fatty acids to total fatty acids (TFAs) ratio, and omega-6 fatty acids to TFAs ratio mediating 2.44%, 2.73%, and 3.53% of the association, respectively.

CONCLUSION

This study suggested that SSB consumption was a risk factor for BC and identified key anthropo-metabolic biomarkers mediating this relationship. Reducing SSB consumption and addressing associated metabolic pathways may offer effective strategies for BC prevention.

Causal effect of life-course adiposity on the risk of respiratory diseases: a Mendelian randomization study

BACKGROUND

There is limited evidence on the causal associations of life-course adiposity with the risk of respiratory diseases. This study aimed to elucidate these associations.

METHODS

Two-sample Mendelian randomization was conducted using genetic instruments of life-course adiposity (including birth weight, childhood BMI, and adulthood adiposity) to estimate their causal effect on respiratory diseases in participants of European ancestry from the UK Biobank, the FinnGen consortium, and other large consortia.

RESULTS

Genetically predicted higher birth weight was associated with decreased risk of acute upper respiratory infections and increased risk of pulmonary embolism, sleep apnea, and lung cancer. Genetically predicted high childhood BMI was associated with increased risk of asthma, COPD, pulmonary embolism, and sleep apnea. However, most of these observed associations were no longer significant after adjusting for adult BMI. Genetically predicted higher adult BMI and WHR were associated with 10 and 4 respiratory diseases, respectively. High adult body fat percentage and visceral adiposity were genetically associated with increased risk of 9 and 11 respiratory diseases, respectively. Consistently, genetically predicted higher whole-body fat mass was associated with increased risk of 8 respiratory diseases.

CONCLUSIONS

This study provides genetic evidence that greater adiposity in childhood and adulthood has a causal effect in increasing the risk of a wide range of respiratory diseases. Furthermore, the effects of childhood obesity on respiratory outcomes may be mediated by adult obesity.

Mendelian Randomization Analysis Identifies Causal Effects of Multi-Site Chronic Pain on Obstructive Sleep Apnea

Background

Observational studies have suggested an association between obstructive sleep apnea (OSA) and chronic pain disorders, but causal evidence have not been confirmed.

Methods

Here we performed Mendelian randomization (MR) study to explore the potential causal association and mediating roles of modifiable factors between multi-site chronic pain (MCP) and OSA. Independent single nucleotide polymorphisms (SNPs) (N=26) from MCP GWAS (n=387,649) in the UK Biobank were used as instrumental variables to test associations with OSA from the FinnGen consortium, which encompassed 16,761 individuals with OSA cases and 201,194 individuals without OSA.

Results

MR analyses provide genetic evidence to predict MCP on the risk of OSA. Specifically, a per-site increase in multi-site chronic pain was linked to a 184% higher risk of OSA (ORIVW = 1.84, 95% CI = 1.29-2.63, p = 7.24×10-4). However, we also performed reverse association analyses and found no significant casual effect of OSA on MCP. MR estimates were in agreement regardless of the method used, such as MR-egger, weighted median and weighted mode, thereby demonstrating the accuracy of the causal associations. Through mediation analyses, we found that body mass index (BMI), waist circumference, and educational attainment explained a substantial proportion of the association between MCP and OSA (proportion mediated=21.13%; 26.57% and 9.66% respectively).

Conclusion

Our findings suggest that both pain management interventions, prevention of obesity and health education are likely to be effective strategies to reduce OSA risk in individuals with MCP.

Causal Effects of 25-Hydroxyvitamin D on Metabolic Syndrome and Metabolic Risk Traits: A Bidirectional Two-Sample Mendelian Randomization Study

Background/Objectives: Individuals with metabolic syndrome (MetS) present reduced 25(OH)D levels. We performed a two-sample Mendelian randomization (MR) study to investigate whether causal relationships exist between 25(OH)D levels and MetS/MetS risk traits, including waist circumference, body mass index (BMI), hypertension (systolic/diastolic blood pressure), triglyceride, high-density lipoprotein cholesterol, and glucose levels. Methods: We employed genetic variants related to 25(OH)D levels from the SUNLIGHT Consortium and a European genome-wide association study meta-analysis, including UK Biobank (UKB) data, as well as variants for MetS and MetS risk traits from UKB and multiple European consortia. Several MR methods were used, i.e., inverse-variance weighted, weighted median, and MR-Egger regression. Heterogeneity and horizontal pleiotropy analyses were performed to ensure the stability of candidate single-nucleotide polymorphisms (SNPs) as the instrumental variable. We first conducted univariable MR to investigate the relationship between 25(OH)D levels and MetS, including its related risk traits, and subsequently performed multivariable MR to adjust for potential confounders. Results: This study did not provide evidence of a causal relationship between 25(OH)D levels and MetS/MetS risk traits. However, we found that several risk traits of MetS, such as waist circumference, BMI, and TG, had an inverse-causal relationship with 25(OH)D levels, suggesting that 25(OH)D levels could be secondary consequences of metabolic illnesses. Conclusions: We identified no causal relationship between 25(OH)D levels and MetS/MetS risk factors. However, 25(OH)D levels may result from MetS traits.

