Genetic Epidemiological Studies Research Articles

Conceptual frameworks for the integration of genetic and social epidemiology in complex diseases

Uncovering the root causes of complex diseases requires complex approaches, yet many studies continue to isolate the effects of genetic and social determinants of disease. Epidemiologic efforts that under-utilize genetic epidemiology methods and findings may lead to incomplete understanding of disease. Meanwhile, genetic epidemiology studies are often conducted without consideration of social and environmental context, limiting the public health impact of genomic discoveries. This divide endures despite shared goals and increases in interdisciplinary data due to a lack of shared theoretical frameworks and differing language. Here, we demonstrate that bridging epidemiological divides does not require entirely new ways of thinking. Existing social epidemiology frameworks including Ecosocial theory and Fundamental Cause Theory, can both be extended to incorporate principles from genetic epidemiology. We show that genetic epidemiology can strengthen, rather than detract from, efforts to understand the impact of social determinants of health. In addition to presenting theoretical synergies, we offer practical examples of how genetics can improve the public health impact of epidemiology studies across the field. Ultimately, we aim to provide a guiding framework for trainees and established epidemiologists to think about diseases and complex systems and foster more fruitful collaboration between genetic and traditional epidemiological disciplines.

Conceptual frameworks for the integration of genetic and social epidemiology in complex diseases

Uncovering the root causes of complex diseases requires complex approaches, yet many studies continue to isolate the effects of genetic and social determinants of disease. Epidemiologic efforts that under-utilize genetic epidemiology methods and findings may lead to incomplete understanding of disease. Meanwhile, genetic epidemiology studies are often conducted without consideration of social and environmental context, limiting the public health impact of genomic discoveries. This divide endures despite shared goals and increases in interdisciplinary data due to a lack of shared theoretical frameworks and differing language. Here, we demonstrate that bridging epidemiological divides does not require entirely new ways of thinking. Existing social epidemiology frameworks including Ecosocial theory and Fundamental Cause Theory, can both be extended to incorporate principles from genetic epidemiology. We show that genetic epidemiology can strengthen, rather than detract from, efforts to understand the impact of social determinants of health. In addition to presenting theoretical synergies, we offer practical examples of how genetics can improve the public health impact of epidemiology studies across the field. Ultimately, we aim to provide a guiding framework for trainees and established epidemiologists to think about diseases and complex systems and foster more fruitful collaboration between genetic and traditional epidemiological disciplines.

Global prevalence of hereditary thrombotic thrombocytopenic purpura determined by genetic analysis

AbstractHereditary thrombotic thrombocytopenic purpura (hTTP) is a rare autosomal recessive, life-threatening disorder caused by a severe deficiency of the plasma enzyme, ADAMTS13. The current estimated prevalence of hTTP in different regions of the world, 0.5 to 2.0 patients per million, is determined by the frequency of diagnosed patients. To evaluate more accurately the worldwide prevalence of hTTP, and also the prevalence within distinct ethnic groups, we used data available in exome and genome sequencing of 807 162 (730 947 exomes, 76 215 genomes) patients reported recently by the Genome Aggregation Database (gnomAD version 4.1). Among 1 614 324 analyzed alleles in the gnomAD population we identified 6321 distinct ADAMTS13 variants. Of these 6321 variants, 758 were defined as pathogenic; 140 (18%) variants had been previously reported and 618 (82%) were novel (predicted as pathogenic). In total 10 154 alleles (0.6%) were carrying the reported or predicted pathogenic variants; 7759 (77%) with previously reported variants. Considering all 758 pathogenic variants and also only the 140 previously reported variants, we estimated a global hTTP prevalence of 40 and 23 cases per 106, respectively. Considering only the 140 previously reported variants, the highest estimated prevalence was in East Asians (42 per 106). The estimated prevalences of other populations were: Finnish, 32 per 106; non-Finnish Europeans, 28 per 106; Admixed Americans, 19 per 106; Africans/African Americans, 6 per 106; and South Asians, 4 per 106. The lowest prevalences were Middle Eastern, 1 per 106 and Ashkenazi Jews, 0.7 per 106. This population-based genetic epidemiology study reports that hTTP prevalence is substantially higher than the currently estimated prevalence based on diagnosed patients. Many patients with hTTP may not be diagnosed or may have died during the neonatal period.

