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|  Jackson State University |
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| Jackson State University |
The JHS is the largest single-site longitudinal, population-based, cohort study of 5,302 persons initiated in the fall of 2000 to prospectively investigate the determinants of CVD among African Americans in the Jackson, MS metropolitan statistical area. The JHS investigates the various genotype and phenotype factors that affect high blood pressure, heart disease, strokes, diabetes and other important diseases in African Americans.
The primary objective of the Jackson Heart Study is to investigate the causes of cardiovascular disease (CVD) in African Americans to learn how to best prevent this group of diseases in the future. More specific objectives include:
1. Identification of factors, which influence the development, and worsening of CVD in African Americans, with an emphasis on manifestations related to high blood pressure (such as remodeling of the left ventricle of the heart, coronary artery disease, heart failure, stroke and disorders affecting the blood vessels of the kidney).
2. Building research capabilities in minority institutions at the undergraduate and graduate level by developing partnerships between minority and majority institutions and enhancing participation of minority investigators in large-scale epidemiologic studies.
3. Attracting minority students to and preparing them for careers in health sciences.
Jackson Heart Study Analytes and Biospecimen in Repository- Exam: Blood and Urine Analytes
Exam 1 Blood and Urine Analytes
Blood/Plasma/Serum
Aldosterone
C-reactive protein
Chamydia antibody
Total Cholesterol
HDL Cholesterol
LDL Cholesterol
Complete Blood Count
Cortisol
Creatinine
Endothelin
Glucose
HbA1c
Homocysteine
Insulin
Leptin
Lp(a)
Plasma renin*
Potassium
Sodium
Triglycerides
Uric Acid
Urine (Spot & 24-Hr*)
Albumin
Chloride
Creatinine
Potassium
Sodium
Albumin/Creatinine ratio(Computed)
Note: *: Subset of cohort
Exam 2 Blood and Urine Analytes
Blood/Plasma/Serum
C-reactive protein
Total Cholesterol
HDL Cholesterol
LDL Cholesterol
Glucose
HbA1c
Triglycerides
Spot Urine
Albumin
Creatinine
Albumin/Creatinine ratio (Computed)
Jackson Heart Study Analytes and Biospecimen in Repository- Exam: Biospecimen in Repository
Exams 1 and 2: Biospecimen in Repository
DNA*
Serum
Plasma (Preserved with EDTA)
Plasma (Preserved with Citrate)
Plasma (Preserved with Aprotinin & EDTA)
Urine
*Note: Exam 2 DNA was only obtained from participants whose DNA was not obtained at Exam 1.
"White blood cell count (WBC) is an important clinical marker that varies among different ethnic groups. African Americans are known to have a lower WBC than European Americans. We surveyed the entire genome for loci underlying this difference in WBC by using admixture mapping. We analyzed data from African American participants in the Health, Aging, and Body Composition Study and the Jackson Heart Study. Participants of both studies were genotyped across >or= 1322 single nucleotide polymorphisms that were pre-selected to be informative for African versus European ancestry and span the entire genome. We used these markers to estimate genetic ancestry in each chromosomal region and then tested the association between WBC and genetic ancestry at each locus. We found a locus on chromosome 1q strongly associated with WBC (p < 10(-12)). The strongest association was with a marker known to affect the expression of the Duffy blood group antigen. Participants who had both copies of the common West African allele had a mean WBC of 4.9 (SD 1.3); participants who had both common European alleles had a mean WBC of 7.1 (SD 1.3). This variant explained approximately 20% of population variation in WBC. We used admixture mapping, a novel method for conducting genetic-association studies, to find a region that was significantly associated with WBC on chromosome 1q. Additional studies are needed to determine the biological mechanism for this effect and its clinical implications."
"BACKGROUND: Socioeconomic status (SES) is recognized as a key social environmental factor because it has implications for access to resources that help individuals care for themselves and others. Few studies have examined the association of SES with chronic kidney disease (CKD) in high-risk populations.
STUDY DESIGN: Single-site longitudinal population-based cohort.
SETTING & PARTICIPANTS: Data for this study were drawn from the baseline examination of the Jackson Heart Study. The analytic cohort consisted of 3,430 African American men and women living in the tricounty region of the Jackson, MS, metropolitan area with complete data to determine CKD status.
PREDICTOR: High SES (defined as having a family income at least 3.5 times the poverty level or having at least 1 undergraduate degree).
OUTCOMES & MEASUREMENTS: CKD (defined as the presence of albuminuria or decreased estimated glomerular filtration rate [<60 mL/min/1.73 m(2)]). Associations were explored using bivariable analyses and multivariable logistic regression analyses adjusting for CKD and cardiovascular disease risk factors, as well as demographic factors.
RESULTS: The prevalence of CKD in the Jackson Heart Study was 20% (865 of 3,430 participants). Proportions of the Jackson Heart Study cohort with albuminuria and decreased estimated glomerular filtration rate were 12.5% (429 of 3,430 participants) and 10.1% (347 of 3,430 participants), respectively. High SES was associated inversely with CKD. The odds of having CKD were 41% lower for affluent participants than their less affluent counterparts. There were no statistically significant interactions between sex and education or income, although subgroup analysis showed that high income was associated with CKD in men (OR, 0.47; 95% CI, 0.23-0.97), but not women (OR, 0.64; 95% CI, 0.40-1.03).
LIMITATIONS: Models were estimated using cross-sectional data.
CONCLUSION: CKD is associated with SES. Additional research is needed to elucidate the impact of wealth and social contexts in which individuals are embedded and the mediating effects of sociocultural factors."
Abstract
OBJECTIVE: This paper describes the preparation of genetic materials and the recruitment and initial characterization of a nested Family Study within the Jackson Heart Study (JHS) METHODS: Genomic DNA was prepared from all consenting JHS participants. In addition, family members of a subset of JHS participants were recruited to the JHS Family Study to allow heritability and linkage analyses and family-based association studies. Family Study participants completed the same questionnaires, measures, and procedures as all other JHS participants and provided blood samples for lymphocyte cryopreservation and transformation.
RESULTS: DNA samples were obtained from 4726 JHS participants, including 1499 members of 291 families. In the family cohort, estimated heritabilities of body mass index, selected lipid levels, and blood pressure are highly significant, supporting the validity of the sample.
DISCUSSION: The JHS data and genetic materials (DNA and cryopreserved cells) offer valuable opportunities to identify susceptibility alleles for common complex diseases by positional and candidate gene approaches.
Abstract
OBJECTIVES: Intake and status of carotenoids have been associated with chronic disease. The objectives of this study were to examine the association between carotenoid intakes as measured by two regional food-frequency questionnaires (FFQs) and their corresponding measures in serum, and to report on dietary food sources of carotenoids in Jackson Heart Study (JHS) participants.
DESIGN: Cross-sectional analysis of data for 402 African American men and women participating in the Diet and Physical Activity Sub-Study (DPASS) of the JHS.
RESULTS: Mean serum carotenoid concentrations and intakes in this population were comparable to those reported for the general US population. After adjustment for covariates, correlations between serum and dietary measures of each carotenoid, for the average of the recalls (deattenuated), the short FFQ and the long FFQ, respectively, were: 035 and 0-carotene; 026 and 0-carotene; 017 and 0-carotene; 034 and 0-cryptoxanthin; 015 and 037, 014 for lycopene. Major dietary sources of -carotene and lutein plus zeaxanthin, mustard, turnip and collard greens; of beta-cryptoxanthin, orange juice; and of lycopene, tomato juice.
CONCLUSIONS: On average, carotenoid intakes and serum concentrations are not lower in this southern African American population than the general US population. The two regional FFQs developed for a southern US population and used as dietary assessment tools in the JHS appear to provide reasonably valid information for most of these carotenoids.
Abstract
BACKGROUND: Electrocardiographic QT interval prolongation is a risk factor for sudden cardiac death and drug-induced arrhythmia. The clinical correlates and heritability of QT interval duration in blacks have not been well studied despite their higher risk for sudden cardiac death compared with non-Hispanic whites. We sought to investigate potential correlates of the QT interval and estimate its heritability in the Jackson Heart Study.