Combining evidence from human genetic and functional screens to identify pathways altering obesity and fat distribution

Overall adiposity and body fat distribution are heritable traits associated with altered risk of cardiometabolic disease and mortality. Performing rare variant (minor allele frequency<1%) association testing using exome-sequencing data from 402,375 participants in the UK Biobank (UKB) for nine overall and tissue-specific fat distribution traits, we identified 19 genes where putatively damaging rare variation associated with at least one trait (Bonferroni-adjusted P <1.58×10 -7 ) and 50 additional genes at FDR≤1% ( P ≤4.37×10 -5 ). These 69 genes exhibited significantly higher (one-sided t -test P =3.58×10 -18 ) common variant prioritisation scores than genes not significantly enriched for rare putatively damaging variation, with evidence of monotonic allelic series (dose-response relationships) among ultra-rare variants (minor allele count≤10) in 22 genes. Combining rare and common variation evidence, allelic series and longitudinal analysis, we selected 14 genes for CRISPR knockdown in human white adipose tissue cell lines. In three previously uncharacterised target genes, knockdown increased (two-sided t -test P <0.05) lipid accumulation, a cellular phenotype relevant for fat mass traits, compared to Cas9-empty negative controls: COL5A3 (fold change [FC]=1.72, P =0.0028), EXOC7 (FC=1.35, P =0.0096), and TRIP10 (FC=1.39, P =0.0157); furthermore, knockdown of PPARG (FC=0.25, P =5.52×10 -7 ) and SLTM (FC=0.51, P =1.91×10 -4 ) resulted in reduced lipid accumulation. Integrating across population-based genetic and in vitro functional evidence, we highlight therapeutic avenues for altering obesity and body fat distribution by modulating lipid accumulation.

Trans-ancestral rare variant association study with machine learning-based phenotyping for metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Genome-wide association studies (GWAS) have identified common variants associated with metabolic dysfunction-associated steatotic liver disease (MASLD). However, rare coding variant studies have been limited by phenotyping challenges and small sample sizes. We test associations of rare and ultra-rare coding variants with proton density fat fraction (PDFF) and MASLD case-control status in 736,010 participants of diverse ancestries from the UK Biobank, All of Us, and BioMe and performed a trans-ancestral meta-analysis. We then developed models to accurately predict PDFF and MASLD status in the UK Biobank and tested associations with these predicted phenotypes to increase statistical power.

RESULTS

The trans-ancestral meta-analysis with PDFF and MASLD case-control status identifies two single variants and two gene-level associations in APOB, CDH5, MYCBP2, and XAB2. Association testing with predicted phenotypes, which replicates more known genetic variants from GWAS than true phenotypes, identifies 16 single variants and 11 gene-level associations implicating 23 additional genes. Two variants were polymorphic only among African ancestry participants and several associations showed significant heterogeneity in ancestry and sex-stratified analyses. In total, we identified 27 genes, of which 3 are monogenic causes of steatosis (APOB, G6PC1, PPARG), 4 were previously associated with MASLD (APOB, APOC3, INSR, PPARG), and 23 had supporting clinical, experimental, and/or genetic evidence.

CONCLUSIONS

Our results suggest that trans-ancestral association analyses can identify ancestry-specific rare and ultra-rare coding variants in MASLD pathogenesis. Furthermore, we demonstrate the utility of machine learning in genetic investigations of difficult-to-phenotype diseases in trans-ancestral biobanks.

Causal Relationship Between Intelligence, Noncognitive Education, Cognition and Urinary Tract or Kidney Infection: A Mendelian Randomization Study

Background

The occurrence of urinary tract or kidney infection is correlated with intelligence, noncognitive education and cognition, but the causal relationship between them remains uncertain, and which risk factors mediate this causal relationship remains unknown.

Methods

The intelligence (n=269,867), noncognitive education (n=510,795) and cognition data (n=257,700) were obtained from genome-wide association studies (GWAS) conducted in individuals of European ethnicities. The genetic associations between these factors and urinary tract or kidney infection (UK Biobank, n=397,867) were analyzed using linkage disequilibrium score regression. We employed a two-sample univariate and multivariate Mendelian randomization to evaluate the causal relationship, and utilized a two-step Mendelian randomization to examine the involvement of 28 potential mediators and their respective mediating proportions.

