Genome Health Study Research Articles

Network analysis of the genomic basis of the placebo effect.

The placebo effect is a phenomenon in which patients who are given an inactive treatment (e.g., inert pill) show a perceived or actual improvement in a medical condition. Placebo effects in clinical trials have been investigated for many years especially because placebo treatments often serve as the control arm of randomized clinical trial designs. Recent observations suggest that placebo effects may be modified by genetics. This observation has given rise to the term "placebome," which refers to a group of genome-related mediators that affect an individual's response to placebo treatments. In this study, we conduct a network analysis of the placebome and identify a placebome module in the comprehensive human interactome using a seed-connector algorithm. The placebome module is significantly enriched with neurotransmitter signaling pathways and brain-specific proteins. We validate the placebome module using a large cohort of the Women's Genome Health Study (WGHS) trial and demonstrate that the placebome module is significantly enriched with genes whose SNPs modify the outcome in the placebo arm of the trial. To gain insights into placebo effects in different diseases and drug treatments, we use a network proximity measure to examine the closeness of the placebome module to different disease modules and drug target modules. The results demonstrate that the network proximity of the placebome module to disease modules in the interactome significantly correlates with the strength of the placebo effect in the corresponding diseases. The proximity of the placebome module to molecular pathways affected by certain drug classes indicates the existence of placebo-drug interactions. This study is helpful for understanding the molecular mechanisms mediating the placebo response, and sets the stage for minimizing its effects in clinical trials and for developing therapeutic strategies that intentionally engage it.

Genetic Risk, Adherence to a Healthy Lifestyle, and Coronary Disease

BackgroundBoth genetic and lifestyle factors contribute to individual-level risk of coronary artery disease. The extent to which increased genetic risk can be offset by a healthy lifestyle is unknown.MethodsUsing a polygenic score of DNA sequence polymorphisms, we quantified genetic risk for coronary artery disease in three prospective cohorts — 7814 participants in the Atherosclerosis Risk in Communities (ARIC) study, 21,222 in the Women’s Genome Health Study (WGHS), and 22,389 in the Malmö Diet and Cancer Study (MDCS) — and in 4260 participants in the cross-sectional BioImage Study for whom genotype and covariate data were available. We also determined adherence to a healthy lifestyle among the participants using a scoring system consisting of four factors: no current smoking, no obesity, regular physical activity, and a healthy diet.ResultsThe relative risk of incident coronary events was 91% higher among participants at high genetic risk (top quintile of polygenic scores) than among those at low genetic risk (bottom quintile of polygenic scores) (hazard ratio, 1.91; 95% confidence interval [CI], 1.75 to 2.09). A favorable lifestyle (defined as at least three of the four healthy lifestyle factors) was associated with a substantially lower risk of coronary events than an unfavorable lifestyle (defined as no or only one healthy lifestyle factor), regardless of the genetic risk category. Among participants at high genetic risk, a favorable lifestyle was associated with a 46% lower relative risk of coronary events than an unfavorable lifestyle (hazard ratio, 0.54; 95% CI, 0.47 to 0.63). This finding corresponded to a reduction in the standardized 10-year incidence of coronary events from 10.7% for an unfavorable lifestyle to 5.1% for a favorable lifestyle in ARIC, from 4.6% to 2.0% in WGHS, and from 8.2% to 5.3% in MDCS. In the BioImage Study, a favorable lifestyle was associated with significantly less coronary-artery calcification within each genetic risk category.ConclusionsAcross four studies involving 55,685 participants, genetic and lifestyle factors were independently associated with susceptibility to coronary artery disease. Among participants at high genetic risk, a favorable lifestyle was associated with a nearly 50% lower relative risk of coronary artery disease than was an unfavorable lifestyle. (Funded by the National Institutes of Health and others.)

Physical and neurobehavioral determinants of reproductive onset and success.

