Gene-environment interaction for hypertension among African American women across generations

Single-nucleotide polymorphisms in genes associated with the vitamin D pathway related to clinical and therapeutic outcomes of American tegumentary leishmaniasis

Background

The vitamin D pathway contributes to the microbicidal activity of macrophages against Leishmania infection. In addition to induction of this pathway, interferon-gamma (IFNγ), interleukin (IL)-15, and IL32γ are part of a network of pro-inflammatory cytokines. The aim of this study was to evaluate single-nucleotide polymorphisms (SNPs) in the components of the vitamin D pathway and associated cytokine genes that could be related to resistance or susceptibility to American tegumentary leishmaniasis (ATL).

Methods

The expressions of IFNG, IL15, IL32, CYP27B1, VDR, and other pro-inflammatory cytokines TNF, IL6, and IL17 genes were evaluated using real-time polymerase chain reaction (qPCR) in lesions of patients with localized cutaneous leishmaniasis (LCL) or mucosal leishmaniasis (ML). SNP genotypes/alleles (in IL15, IL32, CYP27B1, and VDR) were evaluated by TaqMan PCR assays using DNA from the blood of patients and healthy individuals. Serum vitamin D levels were determined by chemiluminescence.

Results

Vitamin D pathway-associated genes were expressed in cutaneous as well as mucosal lesions. IFNG, IL6, and IL17 were more highly expressed in ML than in LCL. In contrast, IL32γ/CYP27B1/VDR mRNAs were mainly correlated in LCL, and IL32γ in ML makes strong connections with all cytokines. The SNP IL32 rs1555001 was less frequent in patients with ML. In addition, some SNPs appear to influence the VDR and CYP27B1 (IL15 rs10519613 and IL15 rs3775597) and IL6 (VDR rs7975232) expressions in LCL and the IL17 expression in ML (IL15 rs3775597). Gene expression was also correlated with clinical parameters, such as number of lesions (CYP27B1 mRNA) and treatment failure (VDR mRNA). In addition, one SNP was associated with treatment failure in ML (VDR rs7975232).

Conclusions

Our findings suggested that some SNPs in the vitamin D pathway-associated genes can be related to resistance and therapeutic outcomes of ATL. They are promising candidates that need to be further evaluated to understand their biological effects in the control or immunopathogenesis of ATL.

Effect of interaction between occupational stress and polymorphisms of MTHFR gene and SELE gene on hypertension

BACKGROUND

Gene-environment interaction is related to the prevalence of hypertension, but the impact of genetic polymorphisms on hypertension may vary due to different geography and population.

OBJECTIVE

To explore the impact of the interaction among occupational stress and MTHFR gene and SELE gene polymorphism on the prevalence of hypertension in Xinjiang oil workers.

METHODS

A case-control study was conducted on 310 oil workers. In an oilfield base in Karamay City, Xinjiang, 155 hypertensive patients aged 18~60 years old with more than one year of service were selected as the case group, and 155 oil workers without hypertension were selected as the control group according to the 1:1 matching principle (matching conditions: the gender and shift were the same. The age is around 2 years old). The Occupational Stress Scale was used to evaluate the degree of occupational stress, PCR technique was used to detect MTHFR and SELE gene polymorphism, Logistic regression analysis was used to analyze the effects of gene and occupational stress on hypertension, and gene-gene and gene-environment interactions were analyzed by generalized multi-factor dimension reduction method.

RESULTS

The G98T polymorphism of SELE gene (χ² = 6.776, P = 0.034), the C677T (χ² = 7.130, P = 0.028) and A1298C (χ² = 12.036, P = 0.002) loci of MTHFR gene and the degree of occupational stress (χ² = 11.921, P = 0.003) were significantly different between the case group and the control group. The genotypes GT at the G98T polymorphism of the SELE gene (OR = 2.151, 95% CI [1.227-3.375]), and the dominant model (AC/CC vs AA, OR = 1.925, 95% CI [1.613-3.816]); AC and CC at the A1298C polymorphism of the MTHFR gene (OR _AC = 1.917, 95% CI [1.064-3.453]; OR _CC = 2.233, 95% CI [1.082-4.609]), the additive model (CC vs AA, OR = 2.497, 95% CI [1.277-4.883]) and the dominant model (AC/CC vs AA, OR = 2.012, 95% CI [1.200-3.373]); at the C677T polymorphism of the MTHFR gene CT and TT (OR _CT = 1.913, 95% CI [1.085-3.375]; OR _TT = 3.117, 95% CI [1.430-6.795]), the additive model (CC vs AA, OR = 1.913, 95% CI [1.085-3.375]) and the dominant model (AC/CC vs AA, OR = 2.012, 95% CI [1.200-3.373]), which could increase hypertension risk (P < 0.05). The gene-gene interaction showed that there was a positive interaction between the A1298C and C677T sites of the MTHFR gene, and the gene-occupational stress interaction showed that there was a positive interaction between the A1298C and C677T sites of the MTHFR gene and the occupational stress.