Anthropometric traits and risk of multiple myeloma: differences by race, sex and diagnostic clinical features

BackgroundObesity is an established modifiable risk factor for multiple myeloma (MM). However, associations of obesity and MM risk in Black populations, for whom obesity and MM are more common, is less clear.MethodsUsing participants enrolled in the Integrative Molecular And Genetic Epidemiology study, we evaluated the association of anthropometric traits with MM risk overall, stratified by race and sex. Among cases, we assessed the association of BMI with the presence of myeloma-defining events.ResultsWe observed an 18% increase in MM risk for every 5 kg/m2 increase in usual adult BMI. Participants with severe obesity (BMI ≥ 40 kg/m2) had the highest risk compared to those with a normal usual adult BMI (18.5–24.9 kg/m2; OR = 1.87, 95% CI 1.25–2.80), particularly among Black men (OR = 3.94, 95% CI 0.90–17.36). Furthermore, MM cases with overweight/obesity (BMI ≥ 25 kg/m2) were more likely to present at diagnosis with low renal function (OR = 1.62, 95% CI 1.09–2.40), deletion 13q (OR = 1.73, 95% CI 1.08–2.76) and lytic lesions or compression fractures (OR = 2.39, 95% CI 0.82–7.01) and less likely to present with severe diffuse osteopenia (OR = 0.51, 95% CI 0.31–0.81).ConclusionsFindings underscore the importance of obesity as a modifiable risk factor for MM, particularly in high-risk populations, and for the clinical presentation of disease.

The genetics of trichotillomania and excoriation disorder: A systematic review

BackgroundTrichotillomania (TTM) and excoriation disorder (ED) are impairing obsessive-compulsive related disorders that are common in the general population and for which there are no clear first-line medications, highlighting the need to better understand the underlying biology of these disorders to inform treatments. Given the importance of genetics in obsessive-compulsive disorder (OCD), evaluating genetic factors underlying TTM and ED may advance knowledge about the pathophysiology of these body-focused repetitive behaviors. AimIn this systematic review, we summarize the available evidence on the genetics of TTM and ED and highlight gaps in the field warranting further research. MethodWe systematically searched Embase, PsycInfo, PubMed, Medline, Scopus, and Web of Science for original studies in genetic epidemiology (family or twin studies) and molecular genetics (candidate gene and genome-wide) published up to June 2023. ResultsOf the 3536 records identified, 109 studies were included in this review. These studies indicated that genetic factors play an important role in the development of TTM and ED, some of which may be shared across the OCD spectrum, but there are no known high-confidence specific genetic risk factors for either TTM or ED. ConclusionsOur review underscores the need for additional genome-wide research conducted on the genetics of TTM and ED, for instance, genome-wide association and whole-genome/whole-exome DNA sequencing studies. Recent advances in genomics have led to the discovery of risk genes in several psychiatric disorders, including related conditions such as OCD, but to date, TTM and ED have remained understudied.

Plasmodium ovale spp dhfr mutations associated with reduced susceptibility to pyrimethamine in sub-Saharan Africa: a retrospective genetic epidemiology and functional study

Mutations in the Plasmodium falciparum dhfr gene confer resistance to pyrimethamine, which is widely used for malaria chemoprevention in Africa. We aimed to evaluate the frequency and evolution of dhfr mutations in Plasmodium ovale spp in Africa and their functional consequences, which are incompletely characterised. We analysed dhfr mutations and their frequencies in P ovale spp isolates collected between Feb 1, 2004, and Aug31, 2023, from the French National Malaria Reference Centre collection and from field studies in Benin, Gabon, and Kenya. Genetic patterns of positive selection were investigated. Full-length recombinant wild-type and mutant DHFR enzymes from both P ovale curtisi and P ovale wallikeri were expressed in bacteria to test whether the most common mutations reduced pyrimethamine susceptibility. We included 518 P ovale spp samples (314 P ovale curtisi and 204 P ovale wallikeri). In P ovale curtisi, Ala15Ser-Ser58Arg was the most common dhfr mutation (39%; 124 of 314 samples). In P ovale wallikeri, dhfr mutations were less frequent, with Phe57Leu-Ser58Arg reaching 17% (34 of 204 samples). These two mutants were the most prevalent in central and east Africa and were fixed in Kenyan isolates. We detected six and four other non-synonymous mutations, representing 8% (24 isolates) and 2% (five isolates) of the P ovale curtisi and Povale wallikeri isolates, respectively. Whole-genome sequencing and microsatellite analyses revealed reduced genetic diversity around themutant pocdhfr and powdhfr genes. The mutant DHFR proteins showed structural changes at the pyrimethamine binding site in-silico, confirmed by a 4-times increase in pyrimethamine half-maximal inhibitory concentration in an Escherichia coli growth assay for the Phe57Leu-Ser58Arg mutant and 50-times increase for the Ala15Ser-Ser58Arg mutant, compared with the wild-type counterparts. The widespread use of sulfadoxine-pyrimethamine for malaria chemoprevention might have exerted fortuitous selection pressure for dhfr mutations in P ovale spp. This calls for closer monitoring of dhfr and dhps mutations in P ovale spp. French Ministry of Health, Agence Nationale de la Recherche, and Global Emerging Infections Surveillance branch of the Armed Forces Health Surveillance Division.