The ages of puberty, first sexual intercourse and first birth signify the onset of reproductive ability, behavior and success, respectively. In a genome-wide association study of 125,667 UK Biobank participants, we identify 38 loci associated (P < 5 × 10(-8)) with age at first sexual intercourse. These findings were taken forward in 241,910 men and women from Iceland and 20,187 women from the Women's Genome Health Study. Several of the identified loci also exhibit associations (P < 5 × 10(-8)) with other reproductive and behavioral traits, including age at first birth (variants in or near ESR1 and RBM6-SEMA3F), number of children (CADM2 and ESR1), irritable temperament (MSRA) and risk-taking propensity (CADM2). Mendelian randomization analyses infer causal influences of earlier puberty timing on earlier first sexual intercourse, earlier first birth and lower educational attainment. In turn, likely causal consequences of earlier first sexual intercourse include reproductive, educational, psychiatric and cardiometabolic outcomes.

Catechol-O-methyltransferase association with hemoglobin A1c

AimsCatecholamines have metabolic effects on blood pressure, insulin sensitivity and blood glucose. Genetic variation in catechol-O-methyltransferase (COMT), an enzyme that degrades catecholamines, is associated with cardiometabolic risk factors and incident cardiovascular disease (CVD). Here we examined COMT effects on glycemic function and type 2 diabetes. MethodsWe tested whether COMT polymorphisms were associated with baseline HbA1c in the Women's Genome Health Study (WGHS), and Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC), and with susceptibility to type 2 diabetes in WGHS, DIAbetes Genetics Replication And Meta-analysis consortium (DIAGRAM), and the Diabetes Prevention Program (DPP). Given evidence that COMT modifies some drug responses, we examined association with type 2 diabetes and randomized metformin and aspirin treatment. ResultsCOMT rs4680 high-activity G-allele was associated with lower HbA1c in WGHS (β=−0.032% [0.012], p=0.008) and borderline significant in MAGIC (β=−0.006% [0.003], p=0.07). Combined COMT per val allele effects on type 2 diabetes were significant (OR=0.98 [0.96–0.998], p=0.03) in fixed-effects analyses across WGHS, DIAGRAM, and DPP. Similar results were obtained for 2 other COMT SNPs rs4818 and rs4633. In the DPP, the rs4680 val allele was borderline associated with lower diabetes incidence among participants randomized to metformin (HR=0.81 [0.65–1.00], p=0.05). ConclusionsCOMT rs4680 high-activity G-allele was associated with lower HbA1c and modest protection from type 2 diabetes. The directionality of COMT associations was concordant with those previously observed for cardiometabolic risk factors and CVD.

Pleiotropy among Common Genetic Loci Identified for Cardiometabolic Disorders and C-Reactive Protein

Pleiotropic genetic variants have independent effects on different phenotypes. C-reactive protein (CRP) is associated with several cardiometabolic phenotypes. Shared genetic backgrounds may partially underlie these associations. We conducted a genome-wide analysis to identify the shared genetic background of inflammation and cardiometabolic phenotypes using published genome-wide association studies (GWAS). We also evaluated whether the pleiotropic effects of such loci were biological or mediated in nature. First, we examined whether 283 common variants identified for 10 cardiometabolic phenotypes in GWAS are associated with CRP level. Second, we tested whether 18 variants identified for serum CRP are associated with 10 cardiometabolic phenotypes. We used a Bonferroni corrected p-value of 1.1×10-04 (0.05/463) as a threshold of significance. We evaluated the independent pleiotropic effect on both phenotypes using individual level data from the Women Genome Health Study. Evaluating the genetic overlap between inflammation and cardiometabolic phenotypes, we found 13 pleiotropic regions. Additional analyses showed that 6 regions (APOC1, HNF1A, IL6R, PPP1R3B, HNF4A and IL1F10) appeared to have a pleiotropic effect on CRP independent of the effects on the cardiometabolic phenotypes. These included loci where individuals carrying the risk allele for CRP encounter higher lipid levels and risk of type 2 diabetes. In addition, 5 regions (GCKR, PABPC4, BCL7B, FTO and TMEM18) had an effect on CRP largely mediated through the cardiometabolic phenotypes. In conclusion, our results show genetic pleiotropy among inflammation and cardiometabolic phenotypes. In addition to reverse causation, our data suggests that pleiotropic genetic variants partially underlie the association between CRP and cardiometabolic phenotypes.

