Race and region are associated with nutrient intakes among black and white men in the United States

Dietary Patterns, Apolipoprotein L1 Risk Genotypes, and CKD Outcomes Among Black Adults in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study

Rationale & Objective

Dietary factors may impact inflammation and interferon production, which could influence phenotypic expression of Apolipoprotein1 (APOL1) genotypes. We investigated whether associations of dietary patterns with kidney outcomes differed by APOL1 genotypes.

Study Design

Prospective cohort.

Settings & Participants

5,640 Black participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS).

Exposures

Five dietary patterns derived from food frequency questionnaires: Convenience foods, Southern, Sweets and Fats, Plant-based, and Alcohol/Salads.

Outcomes

Incident chronic kidney disease (CKD), CKD progression, and kidney failure. Incident CKD was defined as a change in estimated glomerular filtration rate (eGFR) to <60 mL/min/1.73 m2 accompanied by a ≥25% decline from baseline eGFR or development of kidney failure among those with baseline eGFR ≥60 mL/1.73 m2 body surface area. CKD progression was defined as a composite of 40% reduction in eGFR from baseline or development of kidney failure in the subset of participants who had serum creatinine levels at baseline and completed a second in-home visit/follow-up visit.

Analytical Approach

We examined associations of dietary pattern quartiles with incident CKD (n=4,188), CKD progression (n=5,640), and kidney failure (n=5,640). We tested for statistical interaction between dietary patterns and APOL1 genotypes for CKD outcomes and explored stratified analyses by APOL1 genotypes.

Results

Among 5,640 Black REGARDS participants, mean age was 64 years (standard deviation = 9), 35% were male, and 682 (12.1%) had high-risk APOL1 genotypes. Highest versus lowest quartiles (Q4 vs Q1) of Southern dietary pattern were associated with higher adjusted odds of CKD progression (OR, 1.28; 95% CI, 1.01-1.63) but not incident CKD (OR, 0.92; 95% CI, 0.74-1.14) or kidney failure (HR, 1.48; 95% CI, 0.90-2.44). No other dietary patterns showed significant associations with CKD. There were no statistically significant interactions between APOL1 genotypes and dietary patterns. Stratified analysis showed no consistent associations across genotypes, although Q3 and Q4 versus Q1 of Plant-based and Southern patterns were associated with lower odds of CKD progression among APOL1 high- but not low-risk genotypes.

Limitations

Included overlapping dietary patterns based on a single time point and multiple testing.

Conclusions

In Black REGARDS participants, Southern dietary pattern was associated with increased risk of CKD progression. Analyses stratified by APOL1 genotypes suggest associations may differ by genetic background, but these findings require confirmation in other cohorts.

Racial differences in sympathetic nervous system indicators: Implications and challenges for research

Growing evidence indicates the presence of racial differences in sympathetic nervous system (SNS) functioning, yet the nature of these differences is unclear and appears to vary across different indices of SNS activity. Moreover, racial differences among commonly used indices of SNS activity are under-investigated. This systematic review examines racial differences among widely used resting SNS indices, such as electrodermal activity (EDA), pre-ejection period (PEP), and salivary alpha-amylase (sAA). Our review reveals that Black participants have consistently been found to display lower resting EDA compared to White participants. The few studies that have investigated or reported racial differences in PEP and sAA yield mixed findings about whether racial differences exist. We discuss potential reasons for racial differences in SNS activity, such as index-specific factors, lab confounds, psychosocial environmental factors, and their interactions. We outline a framework characterizing possible contributors to racial differences in SNS functioning. Lastly, we highlight the implications of several definitional, analytic, and interpretive issues concerning the treatment of group differences in psychophysiological activity and provide future recommendations.