CONCLUSION

The interaction of gene mutation and occupational stress in Xinjiang oil workers maybe increase the risk of hypertension.

Prevalence and determinants of blood pressure variability in pygmies of Southern region Cameroon

INTRODUCTION

The impact of urbanization and living conditions on the prevalence of hypertension in the Cameroonian population is poorly known.

AIM

To evaluate the prevalence and determinants of blood pressure (BP) in adult Pygmies and Bantus living in urban and rural areas of Southern Cameroon.

PARTICIPANTS AND METHODS

This was a cross-sectional comparative study of 406 adults (96 urban Bantus, 100 urban Pygmies, 111 rural Bantus and 99 tropical rainforest Pygmies with a traditional Pygmies way of life), recruited in Southern Cameroon (mean age 42 ± 17 years; 56.7% women). Sociodemographic, anthropometric and BP parameters were collected. Hypertension was defined as BP at least 140/90 mmHg and/or use of BP-lowering drug(s).

RESULTS

The age-standardized prevalence of hypertension in urban Bantus, rural Bantus, urban Pygmies and traditional Pygmies was 18.0, 13.5, 9.3 and 4.1%, respectively. Mean SBP and DBP differed significantly according to Bantu vs. Pygmy ethnicity, and urban vs. rural residency. After multiple adjustments, mean arterial pressure was significantly associated with age, BMI, Bantu ancestry and urban residency.

CONCLUSION

Bantu ethnicity and urban residency are significantly associated with high-BP among people from Southern Cameroon.

Genetic Basis of Blood-Based Traits and Their Relationship With Performance and Environment in Beef Cattle at Weaning

The objectives of this study were to explore the usefulness of blood-based traits as indicators of health and performance in beef cattle at weaning and identify the genetic basis underlying the different blood parameters obtained from complete blood counts (CBCs). Disease costs represent one of the main factors determining profitability in animal production. Previous research has observed associations between blood cell counts and an animal’s health status in some species. CBC were recorded from approximately 570 Angus based, crossbred beef calves at weaning born between 2015 and 2016 and raised on toxic or novel tall fescue. The calves (N = ∼600) were genotyped at a density of 50k SNPs and the genotypes (N = 1160) were imputed to a density of 270k SNPs. Genetic parameters were estimated for 15 blood and 4 production. Finally, with the objective of identifying the genetic basis underlying the different blood-based traits, genome-wide association studies (GWAS) were performed for all traits. Heritability estimates ranged from 0.11 to 0.60, and generally weak phenotypic correlations and strong genetic correlations were observed among blood-based traits only. Genome-wide association study identified ninety-one 1-Mb windows that accounted for 0.5% or more of the estimated genetic variance for at least 1 trait with 21 windows overlapping across two or more traits (explaining more than 0.5% of estimated genetic variance for two or more traits). Five candidate genes have been identified in the most interesting overlapping regions related to blood-based traits. Overall, this study represents one of the first efforts represented in scientific literature to identify the genetic basis of blood cell traits in beef cattle. The results presented in this study allow us to conclude that: (1) blood-based traits have weak phenotypic correlations but strong genetic correlations among themselves. (2) Blood-based traits have moderate to high heritability. (3) There is evidence of an important overlap of genetic control among similar blood-based traits which will allow for their use in improvement programs in beef cattle.