Efficient Bayesian mixed-model analysis increases association power in large cohorts.

Linear mixed models are a powerful statistical tool for identifying genetic associations and avoiding confounding. However, existing methods are computationally intractable in large cohorts, and may not optimize power. All existing methods require time cost O(MN2) (where N = #samples and M = #SNPs) and implicitly assume an infinitesimal genetic architecture in which effect sizes are normally distributed, which can limit power. Here, we present a far more efficient mixed model association method, BOLT-LMM, which requires only a small number of O(MN)-time iterations and increases power by modeling more realistic, non-infinitesimal genetic architectures via a Bayesian mixture prior on marker effect sizes. We applied BOLT-LMM to nine quantitative traits in 23,294 samples from the Women’s Genome Health Study (WGHS) and observed significant increases in power, consistent with simulations. Theory and simulations show that the boost in power increases with cohort size, making BOLT-LMM appealing for GWAS in large cohorts.

Common Genetic Variations in the Vitamin D Pathway in Relation to Blood Pressure

Vitamin D is involved in blood pressure (BP) regulation. Genetic variations may influence the effect of vitamin D on BP, but data from epidemiologic studies remain inconsistent. We conducted a comprehensive genetic association study in the Women's Genome Health Study (WGHS) with genome-wide genotype data among 23,294 women of European ancestry and in the International Consortium of Blood Pressure (ICBP) with genome-wide meta-analysis results from 69,395 men and women of European ancestry. First, we found none of 5 selected vitamin D-related candidate single nucleotide polymorphisms (SNPs) was associated with systolic BP (SBP) or diastolic BP (DBP). Second, in 61 candidate SNPs involved in vitamin D metabolism and signaling, rs1507023 (in RBFOX1) and rs2296241 (in CYP24A1) showed significant associations with SBP, DBP, mean arterial pressure, or pulse pressure in the WGHS before, but not after, multiple testing corrections. Nominally significant associations in the ICBP were also not significant after corrections. Third, among 24 candidate genes across vitamin D pathway, associations with BP traits that meet gene-wide significance level were found for NCOA3 (rs2235734), RXRA (rs875444), DHCR7 (rs1790370), VDR (rs2544037), and NCOR2 (rs1243733, rs1147289) in the WGHS and NCOR1, TP53BP1, and TYRP1 in the ICBP. However, none of these associations reached significance threshold in both studies. Our study did not replicate previously observed associations of vitamin D-related SNPs with BP. There was suggestive evidence for associations in other vitamin D pathway genes; however, these associations either did not reach the significance threshold or were not replicated.

Abstract P257: Common Genetic Variations in the Vitamin D Pathway in Relation to Blood Pressure

Background: Vitamin D is involved in the regulation of blood pressure (BP) through multiple mechanisms. Genetic variation may influence the effect of vitamin D on BP, but data from epidemiologic studies remain limited. Methods: We conducted a comprehensive genetic association study to investigate the variants in an expanded vitamin D metabolism and signaling pathway in relation to BP. Analyses were conducted in the Women’s Genome Health Study (WGHS) with genome-wide genotype data among 23,294 women of European ancestry and in the International Consortium of Blood Pressure (ICBP) with published genome-wide meta-analysis results from 69,395 men and women of European ancestry. Results: Analyses were conducted in three stages. First, among 5 candidate single-nucleotide polymorphisms (SNPs) in the vitamin D related genes that were previously found associated with BP, none was associated with systolic (SBP) or diastolic BP (DBP) in the WGHS or ICBP. Second, in an expanded set of 61 SNPs involved in vitamin D metabolism and signaling pathway, rs1507023 (in RBFOX1 ) and rs2296241 (in CYP24A1 ) showed nominally significant associations with SBP, DBP, mean arterial pressure (MAP), or pulse pressure (PP) in the WGHS, but the associations were no longer significant after correction for multiple hypothesis testing. Similarly, nominally significant associations found in the ICBP were also not significant after multiple testing corrections. Third , among 24 candidate genes across the vitamin D pathway, associations with BP traits that meet gene-wide significance level (gene-based empirical p&lt;0.05) were found in the WGHS for NCOA3 (rs2235734), RXRA (rs875444), DHCR7 (rs1790370), VDR (rs2544037), and NCOR2 (rs1243733 and rs1147289). Similar gene-wide significant associations (gene-based p&lt;0.05) with SBP or DBP were found in the ICBP for NCOR1 , TP53BP1 and TYRP1 . After further correction for number of genes in the pathway, however, only the association of TYRP1 with SBP in the ICBP reached significance threshold. Further, the WGHS observed associations were not replicated in the ICBP, and vice versa. Conclusions: Our study in large samples of Caucasian population did not replicate several previously observed associations of candidate SNPs in the vitamin D pathway with BP. However, we found suggestive evidence for associations of other vitamin D pathway gene variants with BP traits. Future studies are needed to replicate our findings.

