Publications by authors named "Ching-Ti Liu"

Gaussian Graphical Models (GGMs) are a type of network modeling that uses partial correlation rather than correlation for representing complex relationships among multiple variables. The advantage of using partial correlation is to show the relation between two variables after "adjusting" for the effects of other variables and leads to more parsimonious and interpretable models. There are well established procedures to build GGMs from a sample of independent and identical distributed observations.

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Polygenic scores (PGSs) for body mass index (BMI) may guide early prevention and targeted treatment of obesity. Using genetic data from up to 5.1 million people (4.

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Serum lipid levels, which are influenced by both genetic and environmental factors, are key determinants of cardiometabolic health and are influenced by both genetic and environmental factors. Improving our understanding of their underlying biological mechanisms can have important public health and therapeutic implications. Although psychosocial factors, including depression, anxiety, and perceived social support, are associated with serum lipid levels, it is unknown if they modify the effect of genetic loci that influence lipids.

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Background: This study investigated Lp(a) (lipoprotein(a)) levels with heart failure (HF) incidence overall and ejection fraction (EF) subtypes among Black and White participants in a pooled analysis of MESA (Multi-Ethnic Study of Atherosclerosis), FOS (Framingham Offspring Study), and ARIC (Atherosclerosis Risk in Communities Study).

Methods: This study was conducted among 16 771 White and Black participants in ARIC (N=10 347), MESA (N=4150), and FOS (N=2274). Baseline was time of Lp(a) measurement (ARIC Visit 4: 1996-1998; MESA Visit 1: 2000-2002; FOS Cycle 6: 1995-1998).

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Background: Lean body mass is a crucial physiological component of body composition. Although lean body mass has a high heritability, studies evaluating the genetic determinants of lean mass (LM) have to date been limited largely to genome-wide association studies (GWAS) and common variants. Using whole genome sequencing (WGS)-based studies, we aimed to discover novel genetic variants associated with LM in population-based cohorts with multiple ancestries.

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Elevated lipoprotein(a) [Lp(a)] is associated with increased incidence of atherosclerotic cardiovascular disease (ASCVD). We aimed to assess the utility of Lp(a) as an ASCVD risk-enhancing factor, as recommended by the 2019 ACC/AHA guidelines on ASCVD primary prevention, and to determine whether C-reactive protein (CRP) modifies the association of elevated Lp(a) with ASCVD risk. Lp(a), high sensitivity CRP (hs-CRP), and other ASCVD risk factors, including blood lipids, blood pressure, diabetes status, body weight and height, and smoking, were measured in 15,933 participants (median age 61.

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: Diabetes mellitus is a major cause of death and a significant risk factor for cardiovascular disease, kidney failure, neuropathy, and retinopathy. Our objectives were to develop a diabetes risk model and apply it to a large population. : Non-diabetic adults in the Framingham Offspring Study ( = 2416) were followed for 10 years for new diabetes.

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Obesity is a major public health crisis associated with high mortality rates. Previous genome-wide association studies (GWAS) investigating body mass index (BMI) have largely relied on imputed data from European individuals. This study leveraged whole-genome sequencing (WGS) data from 88,873 participants from the Trans-Omics for Precision Medicine (TOPMed) Program, of which 51% were of non-European population groups.

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Although both short and long sleep duration are associated with elevated hypertension risk, our understanding of their interplay with biological pathways governing blood pressure remains limited. To address this, we carried out genome-wide cross-population gene-by-short-sleep and long-sleep duration interaction analyses for three blood pressure traits (systolic, diastolic, and pulse pressure) in 811,405 individuals from diverse population groups. We discovered 22 novel gene-sleep duration interaction loci for blood pressure, mapped to 23 genes.

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Elevated fasting insulin levels (FI), indicative of altered insulin secretion and sensitivity, may precede type 2 diabetes (T2D) and cardiovascular disease onset. In this study, we group FI-associated genetic variants based on their genetic and phenotypic similarities and identify seven clusters with distinct mechanisms contributing to elevated FI levels. Clusters fall into two types: "non-diabetogenic hyperinsulinemia," where clusters are not associated with increased T2D risk, and "diabetogenic hyperinsulinemia," where T2D associations are driven by body fat distribution, liver function, circulating lipids, or inflammation.

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Most genetic variants associated with complex traits and diseases occur in non-coding genomic regions and are hypothesized to regulate gene expression. To understand the genetics underlying gene expression variability, we characterize 14,324 ancestrally diverse RNA-sequencing samples from the NHLBI Trans-Omics for Precision Medicine (TOPMed) program and integrate whole genome sequencing data to perform and expression and splicing quantitative trait locus (-/trans-e/sQTL) analyses in six tissues and cell types, most notably whole blood (N=6,454) and lung (N=1,291). We show this dataset enables greater detection of secondary cis-e/sQTL signals than was achieved in previous studies, and that secondary cis-eQTL and primary trans-eQTL signal discovery is not saturated even though eGene discovery is.

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Background: Gene-environment interactions may enhance our understanding of hypertension. Our previous study highlighted the importance of considering psychosocial factors in gene discovery for blood pressure (BP) but was limited in statistical power and population diversity. To address these challenges, we conducted a multi-population genome-wide association study (GWAS) of BP accounting for gene-depressive symptomatology (DEPR) interactions in a larger and more diverse sample.

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Large-scale whole-genome sequencing (WGS) studies have improved our understanding of the contributions of coding and noncoding rare variants to complex human traits. Leveraging association effect sizes across multiple traits in WGS rare variant association analysis can improve statistical power over single-trait analysis, and also detect pleiotropic genes and regions. Existing multi-trait methods have limited ability to perform rare variant analysis of large-scale WGS data.

