Genome-wide association study for serum urate concentrations and gout among African Americans identifies genomic risk loci and a novel URAT1 loss-of-function allele

Serum urate concentrations are highly heritable and elevated serum urate is a key risk factor for gout. Genome-wide association studies (GWAS) of serum urate in African American (AA) populations are lacking. We conducted a meta-analysis of GWAS of serum urate levels and gout among 5820 AA and a large candidate gene study among 6890 AA and 21 708 participants of European ancestry (EA) within the Candidate Gene Association Resource Consortium. Findings were tested for replication among 1996 independent AA individuals, and evaluated for their association among 28 283 EA participants of the CHARGE Consortium. Functional studies were conducted using (14)C-urate transport assays in mammalian Chinese hamster ovary cells. In the discovery GWAS of serum urate, three loci achieved genome-wide significance (P< 5.0 × 10(-8)): a novel locus near SGK1/SLC2A12 on chromosome 6 (rs9321453, P= 1.0 × 10(-9)), and two loci previously identified in EA participants, SLC2A9 (P= 3.8 × 10(-32)) and SLC22A12 (P= 2.1 × 10(-10)). A novel rare non-synonymous variant of large effect size in SLC22A12, rs12800450 (minor allele frequency 0.01, G65W), was identified and replicated (beta -1.19 mg/dl, P= 2.7 × 10(-16)). (14)C-urate transport assays showed reduced urate transport for the G65W URAT1 mutant. Finally, in analyses of 11 loci previously associated with serum urate in EA individuals, 10 of 11 lead single-nucleotide polymorphisms showed direction-consistent association with urate among AA. In summary, we identified and replicated one novel locus in association with serum urate levels and experimentally characterize the novel G65W variant in URAT1 as a functional allele. Our data support the importance of multi-ethnic GWAS in the identification of novel risk loci as well as functional variants.

Association of genetic variation with systolic and diastolic blood pressure among African Americans: the Candidate Gene Association Resource study

The prevalence of hypertension in African Americans (AAs) is higher than in other US groups; yet, few have performed genome-wide association studies (GWASs) in AA. Among people of European descent, GWASs have identified genetic variants at 13 loci that are associated with blood pressure. It is unknown if these variants confer susceptibility in people of African ancestry. Here, we examined genome-wide and candidate gene associations with systolic blood pressure (SBP) and diastolic blood pressure (DBP) using the Candidate Gene Association Resource (CARe) consortium consisting of 8591 AAs. Genotypes included genome-wide single-nucleotide polymorphism (SNP) data utilizing the Affymetrix 6.0 array with imputation to 2.5 million HapMap SNPs and candidate gene SNP data utilizing a 50K cardiovascular gene-centric array (ITMAT-Broad-CARe [IBC] array). For Affymetrix data, the strongest signal for DBP was rs10474346 (P= 3.6 × 10(-8)) located near GPR98 and ARRDC3. For SBP, the strongest signal was rs2258119 in C21orf91 (P= 4.7 × 10(-8)). The top IBC association for SBP was rs2012318 (P= 6.4 × 10(-6)) near SLC25A42 and for DBP was rs2523586 (P= 1.3 × 10(-6)) near HLA-B. None of the top variants replicated in additional AA (n = 11 882) or European-American (n = 69 899) cohorts. We replicated previously reported European-American blood pressure SNPs in our AA samples (SH2B3, P= 0.009; TBX3-TBX5, P= 0.03; and CSK-ULK3, P= 0.0004). These genetic loci represent the best evidence of genetic influences on SBP and DBP in AAs to date. More broadly, this work supports that notion that blood pressure among AAs is a trait with genetic underpinnings but also with significant complexity.

Age is positively associated with high-density lipoprotein cholesterol among African Americans in cross-sectional analysis: the Jackson Heart Study

BACKGROUND

African Americans have historically had high high-density lipoprotein cholesterol (HDL-C) compared with other races and ethnicities.

OBJECTIVE

We sought to characterize whether there is a cross-sectional association between age and HDL-C in a contemporary community-based study of African Americans.

METHODS

Cross-sectional data were modeled by logistic regression for predictors of HDL-C among African Americans, ages 35-74, participating in the baseline examination of a community-based study of cardiovascular disease in Jackson, Mississippi, during 2000-2004. After excluding persons taking lipid-lowering medications, hormone replacement therapy, oral contraceptives, or thyroid replacement, the analytical data set comprised 2420 persons (1370 women, 1050 men).