METHODS AND RESULTS: The Jackson Heart Study comprises a sample of blacks residing in Jackson, Miss, of whom 5302 individuals with data at the baseline examination were available for study. Jackson Heart Study participants on QT-altering medications, with bundle-branch block, paced rhythm, atrial fibrillation/flutter, or other arrhythmias were excluded, resulting in a sample of 4660 individuals eligible for analyses. The relation between QT and potential covariates was tested using multivariable stepwise linear regression. Heritability was estimated using Sequential Oligogenic Linkage Analysis Routine in a subset of 1297 Jackson Heart Study participants in 292 families; the remaining sample included unrelated individuals. In stepwise multivariable linear regression analysis, covariates significantly associated with QT interval duration included R-R interval, sex, QRS duration, age, serum potassium, hypertension, body mass index, coronary heart disease, diuretic use, and Sokolow-Lyon voltage (P < or = 0.01 for all). The heritability of QT interval duration in the age-, sex-, and R-R interval-adjusted model and in the fully adjusted model was 0.41 (SE, 0.07) and 0.40 (SE, 0.07; P < 10(-11) for both), respectively.
CONCLUSIONS: There is substantial heritability of adjusted QT interval in blacks, supporting the need for further investigation to identify its genetic determinants.
Abstract
OBJECTIVE: Health of African Americans is seriously threatened by unremitting epidemics of diabetes and cardiovascular disease (CVD). However, the role of metabolic syndrome in the African-American population has not been investigated widely. This study examined the prevalence of metabolic syndrome and assessed its cross-sectional relationship to CVD in the Jackson Heart Study (JHS) cohort.
RESEARCH DESIGN AND METHODS: A total of 5,302 participants aged >or=21 years who were recruited at baseline during 2000-2004 were analyzed for this study. Adjusted odds ratios (ORs) were estimated in a logistic regression analysis for coronary heart disease (CHD) and cerebrovascular disease (CBD) in those with and without coexisting metabolic syndrome. Diabetic participants were excluded.
RESULTS: Among those aged 35-84 years, metabolic syndrome prevalence was 43.3% in women and 32.7% in men. Elevated blood pressure (70.4%), abdominal obesity (64.6%), and low HDL cholesterol (37.2%) were highly prevalent among those with metabolic syndrome. Prevalence rates for CVD, CHD, and CBD were 12.8, 8.7, and 5.8%, respectively. After adjustment for age and sex, metabolic syndrome was associated with increased age- and sex-adjusted ORs for CVD (OR 1.7 [95% CI 1.4-2.1]), CHD (1.7 [1.4-2.2]), and CBD (1.7 [1.3-2.3]) compared with those without CVD, CHD, or CBD.
CONCLUSION: Metabolic syndrome prevalence in the JHS is among the highest reported for population-based cohorts worldwide and is significantly associated with increased ORs for CVD, CHD, and CBD. Abdominal obesity, increased blood pressure, and low HDL cholesterol (without triglyceride elevation) are surprisingly prominent. A high prevalence of low HDL emerges as a leading contributor to metabolic syndrome among African Americans in this large African-American cohort.
"OBJECTIVES: The objective of this study is to investigate the distribution and determinants of diastolic function in a middle-aged cohort of African Americans (AA).
BACKGROUND: The distribution and determinants of left ventricular (LV) diastolic function in AA are not well-described despite high rates of AA with diastolic heart failure and a five-fold higher risk of death in those with diastolic dysfunction (DD) compared to normal diastolic function.
METHODS: Four categories of diastolic function were defined in JHS participants undergoing echocardiograms at the first examination (2001-2004) using mitral and pulmonary vein velocities. Investigators used logistic regression to assess the independent relation of DD to traditional risk factors and LV systolic dysfunction.
RESULTS: Of the 3,571 study participants (mean age, 56 +/- 12 years; 63.9% female), 70.4% had normal diastolic function, and 18.0%, 10.6%, and 0.9% had mild, moderate, and severe DD, respectively. In the multivariable analysis, DD was significantly related to age (OR 1.2, 95% CI 1.1-1.4), male sex (OR 1.3 CI 1.0-1.5), LV systolic dysfunction (OR 1.5, CI 1.2-2.0), body mass index (OR 0.8, CI 0.8-0.9), and heart rate (OR 1.2; CI 1.1-1.2). The severity of DD was significantly related with age (OR 0.3; CI 0.3, 0.4), male sex (OR 1.6; CI 1.2-2.2), hypertension (OR 0.6, CI 0.4-0.8), and heart rate (OR 0.7; CI 0.6-0.8).
CONCLUSION: This is the largest community-based analysis of LV diastolic function in middle-aged AA. DD was present in 29.5% and independently related to several traditional risk factors and LV systolic dysfunction."
Abstract
BACKGROUND: Despite the high prevalence of cardiovascular disease documented among the African-American population, there has been little emphasis on the role of dyslipidemia as a prominent risk factor in this large subpopulation. Questions of medication efficacy also have been raised. Together, these factors may have affected awareness, diagnosis, and treatment rates.
METHODS AND RESULTS: Dyslipidemia was defined as the presence of either hypercholesterolemia or hypertriglyceridemia using National Cholesterol Education Program III criteria and the fasting lipid measurements, self-reported treatment history, and medication survey available from 5302 Jackson Heart Study participants. Dyslipidemia was more common in men (compared with women) aged less than 50 years and increased with age in both genders. Hypercholesterolemia prevalence rates approached 50% in women aged more than 65 years. The lifestyle-related attributes found to be related to prevalence were being overweight and less physically active, and all disease status variables exhibited significant (P<.05) associations. Awareness of hypercholesterolemia is approximately 55% or more in both men and women aged more than 35 years. Treatment rates lag far behind awareness, particularly in younger adult men, and less than 50% of women and men aged less than 65 years were treated for hypercholesterolemia.
CONCLUSION: Higher rates of identification and effective treatment of dyslipidemia are clearly needed in this, and probably other African-American communities. Despite the less than optimal treatment, the identification and importance of the known cardiovascular disease states and risk factors in these analyses suggest the adoption of National Cholesterol Education Program III "high-risk strategy" algorithms in treatment recommendations and decisions by providers is occurring.
Abstract
BACKGROUND AND PURPOSE: Despite theories that link stroke to left ventricular mass, few large, population-based studies have examined the predictive value of echocardiographically derived left ventricular mass index (LVMI) to incident stroke in African Americans.
METHODS: Participants in the Jackson cohort of the Atherosclerotic Risk in Communities study have had extensive baseline evaluations, have undergone echocardiography during the third examination (1993-1995), and have been followed up for incident cardiovascular disease including ischemic stroke.
RESULTS: The study population consisted of 1792 participants, of whom 639 (35.7%) were men and the mean+/-SD age was 58.8+/-5.7 years. Compared with those without ischemic stroke, those with ischemic stroke had a higher frequency of hypertension (85.6% vs 58.7%) and diabetes (46.9% vs 21.0%). Left ventricular hypertrophy was more prevalent in those with stroke (62.2% vs 38.6%). During a median follow-up of 8.8 years, 98 incident strokes occurred (6.5 per 1000 person-years). LVMI was independently associated with stroke after adjusting for age, sex, hypertension, systolic blood pressure, smoking, diabetes, total to HDL cholesterol ratio, body mass index, and low left ventricular ejection fraction (adjusted hazard ratio per 10 g/m(2.7) increment of LVMI=1.15; 95% CI, 1.02 to 1.28). The relation remained statistically significant after adding left atrial size and mitral annular calcification to the multivariable model.
CONCLUSIONS: In this large, population-based African American cohort, we found that echocardiographic LVMI was an independent predictor of incident ischemic stroke even after taking into account traditional clinical risk factors.
Abstract
BACKGROUND: Despite the potential link between mitral annular calcification (MAC) and atherosclerosis, there is limited data regarding the prevalence of MAC in African Americans and its relationship with coronary heart disease (CHD)events in this high-risk population.
METHODS: The study population included 2409 African American participants of the Artherosclerotic Risk in Communities study (ARIC) undergoing echo examinations between 1993-1996. The primary outcome was incident CHD events [defined as fatal coronary event, hospitalized myocardial infarction or cardiac procedure]. MAC was considered a binary variable (yes/no). The Cox proportional hazard model was used for the analysis and the model was adjusted for gender, age, body mass index, hypertension, diabetes, smoking status, renal function (based on serum creatinine), high LDL and low HDL.