Prevalence of Cardiometabolic Risk Factors Among People Living with HIV in Southern Texas

The aim of this study is to estimate the prevalence of cardiometabolic risk factors among people living with HIV (PLWH) in the south Texas region between 2014 and 2018. A total of 2,808 PLWH from the southern Texas region were included using electronic medical records from a combination of health care system databases. The prevalence of cardiometabolic factors such as elevated blood pressure (BP), triglycerides, total cholesterol and blood glucose, low high-density lipoprotein cholesterol (HDL-C), and obesity was evaluated. The association between cardiometabolic risk factors and age, sex, race/ethnicity, and HIV-related variables was evaluated using logistic regression. Approximately 50.8% had elevated BP, followed by low HDL-C (41.7%), elevated glucose (40.3%), elevated triglycerides (35.5%), obesity (27.8%), and elevated total cholesterol (20%). Hispanics had a higher prevalence of low HDL-C (45.5% vs. 39.7%, p = .012), elevated glucose (48.9% vs. 36.3%, p < .001), elevated triglycerides (40.4% vs. 33.0%, p = .001), and obesity (31.3% vs. 26.0%, p = .004) than non-Hispanics. Females had a higher prevalence of low HDL-C (51.9% vs. 39.1%, p < .001), elevated total cholesterol (24.4% vs. 18.8%, p = .010), and obesity (49.5% vs. 21.8%, p < .001) than males. Variables such as age, sex, race/ethnicity, CD4⁺ T cell count, and viral load use were associated with multiple cardiometabolic risk factors. The prevalence of cardiometabolic risk factors remains high among PLWH in the southern Texas region, especially among Hispanics and females.

Magnesium levels in relation to rates of preterm birth: a systematic review and meta-analysis of ecological, observational, and interventional studies

CONTEXT

Experimental studies suggest that magnesium levels in pregnant women may affect the length of gestation, as magnesium affects the activity of smooth muscle in the uterus. Little is known about the association between magnesium levels or supplementation and the rate of preterm birth.

OBJECTIVE

The aim of this systematic review was to summarize the data on magnesium soil levels and preterm birth rates from ecological, observational, and interventional studies.

DATA SOURCES

Soil magnesium levels were obtained from US Geological Survey data, and preterm birth rates were acquired from the March of Dimes Foundation. Relevant epidemiological and clinical studies published until April 2019 in peer-reviewed journals were retrieved from PubMed, Google Scholar, and related reference lists.

STUDY SELECTION

Original studies published in English, conducted in humans, and in which magnesium (dietary/supplemental intake or biomarkers) was an exposure and preterm birth was an outcome were included.

DATA EXTRACTION

Eleven studies were included in the systematic review. Meta-analysis was performed on 6 studies. Overall relative risk (RR) and corresponding 95%CIs for risk of preterm birth in relation to magnesium supplementation were estimated by a random-effects model.

RESULTS

The ecological study revealed an inverse correlation between magnesium content in soil and rates of preterm birth across the United States (r = -0.68; P < 0.001). Findings from 11 observational studies generally support an inverse association between serum magnesium levels and rates of preterm birth. Of the 6 eligible randomized controlled trials, which included 3068 pregnant women aged 20 to 35 years and 352 preterm infants, the pooled RR was 0.58 (95%CI, 0.35-0.96) for women in the magnesium supplementation group compared with women in the control group.

CONCLUSIONS

Accumulated evidence from ecological, observational, and interventional studies consistently indicates that adequate magnesium intake during pregnancy may help reduce the incidence of preterm birth.

No evidence of racial disparities in blood pressure salt sensitivity when potassium intake exceeds levels recommended in the US dietary guidelines

On average, black individuals are widely believed to be more sensitive than white individuals to blood pressure (BP) effects of changes in salt intake. However, few studies have directly compared the BP effects of changing salt intake in black versus white individuals. In this narrative review, we analyze those studies and note that when potassium intake substantially exceeds the recently recommended US dietary goal of 87 mmol/day, black adults do not appear more sensitive than white adults to BP effects of short-term or long-term increases in salt intake (from an intake ≤50 mmol/day up to 150 mmol/day or more). However, with lower potassium intakes, racial differences in salt sensitivity are observed. Mechanistic studies suggest that racial differences in salt sensitivity are related to differences in vascular resistance responses to changes in salt intake mediated by vasodilator and vasoconstrictor pathways. With respect to cause and prevention of racial disparities in salt sensitivity, it is noteworthy that 1) on average, black individuals consume less potassium than white individuals and 2) consuming supplemental potassium bicarbonate, or potassium rich foods can prevent racial disparities in salt sensitivity. However, the new US dietary guidelines reduced the dietary potassium goal well below the amount associated with preventing racial disparities in salt sensitivity. These observations should motivate research on the impact of the new dietary potassium guidelines on racial disparities in salt sensitivity, the risks and benefits of potassium-containing salt substitutes or supplements, and methods for increasing consumption of foods rich in nutrients that protect against salt-induced hypertension.