Abstract 04: Fried Food Consumption and Genetic Predisposition to Obesity

Background: Fried food consumption has been associated with obesity; little is known about whether genetic background modifies this association. Methods: We analyzed interactions between a genetic risk score (GRS) based on 32 BMI-associated variants and fried food consumption on body mass index (BMI) and obesity in 9623 women from the Nurses’ Health Study (NHS) and 6379 men from the Health Professionals Follow-up Study (HPFS) and in a replication cohort of 21426 women from the Women’s Genome Health Study (WGHS). Results: An interaction between fried food consumption and the GRS on BMI was identified in both NHS and HPFS (P for interaction≤0.001). Among participants in the highest tertile of the GRS, the differences in BMI between individuals who consumed fried foods ≥4times/week and those consumed &lt;1time/week amounted to 1.0 in women and 0.7 kg/m2 in men, whereas the corresponding differences were 0.5 and 0.4 kg/m2 in the lowest tertile of the GRS. The gene-diet interaction was replicated in the WGHS (P for interaction&lt;0.001). Viewed differently, the genetic association with adiposity was strengthened with higher consumption of fried foods. In the combined three cohorts, the differences in BMI per 10 risk alleles were 1.2, 1.6, and 2.4 kg/m2 for fried food consumption&lt;1, 1-3 and ≥4times/week (P for interaction&lt;0.001) (Figure); and the odds ratios (95% CI) for obesity per 10 risk alleles were 1.60 (1.38-1.84), 2.13 (1.74-2.60) and 2.65 (2.08-3.39) across the three categories of consumption (P for interaction=0.002). In addition, we found that the individual variants in genes highly expressed or known to act in the central nervous system showed significant interactions, with the FTO variant showing the strongest result (P for interaction&lt;0.001). Conclusion: Fried food consumption may interact with genetic background in relation to obesity, highlighting the particular importance of reducing fried food consumption in individuals genetically predisposed to obesity.

Fried food consumption, genetic risk, and body mass index: gene-diet interaction analysis in three US cohort studies

Objective To examine the interactions between genetic predisposition and consumption of fried food in relation to body mass index (BMI) and obesity.Design Prospective cohort study.Setting Health professionals in the United...

Gene variations of ROCKs and risk of ischaemic stroke: the Women's Genome Health Study

Recent animal and human studies have demonstrated the importance of the ROCK (RhoA/Rho-associated kinase) pathway in IsST (ischaemic stroke). Whether the genetic variation within ROCK-associated genes modulates the risk of IsST remains elusive. The association between 66 tSNPs [tagging SNPs (single nucleotide polymorphisms)] of three ROCK-associated genes [ROCK1, ROCK2 and ARHGEF10 (Rho guanine-nucleotide-exchange factor 10)] and the incidence of IsST was investigated in 23294 Caucasian female participants of the prospective WGHS (Women's Genome Health Study). All were free of known cancer and cardiovascular disease at baseline. During a 15-year follow-up period, 323 participants developed their first ever IsST. Multivariable Cox regression analysis was performed to investigate the relationship between genotypes and risk of IsST assuming an additive genetic model. Haplotype-block analysis was also performed. A total of ten tSNPs were associated with the risk of IsST (three in ARHGEF10 and seven in ROCK1; P<0.050). Further investigation using the haplotype-block analysis revealed a similar significant association of pre-specified haplotypes of ROCK1 with the risk of IsST (P=0.005). If corroborated in other large prospective studies, the findings of the present study suggest that genetic variation within the ROCK-associated pathway gene loci examined, and in particular ROCK1 gene variation, may influence the risk of IsST.