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Background And Aims: Individuals with steatotic liver disease (SLD) are at high cardiovascular disease (CVD) risk, but approaches to characterise and mitigate this risk are limited. By investigating relations, and shared metabolic pathways, of hepatic steatosis/fibrosis and cardiorespiratory fitness (CRF), we sought to identify new avenues for CVD risk reduction in SLD.

Methods: In Framingham Heart Study (FHS) participants (N = 2722, age 54 ± 9 years, 53% women), vibration-controlled transient elastography (VCTE) was performed between 2016-2019 to assess hepatic steatosis (continuous attenuation parameter [CAP]) and fibrosis (liver fibrosis measure [LSM]).

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Article Synopsis
  • A study explored how different biological factors (like proteins and metabolites) can help identify distinct groups of people with obesity who have varying risks for heart and metabolic diseases.
  • Using data from 243 participants, researchers found two groups: one (iCluster1) with favorable cholesterol levels and another (iCluster2) with higher BMI and inflammation levels.
  • The findings suggest these groups could reflect different stages of obesity-related issues, potentially influenced by factors like diet and behavior, despite similar ages across the groups.
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  • The study investigates how rare non-coding genetic variations affect complex traits, specifically focusing on human height by analyzing data from over 333,100 individuals across three large datasets.
  • Researchers found 29 significant rare variants linked to height, with impacts ranging from a decrease of 7 cm to an increase of 4.7 cm, after considering previously known variants.
  • The team also identified specific non-coding variants near key genes associated with height, demonstrating a new method for understanding the effects of rare variants in regulatory regions using whole-genome sequencing.
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  • * We found 17 genetic loci associated with sleep duration impacting lipid levels, with 10 of them being newly identified and linked to sleep-related disturbances in lipid metabolism.
  • * The research points to potential drug targets that could lead to new treatments for lipid-related issues in individuals with sleep problems, highlighting the connection between sleep patterns and cardiovascular health.
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  • Genome-wide association studies have found numerous genetic loci linked to glycemic traits, but connecting these loci to specific genes and biological pathways remains a challenge.
  • Researchers conducted meta-analyses of exome-array studies across four glycemic traits, analyzing data from over 144,000 participants, which led to the identification of coding variant associations in more than 60 genes.
  • The study revealed significant pathways related to insulin secretion, zinc transport, and fatty acid metabolism, enhancing understanding of glycemic regulation and making data available for further research.
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Although both short and long sleep duration are associated with elevated hypertension risk, our understanding of their interplay with biological pathways governing blood pressure remains limited. To address this, we carried out genome-wide cross-population gene-by-short-sleep and long-sleep duration interaction analyses for three blood pressure traits (systolic, diastolic, and pulse pressure) in 811,405 individuals from diverse population groups. We discover 22 novel gene-sleep duration interaction loci for blood pressure, mapped to 23 genes.

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Genome-wide association studies (GWAS) have identified numerous body mass index (BMI) loci. However, most underlying mechanisms from risk locus to BMI remain unknown. Leveraging omics data through integrative analyses could provide more comprehensive views of biological pathways on BMI.

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  • Osteoporosis and cardiovascular disease often occur together in older adults, but no direct causal link has been established between them.
  • A study involving 1,391 participants from the Framingham Heart Study assessed the relationship between vascular function and bone health, hypothesizing that poor vascular function negatively impacts bone density and strength.
  • The findings indicated that while poorer vascular function was initially associated with lower bone quality metrics, these associations were not significant after considering factors like age and sex, suggesting that aging-related vascular dysfunction may not be a direct cause of osteoporosis in older individuals.
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  • The study aimed to find genetic risk factors for cardiovascular disease (CVD) in individuals with type 2 diabetes (T2D) through a genome-wide association approach.
  • Out of 49,230 T2D participants, 8,956 experienced incident CVD events, revealing three new genetic loci associated with increased CVD risk and confirming five known coronary artery disease variants.
  • The findings suggest both novel and established genetic factors contribute to CVD risk in T2D patients, highlighting the importance of genetic screening in this population.
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Gaussian Graphical Models (GGM) have been widely used in biomedical research to explore complex relationships between many variables. There are well established procedures to build GGMs from a sample of independent and identical distributed observations. However, many studies include clustered and longitudinal data that result in correlated observations and ignoring this correlation among observations can lead to inflated Type I error.

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  • A study examined the link between body mass index (BMI) changes in middle adulthood and the risk of fractures in late adulthood, revealing that maintaining a stable BMI may lower fracture risks later in life.
  • The research analyzed data from 1,772 participants over 17 years, finding that those who moved from overweight to normal weight faced a significantly higher fracture risk after age 65 compared to those who remained in a normal to slightly overweight BMI range.
  • The findings suggest that maintaining a slight increase in weight during midlife could be beneficial for reducing fracture risk in later years, urging overweight individuals to avoid significant weight loss.
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Although both short and long sleep duration are associated with elevated hypertension risk, our understanding of their interplay with biological pathways governing blood pressure remains limited. To address this, we carried out genome-wide cross-population gene-by-short-sleep and long-sleep duration interaction analyses for three blood pressure traits (systolic, diastolic, and pulse pressure) in 811,405 individuals from diverse population groups. We discover 22 novel gene-sleep duration interaction loci for blood pressure, mapped to genes involved in neurological, thyroidal, bone metabolism, and hematopoietic pathways.

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