Omics for Nurse Scientists Conducting Environmental Health Research

Nurse scientists are ideally positioned to perform environmental health research and it is critical that the role of omics in the complex relationships between environmental exposures and an individual's unique physiology in human health outcomes be appreciated. Importantly, omics can offer nurse scientists a tool to measure exposure, demonstrate molecular phenotypic changes associated with exposure, and potentially uncover mechanisms of exposure-related disease or negative health outcomes. The purpose of this summary is to serve as an overview of omics methodologies for nurse scientists conducting environmental health research and provides future directions of this work as well as exemplar funding opportunities that demonstrate the growing need and interest in this area. The intersection of nursing and exposure science will accelerate the work in environmental health and bring forth translation of research findings into clinical and community practice. Importantly, this information can better help us understand the variation in response to the environment and support environmental health policy change at the local, state, and federal level to improve community health and well-being.

mRNA expression profile in peripheral blood mononuclear cells based on ADRB1 Ser49Gly and Arg389Gly polymorphisms in essential hypertension - a case-control pilot investigation in South Indian population

BACKGROUND

β1-Adrenoreceptor (ADRB1) genetic polymorphisms are widely studied for susceptibility to many cardiovascular diseases such as essential hypertension. However, the mRNA expression of ADRB1 is rarely studied.

METHODS

A case-control pilot study with 292 hypertensives and 324 controls was designed to evaluate the role of the Ser49Gly and Arg389Gly, which are commonly studied single nucleotide polymorphisms (SNP), in the mRNA levels of ADRB1, in conjunction with its genetic predisposition to essential hypertension.

RESULTS

Differential expression of ADRB1 mRNA was seen between hypertensives and controls (p<0.01) based on genetic variants of Ser49Gly. Among hypertensive subjects, Ser49Ser and Gly49Gly were highly expressed in comparison to Ser49Gly (p<0.05 and p<0.01, respectively), whereas genetic variants of Arg389Gly did not demonstrate any such variations. We found no association between the ADRB1 SNPs viz., Ser49Gly and Arg389Gly and essential hypertension.

CONCLUSIONS

The increased mRNA levels of Gly49Gly may indicate a plausible role in the interindividual variations in drug response. Further, ADRB1 polymorphisms did not contribute to the genetic risk of essential hypertension. Studies with larger sample size are warranted to confirm these observations in the South Indian population.

Joint Influence of SNPs and DNA Methylation on Lipids in African Americans From Hypertensive Sibships

INTRODUCTION

Plasma concentrations of lipids (i.e., total cholesterol, high-density cholesterol, low-density cholesterol, and triglycerides) are amenable to therapeutic intervention and remain important factors for assessing risk of cardiovascular diseases. Some of the observed variability in serum lipid concentrations has been associated with genetic and epigenetic variants among cohorts with European ancestry (EA). Serum lipid levels have also been associated with genetic variants in multiethnic populations.

METHODS

The purpose of this study was to determine whether single-nucleotide polymorphisms (SNPs) and DNA methylation (DNAm) differences contribute to lipid variation among African Americans ([AAs], N = 739) in the Genetic Epidemiology Network of Arteriopathy (GENOA) study.

RESULTS

Previous meta-analyses identified 161 SNPs that are associated with lipid traits in populations of EA. We evaluated these SNPs and 66 DNAm sites within the genes containing the SNPs in the GENOA cohort using linear mixed-effects modeling. We did not identify any significant associations of SNPs or DNAm with serum lipid levels. These results suggest that the SNPs identified as being significant for lipid levels through the EA genome-wide association studies may not be significant across AA populations.

CONCLUSIONS

Reductions in morbidity and mortality due to variation in lipids among AAs may be achieved through a better understanding of the genetic and epigenetic factors associated with serum lipid levels for early and appropriate screening. Further large-scale studies specifically within AA and other non-EA populations are warranted.

The Metabolic Syndrome and Its Components in African-American Women: Emerging Trends and Implications

The Metabolic Syndrome (MetS) is recognized as a predictor of cardiovascular outcomes and type 2 diabetes (T2DM). The MetS is a constellation of clinical and metabolic risk factors that include abdominal obesity, dyslipidemia, glucose intolerance, and hypertension. There are ethnic and racial differences in the prevalence of MetS and its components. In general, African-Americans have lower prevalence of MetS when compared to whites, but suffer disproportionately from higher cardiovascular mortality and T2DM. Specifically, African-American women (AAW) have higher rates of T2DM and cardiovascular mortality despite a more favorable lipid and lipoprotein profile. This is paradoxical. However, there is a general upward trend in the prevalence of MetS in the US. The reasons are debatable, but could be multifactorial, including genetics and environmental factors. Thus, there is a need to understand the increasing trend in the MetS, its components, and the associated outcomes for AAW. Therefore, the purpose of this mini review is to (1) understand the increasing prevalence of MetS and its components in AAW and (2) provide suggestions for future prevention of cardiovascular disease and T2DM in AAW.