PRDM16 rs2651899 Variant Is a Risk Factor for Chinese Common Migraine Patients

Recent genome-wide association studies (GWAS) have identified 3 loci in or near PRDM16 (1p36.32, rs2651899), LRP1 (12q13.3, rs11172113) and TRPM8 (2q37.1, rs10166942) in the population-based Women's Genome Health Study (WGHS) of migraine, and 2 loci in or near TRPM8 and LRP1 were repeated in European GWAS study. To evaluate whether the same variants are related to migraine in Chinese population, we investigated migraine with aura (MA) and migraine without aura (MO) patients of Chinese Han ethnicity in mainland China. A case-control study in a cohort of 207 migraine cases and 205 ethnically matched controls was conducted by using the dual-color fluorescence resonance energy transfer (FRET) probes analysis. The genotypes of all polymorphisms in 2 groups followed the Hardy-Weinberg equilibrium. We found significant differences in allele distribution of rs2651899 variant in PRDM16 between MO patients and control subjects (P = .049, OR = 1.335, 95%CI 1.001-1.782), and there were no difference between MA patients and controls in the frequency of genotype and allele. Also, no significant differences in genotypic and allelic distributions between MA or MO patients and controls were observed in the polymorphisms of rs10166942 of TRPM8 and rs11172113 of LRP1, and there was no significant difference comparing male with female in all loci. Our data suggested that rs2651899 variant in PRDM16 plays a potential role in Chinese MO migraine susceptibility, and gender may not play a role.

Physical Activity, Genes for Physical Fitness, and Risk of Coronary Heart Disease

Both physical activity and physical fitness are associated with decreased coronary heart disease (CHD) risk. Our objective was to determine whether genes associated with physical fitness modify the association between physical activity and CHD. We conducted a prospective cohort study among 23,016 initially healthy women in the Women's Genome Health Study. Leisure time physical activity was reported at entry and during follow-up. A total of 58 single nucleotide polymorphisms associated with physical fitness were identified from published literature and summed to create four separate genetic scores related to phenotypes of endurance, muscle strength, V˙O2max, and overall fitness. During a median of 14.4 yr, 320 incident CHD events occurred. Increased physical activity was associated with lower CHD risk in multivariable-adjusted models (P = 0.0008). Independent of physical activity, only muscle strength genetic score was inversely associated with CHD risk (P = 0.05). There was no evidence that the inverse relation between physical activity and CHD was modified by any of the genetic scores for physical fitness. For overall fitness genetic score, the hazard ratio (HR) per 500 kcal·wk of physical activity was 0.85 (95% confidence interval [CI] = 0.72-1.00) in the highest quartile of genetic score and 0.79 (95% CI = 0.67-0.92) in the lowest quartile (P, interaction = 0.50). For V˙O2max genetic score, the HR was 0.86 (95% CI = 0.72-1.02) and 0.84 (95% CI = 0.72-0.98), respectively (P, interaction = 0.59). In this large prospective cohort of women, genes associated with physical fitness did not modify the inverse association between physical activity and CHD risk.