Screening of premature ovarian insufficiency associated genes in Hungarian patients with next generation sequencing

BackgroundPremature ovarian insuffiency (POI) is one of the main cause behind infertility. The genetic analysis of POI should be part of the clinical diagnostics, as several genes have been implicated in the genetic background of it. The aim of our study was to analyse the genetic background of POI in a Hungarian cohort.MethodsThe age of onset was between 15 and 39 years. All patients had the 46,XX karyotype and they were prescreened for the most frequent POI associated FMR1 premutation. To identify genetic alterations next-generation sequencing (NGS) of 31 genes which were previously associated to POI were carried out in 48 unrelated patients from Hungary.ResultsMonogenic defect was identified in 16.7% (8 of 48) and a potential genetic risk factor was found in 29.2% (14 of 48) and susceptible oligogenic effect was described in 12.5% (6 of 48) of women with POI using the customized targeted panel sequencing. The genetic analysis identified 8 heterozygous damaging and 4 potentially damaging variants in POI-associated genes. Further 10 potential genetic risk factors were detected in seven genes, from which EIF2B and GALT were the most frequent. These variants were related to 15 genes: AIRE, ATM, DACH2, DAZL, EIF2B2, EIF2B4, FMR1, GALT, GDF9, HS6ST2, LHCGR, NOBOX, POLG, USP9X and XPNPEP2. In six cases, two or three coexisting damaging mutations and risk variants were identified.ConclusionsPOI is characterized by heterogenous phenotypic features with complex genetic background that contains increasing number of genes. Deleterious variants, which were detected in our cohort, related to gonadal development (oogenesis and folliculogenesis), meiosis and DNA repair, hormonal signaling, immune function, and metabolism which were previously associated with the POI phenotype. This is the first genetic epidemiology study targeting POI associated genes in Hungary. The frequency of variants in different POI associated genes were similar to the literature, except EIF2B and GALT. Both of these genes potential risk factor were detected which could influence the phenotype, although it is unlikely that they can be responsible for the development of the disease by themselves. Advances of sequencing technologies make it possible to aid diagnostics of POI Since individual patients show high phenotypic variance because of the complex network controlling human folliculogenesis. Comprehensive NGS screening by widening the scope to genes which were previously linked to infertility may facilitate more accurate, quicker and cheaper genetic diagnoses for POI. The investigation of patient’s genotype could support clinical decision-making process and pave the way for future clinical trials and therapies.

Ectopical expression of bacterial collagen-like protein supports its role as adhesin in host-parasite coevolution.

For a profound understanding of antagonistic coevolution, it is necessary to identify the coevolving genes. The bacterium Pasteuria and its host, the microcrustacean Daphnia, are a well-characterized paradigm for co-evolution, but the underlying genes remain largely unknown. A genome-wide association study suggested a Pasteuria collagen-like protein 7 (Pcl7) as a candidate mediating parasite attachment and driving its coevolution with the host. Since Pasteuria ramosa cannot currently be genetically manipulated, we used Bacillus thuringiensis to express a fusion protein of a Pcl7 carboxy-terminus from P. ramosa and the amino-terminal domain of a B. thuringiensis collagen-like protein (CLP). Mutant B. thuringiensis (Pcl7-Bt) spores but not wild-type B. thuringiensis (WT-Bt) spores attached to the same site of susceptible hosts as P. ramosa. Furthermore, Pcl7-Bt spores attached readily to susceptible host genotypes, but only slightly to resistant host genotypes. These findings indicated that the fusion protein was properly expressed and folded and demonstrated that indeed the C-terminus of Pcl7 mediates attachment in a host genotype-specific manner. These results provide strong evidence for the involvement of a CLP in the coevolution of Daphnia and P. ramosa and open new avenues for genetic epidemiological studies of host-parasite interactions.

