Multi-ancestry transcriptome-wide association analyses yield insights into tobacco use biology and drug repurposing.

Most transcriptome-wide association studies (TWASs) so far focus on European ancestry and lack diversity. To overcome this limitation, we aggregated genome-wide association study (GWAS) summary statistics, whole-genome sequences and expression quantitative trait locus (eQTL) data from diverse ancestries. We developed a new approach, TESLA (multi-ancestry integrative study using an optimal linear combination of association statistics), to integrate an eQTL dataset with a multi-ancestry GWAS. By exploiting shared phenotypic effects between ancestries and accommodating potential effect heterogeneities, TESLA improves power over other TWAS methods. When applied to tobacco use phenotypes, TESLA identified 273 new genes, up to 55% more compared with alternative TWAS methods. These hits and subsequent fine mapping using TESLA point to target genes with biological relevance. In silico drug-repurposing analyses highlight several drugs with known efficacy, including dextromethorphan and galantamine, and new drugs such as muscle relaxants that may be repurposed for treating nicotine addiction.

Genetic diversity fuels gene discovery for tobacco and alcohol use.

Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury1-4. These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries5. Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.

Rare genetic variants explain missing heritability in smoking.

Common genetic variants explain less variation in complex phenotypes than inferred from family-based studies, and there is a debate on the source of this 'missing heritability'. We investigated the contribution of rare genetic variants to tobacco use with whole-genome sequences from up to 26,257 unrelated individuals of European ancestries and 11,743 individuals of African ancestries. Across four smoking traits, single-nucleotide-polymorphism-based heritability ([Formula: see text]) was estimated from 0.13 to 0.28 (s.e., 0.10-0.13) in European ancestries, with 35-74% of it attributable to rare variants with minor allele frequencies between 0.01% and 1%. These heritability estimates are 1.5-4 times higher than past estimates based on common variants alone and accounted for 60% to 100% of our pedigree-based estimates of narrow-sense heritability ([Formula: see text], 0.18-0.34). In the African ancestry samples, [Formula: see text] was estimated from 0.03 to 0.33 (s.e., 0.09-0.14) across the four smoking traits. These results suggest that rare variants are important contributors to the heritability of smoking.

Exome-chip meta-analysis identifies association between variation in ANKRD26 and platelet aggregation.

Previous genome-wide association studies (GWAS) have identified several variants associated with platelet function phenotypes; however, the proportion of variance explained by the identified variants is mostly small. Rare coding variants, particularly those with high potential for impact on protein structure/function, may have substantial impact on phenotype but are difficult to detect by GWAS. The main purpose of this study was to identify low frequency or rare variants associated with platelet function using genotype data from the Illumina HumanExome Bead Chip. Three family-based cohorts of European ancestry, including ~4,000 total subjects, comprised the discovery cohort and two independent cohorts, one of European and one of African American ancestry, were used for replication. Optical aggregometry in platelet-rich plasma was performed in all the discovery cohorts in response to adenosine diphosphate (ADP), epinephrine, and collagen. Meta-analyses were performed using both gene-based and single nucleotide variant association methods. The gene-based meta-analysis identified a significant association (P = 7.13 × 10-7) between rare genetic variants in ANKRD26 and ADP-induced platelet aggregation. One of the ANKRD26 SNVs - rs191015656, encoding a threonine to isoleucine substitution predicted to alter protein structure/function, was replicated in Europeans. Aggregation increases of ~20-50% were observed in heterozygotes in all cohorts. Novel genetic signals in ABCG1 and HCP5 were also associated with platelet aggregation to ADP in meta-analyses, although only results for HCP5 could be replicated. The SNV in HCP5 intersects epigenetic signatures in CD41+ megakaryocytes suggesting a new functional role in platelet biology for HCP5. This is the first study to use gene-based association methods from SNV array genotypes to identify rare variants related to platelet function. The molecular mechanisms and pathophysiological relevance for the identified genetic associations requires further study.

Diabetes and Platelet Response to Low-Dose Aspirin.