Sugar-Sweetened Beverages and Genetic Risk of Obesity

The worldwide obesity epidemic has been largely attributed to marked changes in diet and lifestyle in the last 3 decades. Strong evidence from numerous studies supports a positive association between increased consumption of sugar-sweetened beverages and the risk of obesity. It is unclear whether increased intake of such beverages is associated with a genetic predisposition to adiposity. Large-scale genome-wide association studies have identified 32 loci within the genome associated with the body mass index (BMI). This longitudinal cohort study was designed to test the hypothesis that high intake of sugar-sweetened beverages is associated with a genetic predisposition for obesity. Prospective data were obtained for 6934 women enrolled in the Nurses’ Health Study (NHS) and for 4423 men from the Health Professionals Follow-up Study (HPFS), and also for 21,740 women enrolled in a replication cohort, the Women’s Genome Health Study (WGHS). The interaction between the intake of sugar-sweetened beverages and BMI was analyzed. The genetic predisposition score was calculated on the basis of the 32 loci previously shown to have an established association with BMI. The difference in BMI for each increment of 10 risk alleles was stratified according to 4 categories of beverage intake (<1 serving per month, 1–4 servings per month, 2–6 servings per week, and ≥1 servings per day). The genetic association with BMI in the NHS and HPFS cohorts was stronger in participants with a higher intake of sugar-sweetened beverages than in those with a lower intake. The pooled data in the 2 cohorts showed that the relative risk (RR) of genetic predisposition according to increased BMI for an increment of 10 risk alleles was 1.00 for an intake of less than 1 serving per month, 1.20 for 1 to 4 servings per month, 1.37 for 2 to 6 servings per week, and 1.85 for 1 or more servings per day (P < 0.001 for interaction). Using the same categories of beverage intake, the RR of incident obesity per increment of 10 risk alleles was 1.19 (95% confidence interval [CI], 0.90–1.59), 1.67 (95% CI, 1.28–2.16), 1.58 (95% CI, 1.01–2.47), and 5.06 (95% CI, 1.66–15.5) (P = 0.02 for interaction). Similar results were found in the WGHS cohort. In that cohort, the RR of incident obesity per increment of 10 risk alleles was 1.40 (95% CI, 1.19–1.64), 1.50 (95% CI, 1.16–1.93), 1.54 (95% CI, 1.21–1.94), and 3.16 (95% CI, 2.03–4.92) (P = 0.007 for interaction). These findings suggest that greater intake of sugar-sweetened beverages is associated with a more pronounced genetic predisposition to elevated BMI and obesity risk.

Genetic variation of fifteen folate metabolic pathway associated gene loci and the risk of incident head and neck carcinoma: The Women's Genome Health Study

ObjectiveRecent studies have demonstrated the importance of folate metabolic pathway (FMP) in the pathogenesis of head and neck carcinoma (HNC). Whether the genetic variation within the FMP associated genes modulates HNC remains elusive. To date, prospective, epidemiological data on the relationship of FMP gene variation with the risk of HNC are sparse. MethodsThe association between 203 tag-SNPs (tSNPs) of 15 FMP associated genes (CBS, BHMT, DHFR, FOLR1, FOLR2, FOLR3, MTHFR, MTR, MTRR, MTHFD1, RFC1, SHMT1, SLC19A1, TCN2, and TYMS) and incident HNC was investigated in 23,294 Caucasian female participants of the prospective Women's Genome Health Study. All were free of known cancer at baseline. During a 15-year follow-up period, 55 participants developed a first ever HNC. Multivariable Cox regression analysis was performed to investigate the relationship between genotypes and HNC risk assuming an additive genetic model. Haplotype-block analysis was also performed. ResultsA total of 11 tSNPs within DHFR, MTHFR, RFC1, and TYMS were associated with HNC risk (all p-uncorrected <0.050). Further investigation using the haplotype-block analysis revealed an association of several prespecified haplotypes of RFC1 with HNC risk (all p-uncorrected <0.050). ConclusionIf corroborated in other large prospective studies, the present findings suggest that genetic variation within the folate metabolic pathway gene loci examined, in particular, the replication factor C-1 (RFC1) gene variation may influence HNC risk.