RESULTS: Of the 2409 in the study population, 1549 (64%) were women and the mean age was 59.2 +/- 5.8 years (range 49-75). MAC was positively associated with age and renal function. The overall prevalence of MAC was 4.6% for women and 5.6% for men. In participants aged >or= 70, the prevalence of MAC was 10% in women and 15.2% in men. During a median follow-up of 4.8 years, there were 237 total incident CHD events recorded. After adjustment, the hazard ratio for CHD events among the MAC subgroup was 2.32 (95% CI, 1.11-4.87).
CONCLUSIONS: In this relatively young population of middle-aged African Americans, the prevalence of MAC is low; however, the presence of MAC incurs a significant risk for coronary events.
"C-reactive protein (CRP) has been studied largely in white non-Hispanic cohorts. There is limited information on CRP's range of values, heritability, and relation to cardiovascular disease risk factors in African Americans. The aim of this study was to evaluate the distribution, clinical correlates, heritability, and genetic linkage of log-transformed CRP in participants in the middle-aged to elderly African American cohort in the community-based Jackson Heart Study. The distribution and correlates of CRP were analyzed for the entire study cohort who underwent the first examination (2001 to 2004). Heritability was estimated for the family cohort nested within the larger Jackson Heart Study (246 families, n = 1,317). The relation between CRP and cardiovascular disease risk factors was tested with multivariable stepwise regression analyses. Heritability was estimated using a variance-components method. Linkage analysis was performed using the multipoint variance-components approach. The study sample consisted of 4,919 participants (mean age 55 +/- 13 years, 63% women); the median CRP concentration was 2.7 mg/L. In stepwise models, traditional risk factors explained 23.8% of CRP's variability, with body mass index (partial R(2) = 13.6%) explaining 57.1% of the variability of CRP due to traditional risk factors. The heritability of CRP (adjusted for age, gender, and body mass index) was 0.45. The strongest linkage evidence for CRP was observed on chromosome 11 (11p13 to 11p11.2), with a logarithm of odds score of 2.72. In conclusion, in this large population-based cohort of African Americans, circulating CRP concentration was heritable and associated with several traditional cardiovascular risk factors, particularly body mass index."
Abstract
BACKGROUND: Genome-wide association studies in cohorts of European descent have identified novel genomic regions as associated with lipids, but their relevance in African Americans remains unclear.
METHODS AND RESULTS: We genotyped 8 index single nucleotide polymorphisms (SNPs) and 488 tagging SNPs across 8 novel lipid loci in the Jackson Heart Study, a community-based cohort of 4605 African Americans. For each trait, we calculated residuals adjusted for age, sex, and global ancestry and performed multivariable linear regression to detect genotype-phenotype association with adjustment for local ancestry. To explore admixture effects, we conducted stratified analyses in individuals with a high probability of 2 African ancestral alleles or at least 1 European allele at each locus. We confirmed 2 index SNPs as associated with lipid traits in African Americans, with suggestive association for 3 more. However, the effect sizes for 4 of the 5 associated SNPs were larger in the European local ancestry subgroup compared with the African local ancestry subgroup, suggesting that the replication is driven by European ancestry segments. Through fine-mapping, we discovered 3 new SNPs with significant associations, 2 with consistent effect on triglyceride levels across ancestral groups: rs636523 near DOCK7/ANGPTL3 and rs780093 in GCKR. African linkage disequilibrium patterns did not assist in narrowing association signals.
CONCLUSIONS: We confirm that 5 genetic regions associated with lipid traits in European-derived populations are relevant in African Americans. To further evaluate these loci, fine-mapping in larger African American cohorts and/or resequencing will be required.
Abstract
Genome-wide association analysis in populations of European descent has recently found more than a hundred genetic variants affecting risk for common disease. An open question, however, is how relevant the variants discovered in Europeans are to other populations. To address this problem for cardiovascular phenotypes, we studied a cohort of 4,464 African Americans from the Jackson Heart Study (JHS), in whom we genotyped both a panel of 12 recently discovered genetic variants known to predict lipid profile levels in Europeans and a panel of up to 1,447 ancestry informative markers allowing us to determine the African ancestry proportion of each individual at each position in the genome. Focusing on lipid profiles -- HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), and triglycerides (TG) -- we identified the lipoprotein lipase (LPL) locus as harboring variants that account for interethnic variation in HDL-C and TG. In particular, we identified a novel common variant within LPL that is strongly associated with TG (p = 2.7 x 10(-6)) and explains nearly 1% of the variability in this phenotype, the most of any variant in African Americans to date. Strikingly, the extensively studied "gain-of-function" S447X mutation at LPL, which has been hypothesized to be the major determinant of the LPL-TG genetic association and is in trials for human gene therapy, has a significantly diminished strength of biological effect when it is found on a background of African rather than European ancestry. These results suggest that there are other, yet undiscovered variants at the locus that are truly causal (and are in linkage disequilibrium with S447X) or that work synergistically with S447X to modulate TG levels. Finally, we find systematically lower effect sizes for the 12 risk variants discovered in European populations on the African local ancestry background in JHS, highlighting the need for caution in the use of genetic variants for risk assessment across different populations.
Abstract
OBJECTIVE: Obesity is a major driver of cardiometabolic risk. Abdominal visceral adipose tissue (VAT) and sc adipose tissue (SAT) may confer differential metabolic risk profiles. We investigated the relations of VAT and SAT with cardiometabolic risk factors in the Jackson Heart Study cohort.
METHODS: Participants from the Jackson Heart Study (n=2477; 64% women; mean age, 58 yr) underwent multidetector computed tomography, and the volumetric amounts of VAT and SAT were assessed between 2007 and 2009. Cardiometabolic risk factors were examined by sex in relation to VAT and SAT.
RESULTS: Men had a higher mean volume of VAT (873 vs. 793 cm3) and a lower mean volume of SAT (1730 vs. 2659 cm3) than women (P=0.0001). Per 1-sd increment in either VAT or SAT, we observed elevated levels of fasting plasma glucose and triglyceride, lower levels of high-density lipoprotein-cholesterol, and increased odds ratios for hypertension, diabetes, and metabolic syndrome. The effect size of VAT in women was larger than that of SAT [fasting plasma glucose, 5.51±1.0 vs. 3.36±0.9; triglyceride, 0.17±0.01 vs. 0.05±0.01; high-density lipoprotein-cholesterol, -5.36±0.4 vs. -2.85±0.4; and odds ratio for hypertension, 1.62 (1.4-1.9) vs. 1.40 (1.2-1.6); diabetes, 1.82 (1.6-2.1) vs. 1.58 (1.4-1.8); and metabolic syndrome, 3.34 (2.8-4.0) vs. 2.06 (1.8-2.4), respectively; P<0.0001 for difference between VAT and SAT]. Similar patterns were also observed in men. Furthermore, VAT remained associated with most risk factors even after accounting for body mass index (P ranging from 0.006-0.0001). The relationship of VAT to most risk factors was significantly different between women and men.
CONCLUSIONS: Abdominal VAT and SAT are both associated with adverse cardiometabolic risk factors, but VAT remains more strongly associated with these risk factors. The results from this study suggest that relations with cardiometabolic risk factors are consistent with a pathogenic role of abdominal adiposity in participants of African ancestry.
The Jackson Heart Study is the largest study in history to investigate the inherited (genetic) factors that affect high blood pressure, heart disease, strokes, diabetes and other important diseases in African Americans. The JHS is a large, community-based, observational study whose 5301 participants were recruited from among the non-institutionalized African-American adults from urban and rural areas of the three counties (Hinds, Madison, and Rankin) that make up the Jackson, MS, metropolitan statistical area (MSA).