Genotype-Based Epigenetic Differences in Monozygotic Twins Discordant for Positive Antithyroglobulin Autoantibodies

Background: Epigenetic factors associated with the development of autoimmune diseases are unclear. Monozygotic twin pairs discordant for positive antithyroglobulin autoantibodies (TgAb) are useful to examine the epigenetic factors because of their identical genetic background. This study aimed to clarify the discordant epigenetic differences affecting the development of TgAb. Methods: Subjects were selected from 257 Japanese monozygotic twins, recruited from the registry established by the Center for Twin Research at Osaka University. TgAb positive concordant (PC) pairs were 5.7% (four pairs) and 9.6% (18 pairs) of male and female pairs, respectively. TgAb discordant (DC) pairs were 11.4% (eight pairs) and 8.0% (15 pairs) of male and female pairs, respectively. TgAb negative concordant (NC) pairs were 78.6% (55 pairs) of male pairs and 74.3% (139 pairs) of female pairs. To perform stricter grouping, the cut-off value for positive TgAb was set to 50.0 IU/mL (TgAb negative: <28.0 IU/mL; TgAb positive: ≥50.0 IU/mL; TgAb borderline: ≥28.0 IU/mL and <50.0 IU/mL). Nineteen discordant (6 male and 13 female pairs) and 185 concordant pairs (48 male and 137 female pairs) for TgAb positivity were finally examined. DNA methylation levels of genomic DNA were evaluated using the Infinium HumanMethylation450 BeadChip Kit. Gene polymorphisms were also genotyped using the Omni5-4 BeadChip Kit to clarify genetic background specific for discordant twins. Results: No CpG sites were found with significant within-pair differences of methylation levels in TgAb DC pairs after correction for multiple comparisons. However, 155 polymorphisms specific for TgAb DC pairs were significantly different in genotype frequencies from those of concordant pairs, and none of them were located on the HLA region of chromosome 6. In TgAb DC pairs with some specific genotypes of these polymorphisms, four CpG sites were observed exhibiting significant within-pair differences in each DC pair, even after correction for multiple comparisons. Conclusions: This study found that the genetic background specific for TgAb DC twins who are susceptible to epigenetic changes are different from that specific for TgAb PC twins, and it clarified the genotype-based epigenetic differences in TgAb DC monozygotic twins.

Impact of Clinical Factors on the Achievement of Target Blood Pressure in Hypertensive Patients from Ivanovo Region of Russia: Data of 2015

INTRODUCTION

In Russia, blood pressure (BP) control is below the optimal. The little is known about regional features and barriers to adequate BP control in Russian primary care.

AIM

To evaluate the impact of clinical factors on achieving the target BP in hypertensive patients in one region of Russia.

METHODS

Retrospective medical data of 2015 on 11,129 patients (31.4% male) with hypertension (Htn) from Ivanovo region of Russia were examined. Achievement of target BP was assessed in all patients. We study association between BP control and clinical factors.

RESULTS

45.9% of studied patients with Htn had controlled BP. The frequency of achieving the target BP in subsets of hypertensive patients was 37.8% in patients with diabetes, 39.5% in patients with coronary artery disease, and 29.9% in patients with chronic heart failure. The main clinical factors associated with achieving the target BP in studied hypertensive patients were the advice on alcohol consumption, advice on smoking cessation, and advice on weight reduction. Therapy with main antihypertensive drugs (in particular, beta-blockers and thiazide diuretics) were also factors of optimal BP control in these patients. Comorbidities (chronic heart failure and cardiovascular diseases requiring the prescription of aspirin and statins) and family history of coronary artery disease were associated with inadequate BP control. A negative effect of some antihypertensive drugs (potassium sparing diuretics, ARBs, ACE-Is, and dihydropyridine CCBs) on BP control that was found out in our study requires further investigation. Other studied factors had no influence on BP control in patients with Htn from Ivanovo region.

CONCLUSION

We identified regional factors of BP control in hypertensive patients from Ivanovo region of Russia. It is shown that individual medical education (in particular, medical advices) is the most important factor of optimal BP control. The intervention with antihypertensive therapy (beta-blockers and thiazide diuretics) facilitates the achievement of target BP. Comorbidity and age reduce the frequency of achieving the target BP.

Genome Sequencing Technologies and Nursing: What Are the Roles of Nurses and Nurse Scientists?

BACKGROUND

Advances in DNA sequencing technology have resulted in an abundance of personalized data with challenging clinical utility and meaning for clinicians. This wealth of data has potential to dramatically impact the quality of healthcare. Nurses are at the focal point in educating patients regarding relevant healthcare needs; therefore, an understanding of sequencing technology and utilizing these data are critical.