Results

The genetic correlation coefficients of intelligence, noncognitive education, cognition, and urinary tract or kidney infection were -0.338, -0.218, and -0.330. The Mendelian randomization using the inverse variance weighted method revealed each 1-SD increase in intelligence, the risk of infection decreased by 15.9%, while after adjusting for noncognitive education, the risk decreased by 20%. For each 1-SD increase in noncognitive education, the risk of infection decreased by 8%, which further reduced to 7.1% after adjusting for intelligence and to 6.7% after adjusting for cognition. For each 1-SD increase in cognition, the risk of infection decreased by 10.8%, increasing to 11.9% after adjusting for noncognitive education. The effects of intelligence and cognition are interdependent. 2 out of 28 potential mediating factors exhibited significant mediation effects in the causal relationship between noncognitive education and urinary tract or kidney infection, with body mass index accounting for 12.1% of the mediation effect and smoking initiation accounting for 14.7%.

Conclusion

Enhancing intelligence, noncognitive education, and cognition can mitigate the susceptibility to urinary tract or kidney infection. Noncognitive education exhibited independent effect, while body mass index and smoking initiation assuming a mediating role.

Using multiomic integration to improve blood biomarkers of major depressive disorder: a case-control study

BACKGROUND

Major depressive disorder (MDD) is a leading cause of disability, with a twofold increase in prevalence in women compared to men. Over the last few years, identifying molecular biomarkers of MDD has proven challenging, reflecting interactions among multiple environmental and genetic factors. Recently, epigenetic processes have been proposed as mediators of such interactions, with the potential for biomarker development.

METHODS

We characterised gene expression and two mechanisms of epigenomic regulation, DNA methylation (DNAm) and microRNAs (miRNAs), in blood samples from a cohort of individuals with MDD and healthy controls (n = 169). Case-control comparisons were conducted for each omic layer. We also defined gene coexpression networks, followed by step-by-step annotations across omic layers. Third, we implemented an advanced multiomic integration strategy, with covariate correction and feature selection embedded in a cross-validation procedure. Performance of MDD prediction was systematically compared across 6 methods for dimensionality reduction, and for every combination of 1, 2 or 3 types of molecular data. Feature stability was further assessed by bootstrapping.

FINDINGS

Results showed that molecular and coexpression changes associated with MDD were highly sex-specific and that the performance of MDD prediction was greater when the female and male cohorts were analysed separately, rather than combined. Importantly, they also demonstrated that performance progressively increased with the number of molecular datasets considered.

INTERPRETATION

Informational gain from multiomic integration had already been documented in other medical fields. Our results pave the way toward similar advances in molecular psychiatry, and have practical implications for developing clinically useful MDD biomarkers.

FUNDING

This work was supported by the Centre National de la Recherche Scientifique (contract UPR3212), the University of Strasbourg, the Université Sorbonne Paris Nord, the Université Paris Cité, the Fondation de France (FdF N° Engt:00081244 and 00148126; ECI, IY, RB, PEL), the French National Research Agency (ANR-18-CE37-0002, BE, CMC, ADD, PEL, ECI; ANR-18-CE17-0009, ADD; ANR-19-CE37-0010, PEL; ANR-21-RHUS-009, ADD, BE, CMC, CCB; ANR-22-PESN-0013, ADD), the Fondation pour la Recherche sur le Cerveau (FRC 2019, PEL), Fondation de France (2018, BE, CMC, ADD) and American Foundation for Suicide Prevention (AFSP YIG-1-102-19; PEL).

Hepatic lipid metabolism is altered in Ubiad1+/- mice of both sexes

UbiA prenyltransferase domain containing 1 (Ubiad1) has the potential to affect cholesterol and phospholipid levels in different cell types. We previously identified Ubiad1 as a candidate gene for regulating subcutaneous fat pad weight in a mouse genome-wide association study. Here we evaluated the relationship between Ubiad1 and obesity-related traits in cohorts of humans and mice, and in Ubiad1+/- mice fed a high-fat diet. In both humans and mice, adipose tissue Ubiad1 mRNA expression correlated negatively with adiposity and positively with mitochondria-related genes. To determine the role of Ubiad1 in high-fat diet-induced obesity, we disrupted the Ubiad1 gene in mice. Deletion of Ubiad1 was embryonically lethal in C57BL/6 N mice, preventing analysis of adult Ubiad1-/- mice. Thus, male and female Ubiad1+/+ and Ubiad1+/- mice were fed high-fat diet for 10 weeks, with no difference in weight gain and adipose tissue organ weights observed between the genotypes. Analysis of liver mRNA expression revealed that Ubiad1 heterozygosis (Ubiad1+/-) altered several pathways involved in lipid metabolism. Detailed lipid quantification with HPLC-qTOF/MS showed increased levels of hepatic ceramides in female Ubiad1+/- mice, whereas phosphatidylglycerols, phosohatidylinositol and lysophosphatidylethanolamines were reduced in male Ubiad1+/- mice. Our findings reveal sex-specific effects of Ubiad1 expression on hepatic lipid metabolism.