Differences in Nutrient Intake and Diet Quality Between Non-Hispanic Black and Non-Hispanic White Men in the United States

OBJECTIVES

Non-Hispanic black (NHB) men have higher rates of chronic disease than men in other racial/ethnic groups. Poor diet quality is one risk factor for chronic disease, but research on the diet quality and nutrient intake of NHB men is sparse. The objective of this study was to describe and compare the diet quality and nutrient intake of NHB and non-Hispanic white (NHW) men in the United States.

METHODS

We analyzed cross-sectional data on 5050 men (31.3% NHB, 68.7% NHW) who participated in the National Health and Nutrition Examination Survey (NHANES) during 2007-2012. To assess diet quality, we calculated Healthy Eating Index (HEI)-2010 scores from each participant's 24-hour recall data. We used logistic regression models to determine if NHB men had lower odds of meeting dietary recommendations for nutrient intake than NHW men. We used linear regression models to identify significant differences in HEI-2010 scores between NHB and NHW men.

RESULTS

After adjusting for sociodemographic measures, NHB and NHW men had similar diet quality (P = .59). Compared with NHW men, NHB men had lower odds of meeting recommendations for dietary fiber and cholesterol intake and higher odds of meeting recommendations for saturated fat and sodium intake.

CONCLUSION

Differences between NHB and NHW men in the intake of certain nutrients may be related to chronic disease disparities. Future research should consider racial/ethnic differences in dietary intake among men and the impact these differences have on men's health.

Dietary Patterns and Incident Heart Failure in U.S. Adults Without Known Coronary Disease

BACKGROUND

Dietary patterns and associations with incident heart failure (HF) are not well established in the United States.

OBJECTIVES

The purpose of this study was to determine associations of 5 dietary patterns with incident HF hospitalizations among U.S. adults.

METHODS

The REGARDS (REasons for Geographic and Racial Differences in Stroke) trial is a prospective cohort of black and white adults followed from 2003 to 2007 through 2014. Inclusion criteria included completion of a food frequency questionnaire and no baseline coronary heart disease or HF. Five dietary patterns (convenience, plant-based, sweets, Southern, and alcohol/salads) were derived from principal component analysis. The primary endpoint was incident HF hospitalization.

RESULTS

This study included 16,068 participants (mean age 64.0 ± 9.1 years, 58.7% women, 33.6% black participants, 34.0% residents of the stroke belt). After a median of 8.7 years of follow-up, 363 participants had incident HF hospitalizations. Compared with the lowest quartile, the highest quartile of adherence to the plant-based dietary pattern was associated with a 41% lower risk of HF in multivariable-adjusted models (hazard ratio: 0.59; 95% confidence interval: 0.41 to 0.86; p = 0.004). Highest adherence to the Southern dietary pattern was associated with a 72% higher risk of HF after adjusting for age, sex, and race and for other potential confounders (education, income, region of residence, total energy intake, smoking, physical activity, and sodium intake; hazard ratio: 1.72; 95% confidence interval: 1.20 to 2.46; p = 0.005). However, the association was attenuated and no longer statistically significant after further adjusting for body mass index in kg/m², waist circumference, hypertension, dyslipidemia, diabetes mellitus, atrial fibrillation, and chronic kidney disease. No statistically significant associations were observed with incident HF with reduced or preserved ejection fraction hospitalizations and the dietary patterns. No associations were observed with the other 3 dietary patterns.

CONCLUSIONS

Adherence to a plant-based dietary pattern was inversely associated with incident HF risk, whereas the Southern dietary pattern was positively associated with incident HF risk.

Self-Reported Measures of Discretionary Salt Use Accurately Estimated Sodium Intake Overall but not in Certain Subgroups of US Adults from 3 Geographic Regions in the Salt Sources Study

BACKGROUND

Excess sodium intake can increase blood pressure, and high blood pressure is a major risk factor for cardiovascular disease. Accurate population sodium intake estimates are essential for monitoring progress toward reduction, but data are limited on the amount of sodium consumed from discretionary salt.

OBJECTIVES

The aim of this study was to compare measured sodium intake from salt added at the table with that estimated according to the Healthy People 2020 (HP 2020) methodology.