AIM

The objective of this study was to explicate the role of nurses and nurse scientists as integral members of healthcare teams in improving understanding of DNA sequencing data and translational genomics for patients.

APPROACH

A history of the nurse role in newborn screening is used as an exemplar.

DISCUSSION

This study serves as an exemplar on how genome sequencing has been utilized in nursing science and incorporates linkages of other omics approaches used by nurses that are included in this special issue. This special issue showcased nurse scientists conducting multi-omic research from various methods, including targeted candidate genes, pharmacogenomics, proteomics, epigenomics, and the microbiome. From this vantage point, we provide an overview of the roles of nurse scientists in genome sequencing research and provide recommendations for the best utilization of nurses and nurse scientists related to genome sequencing.

Genetic Loci and Novel Discrimination Measures Associated with Blood Pressure Variation in African Americans Living in Tallahassee

Sequencing of the human genome and decades of genetic association and linkage studies have dramatically improved our understanding of the etiology of many diseases. However, the multiple causes of complex diseases are still not well understood, in part because genetic and sociocultural risk factors are not typically investigated concurrently. Hypertension is a leading risk factor for cardiovascular disease and afflicts more African Americans than any other racially defined group in the US. Few genetic loci for hypertension have been replicated across populations, which may reflect population-specific differences in genetic variants and/or inattention to relevant sociocultural factors. Discrimination is a salient sociocultural risk factor for poor health and has been associated with hypertension. Here we use a biocultural approach to study blood pressure (BP) variation in African Americans living in Tallahassee, Florida by genotyping over 30,000 single nucleotide polymorphisms (SNPs) and capturing experiences of discrimination using novel measures of unfair treatment of self and others (n = 157). We perform a joint admixture and genetic association analysis for BP that prioritizes regions of the genome with African ancestry. We only report significant SNPs that were confirmed through our simulation analyses, which were performed to determine the false positive rate. We identify eight significant SNPs in five genes that were previously associated with cardiovascular diseases. When we include measures of unfair treatment and test for interactions between SNPs and unfair treatment, we identify a new class of genes involved in multiple phenotypes including psychosocial distress and mood disorders. Our results suggest that inclusion of culturally relevant stress measures, like unfair treatment in African Americans, may reveal new genes and biological pathways relevant to the etiology of hypertension, and may also improve our understanding of the complexity of gene-environment interactions that underlie complex diseases.

A perspective for sequencing familial hypercholesterolaemia in African Americans

African Americans suffer disproportionately from poor cardiovascular health outcomes despite similar proportions of African Americans and Americans of European ancestry experiencing elevated cholesterol levels. Some of the variation in cardiovascular outcomes is due to confounding effects of other risk factors, such as hypertension and genetic influence. However, genetic variants found to contribute to variation in serum cholesterol levels in populations of European ancestry are less likely to replicate in populations of African ancestry. To date, there has been limited follow-up on variant discrepancies or on identifying variants that exist in populations of African ancestry. African and African-American populations have the highest levels of genetic heterogeneity, which is a factor that must be considered when evaluating genetic variants in the burgeoning era of personalised medicine. Many of the large published studies identifying genetic variants associated with disease risk have evaluated populations of mostly European ancestry and estimated risk in other populations based on these findings. The purpose of this paper is to provide a perspective, using familial hypercholesterolaemia as an exemplar, that studies evaluating genetic variation focused within minority populations are necessary to identify factors that contribute to disparities in health outcomes and realise the full utility of personalised medicine.

The Intergenerational Impact of Genetic and Psychological Factors on Blood Pressure (InterGEN) Study: Design and Methods for Complex DNA Analysis

The Intergenerational Impact of Genetic and Psychological Factors on Blood Pressure (InterGEN) study aims to delineate the independent and interaction effects of genomic (genetic and epigenetic) and psychological-environmental (maternally perceived racial discrimination, mental health, and parenting behavior) factors on blood pressure (BP) among African American mother-child dyads over time. The purpose of this article is to describe the two-step genetic and epigenetic approach that will be executed to explore Gene × Environment interactions on BP using a longitudinal cohort design. Procedure for the single collection of DNA at Time 1 includes the use of the Oragene 500-format saliva sample collection tube, which provides enough DNA for both the Illumina Multi-Ethnic Genotyping and 850K EPIC methylation analyses. BP readings, height, weight, percentage of body fat, and percentage of body water will be measured on all participants every 6 months for 2 years for a total of 4 time points. Genomic data analyses to be completed include multivariate modeling, assessment of population admixture and structure, and extended analyses including Bonferroni correction, false discovery rate methods, Monte Carlo approach, EIGENSTRAT methods, and so on, to determine relationships among both main and interaction effects of genetic, epigenetic, and psychological environmental factors on BP.