Effect of fat distribution on left ventricular structure and function in different sexes: a Mendelian randomization study

Background

Although there is an interaction between sex, body fat distribution, and cardiac structure and function, these relationships have not been fully elucidated yet. This study aims to reveal the causal relationship between genetic determinants of fat distribution pattern and function of the left ventricular structure in different sexes.

Methods

Genetic variants for waist circumference, hip circumference, waist-to-hip ratio (WHR), and body mass index (BMI) were selected from genome-wide association studies conducted in European samples. The dataset for left ventricular (LV) parameters was obtained from over 35,000 European samples in the UK Biobank Cardiovascular Magnetic Resonance sub-study. Two-sample Mendelian randomization (MR) analysis was employed to explore causal relationships.

Results

After adjusting for BMI, WHR shows a positive causal relationship with LV hypertrophy and a significant negative causal relationship with LV volume and diastolic function. In further subgroup analysis, we only found similar results in WHR among the female population (FWHR), while in the male population, there was no significant causal relationship between MWHR and LV hypertrophy and diastolic function. Additionally, in our MR analysis, no causal relationship was found between WHR and LVEF.

Conclusions

This study indicates that the fat distribution pattern has unique effects on the structure and function of the LV, and these effects vary by sex. This study provides evidence for a causal relationship between fat distribution and LV structure and function across both sexes.

LRP5 promotes adipose progenitor cell fitness and adipocyte insulin sensitivity

BACKGROUND

WNT signaling plays a key role in postnatal bone formation. Individuals with gain-of-function mutations in the WNT co-receptor LRP5 exhibit increased lower-body fat mass and potentially enhanced glucose metabolism, alongside high bone mass. However, the mechanisms by which LRP5 regulates fat distribution and its effects on systemic metabolism remain unclear. This study aims to explore the role of LRP5 in adipose tissue biology and its impact on metabolism.

METHODS

Metabolic assessments and imaging were conducted on individuals with gain- and loss-of-function LRP5 mutations, along with age- and BMI-matched controls. Mendelian randomization analyses were used to investigate the relationship between bone, fat distribution, and systemic metabolism. Functional studies and RNA sequencing were performed on abdominal and gluteal adipose cells with LRP5 knockdown.

RESULTS

Here we show that LRP5 promotes lower-body fat distribution and enhances systemic and adipocyte insulin sensitivity through cell-autonomous mechanisms, independent of its bone-related functions. LRP5 supports adipose progenitor cell function by activating WNT/β-catenin signaling and preserving valosin-containing protein (VCP)-mediated proteostasis. LRP5 expression in adipose progenitors declines with age, but gain-of-function LRP5 variants protect against age-related fat loss in the lower body.

CONCLUSIONS

Our findings underscore the critical role of LRP5 in regulating lower-body fat distribution and insulin sensitivity, independent of its effects on bone. Pharmacological activation of LRP5 in adipose tissue may offer a promising strategy to prevent age-related fat redistribution and metabolic disorders.

Consumer Product Chemical Mixtures and Oxylipin-Mediated Inflammation and Oxidative Stress during Early Pregnancy: Findings from a Large US Pregnancy Cohort

Consumer product chemicals pose an environmental risk to public health. Exposure during pregnancy to consumer product chemicals, particularly phthalates and phenols, may increase the susceptibility to pregnancy disorders by dysregulating inflammation and oxidative stress. However, existing studies rely on downstream and nonmodifiable markers of these processes. Oxylipins are oxidized lipids that act as key upstream drivers of inflammation and oxidative stress. Importantly, oxylipins are responsive to therapeutic interventions and thus potentially modifiable. Using recent advances in lipidomics and statistical approaches to address both individual chemical biomarkers and their mixtures, we determined associations between early pregnancy biomarkers of consumer product chemical exposure and oxylipins in a large prospective cohort. Overall, our results revealed associations among oxylipins produced across several biosynthetic pathways, suggesting a pattern indicative of dysregulated inflammation and elevated levels of oxidative stress. Phthalate metabolites were the primary drivers of associations, particularly for metabolites of low molecular weight phthalates, often used in personal care products. However, we found similar associations for a biomarker of a phthalate replacement that is increasingly used in consumer products. Our study provides observational evidence of specific physiological pathways that may be dysregulated by exposure to consumer product chemicals, including legacy phthalates and phthalate replacements.