METHODS

Data were analyzed from the 2014 Salt Sources Study, a cross-sectional convenience sample of 450 white, black, Asian, and Hispanic adults living in Alabama, Minnesota, and California. Sodium intake from foods and beverages was assessed for each participant through the use of 24-h dietary recalls. Estimated sodium intake from salt used at the table was assessed from self-reported frequency and estimated amounts from a previous study (HP 2020 methodology). Measured intake was assessed through the use of duplicate salt samples collected on recall days.

RESULTS

Among all study participants, estimated and measured mean sodium intakes from salt added at the table were similar, with a nonsignificant difference of 8.9 mg/d (95% CI: -36.6, 54.4 mg/d). Among participants who were non-Hispanic Asian, Hispanic, had a bachelor's degree or higher education, lived in California or Minnesota, did not report hypertension, or had normal BMI, estimated mean sodium intake was 77-153 mg/d greater than measured intake (P < 0.05). The estimated mean sodium intake was 186-300 mg/d lower than measured intake among participants who were non-Hispanic black, had a high school degree or less, or reported hypertension (P < 0.05).

CONCLUSIONS

The HP 2020 methodology for estimating sodium consumed from salt added at the table may be appropriate for the general US adult population; however, it underestimates intake in certain population subgroups, particularly non-Hispanic black, those with a high school degree or less, or those with self-reported hypertension. This study was registered at clinicaltrials.gov as NCT02474693.

Secular trends in regional differences in nutritional biomarkers and self-reported dietary intakes among American adults: National Health and Nutrition Examination Survey (NHANES) 1988-1994 to 2009-2010

OBJECTIVE

To understand the contribution of regional differentials in dietary exposures to regional gradients in health, we examined 20-year trends in the association of US census region of residence with nutritional biomarkers and dietary intakes of American adults.

DESIGN

Observational.

SETTING

The biomarker and 24 h dietary recall data were from the National Health and Nutrition Examination Surveys (NHANES) conducted during 1988-1994 and 1999-2010. The US census region was operationalized as Northeast, Midwest, South and West. Nutritional biomarker outcomes were serum folate, vitamins B6, B12, C, D and E, and carotenoids; dietary outcomes were intakes of nutrients, food groups and eating patterns.

SUBJECTS

US adults, n>8000-40 000 for biomarkers and >43 000 for dietary outcomes.

RESULTS

The interactions of survey time period and region were not significant for the examined biomarker and dietary outcomes, indicating similar secular trends among regions. The main effect of region was significant for all nutritional biomarkers except serum vitamin B6, most dietary micronutrients, food groups and eating patterns (P<0·001). The mean serum folate, vitamins B12, C and E, and all carotenoid (except lycopene) biomarker levels, and intakes of dietary fibre, vitamins A, E, C and B6, folate, K, Ca, Mg and Fe, fruits, vegetables and whole grains, were higher in the West and Northeast regions, relative to the South and Midwest regions.

CONCLUSIONS

Overall, the regional gradients in dietary exposure, expressed objectively as biomarkers or as self-reported nutrient and food group intakes, paralleled trajectories reported for health outcomes and were remarkably persistent over time.

Effects of potassium supplements on glucose metabolism in African Americans with prediabetes: a pilot trial

Background: Low potassium has been identified both as a risk factor for type 2 diabetes and as a mediator of the racial disparity in diabetes risk. Low potassium could be a potentially modifiable risk factor, particularly for African Americans.Objective: We sought to determine the effects of potassium chloride (KCl) supplements, at a commonly prescribed dose, on measures of potassium and glucose metabolism.Design: Among African-American adults with prediabetes, we conducted a double-blinded pilot randomized controlled trial that compared the effects of 40 mEq K/d as KCl supplements with a matching placebo, taken for 3 mo, on measures of potassium and glucose metabolism, with measures collected from frequently sampled oral-glucose-tolerance tests (OGTTs).Results: Twenty-seven of 29 recruited participants completed the trial. Participants had high adherence to the study medication (92% by pill count). Participants in both groups gained weight, with an overall mean ± SD weight gain of 1.24 ± 2.03 kg. In comparison with participants who received placebo, urine potassium but not serum potassium increased significantly among participants randomly assigned to receive KCl (P = 0.005 and 0.258, respectively). At the end of the study, participants taking KCl had stable or improved fasting glucose, with a mean ± SD change in fasting glucose of -1.1 ± 8.4 mg/dL compared with an increase of 6.1 ± 7.6 mg/dL in those who received placebo (P = 0.03 for comparison between arms). There were no significant differences in glucose or insulin measures during the OGTT between the 2 groups, but there was a trend for improved insulin sensitivity in potassium-treated participants.Conclusions: In this pilot trial, KCl at a dose of 40 mEq/d did not increase serum potassium significantly. However, despite weight gain, KCl prevented worsening of fasting glucose. Further studies in larger sample sizes, as well as with interventions to increase serum potassium more than was achieved with our intervention, are indicated to definitively test this potentially safe and inexpensive approach to reducing diabetes risk. This trial was registered at clinicaltrials.gov as NCT02236598.