RESULTS

HDL-C had a significant positive association with age after controlling for serum triglycerides, sex, waist circumference, percent dietary calories from carbohydrates, alcohol use, and leisure physical activity. Sex was a significant effect modifier of this relationship, whereby the increase in HDL-C with age was steeper for women than for men.

CONCLUSIONS

Cross-sectional analysis found a positive association of HDL-C with age while controlling for triglycerides. Careful evaluation of longitudinal data will be needed to confirm whether this is a true effect of aging, or a cohort or survivor effect.

Geographic representation of the jackson heart study cohort to the African-American population in Jackson, Mississippi

Recent advances in geographic information systems software and multilevel methodology provide opportunities for more extensive characterization of "at-risk" populations in epidemiologic studies. The authors used age-restricted, geocoded data from the all-African-American Jackson Heart Study (JHS), 2000-2004, to demonstrate a novel use of the Lorenz curve and Gini coefficient to determine the representativeness of the JHS cohort to the African-American population in a geographic setting. The authors also used a spatial binomial model to assess the geographic variability in participant recruitment across the Jackson, Mississippi, Metropolitan Statistical Area. The overall Gini coefficient, an equality measure that ranges from 0 (perfect equality) to 1 (perfect inequality), was 0.37 (95% confidence interval (CI): 0.30, 0.45), indicating moderate representation. The population of sampled women (Gini coefficient = 0.34, 95% CI: 0.30, 0.39) tended to be more representative of the underlying population than did the population of sampled men (Gini coefficient = 0.49, 95% CI: 0.35, 0.61). Representative recruitment of JHS participants was observed in predominantly African-American and mixed-race census tracts and in the center of the study area, the area nearest the examination clinic. This is of critical importance as the authors continue to explore novel approaches to investigate the geographic variation in disease etiology.

The triglyceride/high-density lipoprotein cholesterol ratio fails to predict insulin resistance in African-American women: an analysis of Jackson Heart Study

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.

Association of socioeconomic status and CKD among African Americans: the Jackson Heart Study

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.

The role of community health advisors in community-based participatory research

Mistrust and fear of research often exist in minority communities because of assumptions, preconceived ideas, and historical abuse and racism that continue to influence research participation. The research establishment is full of well-meaning 'outsider' investigators who recognize discrimination, health disparities, and insufficient health care providers in minority communities, but struggle in breaking through this history of mistrust. This article provides ethical insights from one such 'insider-outsider', community-based participatory research project implemented via community health advisors in the Mississippi Delta. Both community-based participatory research and community health advisors provide opportunities to address the ethical issues of trust, non-maleficence, and justice in minority communities. Implications for ethics-driven nursing research are discussed.

Race, stability of health insurance coverage, and prescription medication use

OBJECTIVE

To determine the effects of health insurance and race on prescription medication use and expense.

METHODS

An observational, non-experimental design was used. Multivariable regression analyses were conducted to evaluate the independent effects of health insurance status and race on prescription medication use and expense while controlling for sociodemographic, geographic, and health status characteristics. The sample consisted of 19,035 participants in the 1996 through 2003 Medical Expenditure Panel Survey.

FINDINGS

European Americans spent about $300 to $400 more and used three to four more prescriptions annually compared to other racial groups. Prescription medication expenses increased as time spent uninsured increased. Participants with part-year coverage filled four fewer prescriptions than those with full-year health insurance coverage. Participants with private coverage spent less on prescription medications compared to those with public and those with dual public and private coverage ($1,194 vs. $1,931 and $2,076, respectively; p < or = 0.001).

CONCLUSIONS

Significant racial and health insurance status disparities in prescription medication use and expenses exist after controlling for sociodemographic, geographic, and health status characteristics.

Methods for retrospective geocoding in population studies: the Jackson Heart Study

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 geocoding2 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.

Physical activity and obesity in African Americans: the Jackson Heart Study

OBJECTIVES

To better understand how obesity and low levels of physical activity (PA) contribute to racial health disparities, we examined the association of PA domains (work, home life, and leisure) with indicators of socioeconomic status and markers of obesity in African Americans.

METHODS

These cross sectional analyses of interview and clinical measures from the baseline visit of the Jackson Heart Study of cardiovascular disease (CVD) in African Americans of the Jackson, Mississippi metropolitan statistical area included 3,174 women and 1,830 men aged 21-95 years. The main measures were active living, sport, work, home life, and total PA scores; participation in regular moderate or vigorous intensity leisure physical activity (MVLPA); demographics, body mass index (BMI), waist circumference (WC) and CVD risk factors.