Abstract 921: The value of cancer genomic data sharing

Abstract Our understanding of and ability to combat cancer relies on the generation, analysis, and sharing of data. The Epidemiology and Genomics Research Program in the National Cancer Institute’s Division of Cancer Control and Population Sciences (DCCPS) has supported generation of large genomic data sets and advocated for and/or required broad sharing of this data. One of DCCPS’s scientific priorities is focused on data strategies namely, “the use, enhancement, expansion, and accessibility of new and existing DCCPS-supported data resources to accelerate cancer control research” (https://cancercontrol.cancer.gov/overview-highlights/2022/future_directions.html).EGRP funded the Genetic Associations and Mechanisms in Oncology (GAME-ON) Initiative, a multidisciplinary collaboration of researchers focused on understanding the genetic architecture, biology, and clinical and epidemiologic utility of common cancer risk variants. This program focused on 5 common cancer types - breast, colorectal, lung, ovarian, and prostate - and required research that incorporated multiple research domains and sharing of any data generated. A major accomplishment of this program was development of the OncoArray genotyping chip, which used information from genetic epidemiology studies, biological/functional analyses, and clinical and epidemiologic insights to create a comprehensive, high-density genotyping array for pan-cancer studies that has led to the discovery of hundreds of new cancer predisposition variants. This chip was used in a massive, coordinated genotyping effort that culminated in the generation of 7 datasets comprising genotyping data for nearly 500,000 individuals. All the data were deposited in dbGaP between 2014 and 2021 and are available (via controlled access) to any investigators. To understand the secondary use of these data, we determined the number of times the data had been downloaded, who downloaded the data, and types of research for which it was used. We also identified publications using OncoArray data and characterized the publications by research type, cancer type, and other details. Through this analysis, we explore how well the GAME-ON initiative and the OncoArray projects promote the DCCPS scientific priority of optimizing secondary research by making the data findable, accessible, interoperable, and reusable (FAIR). Citation Format: Stefanie Nelson, Charlisse Caga Anan, Elizabeth Gillanders. The value of cancer genomic data sharing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 921.

Abstract 848: Influence of young age at diagnosis on the clinical presentation of disease and survival among patients with multiple myeloma

Abstract Background: Age is an important prognostic factor for multiple myeloma (MM). We evaluated the influence of age on the clinical presentation and outcomes among newly diagnosed patients with MM to optimize risk stratification. Methods: In 850 patients with first primary confirmed MM prospectively enrolled in the Integrative Molecular And Genetic Epidemiology (IMAGE) study (2009-2020), we evaluated the presence of diagnostic myeloma-defining events (MDE), progression free survival (PFS) and overall survival (OS) by young age at diagnosis (≤50 years). We evaluated the association of young age with the prevalence of diagnostic MDE, clinical features and chromosomal abnormalities using the prevalence odds ratio (OR) and corresponding 95% confidence interval (CI) calculated from multivariable logistic regression. Median PFS and OS were graphically examined using Kaplan-Meier survival curves with log-rank tests used to compare survival by diagnostic age group. Risks of disease progression and all-cause mortality were estimated using hazard ratios (HR) and corresponding 95% CI calculated from multivariable Cox proportional hazard models. Results.: Of the 850 patients, 15.4% were diagnosed at ≤50 years of age, 54% were male and 40% self-identified as Black. Compared to patients diagnosed with MM over the age of 50, young patients were more likely to self-identify as Black (59.5% vs 40.5%; P<0.0001) and to report a negative smoking history (66.2% v 56.4%; P=0.01), and less likely to present with age-dependent comorbidities including hypertension, hyperlipidemia and diabetes mellitus type II (P≤0.0001). In multivariable analyses, young patients, compared to older patients, were more likely to present at diagnosis with higher median percent bone marrow plasma cells (70% v 55%; P=0.02) and to undergo autologous stem cell transplant (ASCT) as part of their first-line treatment (82.0% v 67.6%; P=0.01) after controlling for sex, race, body mass index, smoking status and comorbidities. We did not observe significant associations of young age with the prevalence of any other MDE, clinical feature or chromosomal abnormality evaluated. The median OS was 106.9 months (range, 0.23-356.1). OS was significantly longer in young patients with MM compared to patients aged greater than 50 years (159 v 99 months, respectively; P<0.001) leading to a suggestive 1.5-fold decreased risk of mortality among younger newly diagnosed patients (HR=0.67, 95% CI 0.39-1.14; P=0.14) after adjusting for sex, International Staging System-stage, adverse cytogenetic abnormalities, and ASCT. We did not observe associations with age and PFS (P=0.81). Conclusions: Findings suggest that newly diagnosed younger patients with MM are more likely to self-identify as Black, present with more bone marrow plasma cells, have less age-dependent comorbidities, and undergo ASCT leading to a suggestive survival advantage. Citation Format: Krystle L. Ong, Kevin D. Arnold, Gayathri Ravi, Luciano J. Costa, Elizabeth E. Brown. Influence of young age at diagnosis on the clinical presentation of disease and survival among patients with multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 848.