Contribution of Dietary Supplements to Nutritional Adequacy in Race/Ethnic Population Subgroups in the United States

The U.S. Centers for Disease Control and Prevention has reported that nutritional deficiencies in the U.S. population vary by age, gender, and race/ethnicity, and could be as high as nearly one third of certain population groups. Based on nationally representative data in 10,698 adults from National Health and Nutrition Examination Surveys (NHANES) primarily from 2009-2012, assessments were made of race/ethnic differences in the impact of dietary supplements on nutrient intake and prevalence of inadequacies. Compared to food alone, use of any dietary supplement plus food was associated with significantly higher intakes of 14 to 16 of 19 nutrients examined in all race/ethnic groups; and significantly (p < 0.01) reduced rates of inadequacy for 8/17 nutrients examined in non-Hispanic whites, but only 3-4/17 nutrients (calcium, and vitamins A, D, and E) for other race/ethnic groups. Across race/ethnic groups an increased prevalence of intakes above the Tolerable Upper Intake Level (UL) was seen for 1-9/13 nutrients, but all were less than 5% of the population. In conclusion, use of dietary supplements is associated with increased micronutrient intake, decreased nutrient inadequacies, and slight increases in prevalence above the UL in all race/ethnicities examined, with greater benefits among non-Hispanic whites.

Hypertension in African Americans

PURPOSE OF REVIEW

African Americans are over-burdened with hypertension resulting in excess morbidity and mortality. We highlight the health impact of hypertension in this population, review important observations regarding disease pathogenesis, and outline evidence-based treatment, current treatment guidelines, and management approaches.

RECENT FINDINGS

Hypertension accounts for 50% of the racial differences in mortality between Blacks and Whites in the USA. Genome-wide association studies have not clearly identified distinct genetic causes for the excess burden in this population as yet. Pathophysiology is complex likely involving interaction of genetic, biological, and social factors prevalent among African Americans. Non-pharmacologic and pharmacologic therapy is required and specific treatment guidelines for this population are varied. Combination therapy is most often necessary and single-pill formulations are most successful in achieving BP targets. Racial health disparities related to hypertension in African Americans are a serious public health concern that warrants greater attention. Multi-disciplinary research to understand the inter-relationship between biological and social factors is needed to guide successful treatments. Comprehensive care strategies are required to successfully address and eliminate the hypertension burden.

Sources of Sodium in US Adults From 3 Geographic Regions

Supplemental Digital Content is available in the text.

Background:

Most US adults consume excess sodium. Knowledge about the dietary sources of sodium intake is critical to the development of effective reduction strategies.

Methods:

A total of 450 adults were recruited from 3 geographic locations: Birmingham, AL (n=150); Palo Alto, CA (n=150); and the Minneapolis–St. Paul, MN (n=150), metropolitan areas. Equal numbers of women and men from each of 4 race/ethnic groups (blacks, Asians, Hispanics, and non-Hispanic whites) were targeted for recruitment. Four record-assisted 24-hour dietary recalls were collected from each participant with special procedures, which included the collection of duplicate samples of salt added to food at the table and in home food preparation.

Results:

Sodium added to food outside the home was the leading source of sodium, accounting for more than two thirds (70.9%) of total sodium intake in the sample. Although the proportion of sodium from this source was smaller in some subgroups, it was the leading contributor for all subgroups. Contribution ranged from 66.3% for those with a high school level of education or less to 75.0% for those 18 to 29 years of age. Sodium inherent to food was the next highest contributor (14.2%), followed by salt added in home food preparation (5.6%) and salt added to food at the table (4.9%). Home tap water consumed as a beverage and dietary supplement and nonprescription antacids contributed minimally to sodium intake (<0.5% each).