Astract
Published studies of the prognostic value of left ventricular (LV) hypertrophy and LV geometric pattern in African-Americans were based on referred or hospitalized patients with hypertension or coronary heart disease. All-cause mortality rates and survival associated with LV geometric pattern were determined using echocardiography in a population-based sample of middle-aged and elderly African-American men and women. During the third (1993 to 1995) visit of the ARIC Study, echocardiography was performed at the Jackson, Mississippi, field center on the cohort of 2,445 African-Americans aged 49 to 75 years. M-Mode LV echocardiographic measurements were available for 1,722 persons. Mortality data were available through December 31, 2003. During the follow-up period (median 8.8 years, maximum 10.4), 160 deaths were identified. In men, multivariable-adjusted hazard ratios for all-cause mortality (compared with men with normal LV geometry) were 1.75 (95% confidence interval [CI] 0.71 to 4.33) in those with concentric LV hypertrophy, 0.38 (95% CI 0.08 to 1.88) in those with eccentric LV hypertrophy, and 0.79 (95% CI 0.41 to 1.54) in those with concentric remodeling. In women, multivariable-adjusted hazard ratios for all-cause mortality (compared with women with normal LV geometry) were 1.17 (95% CI 0.48 to 2.84) in those with concentric LV hypertrophy, 1.23 (95% CI 0.46 to 3.28) in those with eccentric LV hypertrophy, and 1.17 (95% CI 0.60 to 2.28) in those with concentric remodeling. In conclusion, in this population-based cohort of middle-aged and elderly African-Americans free of coronary heart disease, adjustment for baseline differences in cardiovascular disease risk factors and LV mass greatly attenuated the strength of the association between LV pattern and all-cause mortality risk in women. In men, an association between concentric LV hypertrophy and mortality risk remained.
Abstract
BACKGROUND: A substantial portion of the public health burden of heart failure is due to hospitalizations, many of which are for causes other than cardiovascular disease. We assessed whether left ventricular (LV) systolic dysfunction was associated with increased risk of both cardiovascular and noncardiovascular hospitalizations in a community sample of African Americans.
METHODS: African American participants from the Jackson, MS, site of the Atherosclerosis Risk in Communities (ARIC) study who underwent echocardiography were followed for 12 years. Hospitalization rates among individuals with and without LV systolic dysfunction were compared using negative binomial regression.
RESULTS: Among 2,416 participants with echocardiograms, LV systolic dysfunction was found in 61 (2.5%). Participants with LV dysfunction experienced 366 hospitalizations, a rate of 1.27 per person-year, compared with 0.25 per person-year among individuals without LV dysfunction. The incidence rate ratio adjusted for demographics, comorbidities, and other risk factors was 3.11 (95% CI 2.22-4.35). The adjusted rate ratios were 4.76 (95% CI 2.90-7.20) for cardiovascular and 2.67 (95% CI 1.82-3.90) for noncardiovascular diagnoses, with similar findings in the subset of individuals with asymptomatic LV dysfunction. The percentage attributable risks for hospitalizations were 87% and 74% for cardiovascular and noncardiovascular causes (79% and 63% after adjustment).
CONCLUSIONS: African American individuals with LV dysfunction are at an increased risk of hospitalization due to a wide range of causes, with noncardiovascular hospitalizations accounting for nearly half the increased risk. To the extent that estimates of risk focus on cardiovascular morbidity, they may underestimate the true health burden of LV dysfunction.
Abstract
BACKGROUND: The distribution and determinants of left ventricular (LV) geometric patterns and their relation to LV function in African Americans is not well described despite higher rates of LV hypertrophy and cardiovascular mortality reported in this group.
PURPOSE: This study investigates the distribution and clinical correlates of LV geometric patterns and how these patterns relate to function in a population-based African American cohort.
METHODS: The study population included participants in the Jackson cohort of ARIC, who underwent echocardiograms between 1993 and 1995. We defined 4 geometric patterns (normal geometry, concentric remodeling [CR], eccentric hypertrophy [EH], and concentric hypertrophy [CH]) according to LV mass index and relative wall thickness. Multiple logistic regression was used to assess the association of geometric patterns to systolic dysfunction and diastolic dysfunction, adjusting for traditional coronary risk factors.
RESULTS: There were 1849 participants in the study population (mean age 59 years, 65% women). Concentric remodeling and CH were highly prevalent. Concentric hypertrophy and EH groups had the highest rates of hypertension, obesity, and diabetes mellitus. Compared to the normal geometric pattern, EH was related to systolic dysfunction (OR 24.27, CI 6.71-87.80), and CH was related to diastolic dysfunction 1.58 (1.04-2.39). Concentric remodeling was not related to systolic or diastolic dysfunction.
CONCLUSION: In this large middle-aged African American cohort, CR and CH are prevalent. Hypertension, diabetes mellitus, and obesity are associated with both CH and EH. Concentric hypertrophy is strongly associated with diastolic dysfunction; EH is strongly associated with systolic dysfunction. Concentric remodeling, however, is not related to either systolic or diastolic dysfunction.
Abstract
BACKGROUND AND PURPOSE: Previous studies have demonstrated that echocardiographic left ventricular mass (LVM) is an independent risk factor for stroke in whites. Despite the greater burden of stroke, the echocardiographic predictors of stroke in African Americans remain poorly understood.
METHODS: This investigation is a retrospective analysis of prospectively collected data from the Jackson, Miss (all African American), cohort of the Atherosclerotic Risk in the Communities study. Between 1993 and 1995, 2445 participants received an echocardiogram, and a random subset (n=778) received cerebral MRI evaluating presence of infarcts or white matter disease (WMD; >3 on a scale of 0 to 9). Compared with the entire Jackson cohort, the random subset was older, had a lower body mass index (BMI), and a higher systolic blood pressure (SBP). Logistic regression models examined the relations of LVM indexed by height (LVM/height) to MRI findings adjusted for age, gender, BMI, SBP, hypertensive medications, diabetes, total/high-density lipoprotein cholesterol, smoking status, and history of myocardial infarction.
RESULTS: The 667 participants (63% women; 62+/-4 years of age) had a high prevalence of hypertension (68%), obesity (46%), echocardiographic left ventricular hypertrophy (49%), MRI stroke (n=133), and WMD (n=92). Adjusted LVM/height was significantly associated with prevalent MRI stroke (odds ratio [OR], 1.3; 95% CI, 1.1 to 1.7; P=0.02) and WMD (OR, 1.5; 95% CI, 1.1 to 1.9; P=0.006; OR expressed per 1 SD LVM/height, 45 g/m).
CONCLUSIONS: In this randomized subset of a population-based cohort of African American adults, LVM/height was related to MRI evidence of prevalent cerebrovascular disease. The current study supports the hypothesis that LVM/height is an important risk factor for stroke in multiple ethnicities.
Abstract
BACKGROUND: To examine the association of increased plasma leptin concentration with prevalent stroke and coronary heart disease (CHD) and to examine the genetic contributions of leptin to this association in the Jackson Heart Study cohort.
METHODS: A cohort of 5170 participants aged 21-84 years who underwent Exam I during 2000-2004 was analysed. Odds ratios (OR) of prevalent stroke and CHD were calculated using a logistic regression model adjusted for age, smoking, hypertension and waist circumference (WC). Variance component analysis was used to partition the phenotypic variance of leptin into the polygenic and environmental components.
RESULTS: The prevalence of stroke and CHD was 4.04% and 5.85% in women, and 4.88% and 8.92% in men, respectively. Body mass index (BMI) and WC were highly correlated with leptin both in men and women. In multivariate analysis stratified by sex, leptin was significantly associated with stroke (OR = 1.97, 95% CI = 1.21-3.21) in women after adjustment for age, smoking, systolic blood pressure, BMI and WC (P = 0.0079). No significant association was observed in men. Heritability of sex-, age-adjusted log-transformed leptin for this cohort was 38.0% and 37.8% after further adjustment for WC and hypertension, respectively. In addition, a sibship effect was also found to be significant and explained 12.2% of the total variance of leptin (P = 0.007).
CONCLUSION: There is a significant association of leptin with stroke in women, which is partly influenced by the genetic factor. The findings suggest that leptinemia is an independent risk factor for stroke in African American women.
Abstract
BACKGROUND: The metabolic syndrome has been associated with cardiovascular disease, but few studies have examined its relationship with subclinical measures such as echocardiographic left ventricular (LV) mass. This relationship is likely to be of particular importance in blacks, in whom both the metabolic syndrome and LV hypertrophy are common.