Genetics of chronic respiratory disease.

Chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD), asthma and interstitial lung diseases are frequently occurring disorders with a polygenic basis that account for a large global burden of morbidity and mortality. Recent large-scale genetic epidemiology studies have identified associations between genetic variation and individual respiratory diseases and linked specific genetic variants to quantitative traits related to lung function. These associations have improved our understanding of the genetic basis and mechanisms underlying common lung diseases. Moreover, examining the overlap between genetic associations of different respiratory conditions, along with evidence for gene-environment interactions, has yielded additional biological insights into affected molecular pathways. This genetic information could inform the assessment of respiratory disease risk and contribute to stratified treatment approaches.

Sleep and allergic diseases among young Chinese adults from the Singapore/Malaysia Cross-Sectional Genetic Epidemiology Study (SMCGES) cohort

Background and objectiveSleep disruption has been shown to affect immune function and thus influence allergic disease manifestation. The specific effects of sleep on allergic diseases, however, are less well-established; hence, in a unique population of young Chinese adults, we investigated the association between sleep and allergic disease.MethodsYoung Chinese adults recruited from Singapore in the Singapore/Malaysia Cross-Sectional Genetic Epidemiology Study (SMCGES) were analyzed. We used the International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a skin prick test to determine atopic dermatitis (AD), allergic rhinitis (AR), and asthma status. Information regarding total sleep time (TST) and sleep quality (SQ) was also obtained.ResultsOf 1558 participants with a mean age of 25.0 years (SD = 7.6), 61.4% were female, and the mean total sleep time (TST) was 6.8 h (SD = 1.1). The proportions of AD, AR, and asthma were 24.5% (393/1542), 36.4% (987/1551), and 14.7% (227/1547), respectively. 59.8% (235/393) of AD cases suffered from AD-related sleep disturbances, 37.1% (209/564) of AR cases suffered from AR-related sleep disturbances, and 25.1% (57/227) of asthma cases suffered from asthma-related sleep disturbances. Only asthma cases showed a significantly lower mean TST than those without asthma (p = 0.015). Longer TST was significantly associated with lower odds of AR (OR = 0.905, 95% CI = 0.820–0.999) and asthma (OR = 0.852, 95% CI = 0.746–0.972). Linear regression analyses showed that lower TST was significantly associated with asthma (β = − 0.18, SE = 0.076, p-value = 0.017), and AR when adjusted for AR-related sleep disturbances (β = − 0.157, SE = 0.065, p-value = 0.016). Only sleep disturbances due to AR were significantly associated with a poorer SQ (OR = 1.962, 95% CI = 1.245–3.089).ConclusionsWe found that sleep quality, but not sleep duration was significantly poorer among AD cases, although the exact direction of influence could not be determined. In consideration of the literature coupled with our findings, we posit that TST influences allergic rhinitis rather than vice versa. Finally, the association between TST and asthma is likely mediated by asthma-related sleep disturbances, since mean TST was significantly lower among those with nighttime asthma symptoms. Future studies could consider using objective sleep measurements coupled with differential expression analysis to investigate the pathophysiology of sleep and allergic diseases.

Lung Cancer in Ever- and Never-Smokers: Findings from Multi-Population GWAS Studies.