Context: Previous studies have suggested less cardioprotective benefit of aspirin in adults with diabetes, raising concerns about "aspirin resistance" and potentially reduced effectiveness for prevention of cardiovascular disease (CVD). Objective: To examine differences in platelet response to aspirin by diabetes status. Design, Setting, Participants: We examined platelet response before and after aspirin (81 mg/day for 14 days) in 2113 adults (175 with diabetes, 1,938 without diabetes), in the Genetic Study of Aspirin Responsiveness cohort, who had family history of early-onset CVD. Main Outcome Measures: In vivo platelet activation (urinary thromboxane B2), in vitro platelet aggregation to agonists (arachidonic acid, adenosine diphosphate, collagen), and platelet function analyzer-100 closure time. Results: Although adults with diabetes had higher in vivo platelet activation before aspirin, the reduction in in vivo platelet activation after aspirin was similar in those with vs without diabetes. Likewise, the reduction in multiple in vitro platelet measures was similar after aspirin by diabetes status. In regression analyses adjusted for age, sex, race, BMI, smoking, platelet counts, and fibrinogen levels, in vivo platelet activation remained higher in adults with vs without diabetes after aspirin (P = 0.04), but this difference was attenuated after additional adjustment for preaspirin levels (P = 0.10). No differences by diabetes status were noted for any of the in vitro platelet measures after aspirin in fully adjusted models that also accounted for preaspirin levels. Conclusions: In vitro platelet response to aspirin does not differ by diabetes status, suggesting no intrinsic differences in platelet response to aspirin. Instead, factors extrinsic to platelet function should be investigated to give further insights into aspirin use for primary prevention in diabetes.

Genome-Wide Association Study of Heavy Smoking and Daily/Nondaily Smoking in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Introduction: Genetic variants associated with nicotine dependence have previously been identified, primarily in European-ancestry populations. No genome-wide association studies (GWAS) have been reported for smoking behaviors in Hispanics/Latinos in the United States and Latin America, who are of mixed ancestry with European, African, and American Indigenous components. Methods: We examined genetic associations with smoking behaviors in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) (N = 12 741 with smoking data, 5119 ever-smokers), using ~2.3 million genotyped variants imputed to the 1000 Genomes Project phase 3. Mixed logistic regression models accounted for population structure, sampling, relatedness, sex, and age. Results: The known region of CHRNA5, which encodes the α5 cholinergic nicotinic receptor subunit, was associated with heavy smoking at genome-wide significance (p ≤ 5 × 10-8) in a comparison of 1929 ever-smokers reporting cigarettes per day (CPD) > 10 versus 3156 reporting CPD ≤ 10. The functional variant rs16969968 in CHRNA5 had a p value of 2.20 × 10-7 and odds ratio (OR) of 1.32 for the minor allele (A); its minor allele frequency was 0.22 overall and similar across Hispanic/Latino background groups (Central American = 0.17; South American = 0.19; Mexican = 0.18; Puerto Rican = 0.22; Cuban = 0.29; Dominican = 0.19). CHRNA4 on chromosome 20 attained p < 10-4, supporting prior findings in non-Hispanics. For nondaily smoking, which is prevalent in Hispanic/Latino smokers, compared to daily smoking, loci on chromosomes 2 and 4 achieved genome-wide significance; replication attempts were limited by small Hispanic/Latino sample sizes. Conclusions: Associations of nicotinic receptor gene variants with smoking, first reported in non-Hispanic European-ancestry populations, generalized to Hispanics/Latinos despite different patterns of smoking behavior. Implications: We conducted the first large-scale genome-wide association study (GWAS) of smoking behavior in a US Hispanic/Latino cohort, and the first GWAS of daily/nondaily smoking in any population. Results show that the region of the nicotinic receptor subunit gene CHRNA5, which in non-Hispanic European-ancestry smokers has been associated with heavy smoking as well as cessation and treatment efficacy, is also significantly associated with heavy smoking in this Hispanic/Latino cohort. The results are an important addition to understanding the impact of genetic variants in understudied Hispanic/Latino smokers.

Whole exome sequencing in the Framingham Heart Study identifies rare variation in HYAL2 that influences platelet aggregation.