Conclusions:

Sodium added to food outside the home accounted for ≈70% of dietary sodium intake. This finding is consistent with the 2010 Institute of Medicine recommendation for reduction of sodium in commercially processed foods as the primary strategy to reduce sodium intake in the United States.

Clinical Trial Registration:

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02474693.

Daily Intake of Magnesium and its Relation to Urinary Excretion in Korean Healthy Adults Consuming Self-Selected Diets

Magnesium (Mg) is an essential nutrient as a structural constituent of bone and regulator of >300 enzymes. However, studies on intake and urinary excretion of Mg are limited. The purpose of this study was to evaluate Mg intake and its relation to 24-h urinary excretion in healthy adults. Anthropometric measurements and dietary intake by the 24-h recall method were conducted in 80 adults aged 21-69 (average 44.3) years. Urine was collected for 24 h on the day following the dietary survey. Dietary assessment and 24-h urine collection were repeated 3 days later. Daily intake and urinary excretion of Mg were analyzed using Can-Pro and ICP-OES, respectively. The statistical analysis was conducted using SAS program. Mg intake of the subjects was 319 ± 129 mg/day for men and 277 ± 94 mg/day for women and the proportion of subjects who did not meet the estimated average requirement was 50 and 67.5 % for men and women, respectively. Urinary Mg excretion was 30.3 % of the daily Mg intake. Urinary Mg excretion was not significantly correlated with the daily Mg intake. Korean adults are not meeting the recommended intake of Mg, but its urinary excretion suggests homeostasis is not compromised.

Certain Grain Foods Can Be Meaningful Contributors to Nutrient Density in the Diets of U.S. Children and Adolescents: Data from the National Health and Nutrition Examination Survey, 2009-2012

Grain foods may play an important role in delivering nutrients to the diet of children and adolescents. The present study determined grain food sources of energy/nutrients in U.S. children and adolescents using data from the National Health and Nutrition Examination Survey, 2009–2012. Analyses of grain food sources were conducted using a 24-h recall in participants 2–18 years old (N = 6109). Sources of nutrients contained in grain foods were determined using U.S. Department of Agriculture nutrient composition databases and excluded mixed dishes. Mean energy and nutrient intakes from the total diet and from various grain foods were adjusted for the sample design using appropriate weights. All grains provided 14% ± 0.2% kcal/day (263 ± 5 kcal/day), 22.5% ± 0.3% (3 ± 0.1 g/day) dietary fiber, 39.3% ± 0.5% (238 ± 7 dietary folate equivalents (DFE)/day) folate and 34.9% ± 0.5% (5.6 ± 0.1 mg/day) iron in the total diet in children and adolescents. The current analyses showed that certain grain foods, in particular breads, rolls and tortillas, ready-to-eat cereals and quick breads and bread products, are meaningful contributors of folate, iron, thiamin, niacin and dietary fiber, a nutrient of public health concern as outlined by the 2015–2020 Dietary Guidelines for Americans. Thus, specific grain foods contribute to nutrient density and have the potential to increase the consumption of several under-consumed nutrients in children and adolescents.

US Mortality: Influence of Race, Geography and Cardiovascular Risk Among Participants in the Population-Based REGARDS Cohort

OBJECTIVES

We evaluated whether differences in cardiovascular risk factors, as assessed by the Framingham risk scores for stroke and cardiovascular disease (FSRS and FCRS), contributed to disparities in all-cause mortality across race and regional strata of USA.

DESIGN

Race-region-specific FSRS and FCRS scores were computed for 30,086 REGARDS participants who were recruited between January 2003 and October 2007. They were divided across six regions of the "Eight Americas" and then compared after adjusting for race and sex. Kaplan-Meier curves and hazard ratios for all-cause mortality were estimated between regions, first adjusted for age and sex, and then for the risk scores.