RESULTS

The sample was 63% female, 81% high school or college graduates, with 51% aged 45-64 years, and mostly overweight (32%) or obese (53%). Women were less active than men in all domains except home life. Total PA was inversely associated with WC in women and men. The overweight (BMI 25-29.9) group was most active in all domains except work; active living and sport PA and prevalence of MVLPA then declined in a dose response association with increasing BMI. Work PA was associated with the lowest BMI but otherwise with indicators of less favorable socioeconomic status and health.

CONCLUSIONS

Observed differences in PA in African Americans by domain and association with obesity biomarkers suggest areas for future study and intervention to reduce health disparities.

Employment status, coronary heart disease, and stroke among women

PURPOSE

To investigate the association of employment status with coronary heart disease (CHD) and ischemic stroke among middle-aged women.

METHODS

Proportional hazards regression was used to assess the association of employment status, incident CHD, and incident ischemic stroke among 7,058 women, ages 45-64 years at baseline (1987-1989), from the Atherosclerosis Risk in Communities Study.

RESULTS

After adjusting for age and race-field center, women employed outside the home had a decreased risk of CHD (hazard ratio [HR], 0.70; 95% confidence interval [95% CI], 0.56-0.86) and ischemic stroke (HR, 0.62; 95% CI, 0.47-0.84) compared with homemakers. Differences in cardiovascular disease risk factors partially accounted for the association of employment status and CHD (HR, 0.79; 95% CI, 0.63-0.99) and stroke (HR, 0.79; 95% CI, 0.58-1.08). Also, modest differences were noted when the results were stratified by education, with employed women having a lower risk of CHD (HR, 0.65; 95% CI, 0.45-0.93) than homemakers among those with less than a high school education.

CONCLUSIONS

Women employed outside of the home had a lower risk of CHD and stroke compared with homemakers and, for CHD, this association was stronger among women with less than a high school education. These findings suggest additional research into the varied occupational experiences of women, socioeconomic status, and health is warranted.

Dyslipidemia and the treatment of lipid disorders in African Americans

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.

Social environmental stressors, psychological factors, and kidney disease

Kidney disease is one of the most striking examples of health disparities in American public health. Disparities in the prevalence and progression of kidney disease are generally thought to be a function of group differences in the prevalence of kidney disease risk factors such as diabetes, hypertension, and obesity. However, the presence of these comorbidities does not completely explain the elevated rate of progression from chronic kidney disease (CKD) to end-stage renal disease among high-risk populations such as African Americans. We believe that the social environment is an important element in the pathway from CKD risk factors to CKD and end-stage renal disease. This review of the literature draws heavily from social science and social epidemiology to present a conceptual frame specifying how social, economic, and psychosocial factors interact to affect the risks for and the progression of kidney disease.

Social environmental stressors, psychological factors, and kidney disease

Kidney disease is one of the most striking examples of health disparities in American public health. Disparities in the prevalence and progression of kidney disease are generally thought to be a function of group differences in the prevalence of kidney disease risk factors such as diabetes, hypertension, and obesity. However, the presence of these comorbidities does not completely explain the elevated rate of progression from chronic kidney disease (CKD) to end-stage renal disease among high-risk populations such as African Americans. We believe that the social environment is an important element in the pathway from CKD risk factors to CKD and end-stage renal disease. This review of the literature draws heavily from social science and social epidemiology to present a conceptual frame specifying how social, economic, and psychosocial factors interact to affect the risks for and the progression of kidney disease.

Prevalence and awareness of CKD among African Americans: the Jackson Heart Study

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.

Development and psychometric testing of a multidimensional instrument of perceived discrimination among African Americans in the Jackson Heart Study

OBJECTIVE

Assessing the discrimination-health disparities hypothesis requires psychometrically sound, multidimensional measures of discrimination. Among the available discrimination measures, few are multidimensional and none have adequate psychometric testing in a large, African American sample. We report the development and psychometric testing of the multidimensional Jackson Heart Study Discrimination (JHSDIS) Instrument.

METHODS

A multidimensional measure assessing the occurrence, frequency, attribution, and coping responses to perceived everyday and lifetime discrimination; lifetime burden of discrimination; and effect of skin color was developed and tested in the 5302-member cohort of the Jackson Heart Study. Internal consistency was calculated by using Cronbach alpha coefficient. Confirmatory factor analysis established the dimensions, and intercorrelation coefficients assessed the discriminant validity of the instrument.

SETTING

Tri-county area of the Jackson, MS metropolitan statistical area.