Inhibition of platelet reactivity is a common therapeutic strategy in secondary prevention of cardiovascular disease. Genetic and environmental factors influence inter-individual variation in platelet reactivity. Identifying genes that contribute to platelet reactivity can reveal new biological mechanisms and possible therapeutic targets. Here, we examined rare coding variation to identify genes associated with platelet reactivity in a population-based cohort. To do so, we performed whole exome sequencing in the Framingham Heart Study and conducted single variant and gene-based association tests against platelet reactivity to collagen, adenosine diphosphate (ADP), and epinephrine agonists in up to 1,211 individuals. Single variant tests revealed no significant associations (p<1.44×10-7), though we observed a suggestive association with previously implicated MRVI1 (rs11042902, p = 1.95×10-7). Using gene-based association tests of rare and low-frequency variants, we found significant associations of HYAL2 with increased ADP-induced aggregation (p = 1.07×10-7) and GSTZ1 with increased epinephrine-induced aggregation (p = 1.62×10-6). HYAL2 also showed suggestive associations with epinephrine-induced aggregation (p = 2.64×10-5). The rare variants in the HYAL2 gene-based association included a missense variant (N357S) at a known N-glycosylation site and a nonsense variant (Q406*) that removes a glycophosphatidylinositol (GPI) anchor from the resulting protein. These variants suggest that improper membrane trafficking of HYAL2 influences platelet reactivity. We also observed suggestive associations of AR (p = 7.39×10-6) and MAPRE1 (p = 7.26×10-6) with ADP-induced reactivity. Our study demonstrates that gene-based tests and other grouping strategies of rare variants are powerful approaches to detect associations in population-based analyses of complex traits not detected by single variant tests and possible new genetic influences on platelet reactivity.

Platelet-Related Variants Identified by Exomechip Meta-analysis in 157,293 Individuals.

Platelet production, maintenance, and clearance are tightly controlled processes indicative of platelets' important roles in hemostasis and thrombosis. Platelets are common targets for primary and secondary prevention of several conditions. They are monitored clinically by complete blood counts, specifically with measurements of platelet count (PLT) and mean platelet volume (MPV). Identifying genetic effects on PLT and MPV can provide mechanistic insights into platelet biology and their role in disease. Therefore, we formed the Blood Cell Consortium (BCX) to perform a large-scale meta-analysis of Exomechip association results for PLT and MPV in 157,293 and 57,617 individuals, respectively. Using the low-frequency/rare coding variant-enriched Exomechip genotyping array, we sought to identify genetic variants associated with PLT and MPV. In addition to confirming 47 known PLT and 20 known MPV associations, we identified 32 PLT and 18 MPV associations not previously observed in the literature across the allele frequency spectrum, including rare large effect (FCER1A), low-frequency (IQGAP2, MAP1A, LY75), and common (ZMIZ2, SMG6, PEAR1, ARFGAP3/PACSIN2) variants. Several variants associated with PLT/MPV (PEAR1, MRVI1, PTGES3) were also associated with platelet reactivity. In concurrent BCX analyses, there was overlap of platelet-associated variants with red (MAP1A, TMPRSS6, ZMIZ2) and white (PEAR1, ZMIZ2, LY75) blood cell traits, suggesting common regulatory pathways with shared genetic architecture among these hematopoietic lineages. Our large-scale Exomechip analyses identified previously undocumented associations with platelet traits and further indicate that several complex quantitative hematological, lipid, and cardiovascular traits share genetic factors.

Lean Mass and Fat Mass as Contributors to Physical Fitness in an Overweight and Obese African American Population.

OBJECTIVE: To determine the association of lean vs fat mass with fitness in healthy, overweight and obese African Americans from families with early-onset coronary disease. DESIGN: Cross-sectional study. SETTING: Baltimore, Maryland. PARTICIPANTS: 191 healthy, overweight, sedentary African Americans (69% women; aged 44.8 ± 11 years; body mass index 34 ± 5 kg/m2). MAIN OUTCOME MEASURES: Anthropometrics, smoking, blood pressure, lipids, c-reactive protein, and glucose were assessed with standard methods; body composition was determined by dual energy X-ray absorptiometry; cardiorespiratory fitness was expressed as VO(2peak) attained during a maximal treadmill test. RESULTS: In both men and women, greater lean mass was independently associated with higher VO(2peak) (P < .05) and explained > 21% of the variance in VO(2peak), adjusted for body mass index, fat mass, important covariables, and nonindependence of families. CONCLUSIONS: In this cross-sectional study, lean mass was the key determinant of cardiorespiratory fitness, independent of sex, age, and magnitude of obesity. These data provide a strong rationale for examining whether interventions that increase lean mass may also improve fitness, even among high-risk overweight and obese African Americans.