Clinical, molecular, and genetic epidemiology studies displayed remarkable differences between ever- and never-smoking lung cancer. We conducted a stratified multi-population (European, East Asian, and African descent) association study on 44,823 ever-smokers and 20,074 never-smokers to identify novel variants that were missed in the non-stratified analysis. Functional analysis including expression quantitative trait loci (eQTL) colocalization and DNA damage assays, and annotation studies were conducted to evaluate the functional roles of the variants. We further evaluated the impact of smoking quantity on lung cancer risk for the variants associated with ever-smoking lung cancer. Five novel independent loci, GABRA4, intergenic region 12q24.33, LRRC4C, LINC01088, and LCNL1 were identified with the association at two or three populations (P < 5 × 10-8). Further functional analysis provided multiple lines of evidence suggesting the variants affect lung cancer risk through excessive DNA damage (GABRA4) or cis-regulation of gene expression (LCNL1). The risk of variants from 12 independent regions, including the well-known CHRNA5, associated with ever-smoking lung cancer was evaluated for never-smokers, light-smokers (packyear ≤ 20), and moderate-to-heavy-smokers (packyear > 20). Different risk patterns were observed for the variants among the different groups by smoking behavior. We identified novel variants associated with lung cancer in only ever- or never-smoking groups that were missed by prior main-effect association studies. Our study highlights the genetic heterogeneity between ever- and never-smoking lung cancer and provides etiologic insights into the complicated genetic architecture of this deadly cancer.

Genetically determined plasma trefoil factor-3 levels are causally associated with the risk of ulcerative colitis: a Mendelian randomization study

Objectives: Ulcerative colitis (UC) is an inflammatory disease restricted to the colon's mucosal layer. UC is a complex disease with a largely unknown etiology. Mendelian Randomization (MR) is a method that uses variations in genes that have a causal effect of a modifiable exposure to the disease, in genetic epidemiological studies. Trefoil factor 3 (TFF3) is a secreted protein expressed mainly in the colonic mucosa that binds with the mucin 2 protein, forming a protective barrier for the colon mucosa from bacteria and other insults. This study aimed to identify if TFF3 levels in plasma are causally associated with UC. Methods: We performed a two-sample MR study. For exposure instrumental variables (IVs), genetically determined TFF3 levels in plasma proteome quantitative trait locus data were obtained from the published literature. Outcome data were obtained from the GWAS catalog. The “TwoSampleMR” R package was used for MR. The statistical significance of IV effect sizes on the outcome is mainly evaluated by the inverse variance weighted (IVW) method. Results: The IVW test showed considerable statistical significance in all analyzed outcomes except for Crohn’s disease (CD) samples. Heterogeneity and horizontal pleiotropy tests showed no significant results for MR sensitivity analysis. Conclusions: We showed that TFF3 levels in plasma were causally associated with the risk of UC. Increased levels of TFF3 are reversely associated with the risk of UC. The absence of any causal relationship between TFF3 and CD from the same study cohort also supports our causal inference.

BIODEMOGRAPHY OF AGING, CELEBRATING JAMES W. VAUPEL, PHD

Abstract James W. Vaupel, PhD (1945 – 2022), was an international leader in demography and aging research and a pioneer in the field of biodemography. He was a highly creative researcher and very entrepreneurial in the development of new interdisciplinary research environments. This symposium highlights a few of the biodemographic research areas that Dr. Vaupel has been a catalyst for. Denmark was Dr. Vaupel’s home country during the last third of his life, and Dr. Christensen reports on findings from Danish nationwide genetic-epidemiological studies on twins and the oldest old: familial influence on aging phenotypes, cohort differences in health among the oldest old, associations of early life events with late life health, as well as tongue-in-cheek research on perceived age and teeth. Dr. Alberts discusses the ‘invariant rate of aging’ hypothesis that was developed by Vaupel and others. She presents comparative analyses from multiple nonhuman primate populations showing that, while life expectancy can continue to improve, we probably can’t slow the demographic rate of aging. Dr. Campos presents evidence from a wild baboon population in Kenya that glucocorticoid levels—biological markers of stress responses—are strong prognostic indicators of survival and may be key explanations of life span disparities. Dr. Carey presents key discoveries from large-scale studies involving the Mediterranean fruit fly. These include the slowing of mortality at older ages, context-specific sex mortality differentials, a behavioral biomarker for morbidity, dietary conditions for maximizing lifespan versus reproduction and a stationary population identity whereby life lived equals life left.