Exploring the Associations of Obesity and Glycemic Traits with Retinal Vein Occlusion: A Univariate and Multivariable Mendelian Randomization Study

PURPOSE

To explore the genetic links between obesity, glycemic traits and retinal vein occlusion (RVO).

METHODS

Summary-level statistics for obesity and glycemic traits were extracted from publicly available genome-wide association studies (GWAS) of European participants in the IEU Open GWAS database. Genetic associations with clinically diagnosed RVO were obtained from the FinnGenresearch project (372 cases and 182,573 controls). Two-sample Mendelian randomization (MR) and multivariate MR (MVMR) analysis were performed to determine the total effect and direct effect, respectively.

RESULTS

After adjustment for the false discovery rate (FDR), the primary inverse-variance-weighted (IVW) methods indicated that the odds ratios of RVO increased with per 1-standard deviation increased in body mass index (BMI) (OR = 1.94, 95% CI: 1.23-3.08,p-FDR = 0.025), waist circumference (OR = 2.4, 95% CI: 1.36-4.24, p-FDR = 0.019), fasting glucose (OR = 5.01, 95% CI: 2-12.55, p-FDR = 0.0067) and two-hour glucose (OR = 3.17, 95% CI: 1.63-6.18,p-FDR = 0.0067). Higher whole-body fat-free mass (OR = 0.45, 95% CI: 0.26-0.8,p-FDR = 0.025) is a potential protective factor for RVO. In addition, the results of MVMR showed that BMI, whole-body fat-free mass, fasting glucose and two-hour glucose were independent factors that had a direct impact on the onset of RVO.

CONCLUSIONS

Our comprehensive MR analysis suggested significant genetic associations between BMI, whole-body fat-free mass, fasting glucose, two-hour glucose and RVO. This study highlighted the importance of weight, blood glucose management and physical activity for primary prevention and control of RVO.

Insights Into Causal Effects of Genetically Proxied Lipids and Lipid-Modifying Drug Targets on Cardiometabolic Diseases

BACKGROUND

The differential impact of serum lipids and their targets for lipid modification on cardiometabolic disease risk is debated. This study used Mendelian randomization to investigate the causal relationships and underlying mechanisms.

METHODS

Genetic variants related to lipid profiles and targets for lipid modification were sourced from the Global Lipids Genetics Consortium. Summary data for 10 cardiometabolic diseases were compiled from both discovery and replication data sets. Expression quantitative trait loci data from relevant tissues were employed to evaluate significant lipid-modifying drug targets. Comprehensive analyses including colocalization, mediation, and bioinformatics were conducted to validate the results and investigate potential mediators and mechanisms.

RESULTS

Significant causal associations were identified between lipids, lipid-modifying drug targets, and various cardiometabolic diseases. Notably, genetic enhancement of LPL (lipoprotein lipase) was linked to reduced risks of myocardial infarction (odds ratio [OR]1, 0.65 [95% CI, 0.57-0.75], P1=2.60×10-9; OR2, 0.59 [95% CI, 0.49-0.72], P2=1.52×10-7), ischemic heart disease (OR1, 0.968 [95% CI, 0.962-0.975], P1=5.50×10-23; OR2, 0.64 [95% CI, 0.55-0.73], P2=1.72×10-10), and coronary heart disease (OR1, 0.980 [95% CI, 0.975-0.985], P1=3.63×10-14; OR2, 0.64 [95% CI, 0.54-0.75], P2=6.62×10-8) across 2 data sets. Moreover, significant Mendelian randomization and strong colocalization associations for the expression of LPL in blood and subcutaneous adipose tissue were linked with myocardial infarction (OR, 0.918 [95% CI, 0.872-0.967], P=1.24×10-3; PP.H4, 0.99) and coronary heart disease (OR, 0.991 [95% CI, 0.983-0.999], P=0.041; PP.H4=0.92). Glucose levels and blood pressure were identified as mediators in the total effect of LPL on cardiometabolic outcomes.

CONCLUSIONS

The study substantiates the causal role of lipids in specific cardiometabolic diseases, highlighting LPL as a potent drug target. The effects of LPL are suggested to be influenced by changes in glucose and blood pressure, providing insights into its mechanism of action.