Comparison of breast cancer risk in women with and without systemic lupus erythematosus in a Medicare population.

Studies have suggested a decreased breast cancer risk in women with systemic lupus erythematosus. However, these studies enrolled younger patients identified primarily from lupus clinics. We compared the 5-year incidence of breast cancer among women with and without a diagnosis of SLE in a large population-based study of Medicare beneficiaries. We used a 20 % sample to create a cohort of 3,670,138 women from 2006 Medicare claims data with and without SLE at baseline. The study had 80 % power to detect whether the 5-year breast cancer incidence in the SLE cohort was 13 % higher or lower than the non-SLE cohort. Of the 18,423 women with SLE, 21 % were African American and 53 % were ≥65 years. The absolute age-adjusted risk for breast cancer in women with SLE was 2.23 (95 % CI 1.94-2.55) and 2.14 (95 % CI 1.96-2.34) in controls per 100 women. The overall absolute age and race adjusted incidence rate was 1.04 (95 % CI 0.90-1.21). Among women with SLE from "Others" (Hispanic, Native American, and/or Asian), the age-adjusted risk for breast cancer was 2.44 per 100 women (95 % CI 1.07-2.18), and age-adjusted incidence rate was 1.52 (95 % CI 1.07-2.18). In contrast to prior clinic-based studies, this population-based cohort study showed that the risk of breast cancer in women with SLE was not lower than in women without SLE. Women with SLE should follow routine breast cancer screening recommendations for their age group to avoid delay in diagnosis, because the presence of SLE may affect selection of early breast cancer therapies.

Genome-wide association study of platelet aggregation in African Americans.

BACKGROUND: We have previously shown that platelet aggregation has higher heritability in African Americans than European Americans. However, a genome-wide association study (GWAS) of platelet aggregation in African Americans has not been reported. We measured platelet aggregation in response to arachidonic acid, ADP, collagen, or epinephrine by optical aggregometry. The discovery cohort was 825 African Americans from the GeneSTAR study. Two replication cohorts were used: 119 African Americans from the Platelet Genes and Physiology Study and 1221 European Americans from GeneSTAR. Genotyping was conducted with Illumina 1 M arrays. For each cohort, age- and sex-adjusted linear mixed models were used to test for association between each SNP and each phenotype under an additive model. RESULTS: Six SNPs were significantly associated with platelet aggregation (P<5×10(-8)) in the discovery sample. Of these, three SNPs in three different loci were confirmed: 1) rs12041331, in PEAR1 (platelet endothelial aggregation receptor 1), replicated in both African and European Americans for collagen- and epinephrine-induced aggregation, and in European Americans for ADP-induced aggregation; 2) rs11202221, in BMPR1A (bone morphogenetic protein receptor type1A), replicated in African Americans for ADP-induced aggregation; and 3) rs6566765 replicated in European Americans for ADP-induced aggregation. The rs11202221 and rs6566765 associations with agonist-induced platelet aggregation are novel. CONCLUSIONS: In this first GWAS of agonist-induced platelet aggregation in African Americans, we discovered and replicated, novel associations of two variants with ADP-induced aggregation, and confirmed the association of a PEAR1 variant with multi-agonist-induced aggregation. Further study of these genes may provide novel insights into platelet biology.

Prospective associations of coronary heart disease loci in African Americans using the MetaboChip: the PAGE study.