RESULTS

The JHSDIS was psychometrically sound (overall alpha = .78, .84 and .77, respectively, for the everyday and lifetime subscales). Confirmatory factor analysis yielded 11 factors, which confirmed the a priori dimensions represented.

CONCLUSIONS

The JHSDIS combined three scales into a single multidimensional instrument with good psychometric properties in a large sample of African Americans. This analysis lays the foundation for using this instrument in research that will examine the association between perceived discrimination and CVD among African Americans.

Prevalence, awareness, treatment, and control of hypertension in the Jackson Heart Study

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.

Cumulative socioeconomic status across the life course and subclinical atherosclerosis

PURPOSE

The purpose of this study is to investigate the relationship between individual-level and neighborhood-level socioeconomic status (SES) across the life course and subclinical atherosclerosis.

METHODS

Participants from the Atherosclerosis Risk in Communities Study (n=12,332) were queried about individual-level SES and residential addresses across the life course. Individual-level measures were scored and summed to obtain a summary score (I-CumSES), whereas residential addresses were geocoded and linked to census data to obtain a summary neighborhood z score (N-CumSES) to evaluate the association of SES with intima-media thickness (IMT) and peripheral arterial disease (PAD).

RESULTS

A 1-SD lower I-CumSES was associated with greater mean IMT in each race-sex group and greater odds of PAD in white men (odds ratio [OR], 1.28; 95% confidence interval [CI], 0.99-1.64), white women (OR, 1.18; 95% CI, 1.02-1.36), and black women (OR, 1.33; 95% CI, 1.00-1.76). Compared with the highest tertile of N-CumSES, the lowest tertile was associated with greater mean IMT among whites, but was not associated with PAD for whites or blacks. When I-CumSES and N-CumSES were considered simultaneously, associations remained for only I-CumSES and were attenuated after adjustment for cardiovascular disease (CVD) risk factors.

CONCLUSIONS

Lower cumulative individual-level SES across the life course was associated with a greater burden of subclinical atherosclerosis, and this association was mediated in part by CVD risk factors.

Overweight and obesity: prevalence, consequences, and causes of a growing public health problem

This paper provides an overview of the evidence on the current epidemic of obesity in the United States. The prevalence of overweight and obesity now exceeds 60% among US adults, and the rate is rapidly increasing among children and adolescents. Dismal medical, social, and economic consequences are already apparent and likely to worsen without multipronged intervention. Increased rates of hypertension, diabetes, and dyslipidemia, among other medical conditions, threaten to shorten the longevity of the American populace by as much as 5 years. The incidence of depression is increasing and experts suggest this is linked with the increased prevalence of obesity. The cost of obesity-related medical care has increased astronomically since 1987, in addition to lost productivity and income. Novel multidisciplinary, preventive, and therapeutic approaches, and social changes are needed that address the complex interplay of biologic, genetic, and social factors that have created the current obesity epidemic.

Blood pressure usually considered normal is associated with an elevated risk of cardiovascular disease

PURPOSE

Research on the risk of cardiovascular disease among individuals with prehypertension (blood pressure 120/80 to 139/89 mm Hg) is incomplete. Additional information among individuals with a high risk of cardiovascular disease complications may help to focus current and future efforts.

SUBJECTS AND METHODS

We performed a prospective cohort analysis among 8960 middle-aged adults in the Atherosclerosis Risk in Communities (ARIC) study. The exposure variables were blood pressure levels: high normal blood pressure, systolic blood pressure 130-139 mm Hg or diastolic blood pressure 85-89 mm Hg; and normal blood pressure, systolic blood pressure 120-129 mm Hg or diastolic blood pressure 80-84 mm Hg. The outcome was incident cardiovascular disease defined as fatal/nonfatal coronary heart disease, cardiac procedure, silent myocardial infarction, or ischemic stroke. Subgroup analysis was performed among blacks, diabetics, individuals aged 55-64 years, individuals with renal insufficiency, and among individuals with varying levels of low-density lipoprotein (LDL) cholesterol and body mass index (BMI).

RESULTS

Compared with optimal blood pressure (systolic blood pressure <120 mm Hg and diastolic blood pressure <80 mm Hg), the relative risk (RR) of cardiovascular disease for high normal blood pressure was 2.33 (95% confidence interval [CI], 1.85-2.92), and RR for normal blood pressure was 1.81 (1.47-2.22); among blacks: RR for high normal blood pressure was 3.29 (95% CI, 1.68-6.45); among diabetics: RR for high normal blood pressure 4.10 (95% CI, 2.26-7.46); age 55-64 years: RR for high normal blood pressure 2.41 (95% CI, 1.75-3.30) among individuals with renal insufficiency: RR for high normal blood pressure was 1.90 (95% CI, 1.34-2.70); among individuals with BMI >30 kg/m2: RR for high normal blood pressure was 3.56 (95% CI, 1.99-6.35); and among individuals with LDL >160 mg/dL, RR for high normal blood pressure was 1.85 (95% CI, 1.26-2.72).