Unraveling the Link: Mendelian Randomization Reveals Causal Relationship Between Selenium and Metabolic Syndrome

Observational studies have linked selenium and metabolic syndrome (MetS), but the causality remains unclear. Therefore, this study intends to determine the causal relationship between selenium and the risk of MetS and its component features [body mass index (BMI), waist circumference adjusted for BMI (WCadjBMI), triglycerides (TC), HDL-cholesterol (HDL-C), fasting blood glucose (FBG), fasting blood insulin (FBI), systolic blood pressure (SBP), and diastolic blood pressure (DBP)]. This study was designed as the two-sample Mendelian randomization (MR), and genetic variants were obtained from the genome-wide association studies. The inverse variance weighted (IVW) was applied as the primary method, and the MR-Egger, weighted median, and MR-PRESSO were supplemented to assess its robustness. The Bonferroni method was used to correct p-values for multiple tests. Genetically incremented selenium level was related to higher odds ratios of developing the MetS (OR = 1.054, 95% CI = 1.016-1.094, p = 0.0049). As for components, significant causal links were identified between selenium and BMI (β = 0.015, p = 1.321 × 10-5), WCadjBMI (β = 0.033, p = 2.352 × 10-4), HDL-C (β = -0.036, p = 1.352 × 10-8), FBG (β = 0.028, p = 0.001), and FBI (β = 0.028, p = 0.002). No significant association was discovered for SBP (β = -0.076, p = 0.218) and DBP (β = 0.054, p = 0.227). These results were generally supported by the weighted median and MR-PRESSO methods. Our study provided evidence of the causal effect of selenium on MetS risk from the genetic perspective in the European population, and further investigation across diverse populations was warranted.

Time for bed: diet, sleep and obesity in children and adults

Sufficient sleep is necessary for optimal health, daytime performance and wellbeing and the amount required is age-dependent and decreases across the lifespan. Sleep duration is usually affected by age and several different cultural, social, psychological, behavioural, pathophysiological and environmental factors. This review considers how much sleep children and adults need, why this is important, what the consequences are of insufficient sleep and how we can improve sleep. A lack of the recommended amount of sleep for a given age group has been shown to be associated with detrimental effects on health including effects on metabolism, endocrine function, immune function and haemostatic pathways. Obesity has increased worldwide in the last few decades and the WHO has now declared it a global epidemic. A lack of sleep is associated with an increased risk of obesity in children and adults, which may lead to future poor health outcomes. Data from studies in both children and adults suggest that the relationship between sleep and obesity may be mediated by several different mechanisms including alterations in appetite and satiety, sleep timing, circadian rhythm and energy balance. Moreover, there is evidence to suggest that improvements in sleep, in both children and adults, can be beneficial for weight management and diet and certain foods might be important to promote sleep. In conclusion this review demonstrates that there is a wide body of evidence to suggest that sleep and obesity are causally related and recommends that further research is required to inform policy, and societal change.

Systematic Mendelian Randomization Exploring Druggable Genes for Hemorrhagic Strokes

Patients with hemorrhagic stroke have high rates of morbidity and mortality, and drugs for prevention are very limited. Mendelian randomization (MR) analysis can increase the success rate of drug development by providing genetic evidence. Previous MR analyses only analyzed the role of individual drug target genes in hemorrhagic stroke; therefore, we used MR analysis to systematically explore the druggable genes for hemorrhagic stroke. We sequentially performed summary-data-based MR analysis and two-sample MR analysis to assess the associations of all genes within the database with intracranial aneurysm, intracerebral hemorrhage, and their subtypes. Validated genes were further analyzed by colocalization. Only genes that were positive in all three analyses and were druggable were considered desirable genes. We also explored the mediators of genes affecting hemorrhagic stroke incidence. Finally, the associations of druggable genes with other cardiovascular diseases were analyzed to assess potential side effects. We identified 56 genes that significantly affected hemorrhagic stroke incidence. Moreover, TNFSF12, SLC22A4, SPARC, KL, RELT, and ADORA3 were found to be druggable. The inhibition of TNFSF12, SLC22A4, and SPARC can reduce the risk of intracranial aneurysm, subarachnoid hemorrhage, and intracerebral hemorrhage. Gene-induced hypertension may be a potential mechanism by which these genes cause hemorrhagic stroke. We also found that blocking these genes may cause side effects, such as ischemic stroke and its subtypes. Our study revealed that six druggable genes were associated with hemorrhagic stroke, and the inhibition of TNFSF12, SLC22A4, and SPARC had preventive effects against hemorrhagic strokes.

Phenome-Wide Investigation of the Causal Associations Between Pre-Pregnancy Obesity Traits and Gestational Diabetes: A Two-Sample Mendelian Randomization Analyses