METHODS AND RESULTS: Echocardiography, performed at 1 of 4 sites in the Atherosclerosis Risk in Communities (ARIC) Study, was used to assess LV dimensions in 1572 black women and men aged 49 to 75 years in 1993-1996. Participants were categorized by number of metabolic syndrome characteristics (hypertension, dyslipidemia [low HDL cholesterol or high triglycerides], and glucose intolerance). Age-adjusted mean LV mass indexed by height (g/m) increased in a stepwise gradient with increasing number of metabolic syndrome disorders (none, any 1, any 2, all 3) in both women and men (125.1, 143.9, 153.7, 169.3 and 130.5, 148.7, 160.8, 170.2, respectively; P<0.001, tests for trend). Associations were diminished slightly by adjustment for smoking, alcohol intake, and education; additional adjustment for waist circumference resulted in some attenuation, but associations remained statistically significant. Analyses focusing on components of LV mass revealed that posterior wall and interventricular septal thickness, but not LV chamber size, were significantly and independently associated in general with the number of metabolic syndrome disorders. Consistent with these findings, relative wall thickness was also associated with number of disorders. Associations were similar across age and central adiposity. Hypertension had a strong influence on LV mass with additional contributions from dyslipidemia and glucose intolerance; strong synergistic effects of the syndrome beyond its individual components were not observed.
CONCLUSIONS: In this cross-sectional population-based study of black women and men, the degree of metabolic syndrome clustering was strongly related to LV mass and its wall thickness components. These associations are consistent with a possible influence of underlying factors such as insulin resistance or other vascular processes on myocardial thickening and not on chamber size.
"The increasing use of geographic information systems (GIS) in epidemiological population studies requires careful attention to the methods employed in accomplishing geocoding and creating a GIS. Studies have provided limited details, hampering the ability to assess validity of spatial data. The purpose of this paper is to describe the multiphase geocoding methods used to retrospectively create a GIS in the Jackson Heart Study (JHS). We used baseline data from 5,302 participants enrolled in the JHS between 2000 and 2004 in a multiphase process to accomplish geocoding 2 years after participant enrollment. After initial deletion of ungeocodable addresses (n=52), 96% were geocoded using ArcGIS. An interactive method using data abstraction from participant records, use of additional maps and street reference files, and verification of existence of address, yielded successful geocoding of all but 13 addresses. Overall, nearly 99% (n=5,237) of the JHS cohort was geocoded retrospectively using the multiple strategies for improving and locating geocodable addresses. Geocoding validation procedures revealed highly accurate and reliable geographic data. Using the methods and protocol developed provided a reliable spatial database that can be used for further investigation of spatial epidemiology. Baseline results were used to describe participants by select geographic indicators, including residence in urban or rural areas, as well as to validate the effectiveness of the study’s sampling plan. Further, our results indicate that retrospectively developing a reliable GIS for a large, epidemiological study is feasible. This paper describes some of the challenges in retrospectively creating a GIS and provides practical tips that enhanced the success."
Keywords: African Americans, Jackson Heart Study, Cohort studies, Geocoding, Geographic information systems, Spatial distribution
Abstract
OBJECTIVE: Pericardial adipose tissue (PAT), a regional fat depot that surrounds the heart, is associated with an unfavorable cardiometabolic risk factor profile. The associations among PAT, cardiometabolic risk factors, and coronary artery calcification (CAC) and abdominal aortic artery calcification (AAC) in African American populations have not been explored.
RESEARCH DESIGN AND METHODS: A total of 1,414 African Americans (35% men; mean +/- SD age 58 +/- 11 years) drawn from the Jackson Heart Study (JHS) underwent multidetector computed tomography assessment of abdominal visceral adipose tissue (VAT) and PAT between 2007 and 2009. Cardiometabolic risk factors, CAC, and AAC were examined in relation to increments of PAT and VAT.
RESULTS: PAT was significantly correlated with BMI, waist circumference, and VAT (r = 0.35, 0.46, and 0.69; all P < 0.0001). PAT (per 1-SD increase) was associated with elevated levels of systolic blood pressure (P < 0.04), fasting glucose, triglycerides, and C-reactive protein and lower levels of HDL (all P values<0.0001). PAT was also associated with metabolic syndrome (odds ratio [OR] 1.89; P < 0.0001), hypertension (1.48; P < 0.0006), and diabetes (1.40; P < 0.04); all associations were diminished after further adjustment for VAT (most P > 0.05). However, the association of PAT with CAC but not with AAC remained significant (OR 1.34 [95% CI 1.10-1.64]; P < 0.004) after multivariable and VAT adjustment.
CONCLUSIONS: PAT is significantly correlated with most cardiometabolic risk factors and CAC in the JHS cohort. The results suggest that PAT is an important VAT depot that may exert a local effect on the coronary vasculature.
Abstract
OBJECTIVE- Pericardial adipose tissue (PAT), a regional fat depot adjacent to the myocardium, may mediate the complex relation between obesity and cardiac left ventricular (LV) abnormalities. We sought to evaluate the association of PAT with echocardiographic measures of LV abnormalities in the Jackson Heart Study (JHS). RESEARCH DESIGN AND METHODS A total of 1,414 African Americans (35% men; mean age 58 years) from the JHS underwent computed tomographic assessment of PAT and abdominal visceral adipose tissue (VAT) from 2007 to 2009 and echocardiography examination between 2000 and 2004. Echocardiographic measures of left atrial (LA) internal diameter, LV mass, LV ejection fraction (LVEF), and E-wave velocity-to-A-wave velocity ratio (E/A ratio) were examined in relation to PAT, VAT, BMI, and waist circumference (WC). RESULTS All adiposity measures were positively correlated with LA diameter and LV mass and negatively correlated with E/A ratio (P = 0.02 to 0.0001) and were not with LVEF (P = 0.36-0.61). In women, per 1-SD increment of PAT, we observed association with higher LV mass (9.0 ± 1.7 gm, P = 0.0001) and LA diameter (1.0 ± 0.1 mm, P = 0.0001). However, the magnitude of the association between PAT and cardiac measures was similar compared with VAT (P = 0.65 [LV mass]; P = 0.26 [LA diameter]) and was smallercompared with BMI (P = 0.002 [LV mass]; P = 0.01 [LA diameter]) and WC (P = 0.009 [LA diameter]). CONCLUSIONS PAT is correlated with echocardiographic measures of cardiac LV abnormalities, but the association is not stronger than other adiposity measures.
Abstract
BACKGROUND: Chronic kidney disease (CKD) leads to end-stage renal disease and is a growing epidemic throughout the world. In the United States, African Americans have an incidence of end-stage renal disease 4 times that of whites.
STUDY DESIGN: Cross-sectional to examine the prevalence and awareness of CKD in African Americans.
SETTING & PARTICIPANTS: Observational cohort in the Jackson Heart Study (JHS).
PREDICTOR: CKD was defined as an estimated glomerular filtration rate less than 60 mL/min/1.73 m(2), the presence of albuminuria, or dialysis therapy.
OUTCOMES & MEASUREMENTS: Data from the JHS were analyzed. Medical history, including disease awareness and drug therapy, anthropometric measurements, and serum and urine samples, were obtained from JHS participants at the baseline visit. Associations between CKD prevalence and awareness and selected demographic, socioeconomic, health care access, and disease status parameters were assessed by using logistic regression models.
RESULTS: The prevalence of CKD in the JHS was 20%; CKD awareness was only 15.8%. Older participants had a greater prevalence, but also were more aware of CKD. Hypertension, diabetes, cardiovascular disease, hypercholesterolemia, hypertriglyceridemia, increasing age and waist circumference, and being single or less physically active were associated with CKD. Only advancing CKD stage was associated with awareness.
LIMITATIONS: Cross-sectional assessment, single urine measurement.
CONCLUSIONS: The JHS has a high prevalence and low awareness of CKD, especially in those with less severe disease status. This emphasizes the need for earlier diagnosis and increased education of health care providers and the general population.