A Genome-wide study of blood pressure in African Americans accounting for gene-smoking interaction

Cigarette smoking has been shown to be a health hazard. In addition to being considered a negative lifestyle behavior, studies have shown that cigarette smoking has been linked to genetic underpinnings of hypertension. Because African Americans have the highest incidence and prevalence of hypertension, we examined the joint effect of genetics and cigarette smoking on health among this understudied population. The sample included African Americans from the genome wide association studies of HyperGEN (N = 1083, discovery sample) and GENOA (N = 1427, replication sample), both part of the FBPP. Results suggested that 2 SNPs located on chromosomes 14 (NEDD8; rs11158609; raw p = 9.80 × 10⁻⁹, genomic control-adjusted p = 2.09 × 10⁻⁷) and 17 (TTYH2; rs8078051; raw p = 6.28 × 10⁻⁸, genomic control-adjusted p = 9.65 × 10⁻⁷) were associated with SBP including the genetic interaction with cigarette smoking. These two SNPs were not associated with SBP in a main genetic effect only model. This study advances knowledge in the area of main and joint effects of genetics and cigarette smoking on hypertension among African Americans and offers a model to the reader for assessing these risks. More research is required to determine how these genes play a role in expression of hypertension.

Angiotensin-converting enzyme gene polymorphisms and hypertension in occupational noise exposure in Egypt

BACKGROUND

The gene-environment interaction in the pathogenesis of hypertension has not been extensively studied in occupational noise.

OBJECTIVES

The aim of this study was to determine the relationship between noise and hypertension in Egyptian workers, the interaction of angiotensin-converting enzyme (ACE) gene polymorphisms as modifiers, and the possible relationship between noise hearing impairment and hypertension.

METHODS

Study subjects were divided into two groups depending on noise exposure level. The control group (n = 161) was exposed to noise intensity <85 dB and the exposed group (n = 217) was exposed to noise intensity ≧85 dB. A polymerase chain reaction was used to differentiate the various genotypes of ACE insertion/deletion (I/D) and ACE G2350A.

RESULTS

Noise significantly increased the likelihood of hypertension. Carriers of the genotypes AG, GG, and DD were vulnerable to hypertension on noise exposure. No association between hypertension and hearing impairment or noise-induced hearing loss (NIHL) was found.

CONCLUSION

Our results support the association between ACE gene polymorphisms and occurrence of hypertension in noise-exposed workers.

Identification of a genetic variant at 2q12.1 associated with blood pressure in East Asians by genome-wide scan including gene-environment interactions

Background

Genome-wide association studies have identified many genetic loci associated with blood pressure (BP). Genetic effects on BP can be altered by environmental exposures via multiple biological pathways. Especially, obesity is one of important environmental risk factors that can have considerable effect on BP and it may interact with genetic factors. Given that, we aimed to test whether genetic factors and obesity may jointly influence BP.

Methods

We performed meta-analyses of genome-wide association data for systolic blood pressure (SBP) and diastolic blood pressure (DBP) that included analyses of interaction between single nucleotide polymorphisms (SNPs) and the obesity-related anthropometric measures, body mass index (BMI), height, weight, and waist/hip ratio (WHR) in East-Asians (n = 12,030).

Results

We identified that rs13390641 on 2q12.1 demonstrated significant association with SBP when the interaction between SNPs and BMI was considered (P < 5 × 10 ^-8). The gene located nearest to rs13390641, TMEM182, encodes transmembrane protein 182. In stratified analyses, the effect of rs13390641 on BP was much stronger in obese individuals (BMI ≥ 30) than non-obese individuals and the effect of BMI on BP was strongest in individuals with the homozygous A allele of rs13390641.

Conclusions

Our analyses that included interactions between SNPs and environmental factors identified a genetic variant associated with BP that was overlooked in standard analyses in which only genetic factors were included. This result also revealed a potential mechanism that integrates genetic factors and obesity related traits in the development of high BP.