BACKGROUND: Coronary heart disease (CHD) is a leading cause of morbidity and mortality in African Americans. However, there is a paucity of studies assessing genetic determinants of CHD in African Americans. We examined the association of published variants in CHD loci with incident CHD, attempted to fine map these loci, and characterize novel variants influencing CHD risk in African Americans. METHODS AND RESULTS: Up to 8,201 African Americans (including 546 first CHD events) were genotyped using the MetaboChip array in the Atherosclerosis Risk in Communities (ARIC) study and Women's Health Initiative (WHI). We tested associations using Cox proportional hazard models in sex- and study-stratified analyses and combined results using meta-analysis. Among 44 validated CHD loci available in the array, we replicated and fine-mapped the SORT1 locus, and showed same direction of effects as reported in studies of individuals of European ancestry for SNPs in 22 additional published loci. We also identified a SNP achieving array wide significance (MYC: rs2070583, allele frequency 0.02, P = 8.1 × 10(-8)), but the association did not replicate in an additional 8,059 African Americans (577 events) from the WHI, HealthABC and GeneSTAR studies, and in a meta-analysis of 5 cohort studies of European ancestry (24,024 individuals including 1,570 cases of MI and 2,406 cases of CHD) from the CHARGE Consortium. CONCLUSIONS: Our findings suggest that some CHD loci previously identified in individuals of European ancestry may be relevant to incident CHD in African Americans.

Extreme deep white matter hyperintensity volumes are associated with African American race.

BACKGROUND: African Americans (AAs) have a higher prevalence of extreme ischemic white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) than do European Americans (EAs) based on the Cardiovascular Health Study (CHS) score. Ischemic white matter disease, limited to the deep white matter, may be biologically distinct from disease in other regions and may reflect a previously observed trend toward an increased risk of subcortical lacunar infarcts in AAs. We hypothesized that extreme deep WMH volume (DWMV) or periventricular volume (PV) may also have a higher prevalence in AAs. Thus, we studied extreme CHS scores and extreme DWMV and PV in a healthy population enriched for cardiovascular disease risk factors. METHODS: We imaged the brains of 593 subjects who were first-degree relatives of probands with early onset coronary disease prior to 60 years of age. WMHs were manually delineated on 3-tesla cranial MRI by a trained radiology reader; the location and volume of lesions were characterized using automated software. DWMV and PV were measured directly with automated software, and the CHS score was determined by a neuroradiologist. Volumes were characterized as being in the upper 25% versus lower 75% of total lesion volume. Volumes in the upper versus the remaining quartiles were examined for AA versus EA race using multiple logistic regression (generalized estimating equations adjusted for family relatedness) and adjusted for major vascular disease risk factors including age ≥55 years versus <55, sex, current smoking, obesity, hypertension, diabetes and low-density lipoprotein >160 mg/dl. RESULTS: Participants were 58% women and 37% AAs, with a mean age of 51.5 ± 11.0 years (range, 29-74 years). AAs had significantly higher odds of having extreme DWMVs (odds ratio, OR, 1.8; 95% confidence interval, CI, 1.2-2.9; p = 0.0076) independently of age, sex, hypertension and all other risk factors. AAs also had significantly higher odds of having extreme CHS scores ≥3 (OR, 1.3; 95% CI, 1.1-3.6; p = 0.025). Extreme PV was not significantly associated with AA race (OR, 1.3; 95% CI, 0.81-2.1; p = 0.26). CONCLUSIONS: AAs from families with early-onset cardiovascular disease are more likely to have extreme DWMVs (a subclinical form of cerebrovascular disease) and an extreme CHS score, but not extreme PV, independently of age and other cardiovascular disease risk factors. These findings suggest that this AA population is at an increased risk for DWMV and may be at an increased risk for future subcortical stroke. Longitudinal studies are required to see if DWMV is predictive of symptomatic subcortical strokes in this population.

The association of brachial artery diameter with noncalcified coronary plaque burden in apparently healthy individuals.