Abstract
African Americans have higher reported hypertension prevalence and lower control rates than other ethnic groups in the United States. Hypertension prevalence, awareness, treatment, and control (outcomes) and potentially associated demographic, lifestyle, comorbidity, and health care access factors were examined in 5249 adult participants (3362 women and 1887 men) aged 21 to 94 years enrolled in the Jackson Heart Study. Hypertension prevalence (62.9%), awareness (87.3%), treatment (83.2%), and control (66.4%) were high. Control declined with advancing age; estimates for all of the outcomes were higher for women compared with men. Lower socioeconomic status was associated with prevalence and control. Smoking was negatively associated with awareness and treatment, particularly among men. Comorbidities (diabetes, chronic kidney disease, and cardiovascular disease), likely driven by the high rates of obesity, correlated with hypertension prevalence, awareness, treatment, and control. Lack of health insurance was marginally associated with poorer control, whereas use of preventive care was positively associated with prevalence, awareness, and treatment, particularly among men. In comparisons with the 1994-2004 National Health and Nutrition Examination Survey data adjusted to Jackson Heart Study sex, age, and socioeconomic status distribution, control rates among Jackson Heart Study participants appeared to be higher than in their national counterparts and similar to that of whites. These results suggest that public health efforts to increase awareness and treatment among African Americans have been relatively effective. The Jackson Heart Study data indicate that better control rates can be achieved in this high-risk population.
Abstract
This study sought to establish the psychometric properties of a Coping Strategies Inventory Short Form (CSISF) by examining coping skills in the Jackson Heart Study cohort. We used exploratory and confirmatory factor analysis, Pearson's correlation, and Cronbach Alpha to examine reliability and validity in the CSI-SF that solicited responses from 5302 African American men and women between the ages of 35 and 84. One item was dropped from the 16-item CSI-SF, making it a 15-item survey. No significant effects were found for age and gender, strengthening the generalizability of the CSI-SF. The internal consistency reliability analysis revealed reliability between alpha = 0.58-0.72 for all of the scales, and all of the fit indices used to examine the CSI-SF provided support for its use as an adequate measure of coping. This study provides empirical support for utilizing this instrument in future efforts to understand the role of coping in moderating health outcomes
Abstract
Persistently low white blood cell count (WBC) and neutrophil count is a well-described phenomenon in persons of African ancestry, whose etiology remains unknown. We recently used admixture mapping to identify an approximately 1-megabase region on chromosome 1, where ancestry status (African or European) almost entirely accounted for the difference in WBC between African Americans and European Americans. To identify the specific genetic change responsible for this association, we analyzed genotype and phenotype data from 6,005 African Americans from the Jackson Heart Study (JHS), the Health, Aging and Body Composition (Health ABC) Study, and the Atherosclerosis Risk in Communities (ARIC) Study. We demonstrate that the causal variant must be at least 91% different in frequency between West Africans and European Americans. An excellent candidate is the Duffy Null polymorphism (SNP rs2814778 at chromosome 1q23.2), which is the only polymorphism in the region known to be so differentiated in frequency and is already known to protect against
Abstract
To assess the relation between aortic valve sclerosis (AVS) and subsequent occurrence of coronary heart disease (CHD) events, we analyzed echocardiographic data obtained from 2,279 middle-aged African-Americans enrolled in the Jackson Mississippi Atherosclerosis Risk in Communities study cohort who were free of known CHD at the time of the examination. Cox regression analyses demonstrated a hazard ratio of 3.8 for incident first myocardial infarction or fatal CHD after adjusted for multiple risk factors, including markers of inflammation. An amplification of CHD risk in the AVS subgroup with high levels of serum inflammatory markers (the highest quartile of fibrinogen and von Willebrand Factor levels) demonstrated greater than fivefold higher risk of CHD associated with AVS than risk in the lowest quartile.
Abstract
The burden of cardiovascular risk associated with obesity disproportionately affects African Americans and little is known about ethnic/racial differences in the relationship of obesity to cardiometabolic risk. This report assesses whether obesity is similarly associated with cardiometabolic risk factors in African Americans and whites of European ancestry. Cross-sectional observational data from the Jackson Heart Study (JHS) and the Framingham Heart Study (FHS) were compared. This analysis uses participants aged 35-74 years with BMI >18.5 kg/m(2), and free of prevalent cardiovascular disease (CVD), from the initial JHS clinical examination (2000-2004) and the FHS Offspring (1998-2001) and Third Generation (2002-2005) cohorts. Participants were evaluated for the presence of lipid abnormalities, hypertension, and diabetes. Overall, 4,030 JHS (mean age 54 years, 64% women) and 5,245 FHS (mean age 51 years, 54% women) participants were available for analysis. The prevalence of all risk factors except high triglycerides and low high-density lipoprotein (HDL) was substantially higher in JHS (all P < 0.001) and BMI was associated with increasing prevalence of most CVD risk factors within each race. For diabetes mellitus, hypertension, and low HDL, steeper relationships to BMI were observed in FHS than in JHS (P values <0.001-0.016). There were larger proportional increases in risk factor prevalence with increasing BMI in whites than in African Americans. The higher prevalence rates of cardiometabolic risk factors at nearly all levels of BMI in African Americans, however, suggest that additional factors contribute to the burden of CVD risk in African Americans.
Abstract
BACKGROUND: Whether microvascular disease contributes to the development of left ventricular hypertrophy (LVH) is unclear. We examined the relationship of retinal microvascular signs with LVH in an African-American population.
METHODS: A population-based, cross-sectional study of 1,439 middle-aged African-American participants in Jackson, Mississippi. A retinal photograph of one randomly selected eye was obtained and graded for presence of retinal microvascular signs (focal arteriolar narrowing, arterio-venous (AV) nicking, and retinopathy) according to standardized protocols. Retinal vessel diameter was measured from a computer-assisted technique to define generalized arteriolar narrowing. LVH was defined from standardized echocardiography.
RESULTS: In age and gender-adjusted models, retinal microvascular signs (except non-diabetic retinopathy) were significantly associated with LVH, with an odds ratio (OR) of 1.64 (95% confidence interval (CI) 1.29-2.09) for generalized arteriolar narrowing, OR 1.82 (95% CI 1.33-2.50) for focal arteriolar narrowing, and OR 1.35 (95% CI 1.02-1.79) for AV nicking. With further adjustment for cardiovascular (serum total cholesterol, fasting glucose, diabetes, diabetes duration, smoking, body mass index (BMI), waist-to-hip ratio, and exercise level) and hypertension-related factors (mean arterial blood pressure (MABP) at the time of retinal photography and antihypertensive medication use), associations were attenuated but remained significant for generalized and focal arteriolar narrowing, with OR 1.35 (95% CI 1.02-1.78) and OR 1.66 (95% CI 1.16-2.38), respectively.
CONCLUSIONS: Middle-aged African Americans with generalized and focal retinal arteriolar narrowing were more likely to have LVH. This association was explained only partly by cardiovascular risk factors and hypertension.
Abstract
BACKGROUND: Intakes and biochemical concentrations of carotenoids and tocopherols have been associated with chronic diseases.
OBJECTIVE: To describe dietary patterns in Jackson Heart Study participants and to determine if biochemical measurements of antioxidants differ across these.
DESIGN: Cross-sectional analysis of data for 373 African-American men and women (age 35 to 80 years), participating in the Diet and Physical Activity Substudy of the Jackson Heart Study.
METHODS: Dietary intake was assessed with a region specific food frequency questionnaire. Patterns were defined by cluster analysis of food groups, as percent of energy intake.
RESULTS: Four dietary patterns were identified: fast food, Southern, prudent, and juice. Individuals in the fast-food pattern (n=153) had significantly lower serum concentrations of lutein plus zeaxanthin and beta-cryptoxanthin; those in the Southern cluster (n=99) had significantly lower serum alpha-carotene; and those in the prudent (n=63) and juice (n=58) clusters had significantly higher serum alpha-carotene and beta-cryptoxanthin (P<0.05) relative to those in at least one other cluster (all P<0.05). The juice cluster also had higher serum alpha-tocopherol concentrations relative to the fast-food cluster.
CONCLUSIONS: Diets high in fast foods, snacks, soft drinks, and meat were associated with relatively low concentrations of carotenoids and alpha-tocopherol. This pattern contained the largest number of participants, and could contribute to the extensive health disparities seen in this region.