Body mass index modulates blood pressure heritability: the Family Blood Pressure Program

BACKGROUND

Candidate gene and twin studies suggest that interactions between body mass index (BMI) and genes contribute to the variability of blood pressure (BP). To determine whether there is evidence for gene-BMI interactions, we investigated the modulation of BP heritability by BMI using 4,153 blacks, 1,538 Asians, 4,013 whites, and 2,199 Hispanic Americans from the Family Blood Pressure Program.

METHODS

To capture the BP heritability dependence on BMI, we employed a generalized variance components model incorporating linear and Gaussian interactions between BMI and the genetic component. Within each race and network subgroup, we used the Akaike information criterion and likelihood ratio test to select the appropriate interaction function for each BP trait (systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP)) and determine interaction significance, respectively.

RESULTS

BP heritabilities were significantly modified by BMI in the GenNet and SAPPHIRe Networks, which contained the youngest and least-obese participants, respectively. GenNet Whites had unimodal SBP, MAP, and PP heritabilities that peaked between BMI values of 33 and 37kg/m(2). The SBP and MAP heritabilities in GenNet Hispanic Americans, as well as the PP heritability in GenNet blacks, were increasing functions of BMI. The DBP and SBP heritabilities in the SAPPHIRe Chinese and Japanese, respectively, were decreasing functions of BMI.

CONCLUSIONS

BP heritability differed by BMI in the youngest and least-obese networks, although the shape of this dependence differed by race. Use of nonlinear gene-BMI interactions may enhance BP gene discovery efforts in individuals of European ancestry.

Attitudes toward Genetic Testing for Hypertension among African American Women and Girls

Introduction. Although African American (AA) women have the highest prevalence of hypertension and many genetic studies have been conducted to examine this disparity, no published studies have investigated their attitudes toward genetic testing for hypertension. The purpose of the present study was to use the health belief model as a guide to examine attitudes toward perceived barriers and benefits of genetic testing held by AA multigenerational triads and to determine whether they differed by generation, age, education, or income level. Methods. A descriptive correlational research design were used with 183 African American women and girls from Detroit. Correlations between triad membership, age, income, and education level were examined for association with attitudes toward genetic testing. Results. Increasing age and education were associated with significant differences in attitudes regarding benefits (F[2, 160] = 5.19, P = 0.007, d = 0.06) and awareness (F[2, 160] = 6.49, P = 0.002, d = 0.08). No statistically significant differences existed on the three subscales when compared by income levels or triad membership. Conclusions. This highlights the need for increased outreach to younger generations regarding benefits of genetic services. Further research is necessary to determine whether rural and male populations have similar beliefs.

An overview of the genomics of metabolic syndrome

PURPOSE

This article provides a brief overview of the diagnostic criteria and genomic risk factors for the components of metabolic syndrome (MetS).

ORGANIZING CONSTRUCTS

Contributions of cardiovascular, obesity, and diabetes genomic risk factors to the development of MetS as reported in the literature have been reviewed.

FINDINGS

The genomic risk factors for the development of MetS are strongly linked to the genomic risk factors that make up the components of the disease. Many of the cardiovascular and renal genomic risk factors for MetS development are similar to those found in the development of hypertension and dyslipidemia. Obesity may act as a master trigger to turn on the gene expression changes necessary for the other components of the disease. Studies in the genomics of type 2 diabetes show a number of overlapping genes and polymorphisms that influence both the development of diabetes and MetS.

CONCLUSIONS

Although health practitioners now have some insights into the genomics of risk factors associated with MetS, the overall understanding of MetS remains inadequate. Clinical applications based on some of the discussed genomic risk factors are being developed but are not yet available for the diagnosis and treatment of MetS.

CLINICAL RELEVANCE

A broad knowledge of the genomic contributions to disease processes will enable the clinician to better utilize genomics to assess and tailor management of patients.

Effect of environmental and lifestyle factors on hypertension: Shimane COHRE study

Background

In recent years there has been increasing evidence of an association between residential remoteness and hypertension (HTN); however, no study has examined the effects of residential remoteness-lifestyle associations on HTN. The objective of this study was to evaluate the effects of residential remoteness, as measured by road network distance and elevation, and lifestyle associations, including access to daily products as a measure of car use, on HTN in a rural region in Japan.

Method

This is a cross-sectional population based study. We analyzed data from the Shimane COHRE study conducted from 2006 to 2009 in the rural mountainous regions of Japan. After excluding missing data, we conducted a logistic regression analysis of the data for 1,348 individuals and examined the effects of residential remoteness and lifestyle associations, including road network distance, elevation and access to daily products as a measure of car use, on the prevalence of HTN.