Pre-pregnancy obesity was associated with gestational diabetes in observational studies, but whether this relationship is causal remains to be determined. To evaluate whether pre-pregnancy obesity traits causally affect gestational diabetes risk, a two-sample Mendelian randomization (MR) analysis was performed utilizing summary-level statistics from published genome-wide association studies (GWAS). Obesity-related traits included body mass index (BMI), overweight, obesity, obesity class 1, obesity class 2, obesity class 3, childhood obesity, waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), percent liver fat, visceral adipose tissue volume, abdominal subcutaneous adipose tissue volume. Effect estimates were evaluated using the inverse-variance weighting method. Weighted median, MR-Egger, simple mode, and weighted mode were performed as sensitivity analyses. Genetically predicted pre-pregnancy BMI [odds ratio (OR) = 1.68; 95% confidence interval (CI): 1.45-1.95; P = 9.13 × 10-12], overweight (OR = 1.49; 95% CI: 1.21-1.85; P = 2.06 × 10-4), obesity (OR = 1.25; 95% CI: 1.18-1.33; P = 8.01 × 10-13), obesity class 1 (OR = 1.31; 95% CI: 1.17-1.46; P = 1.49 × 10-6), obesity class 2 (OR = 1.26; 95% CI: 1.16-1.37; P = 5.23 × 10-8), childhood obesity (OR = 1.33; 95% CI: 1.23-1.44; P = 4.06 × 10-12), and WHR (OR = 2.35; 95% CI: 1.44-3.83; P = 5.89 × 10-4) were associated with increased risk of gestational diabetes. No significant association was observed with obesity class 3, WC, HC, percent liver fat, visceral adipose tissue volume, or abdominal subcutaneous adipose tissue volume. Similar results were observed in sensitivity analyses. Therefore, genetically predicted pre-pregnancy obesity traits may increase the risk of gestational diabetes. Weight control before pregnancy may be beneficial to prevent gestational diabetes.

Reassessing the link between adiposity and head and neck cancer: a Mendelian randomization study

Background

Adiposity has been associated with an increased risk of head and neck cancer (HNC). Although body mass index (BMI) has been inversely associated with HNC risk among smokers, this is likely due to confounding. Previous Mendelian randomization (MR) studies could not fully discount causality between adiposity and HNC due to limited statistical power. Hence, we aimed to revisit this using the largest genome-wide association study (GWAS) of HNC available, which has more granular data on HNC subsites.

Methods

We assessed the genetically predicted effects of BMI (N=806,834), waist-to-hip ratio (WHR; N=697,734) and waist circumference (N=462,166) on the risk of HNC (N=12,264 cases and 19,259 controls) and its subsites (oral, laryngeal, hypopharyngeal and oropharyngeal cancers) using a two-sample MR framework. We used the inverse variance weighted (IVW) MR approach and multiple sensitivity analyses including the weighted median, weighted mode, MR-Egger, MR-PRESSO, and CAUSE approaches. We also used multivariable MR (MVMR) to explore the direct effects of the adiposity measures on HNC, while accounting for smoking behaviour, a well-known HNC risk factor.

Results

In univariable MR, higher genetically predicted BMI increased the risk of overall HNC (IVW OR=1.17 per 1 standard deviation [1-SD] higher BMI, 95% CI 1.02-1.34, p=0.03), with no heterogeneity across subsites (Q p=0.78). However, the effect was not consistent in sensitivity analyses. The IVW effect was attenuated when smoking was included in the MVMR model (OR accounting for comprehensive smoking index=0.96 per 1-SD higher BMI, 95% CI 0.80-1.15, p=0.64) and CAUSE indicated the IVW results could be biased by correlated pleiotropy. Furthermore, we did not find a link between genetically predicted WHR (IVW OR=1.05 per 1-SD higher WHR, 95% CI 0.89-1.24, p=0.53) or waist circumference and HNC risk (IVW OR=1.01 per 1-SD higher waist circumference, 95% CI 0.85-1.21, p=0.87).

Conclusions

Our findings suggest that adiposity does not play a role in HNC risk.

Interactions between DASH-style diet and ADIPOQ and ARL15 genes polymorphisms on blood pressure and central obesity in Iranian adults

This study aimed to investigate the interactions between the Dietary approaches to stop hypertension (DASH) and the rs1501299 and rs6450176 SNPs in terms of cardiometabolic risk factors. This cross-sectional study was conducted on 387 adults (20-70 years old) residing in Yazd, Iran. The participants were selected from participants in the recruitment phase of the Yazd Health Study (YaHS) which is a population-based cohort of 9,962 adults. The genotypes of rs1501299 and rs6450176 SNPs were determined using the restriction fragment length polymorphism (RFLP) method. Unlike for the G allele carriers of rs1501299, high adherence to the DASH dietary pattern was related to the lower diastolic blood pressure (DBP; P-interaction = 0.014) and systolic blood pressure (SBP; P-interaction = 0.051) in the participants with TT genotype. Moreover, in individuals with the AA genotype of rs6450176 SNP, adherence to this diet was associated with lower SBP (P-interaction = 0.012), waist-to-hip ratio (WHR; P-interaction = 0.026) and waist-to-height ratio (WHtR; P-interaction = 0.040), while in G allele carriers, the mean of these items was greater in individuals with high adherence to the DASH diet. The results suggest that following the DASH diet may be related to lower blood pressure and central obesity indices only in individuals with TT genotype of rs1501299 and AA genotype of rs6450176, respectively, whereas it can be associated with higher WHR and WHtR in G allele carriers of rs6450176.