Sugar-Sweetened Beverages and Genetic Risk of Obesity

BackgroundTemporal increases in the consumption of sugar-sweetened beverages have paralleled the rise in obesity prevalence, but whether the intake of such beverages interacts with the genetic predisposition to adiposity is unknown.MethodsWe analyzed the interaction between genetic predisposition and the intake of sugar-sweetened beverages in relation to body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) and obesity risk in 6934 women from the Nurses' Health Study (NHS) and in 4423 men from the Health Professionals Follow-up Study (HPFS) and also in a replication cohort of 21,740 women from the Women's Genome Health Study (WGHS). The genetic-predisposition score was calculated on the basis of 32 BMI-associated loci. The intake of sugar-sweetened beverages was examined prospectively in relation to BMI.ResultsIn the NHS and HPFS cohorts, the genetic association with BMI was stronger among participants with higher intake of sugar-sweetened beverages than among those with lower intake. In the combined cohorts, the increases in BMI per increment of 10 risk alleles were 1.00 for an intake of less than one serving per month, 1.12 for one to four servings per month, 1.38 for two to six servings per week, and 1.78 for one or more servings per day (P<0.001 for interaction). For the same categories of intake, the relative risks of incident obesity per increment of 10 risk alleles were 1.19 (95% confidence interval [CI], 0.90 to 1.59), 1.67 (95% CI, 1.28 to 2.16), 1.58 (95% CI, 1.01 to 2.47), and 5.06 (95% CI, 1.66 to 15.5) (P=0.02 for interaction). In the WGHS cohort, the increases in BMI per increment of 10 risk alleles were 1.39, 1.64, 1.90, and 2.53 across the four categories of intake (P=0.001 for interaction); the relative risks for incident obesity were 1.40 (95% CI, 1.19 to 1.64), 1.50 (95% CI, 1.16 to 1.93), 1.54 (95% CI, 1.21 to 1.94), and 3.16 (95% CI, 2.03 to 4.92), respectively (P=0.007 for interaction).ConclusionsThe genetic association with adiposity appeared to be more pronounced with greater intake of sugar-sweetened beverages. (Funded by the National Institutes of Health and others.)

An X chromosome association scan of the Norfolk Island genetic isolate provides evidence for a novel migraine susceptibility locus at Xq12.

Migraine is a common and debilitating neurovascular disorder with a complex envirogenomic aetiology. Numerous studies have demonstrated a preponderance of women affected with migraine and previous pedigree linkage studies in our laboratory have identified susceptibility loci on chromosome Xq24-Xq28. In this study we have used the genetic isolate of Norfolk Island to further analyse the X chromosome for migraine susceptibility loci.An association approach was employed to analyse 14,124 SNPs spanning the entire X chromosome. Genotype data from 288 individuals comprising a large core-pedigree, of which 76 were affected with migraine, were analysed. Although no SNP reached chromosome-wide significance (empirical α = 1×10−5) ranking by P-value revealed two primary clusters of SNPs in the top 25. A 10 SNP cluster represents a novel migraine susceptibility locus at Xq12 whilst a 11 SNP cluster represents a previously identified migraine susceptibility locus at Xq27. The strongest association at Xq12 was seen for rs599958 (OR = 1.75, P = 8.92×10−4), whilst at Xq27 the strongest association was for rs6525667 (OR = 1.53, P = 1.65×10−4). Further analysis of SNPs at these loci was performed in 5,122 migraineurs from the Women’s Genome Health Study and provided additional evidence for association at the novel Xq12 locus (P<0.05).Overall, this study provides evidence for a novel migraine susceptibility locus on Xq12. The strongest effect SNP (rs102834, joint P = 1.63×10−5) is located within the 5′UTR of the HEPH gene, which is involved in iron homeostasis in the brain and may represent a novel pathway for involvement in migraine pathogenesis.

Genetic Determinants of Cardiovascular Events among Women with Migraine: A Genome-Wide Association Study