Abstract
BACKGROUND AND PURPOSE: The association between left atrial (LA) size, ischemic stroke, and death has not been well established in African Americans despite their disproportionately higher rates of stroke and cardiovascular mortality compared to non-Hispanic whites.
METHODS: For the analysis, participants in the Jackson cohort of the Atherosclerosis Risk in Communities Study were followed from the date of the echocardiogram in cycle three to the date of the first ischemic stroke event (or death) or to December 31, 2004 if no ischemic stroke event (or death) was detected.
RESULTS: There were 1886 participants in the study population (mean age 58.9 years, 65% women). Participants in the top quintile of LA diameter indexed to height (LA diameter/height; 2.57 to 3.55 cm/m) were more likely women, hypertensive, diabetic, and obese compared to those not in the top quintile. Over a median follow-up of 9.8 years for ischemic stroke and 9.9 years for all-cause mortality, there were 106 strokes and 242 deaths. In a multivariable model adjusting for traditional clinical risk factors, the top quintile of LA diameter/height was significantly related to ischemic stroke (HR 1.7; 95% CI: 1.1, 2.7) and all-cause mortality (HR 2.0; 95% CI: 1.5, 2.7). After further adjustment for left ventricular (LV) hypertrophy and low LV ejection fraction, the top quintile remained significantly related to all-cause mortality (HR 1.8; 95% CI: 1.3, 2.5).
CONCLUSIONS: In this population-based cohort of African Americans, LA size was a predictor of all-cause mortality after adjusting for traditional cardiovascular risk factors, LV hypertrophy, and low LV ejection fraction.
Abstract
BACKGROUND: Although recent data suggest that the mitral diastolic early-to-late (E/A) ratio may be prognostic in selected population-based cohorts, its predictive value for morbidity and mortality in African Americans has not yet been well studied.
METHODS: The study population consisted of African American participants from the Jackson cohort of the Atherosclerotic Risks in Community Study. Three subgroups of E/A ratios were defined: E/A <0.7, E/A 0.7-1.5, and E/A >1.5, using the middle group as reference. Cox proportional hazard models were used to assess the association between the E/A ratio and both all-cause mortality and incident cardiovascular disease (CVD). The mean follow-up period was 6.8 +/- 1.3 years.
RESULTS: Of the 2211 participants in the study population (mean age 62 years, 65.1% women), 8.2% had an E/A ratio <0.7, 84.7% had an E/A 0.7-1.5, and 7.1% had an E/A >1.5. An E/A >1.5 was independently associated with all-cause mortality (hazard ratio [HR] 2.18, 95% confidence interval [CI] 1.20-4.03) in the multivariable model. An E/A <0.7 was associated with higher all-cause mortality (HR 1.79, 95% CI 1.17-2.73) and incident CVD (HR 1.91, 95% CI 1.29-2.83) compared with a normal E/A in the age and sex adjusted model but was not independently predictive in the multivariable model (P > .05).
CONCLUSIONS: In a population-based cohort of middle-aged African Americans, an E/A >1.5 independently predicts all-cause mortality. An E/A >1.5 and an E/A <0.7 were both associated with incident CVD when adjusted for age and sex alone but were not independently predictive in the multivariable analysis.
Abstract
BACKGROUND: African Americans have an increased incidence and worse prognosis with chronic kidney disease (CKD--estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m2) than their counterparts of European-descent. Inflammation has been related to renal disease in non-Hispanic whites, but there are limited data on the role of inflammation in renal dysfunction in African Americans in the community.
METHODS: We examined the cross-sectional relation of log transformed C-reactive protein (CRP) to renal function (eGFR by Modification of Diet and Renal Disease equation) in African American participants of the community-based Jackson Heart Study's first examination (2000 to 2004). We conducted multivariable linear regression relating CRP to eGFR adjusting for age, sex, body mass index, systolic and diastolic blood pressure, diabetes, total/HDL cholesterol, triglycerides, smoking, antihypertensive therapy, lipid lowering therapy, hormone replacement therapy, and prevalent cardiovascular disease events. In a secondary analysis we assessed the association of CRP with albuminuria (defined as albumin-to-creatinine ratio > 30 mg/g).
RESULTS: Participants (n = 4320, 63.2% women) had a mean age +/- SD of 54.0 +/- 12.8 years. The prevalence of CKD was 5.2% (n = 228 cases). In multivariable regression, CRP concentrations were higher in those with CKD compared to those without CKD (mean CRP 3.2 +/- 1.1 mg/L vs. 2.4 +/- 1.0 mg/L, respectively p < 0.0001). CRP was significantly associated with albuminuria in sex and age adjusted model however not in the multivariable adjusted model (p > 0.05).
CONCLUSION: CRP was associated with CKD however not albuminuria in multivariable-adjusted analyses. The study of inflammation in the progression of renal disease in African Americans merits further investigation.
Abstract
OBJECTIVE We assessed the relation of diabetes and insulin resistance (IR) on left ventricular (LV) structure and function in African Americans. RESEARCH DESIGN AND METHODS Among those receiving echocardiograms in cycle 1 of the Jackson Heart Study, we assessed the sex-specific relation of fasting blood glucose (FBG), diabetes, and IR to LV structure and function, adjusting for age, systolic blood pressure, antihypertensive medications, and BMI. RESULTS Among 2,399 participants, LV mass index (P(women) = 0.0002 and P(men) = 0.02), posterior wall thickness (P(women) = 0.01 and P(men) = 0.05), and interventricular septal wall thickness (P(women) = 0.01) were related to FBG categories. Among those with normal FBG and no diabetes, concentric remodeling and low ejection fraction in women and LV mass index and posterior wall thickness in men were related to IR. CONCLUSIONS In the largest study of its kind in a community-based cohort of African Americans, we found a relation of FBG category and IR to LV structure and function.
Abstract
BACKGROUND: Compared to whites, insulin-resistant African Americans have worse outcomes. Screening programs that could identify insulin resistance early enough for intervention to affect outcome often rely on triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels. Racial differences in TG and HDL-C may compromise the efficacy of these programs in African Americans. A recommendation currently exists to use the TG/HDL-C ratio ≥2.0 to predict insulin resistance in African Americans. The validity of this recommendation needs examination. Therefore, our aim was to determine the ability of TG/HDL-C ratio to predict insulin resistance in African Americans.
METHODS: In 1,903 African Americans [895 men, 1,008 women, age 55 ± 12 years, mean ± standard deviation (SD), range 35-80 years, body mass index (BMI) 31.0 ± 6.4 kg/m(2), range 18.5-55 kg/m(2)] participating in the Jackson Heart Study, a population-based study of African Americans, Jackson, Mississippi tricounty region, insulin resistance was defined by the upper quartile (≥4.43) of homeostasis model assessment of insulin resistance (HOMA-IR). An area under the receiver operating characteristic curve (AUC-ROC) of >0.70 was required for prediction of insulin resistance by TG/HDL-C. The optimal test cutoff was determined by the Youden index.
RESULTS: HOMA-IR was similar in men and women (3.40 ± 2.03 vs. 3.80 ± 2.46, P = 0.60). Women had lower TG (94 ± 49 vs. 109 ± 65 mg/dL P < 0.001) and TG/HDL-C (1.9 ± 1.4 vs. 2.7 ± 2.1, P < 0.001). For men, AUC-ROC for prediction of insulin resistance by TG/HDL-C was: 0.77 ± 0.01, mean ± standard error (SE), with an optimal cutoff of ≥2.5. For women, the AUC-ROC was 0.66 ± 0.01, rendering an optimal cutoff indefinable. When women were divided in two groups according to age, 35-50 years and 51-80 years, the results did not change.
CONCLUSIONS: In African-American men, the recommended TG/HDL-C threshold of 2.0 should be adjusted upward to 2.5. In African-American women, TG/HDL-C cannot identify insulin resistance. The Jackson Heart Study can help determine the efficacy of screening programs in African-Americans.