Association of novel metabolic status with asymptomatic intracranial arterial stenosis: A cross-sectional study

OBJECTIVES

To investigate the association of metabolic status newly defined or obesity with asymptomatic intracranial arterial stenosis (aICAS) among populations in rural China.

METHODS

The cross-sectional study is based on the Rose asymptomatic IntraCranial Artery Stenosis (RICAS) cohort, which enrolled 2005 participants aged 40 years or older without a history of clinical stroke or transient ischemic attack. Metabolically healthy status (MH) was defined by a newly proposed criterion: (1) systolic blood pressure (SBP) < 130 mmHg and without antihypertensive medication; (2) a waist-to-hip ratio (WHR) below 1.03 for men and below 0.95 for women; (3) no diabetes. All participants were categorized based on their metabolic status and obesity. Multivariate logistic regression models were used to investigate the association between metabolic status or obesity and aICAS.

RESULTS

Among 2005 participants, 1597 (79.65%) were defined as metabolically unhealthy status (MU) according to the new criterion. MU was significantly associated with aICAS (OR 2.02, 95% CI 1.11-3.68, P = 0.021), especially moderate-to-severe aICAS (OR 2.43, 95% CI 1.04-5.72, P = 0.042). The prevalence of aICAS increased with the numbers of metabolic disorders (P for linear trend <0.001). Both metabolically unhealthy normal-weight (MUN) (OR 2.11, 95% CI 1.10-4.03, P = 0.025) and metabolically unhealthy obesity (MUO) (OR 3.30, 95% CI 1.64-6.64, P = 0.001) were significantly correlated with aICAS, but not metabolically healthy obesity (MHO). Subgroup analysis further confirmed the association between MU and aICAS risk only in men (P for interaction = 0.042).

CONCLUSIONS

MU defined by the new criterion was significantly associated with aICAS, especially with moderate-to-severe aICAS. This novel criterion effectively identifies individuals with a high prevalence of aICAS among populations with obesity, which could be crucial for stroke prevention.

Glo1 reduction in mice results in age- and sex-dependent metabolic dysfunction

Objectives

Advanced glycation end products (AGEs) have been implicated as an important mediator of metabolic disorders including obesity, insulin resistance, and coronary artery disease. Glyoxalase 1 (Glo1) is a critical enzyme in the clearance of toxic dicarbonyl such as methylglyoxal, precursors of AGEs. The role of AGE-independent mechanisms that underly Glo1-induced metabolic disorders have yet to be elucidated.

Methods

We performed a longitudinal study of female and male Glo1 heterozygous knockdown (Glo1 +/- ) mice with ~50% gene expression and screened metabolic phenotypes such as body weight, adiposity, glycemic control and plasma lipids. We also evaluated atherosclerotic burden, AGE levels, and gene expression profiles across cardiometabolic tissues (liver, adipose, muscle, kidney and aorta) to identify pathway perturbations and potential regulatory genes of Glo1 actions.

Results

Partial loss of Glo1 resulted in obesity, hyperglycemia, dyslipidemia, and alterations in lipid metabolism in metabolic tissues in an age- and sex-dependent manner. Glo1 +/- females displayed altered glycemic control and increased plasma triglycerides, which aligned with significant perturbations in genes involved in adipogenesis, PPARg, insulin signaling, and fatty acid metabolism pathways in liver and adipose tissues. Conversely, Glo1 +/- males developed increased skeletal muscle mass and visceral adipose depots along with changes in lipid metabolism pathways. For both cohorts, most phenotypes manifested after 14 weeks of age. Evaluation of methylglyoxal-derived AGEs demonstrated changes in only male skeletal muscle but not in female tissues, which cannot explain the broad metabolic changes observed in Glo1 +/- mice. Transcriptional profiles suggest that altered glucose and lipid metabolism may be partially explained by alternative detoxification of methylglyoxal to metabolites such as pyruvate. Moreover, transcription factor (TF) analysis of the tissue-specific gene expression data identified TFs involved in cardiometabolic diseases such as Hnf4a (all tissues) and Arntl (aorta, liver, and kidney) which are female-biased regulators and whose targets are altered in response to Glo1 +/- .

Conclusions

Our results indicate that Glo1 reduction perturbs metabolic health and metabolic pathways in a sex- and age-dependent manner without significant changes in AGEs across metabolic tissues. Rather, tissue-specific gene expression analysis suggests that key transcription factors such as Hfn4a and Arntl as well as metabolite changes from alternative methylglyoxal detoxification such as pyruvate, likely contribute to metabolic dysregulation in Glo1 +/- mice.