BackgroundMigraine is associated with an increased risk for cardiovascular disease (CVD). Both migraine and CVD are highly heritable. However, the genetic liability for CVD among migraineurs is unclear.MethodsWe performed a genome-wide association study for incident CVD events during 12 years of follow-up among 5,122 migraineurs participating in the population-based Women's Genome Health Study. Migraine was self-reported and CVD events were confirmed after medical records review. We calculated odds ratios (OR) and 95% confidence intervals (CI) and considered a genome-wide p-value <5×10−8 as significant.ResultsAmong the 5,122 women with migraine 164 incident CVD events occurred during follow-up. No SNP was associated with major CVD, ischemic stroke, myocardial infarction, or CVD death at the genome-wide level; however, five SNPs showed association with p<5×10−6. Among migraineurs with aura rs7698623 in MEPE (OR = 6.37; 95% CI 3.15–12.90; p = 2.7×10−7) and rs4975709 in IRX4 (OR = 5.06; 95% CI 2.66–9.62; p = 7.7×10−7) appeared to be associated with ischemic stroke, rs2143678 located close to MDF1 with major CVD (OR = 3.05; 95% CI 1.98–4.69; p = 4.3×10−7), and the intergenic rs1406961 with CVD death (OR = 12.33; 95% CI 4.62–32.87; p = 5.2×10−7). Further, rs1047964 in BACE1 appeared to be associated with CVD death among women with any migraine (OR = 4.67; 95% CI 2.53–8.62; p = 8.0×10−7).ConclusionOur results provide some suggestion for an association of five SNPs with CVD events among women with migraine; none of the results was genome-wide significant. Four associations appeared among migraineurs with aura, two of those with ischemic stroke. Although our population is among the largest with migraine and incident CVD information, these results must be treated with caution, given the limited number of CVD events among women with migraine and the low minor allele frequencies for three of the SNPs. Our results await independent replication and should be considered hypothesis generating for future research.

Genetic variants of 11 telomere-pathway gene loci and the risk of incident type 2 diabetes mellitus: The Women's Genome Health Study

ObjectiveLeukocyte telomere length shortening has recently been associated with type 2 diabetes mellitus (T2D). Whether this observation was modulated by genetic variation within the telomere-pathway genes remains elusive. To date, no prospective epidemiological data on the relationship of telomere-pathway gene variation with T2D are available. MethodsThe association between 150 tagging-SNPs (tSNPs) of 11 telomere-pathway genes (TERC, UCP1, TERT, POT1, TNKS, TERF1, TNKS2, TEP1, ACD, TERF2 and TERF2IP) and incident T2D was investigated in 22,715 Caucasian female participants of the prospective Women's Genome Health Study. All were free of known cardiovascular disease, cancer and diabetes at baseline. During a 13-year follow-up period, 1445 participants developed an incident T2D. Multivariable Cox regression analysis was performed to investigate the relationship between genotypes and T2D risk assuming an additive genetic model. Haplotype block analysis was also performed. ResultsA total of eleven tSNPs within TERF1, TNKS, TEP1, ACD, and TERF2 were associated with T2D risk (all p-uncorrected <0.050). Further investigation using the haplotype-block analysis again revealed an association of several prespecified haplotypes of TERF1, and TEP1 with T2D risk (all p-uncorrected <0.040). ConclusionIf corroborated in other prospective studies, the present findings suggest that genetic variation within the telomere-pathway gene loci examined may be useful predictor for T2D risk assessment.

Genome-Wide Association Study of Relative Telomere Length

Telomere function is essential to maintaining the physical integrity of linear chromosomes and healthy human aging. The probability of forming proper telomere structures depends on the length of the telomeric DNA tract. We attempted to identify common genetic variants associated with log relative telomere length using genome-wide genotyping data on 3,554 individuals from the Nurses' Health Study and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial that took part in the National Cancer Institute Cancer Genetic Markers of Susceptibility initiative for breast and prostate cancer. After genotyping 64 independent SNPs selected for replication in additional Nurses' Health Study and Women's Genome Health Study participants, we did not identify genome-wide significant loci; however, we replicated the inverse association of log relative telomere length with the minor allele variant [C] of rs16847897 at the TERC locus (per allele β = −0.03, P = 0.003) identified by a previous genome-wide association study. We did not find evidence for an association with variants at the OBFC1 locus or other loci reported to be associated with telomere length. With this sample size we had >80% power to detect β estimates as small as ±0.10 for SNPs with minor allele frequencies of ≥0.15 at genome-wide significance. However, power is greatly reduced for β estimates smaller than ±0.10, such as those for variants at the TERC locus. In general, common genetic variants associated with telomere length homeostasis have been difficult to detect. Potential biological and technical issues are discussed.