OBJECTIVE: Coronary atherosclerosis has been associated with systemic arterial remodeling even in nonatherosclerotic vessels. However, it is not known whether systemic remodeling is differentially associated with the cumulative atherosclerotic process, reflected by putatively quiescent calcified plaque (CP), or with active atherosclerosis, consisting of noncalcified plaque (NCP). We thus examined the association of brachial artery diameter (BAD), an artery that does not suffer clinical atherosclerosis, with the presence and the extent of coronary CP and NCP. METHODS: We studied 688 apparently healthy, asymptomatic participants from 350 families with a history of early-onset coronary artery disease (<60 years of age) by measuring coronary artery disease risk factors and coronary plaque using dual-source computed tomographic angiography. Plaque volumes were quantified using a validated automated method. BAD was measured during diastole using B-mode ultrasound. The association of resting BAD with any detectable plaque, and log-transformed CP and NCP volumes if detectable, was tested using generalized estimating equations adjusted for age, sex, race, current smoking, diabetes, hypertension, BMI, and non-HDL and HDL cholesterol. RESULTS: Higher quintiles of BAD were associated with greater age and male sex (both P<0.001). In the fully adjusted analysis, CP volume was not associated with BAD (P=0.65) but a 1 ml greater NCP volume was associated with a 0.65 mm larger BAD (P=0.027). CONCLUSION: Our results suggest that systemic arterial remodeling of nonatherosclerotic arteries is a dynamic process that is correlated with the extent of putatively active atherosclerotic processes in distant beds but not with inactive accumulated plaque burden.

Targeted deep resequencing identifies coding variants in the PEAR1 gene that play a role in platelet aggregation.

Platelet aggregation is heritable, and genome-wide association studies have detected strong associations with a common intronic variant of the platelet endothelial aggregation receptor1 (PEAR1) gene both in African American and European American individuals. In this study, we used a sequencing approach to identify additional exonic variants in PEAR1 that may also determine variability in platelet aggregation in the GeneSTAR Study. A 0.3 Mb targeted region on chromosome 1q23.1 including the entire PEAR1 gene was Sanger sequenced in 104 subjects (45% male, 49% African American, age = 52±13) selected on the basis of hyper- and hypo- aggregation across three different agonists (collagen, epinephrine, and adenosine diphosphate). Single-variant and multi-variant burden tests for association were performed. Of the 235 variants identified through sequencing, 61 were novel, and three of these were missense variants. More rare variants (MAF<5%) were noted in African Americans compared to European Americans (108 vs. 45). The common intronic GWAS-identified variant (rs12041331) demonstrated the most significant association signal in African Americans (p = 4.020×10(-4)); no association was seen for additional exonic variants in this group. In contrast, multi-variant burden tests indicated that exonic variants play a more significant role in European Americans (p = 0.0099 for the collective coding variants compared to p = 0.0565 for intronic variant rs12041331). Imputation of the individual exonic variants in the rest of the GeneSTAR European American cohort (N = 1,965) supports the results noted in the sequenced discovery sample: p = 3.56×10(-4), 2.27×10(-7), 5.20×10(-5) for coding synonymous variant rs56260937 and collagen, epinephrine and adenosine diphosphate induced platelet aggregation, respectively. Sequencing approaches confirm that a common intronic variant has the strongest association with platelet aggregation in African Americans, and show that exonic variants play an additional role in platelet aggregation in European Americans.

Genome-wide association study for circulating levels of PAI-1 provides novel insights into its regulation.

We conducted a genome-wide association study to identify novel associations between genetic variants and circulating plasminogen activator inhibitor-1 (PAI-1) concentration, and examined functional implications of variants and genes that were discovered. A discovery meta-analysis was performed in 19 599 subjects, followed by replication analysis of genome-wide significant (P < 5 × 10(-8)) single nucleotide polymorphisms (SNPs) in 10 796 independent samples. We further examined associations with type 2 diabetes and coronary artery disease, assessed the functional significance of the SNPs for gene expression in human tissues, and conducted RNA-silencing experiments for one novel association. We confirmed the association of the 4G/5G proxy SNP rs2227631 in the promoter region of SERPINE1 (7q22.1) and discovered genome-wide significant associations at 3 additional loci: chromosome 7q22.1 close to SERPINE1 (rs6976053, discovery P = 3.4 × 10(-10)); chromosome 11p15.2 within ARNTL (rs6486122, discovery P = 3.0 × 10(-8)); and chromosome 3p25.2 within PPARG (rs11128603, discovery P = 2.9 × 10(-8)). Replication was achieved for the 7q22.1 and 11p15.2 loci. There was nominal association with type 2 diabetes and coronary artery disease at ARNTL (P < .05). Functional studies identified MUC3 as a candidate gene for the second association signal on 7q22.1. In summary, SNPs in SERPINE1 and ARNTL and an SNP associated with the expression of MUC3 were robustly associated with circulating levels of PAI-1.