Gene‐level Association Study of Alzheimer’s Disease on CHS and FRAM cohorts

AbstractBackgroundExperimental, clinical, and genetic epidemiological studies continue clarifying important aspects of Alzheimer’s disease (AD) pathological development. Despite this progress the genetic mechanisms of AD regulation remain unclear. One problem that may contribute to slowing further progress in better understanding of these mechanisms deals with difficulties in replication of the results of genetic association studies. To overcome this problem the idea of using a gene‐based analysis in which all common variation within a candidate gene is considered jointly has been suggested. In this paper we investigate to what extent the use of gene‐based analyses resolves the non‐replication problem.MethodWe performed gene‐level and meta‐analysis association studies for two cohorts: Cardiovascular Heart Study (CHS) and Framingham (FRAM) using Alzheimer’s disease as a primary outcome. To support our findings, we also performed meta‐analysis following gene‐enrichment study for both cohorts. Analysis was performed separately for males and females and for both sexes. Additional covariates were age, smoking. Gene‐level analysis was performed with fastBAT and enrichment analysis with ClusterProfiler on KEGG database.ResultOur analysis identified a list of highly significant genes, such as TOMM40, APOC1 (all with FDR‐adjusted p‐value &lt; 0.05) and pathways, such as Cholesterol metabolism, Fluid shear stress and atherosclerosis, Proteoglycans in cancer, Lipid and atherosclerosis showed statistically significant associations (FDR‐adjusted p‐value &lt; 0.05) in both datasets and sexes.Meta‐analysis revealed TOMM40 (p‐value = 2.35E‐16), APOC1 (p‐value 4.46E‐13), ENSG00000259648 (p‐value = 8.88E‐06), PEX7 (p‐value = 4.40E‐05), ENSG00000287274 (p‐value = 5.38E‐05) genes for men and women combined; men exclusively revealed ENSG00000259648, TOMM40, and APOC1 (p‐value&lt;1.75E‐05) and women TOMM40 and APOC1 (p‐value&lt;6E‐08).Gene‐enrichment meta‐analysis revealed NOD‐like receptor signaling pathway (adjusted p‐value 3.23E‐07), Lipid and atherosclerosis (p‐value = 5.93E‐05), Yersinia (p‐value = 1.17E‐04) for men and women combined; for men only the pathways are Lipid and atherosclerosis (p‐value = 3.61E‐03), TGF‐beta signaling pathway (p‐value = 3.61E‐03), AGE‐RAGE signaling pathway in diabetic complications (p‐value = 5.18E‐03); and for women Cholesterol metabolism (p‐value = 3.49E‐07), Fatty acid degradation (p‐value = 1.04E‐06), PPAR signaling pathway (p‐value = 1.23E‐05).ConclusionIn this work we were able to identify statistically significant genes and pathways showed replication across the studies and are potentially useful for uncovering genetic mechanisms of AD. However, other things such as genetic heterogeneity may influence disease developing and needed further exploration.

Polygenic Risk Score, Environmental Tobacco Smoke, and Risk of Lung Adenocarcinoma in Never-Smoking Women in Taiwan

Estimating absolute risk of lung cancer for never-smoking individuals is important to inform lung cancer screening programs. To integrate data on environmental tobacco smoke (ETS), a known lung cancer risk factor, with a polygenic risk score (PRS) that captures overall genetic susceptibility, to estimate the absolute risk of lung adenocarcinoma (LUAD) among never-smokers in Taiwan. The analyses were conducted in never-smoking women in the Taiwan Genetic Epidemiology Study of Lung Adenocarcinoma, a case-control study. Participants were recruited between September 17, 2002, and March 30, 2011. Data analysis was performed from January 17 to July 15, 2022. A PRS was derived using 25 genetic variants that achieved genome-wide significance (P < 5 × 10-8) in a recent genome-wide association study, and ETS was defined as never exposed, exposed at home or at work, and exposed at home and at work. The Individualized Coherent Absolute Risk Estimator software was used to estimate the lifetime absolute risk of LUAD in never-smoking women aged 40 years over a projected 40-year span among the controls by using the relative risk estimates for the PRS and ETS exposures, as well as age-specific lung cancer incidence rates for never-smokers in Taiwan. Likelihood ratio tests were conducted to assess an additive interaction between the PRS and ETS exposure. Data were obtained on 1024 women with LUAD (mean [SD] age, 59.6 [11.4] years, 47.9% ever exposed to ETS at home, and 19.5% ever exposed to ETS at work) and 1024 controls (mean [SD] age, 58.9 [11.0] years, 37.0% ever exposed to ETS at home, and 14.3% ever exposed to ETS at work). The overall average lifetime 40-year absolute risk of LUAD estimated using PRS alone was 2.5% (range, 0.6%-10.3%) among women never exposed to ETS. When integrating both ETS and PRS data, the estimated absolute risk was 3.7% (range, 0.6%-14.5%) for women exposed to ETS at home or work and 5.3% (range, 1.2%-12.1%) for women exposed to ETS at home and work. A super-additive interaction between ETS and the PRS (P = 6.5 × 10-4 for interaction) was identified. This study found differences in absolute risk of LUAD attributed to genetic susceptibility according to levels of ETS exposure in never-smoking women. Future studies are warranted to integrate these findings in expanded risk models for LUAD.