CONCLUSIONS

Individuals with prehypertensive levels of blood pressure have an increased risk of developing cardiovascular disease relative to those with optimal levels. The association is pronounced among blacks, among individuals with diabetes mellitus, and among those with high BMI.

Psychometric examination of the Daily Spiritual experiences Scale

Despite the burgeoning research literature addressing spirituality and its measurements, few instruments have undergone rigorous reliability and validity testing. This study contributed to determining the reliability and validity of the 16- and 6-item Daily Spiritual Experiences Scale (DSES) in a convenience sample of African Americans ages 34-85. Data were collected via self-administered questionnaire including the DSES and sociodemographic variables thought to influence spiritual experiences. Data were analyzed using paired t-tests, ANOVA, inter-class correlation coefficients, Pearson's correlation, and Cronbach's alpha. Both versions were stable over time, internally consistent, and the forms were equivalent and valid in an all-African American sample.

Dietary assessment in African Americans: methods used in the Jackson Heart Study

OBJECTIVES

The dietary assessment methods used in the Jackson Heart Study (JHS) with the entire cohort and a subset of the cohort who participated in a diet and physical activity substudy (DPASS) are reported. These methods were employed to validate culturally explicit data collection instruments developed by Delta Nutrition Intervention Research Initiative (NIRI) for assessing dietary intake in an all African-American cohort.

DESIGN

A validation/calibration design was employed. A short food frequency questionnaire (FFQ) was used with all JHS participants (N=5302). A long FFQ and four 24-hour diet recalls were used for the subset of DPASS participants (n=449).

OUTCOME MEASURES

Completion rates and preliminary macronutrient intakes are reported for the cohort and DPASS methods.

RESULTS

Participants (5302) in the JHS full cohort completed the short FFQ. Of these, 572 were enrolled in the DPASS. A total of 506 participants completed four 24-hour dietary recalls, and 499 completed all six measures, including the long FFQ. Validation of dietary instruments in African Americans will help assure that valid conclusions can be drawn regarding the effects of diet on cardiovascular disease in this population.

Sociocultural methods in the Jackson Heart Study: conceptual and descriptive overview

The Jackson Heart Study (JHS) is a prospective, population-based cohort study designed to investigate risk factors for cardiovascular disease (CVD) in African-American men and women. An aim of the JHS is the elucidation of the role that sociocultural factors play in the excess CVD risk and mortality in African Americans. Considerable evidence is available to document the influence of social, cultural, psychological, and other lifestyle risk factors on cardiovascular outcomes. Far less is known about how these factors affect health outcomes for African Americans. The JHS provides a unique opportunity to evaluate the presence and impact of these factors in this ethnoracial group. This paper describes the rationale and overall approach for sociocultural assessment in the JHS, both generally and for each content area.

Cardiovascular disease event classification in the Jackson Heart Study: methods and procedures

OBJECTIVE

The process of identifying, abstracting, and classifying cardiovascular disease (CVD) endpoints in the Jackson Heart Study (JHS) is described.

METHOD

Trained interviewers conduct telephone annual followup interviews on or near the JHS exam 1 anniversary to ascertain any significant health events since the last JHS contact, including diagnostic tests, hospitalizations, or death. Information on cohort hospitalizations and deaths is transmitted to the medical record abstraction (MRA) unit who review death certificates and hospital records to identify CVD events in the cohort. Interviews with the next of kin and completed questionnaires by physicians and medical examiners or coroners are used to obtain information on deaths in the cohort. A computer-generated diagnosis with follow-up review and adjudication by trained medical personnel completes final, disease-specific event classification of hospitalized and fatal coronary heart disease (CHD), stroke, and congestive heart failure (CHF) events.

DISCUSSION

Surveillance of this well-characterized group of African Americans for CVD events as well as sub- and preclinical manifestations of disease is a central aspect of the JHS. Particular focus is placed on the leading causes of CVD illness and death, including fatal and nonfatal CHD, stroke, and CHF.

Toward resolution of cardiovascular health disparities in African Americans: design and methods of the Jackson Heart Study

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.