Principal Findings

In participants without access to car use, the odds ratios for self-reported HTN (i.e. taking antihypertensive medication) were significantly increased in those living in moderate (odds ratio (OR): 2.21, 95% confidence interval (CI): 1.19–4.08) and far (OR: 2.55, 95% CI: 1.00–6.51) road distances, whereas there were no significant associations in participants with access to car use. There were no significant associations between elevation and HTN for participants either with or without access to car transportation.

Conclusions

Our findings show that specific residential remoteness-hypertension associations vary according to access to daily products as a measure of car use in a rural mountainous area of Japan. These results advance the understanding and importance of considering residential environment, “where people live,” in establishing health policy.

Between candidate genes and whole genomes: time for alternative approaches in blood pressure genetics

Blood pressure has a significant genetic component, but less than 3% of the observed variance has been attributed to genetic variants identified to date. Candidate gene studies of rare, monogenic hypertensive syndromes have conclusively implicated several genes altering renal sodium balance, and studies of essential hypertension have inconsistently implicated over 50 genes in pathways affecting renal sodium balance and other functions. Genome-wide linkage scans have replicated numerous quantitative trait loci throughout the genome, and over 50 single nucleotide polymorphisms (SNPs) have been replicated in multiple genome-wide association studies. These studies provide considerable evidence that epistasis and other interactions play a role in the genetic architecture of blood pressure regulation, but candidate gene studies have limited scope to test for epistasis, and genome-wide studies have low power for both main effects and interactions. This review summarizes the genetic findings to date for blood pressure, and it proposes focused, pathway-based approaches involving epistasis, gene-environment interactions, and next-generation sequencing to further the genetic dissection of blood pressure and hypertension.

Gene-environment effects of SLC4A5 and skin color on blood pressure among African American women

OBJECTIVE

To determine the relationship between genetic polymorphisms and environmental factors (skin color) on blood pressure among African American women.

METHOD

A descriptive study, consisting of 137 African American women from a Midwestern, metropolitan area was conducted. Blood pressure was measured using a digital blood pressure monitor. Self-reporting methods were utilized to obtain information on skin color. Buccal swab saliva samples were obtained for genotyping.

RESULTS

Of the four single nucleotide polymorphisms (SNPs) on the sodium bicarbonate co-transporter gene (SLC4A5) examined in this study, only one SNP (rs10177833) and skin color interaction was found to be associated with systolic blood pressure. The additive effect of rs10177833 on systolic blood pressure is statistically different between women with dark skin color and women with medium skin color (P = .0153). No SNP and skin color interaction was found to be associated with blood pressure readings in other SNPs tested (rs8179526, rs6726450 and rs6731545).

DISCUSSION

These findings of genetic and skin color relatedness to blood pressure is important when considering appropriate diagnostic and treatment plans for African American women with hypertension. African American women with darker skin color may require further assessment for risk factors such as discrimination related stress when being seen by health professionals for hypertension.

Genetic and BMI risks for predicting blood pressure in three generations of West African Dogon women

The study of genetic polymorphisms and body mass index (BMI) among African women in Africa and in the United States contributes to our understanding of the genetic and environmental risk factors for hypertension. African American women have the highest prevalence of hypertension and obesity compared to other ethnic groups in the United States. Using a cross-sectional research design, we examined the effects of genetic and environmental risks of single nucleotide polymorphisms (SNPs) and BMI on blood pressure (BP) among three generations of West African Dogon women (N = 199). We genotyped six SNPs located in the candidate genes known to be related to hypertension. We tested the associations between these SNPs and systolic BP (SBP) and diastolic BP (DBP) with Fisher's exact tests, chi-square tests for independence, and multivariable linear mixed models. The SNP rs8179526 (SLC4A5) was significantly associated with SBP adjusted for age, age(2), and BMI (p = .02). The "C" allele variant of rs8179526 (allele frequency of 0.445) was associated with higher SBP. This SNP did not deviate from the Hardy-Weinberg equilibrium (HWE) with p value of .772. The SNP × BMI interaction effects associated with SBP and DBP were not significant. rs8179526 is located on the SLC4A5 gene on chromosome 2. SLC4A5 encodes a protein that transports sodium and bicarbonate across cell membranes while regulating cellular pH and contains several SNPs linked to elevated BP. Knowledge of the SNP's effect on hypertension among West African women can help health practitioners educate their patients about genetic risks of developing hypertension.