Unappreciated subcontinental admixture in Europeans and European Americans and implications for genetic epidemiology studies

European-ancestry populations are recognized as stratified but not as admixed, implying that residual confounding by locus-specific ancestry can affect studies of association, polygenic adaptation, and polygenic risk scores. We integrate individual-level genome-wide data from ~19,000 European-ancestry individuals across 79 European populations and five European American cohorts. We generate a new reference panel that captures ancestral diversity missed by both the 1000 Genomes and Human Genome Diversity Projects. Both Europeans and European Americans are admixed at the subcontinental level, with admixture dates differing among subgroups of European Americans. After adjustment for both genome-wide and locus-specific ancestry, associations between a highly differentiated variant in LCT (rs4988235) and height or LDL-cholesterol were confirmed to be false positives whereas the association between LCT and body mass index was genuine. We provide formal evidence of subcontinental admixture in individuals with European ancestry, which, if not properly accounted for, can produce spurious results in genetic epidemiology studies.

The Role of Triglyceride-rich Lipoproteins and Their Remnants in Atherosclerotic Cardiovascular Disease.

Atherosclerotic cardiovascular disease (ASCVD) is the world's leading cause of death. ASCVD has multiple mediators that therapeutic interventions target, such as dyslipidaemia, hypertension, diabetes and heightened systemic inflammatory tone, among others. LDL cholesterol is one of the most well-studied and established mediators targeted for primary and secondary prevention of ASCVD. However, despite the strength of evidence supporting LDL cholesterol reduction by multiple management strategies, ASCVD events can still recur, even in patients whose LDL cholesterol has been very aggressively reduced. Hypertriglyceridaemia and elevated levels of triglyceride-rich lipoproteins (TRLs) may be key contributors to ASCVD residual risk. Several observational and genetic epidemiological studies have highlighted the causal role of triglycerides within the TRLs and/or their remnant cholesterol in the development and progression of ASCVD. TRLs consist of intestinally derived chylomicrons and hepatically synthesised very LDL. Lifestyle modification has been considered the first line intervention for managing hypertriglyceridaemia. Multiple novel targeted therapies are in development, and have shown efficacy in the preclinical and clinical phases of study in managing hypertriglyceridaemia and elevated TRLs. This comprehensive review provides an overview of the biology, pathogenicity, epidemiology, and genetics of triglycerides and TRLs, and how they impact the risk for ASCVD. In addition, we provide a summary of currently available and novel emerging triglyceride-lowering therapies in development.

Cancer Incidence and Mortality Estimates in Arab Countries in 2018: A GLOBOCAN Data Analysis.

Arab countries are projecting increase in cancer incidence and mortality; however, there are limited studies that compare the epidemiology of cancer in Arab countries compared with other parts of the world. We used the 2018 Global Cancer Observatory data to compare the age-standardized incidence and mortality estimates in Arab-speaking countries to the rest of the world. Rates for incidence and mortality for all cancers in Arab countries were lower than the world's rates but the incidence rates of non-Hodgkin and Hodgkin lymphoma, bladder, breast, and liver cancers were higher. Arab countries generally had higher mortality-to-incidence ratio than the world's ratio. Incidence rates, even in age-specific groups, varied between subregions of Arab countries (the Levant, Arabian Gulf, and Arab African subregions), and Iraq and Egypt, suggesting some common and unique environmental factors and possible ethnic or genetic heritages. There are essential scopes for improvements in Arab countries including better treatments to reduce the high mortality-to-incidence ratio, and supporting vaccination programs and antiviral treatments that would prevent the prevalent viral infection-related cancers. The high incidence of several cancers in younger Arabs suggests genetic factors and underlines the importance of genetic epidemiology studies. This study is an essential reference to evaluate and monitor the progress of national cancer initiatives in Arab countries for surveillance and prevention programs and improving clinical management. The study also provides a comprehensive snapshot of cancers in a unique region that could shed light on the interplay of environmental, lifestyle, and genetic risk factors.