Ageing, menopause, and ischaemic heart disease mortality in England, Wales, and the United States: modelling study of national mortality data.

OBJECTIVES: To use changes in heart disease mortality rates with age to investigate the plausibility of attributing women's lower heart disease mortality than men to the protective effects of premenopausal sex hormones. DESIGN: Modelling study of longitudinal mortality data with models assuming (i) a linear association between mortality rates and age (absolute mortality) or (ii) a logarithmic association (proportional mortality). We fitted models to age and sex specific mortality rates in the census years 1950 to 2000 for three birth cohorts (1916-25, 1926-35, and 1936-45). DATA SOURCES: UK Office for National Statistics and the US National Center for Health Statistics. Main outcome measure(s) Fit of models to data for England and Wales and for the US. RESULTS: For England-Wales data, proportional increases in ischaemic heart disease mortality fitted the data better than absolute increases (improvement in deviance statistics: women, 58 logarithmic units; men, 37). We identified a deceleration in male mortality after age 45 years (decreasing from 30.3% to 5.2% per age-year, P = 0.042), although the corresponding difference in women was non-significant (P = 0.43, overall trend 7.9% per age-year, P<0.001). By contrast, female breast cancer mortality decelerated significantly after age 45 years (decreasing from 19.3% to 2.6% per age-year, P<0.001). We found similar results in US data. CONCLUSIONS: Proportional age related changes in ischaemic heart disease mortality, suggesting a loss of reparative reserve, fit longitudinal mortality data from England, Wales, and the United States better than absolute age related changes in mortality. Acceleration in male heart disease mortality at younger ages could explain sex differences rather than any menopausal changes in women.

Genome-wide association study identifies a sequence variant within the DAB2IP gene conferring susceptibility to abdominal aortic aneurysm.

We performed a genome-wide association study on 1,292 individuals with abdominal aortic aneurysms (AAAs) and 30,503 controls from Iceland and The Netherlands, with a follow-up of top markers in up to 3,267 individuals with AAAs and 7,451 controls. The A allele of rs7025486 on 9q33 was found to associate with AAA, with an odds ratio (OR) of 1.21 and P = 4.6 x 10(-10). In tests for association with other vascular diseases, we found that rs7025486[A] is associated with early onset myocardial infarction (OR = 1.18, P = 3.1 x 10(-5)), peripheral arterial disease (OR = 1.14, P = 3.9 x 10(-5)) and pulmonary embolism (OR = 1.20, P = 0.00030), but not with intracranial aneurysm or ischemic stroke. No association was observed between rs7025486[A] and common risk factors for arterial and venous diseases-that is, smoking, lipid levels, obesity, type 2 diabetes and hypertension. Rs7025486 is located within DAB2IP, which encodes an inhibitor of cell growth and survival.

Genome-wide meta-analyses identifies seven loci associated with platelet aggregation in response to agonists.

Platelet function mediates both beneficial and harmful effects on human health, but few genes are known to contribute to variability in this process. We tested association of 2.5 million SNPs with platelet aggregation responses to three agonists (ADP, epinephrine and collagen) in two cohorts of European ancestry (N

Effect of obesity on platelet reactivity and response to low-dose aspirin.

Insufficient platelet function suppression by aspirin is a predictor of cardiovascular events in high-risk patients. The authors assessed the impact of obesity on platelet responsiveness before and after 2 weeks of aspirin 81 mg/d in 2014 people. Obese individuals had greater baseline platelet reactivity. Comparing obese and nonobese individuals after aspirin therapy, results for aggregometry to collagen were 6.7 vs 6.1 ohms, P=.008; aggregometry to adenosine diphosphate were 13.1 vs 11.8 ohms,P<.0001; aggregometry to arachidonic acid (AA) were 4.9% vs 8.3% nonzero aggregation, P=.002; urinary excretion of 11-dehydro-thromboxane B2 (Tx-M) were 4.9% vs 8.3% nonzero aggregation, P=.002; and aspirin resistance were 26.% vs 20.5%, P=.002; respectively. These remained significantly different for AA aggregation and Tx-M excretion after adjustment for covariates. Obese individuals have greater native platelet reactivity and retain greater reactivity after suppression by aspirin.