Abstract
African Americans in the southern United States have a high prevalence of chronic disease. Tocopherol intake and status have been associated with protection against several chronic diseases. Our objectives were, therefore, to examine the association between tocopherol intakes as measured by 2 regional FFQ and their corresponding concentrations in serum and to report on dietary sources of tocopherols in 404 men and women participating in the cross-sectional Diet and Physical Activity Sub-Study of the Jackson Heart Study. A large proportion (49% of men and 66% of women) reported dietary supplement use. Only 5.8% of men and 4.5% of women met the estimated average requirement (EAR) for vitamin E from foods alone, whereas 44.2% men and 49.2% women met it from foods and supplements. Total (diet + supplement) intake of alpha-tocopherol was associated with its corresponding measure in serum. Vitamin E supplement use, sex, serum cholesterol, education, and BMI, but not gamma-tocopherol intakes, were associated with serum gamma-tocopherol. For delta-tocopherol, associated variables included sex and serum cholesterol. The top food sources of alpha- and gamma-tocopherol were snack chips and the top food source of delta-tocopherol was margarine. Despite prevalent vitamin E supplement use, more than one-half of this population did not meet the EAR for alpha-tocopherol intake and very few met it from food alone. Supplement use was associated with higher alpha- but lower gamma-tocopherol concentration in serum. The possible health implications of this difference in relative tocopherol subtypes require further study.
Abstract
Total antioxidant performance (TAP) measures antioxidant capacities in both hydrophilic and lipophilic compartments of serum and interactions known to exist between them. Our objective was to assess TAP levels in a subset of Jackson Heart Study (JHS) participants and to examine associations with dietary and total (diet + supplement) intakes of alpha-tocopherol, gamma-tocopherol (diet only), beta-carotene, vitamin C, fruit, vegetables, and nuts, and serum concentrations of alpha-tocopherol, gamma-tocopherol, and beta-carotene. We conducted a cross-sectional analysis of 420 (mean age 61 y; 254 women) African American men and women participating in the Diet and Physical Activity Sub-Study of the JHS in Jackson, Mississippi. In multivariate-adjusted models, we observed positive associations between total alpha-tocopherol, total and dietary beta-carotene, and total vitamin C intakes and TAP levels (P-trend < 0.05). Positive associations were also observed for vegetable, fruit, and total fruit and vegetable intakes (P-trend < 0.05). For serum antioxidant nutrients, alpha-tocopherol but not beta-carotene was associated with serum TAP levels. There were inverse associations for serum gamma-tocopherol and TAP levels. Associations for alpha-tocopherol were seen at intake levels much higher than the current Recommended Dietary Allowance. It may, therefore, be prudent to focus on increasing consumption of fruit, vegetables, nuts, and seeds to increase total antioxidant capacity.
Abstract
OBJECTIVE: The design, overall methods, and major phenotypes for the all-African-American Jackson Heart Study (JHS) are detailed.
METHODS: Participants were enrolled from the three counties that make up the Jackson, Mississippi metropolitan area. Relatives of selected participants were recruited to develop a large, nested family cohort. Participants provided extensive medical and social history, had an array of physical and biochemical measurements and diagnostic procedures, and provided genomic DNA.
RESULTS: Data and biologic materials have been collected from 5302 adult African Americans, including 1499 members of 291 families. Participants have a high prevalence of diabetes, hypertension, obesity, and related disorders.
DISCUSSION: The JHS dataset and biologic materials (serum, DNA, and cryopreserved cells) offer a valuable resource for the study of diseases that are of particular importance to African Americans.
Abstract
BACKGROUND: Physical inactivity has been consistently linked to cardiovascular disease, yet few instruments have been validated for assessment of physical activity in African Americans, a group particularly vulnerable to heart disease. The current study aimed to establish the psychometric properties of the activity survey used in the Jackson Heart Study (JHS) among African Americans, the JHS Physical Activity Cohort survey (JPAC).
METHODS: Test-retest reliability over 2 weeks was assessed using a convenience sample of 40 African Americans. Convergent validity with accelerometer and pedometer data were assessed in 2 samples from the JHS (N = 404 and 294, respectively).
RESULTS: Test-retest reliability was excellent, with intraclass correlations = .99 for the JPAC total and index scores. Higher JPAC total scores were significantly associated with higher raw accelerometer and pedometer counts. Spearman correlations between JPAC total scores and accelerometer (rho = .24) and pedometer counts (rho = .32) were consistent with these results. Most subscales were significantly correlated with the objective measures. The JPAC total score was most strongly associated with objectively-measured activity.
CONCLUSION: This study provides support for the reliability and validity of the JPAC as a tool for assessing physical activity among African Americans across a variety of domains.
Abstract
OBJECTIVE: To examine the relative validity of two food frequency questionnaires (FFQs) developed for use in investigating diet and disease relationships within the adult African-American population in the southern United States.
DESIGN: Cross-sectional analyses of dietary nutrient intake data, comparing four 24-hour dietary recalls with an FFQ developed by the Lower Mississippi Delta Nutrition Intervention Research Initiative, and its shorter version adapted for use in the Jackson Heart Study.
SUBJECTS: A representative subset of participants (n=499, aged 35 to 81 years) from the baseline Jackson Heart Study cohort (N=5,302) was selected for this study. Data collection took place between winter 2000 and spring 2004.
STATISTICAL ANALYSES: Pearson's correlation coefficients (energy adjusted and de-attenuated) for 26 nutrients estimates from each of the FFQs, comparing them with the mean of four 24-hour dietary recalls. The ability of the FFQs to rank individuals based on nutrient intakes was compared to that of the mean of four 24-hour dietary recalls and attenuation coefficients were also calculated.
RESULTS: Median nutrient intake estimates tended to be higher on the long and lower on the short FFQ compared to the median for the mean of four 24-hour dietary recalls. Energy adjusted and deattenuated correlations of FFQ intake estimates with recalls ranged from 0.20 for sodium to 0.70 for carbohydrate for the short FFQ and from 0.23 for polyunsaturated fat to 0.75 for dietary fiber and magnesium for the long. Attenuation coefficients for men on average were 0.42 for the short and 0.49 for the long FFQ. For women, these were 0.31 for the short and 0.42 for the long FFQ.
CONCLUSIONS: Both FFQs appear to be reasonably valid for assessment of dietary intake of adult African Americans in the South. The Lower Mississippi Delta Nutrition Intervention Research Initiative FFQ exhibited higher intake estimates and stronger correlations with recalls than the Jackson Heart Study FFQ for most nutrients analyzed, more so for women than men.
These are various biomedical training and research programs associated with the Jackson Heart Study.
JHS Statistical Computing Request
This is the mechanism used by JHS to solicit and track all data requests for reports, publications, presentations and for ancillary studies. Using this mechanism, investigators who plan to conduct data analysis outside the JHS can obtain a customized dataset based on the requested need.
Requests for JHS data for publication require approval of a JHS Manuscript Proposal. Requests to collect additional data (i.e., on JHS participants) require an approved JHS Ancillary Study. Please note: ANY data request related to an Ancillary Study or Manuscript Proposal will not be reviewed until approval from the Ancillary Study Sub-Committee and/or the Presentations and Publications Sub-Committee is confirmed.
To submit a request for data, you must complete an online Statistical Computing Request. If this is your first time to this website, you must first register. Please complete the registration form below; once registration has been completed, login to the Statistical Computing Request website and proceed with the data request.
All requests will be reviewed by the JHS Data Management Unit and will generally be reviewed within two weeks of the date of submission. Due to the complexity to a number of data requests, please give us as much notice (i.e., preferred deadline) to when the data are needed.
An automated response e-mail from the data request system will be sent to the e-mail address you provide when your request has been successfully submitted. After review, you may be contacted via telephone or email to clarify questions about or details of your request.
JHS Specimen Inventory
This inventory provides a summary of the availability of biological materials collected and stored on the JHS Cohort. This summary is currently based on biological materials collected on JHS Visit 1. Also, this summary is dynamic due to requests for ancillary studies.
JHS Data and Materials Sharing Agreement
This agreement protects the confidentiality and privacy of JHS participants and their families, investigators granted access to the biological materials, genetic analysis data, and clinical data collected by the JHS. These data and materials have been stripped of all personal identifiers. Failure to comply with this Distribution Agreement could result in denial of further access to JHS samples and data. Violation of the confidentiality requirements of this agreement is considered a breach of confidentiality and may leave requesting investigators liable to legal action on the part of JHS participants, their families, or the United States Government.