RESULTS

After adjustment for age, sex, FCRS, and FSRS, there was no difference in mortality among Middle-America Whites versus Low-Income White. However, mortality was lower among Middle-America Blacks (-23 %; p = 0.06) and High-Risk Urban Blacks (-24 %; p = 0.01) compared to Southern Low-Income Rural Blacks. Compared to Middle-American Whites, mortality was higher among Middle-America Blacks (+39 %; p < 0.001), High-Risk Urban Blacks (+35 %; p < 0.001) and Southern Low-Income Rural Blacks (+85 %; p < 0.001).

CONCLUSION

Accounting for cardiovascular risk unmasked a greater disparity in mortality between Blacks and Whites and among Southern Rural Blacks compared to Middle-America Blacks and High-Risk Urban Blacks.

A prospective study of dietary patterns and cancer mortality among Blacks and Whites in the REGARDS cohort

Marked racial differences exist in dietary patterns and obesity, as well as cancer mortality. This study aims to assess whether dietary patterns are associated with cancer mortality overall and by race. We identified 22,041 participants from the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. Dietary patterns were categorized into: Convenience (Chinese and Mexican foods, pasta, pizza), Plant-based (fruits, vegetables), Southern (added fats, fried foods, sugar-sweetened beverages), Sweets/Fats (sugary foods) and Alcohol/Salads (alcohol, green-leafy vegetables, salad dressing). Using Cox regression, we examined the association between quartiles of dietary patterns and cancer mortality, adjusted for potential confounders, overall among all participants and stratified by race. A total of 873 cancer deaths were observed over the 10-year observation period: 582 (66.7%) in Whites and 291 (33.3%) in Blacks. Greater adherence to the Southern dietary pattern was associated with an increased risk of cancer mortality (4th vs. 1st quartile HR: 1.67; 95% CI: 1.32-2.10) overall, especially among Whites (4th vs. 1st quartile HR: 1.59; 95% CI: 1.22-2.08). The convenience (HR: 0.73; 95% CI: 0.56-0.94) and Plant-based (HR: 0.72; 95% CI: 0.55-0.93) dietary patterns were associated with up to a 28% reduced risk of cancer mortality, but only among Whites. Greater adherence to the Southern dietary pattern increased the risk of cancer mortality, while greater adherence to the convenience and Plant-based diets reduced the risk of cancer mortality among Whites. Racial differences were observed in the association between dietary patterns and cancer mortality, but warrant further study.

Novel Risk Factors for Type 2 Diabetes in African-Americans

In the USA, compared to whites, African-Americans are disproportionately impacted by the diabetes epidemic. Traditional diabetes risk factors, such as obesity, are more common among African-Americans, but these traditional risk factors do not explain all of the disparity in diabetes risk. Recent research has identified novel environmental, lifestyle, physiologic, and genetic risk factors for diabetes, some of which appear to impact African-Americans more than whites. This manuscript reviews the recent literature to highlight some of these novel risk factors that may be contributing to the racial disparity in diabetes risk. Further study is needed of the modifiable risk factors for development of interventions to reduce the risk of diabetes in African-Americans, as well as other high-risk populations.

Type II diabetes disparities in diverse women: the potential roles of body composition, diet and physical activity

The rates of diabetes in the USA are rapidly increasing, and vary widely across different racial/ethnic groups. This paper explores the potential contribution of body composition, diet and physical activity in explaining diabetes disparities across women of different racial and ethnic backgrounds. For body composition, racial/ethnic groups differ widely by BMI, distribution of body mass and quantity and type of adipose tissue. Dietary patterns that vary across race/ethnicity include consumption of meat, added sugars, high-glycemic carbohydrates and fast food. Additionally, physical activity patterns of interest include aerobic versus muscle-strengthening exercises, and the purpose of physical activity (leisure, occupation, or transportation). Overall, these variables provide a partial picture of the source of these widening disparities, and could help guide future research in addressing and reducing diabetes disparities.

Metabolically Healthy Obesity Is Not Associated with Food Intake in White or Black Men

BACKGROUND

Healthy obese individuals may be protected against adverse health outcomes. Diet and race might influence healthy obesity, but data on their roles and interactions on the phenotype are limited.

OBJECTIVE

We compared the food intake of metabolically healthy obese men to those of other weight status-metabolic health phenotypes.

METHODS

Men (n = 4855) aged ≥ 45 y with BMI ≥ 18.5 kg/m(2) and free of cardiovascular diseases, diabetes, and cancer were evaluated in a cross-sectional study of the REGARDS (REasons for Geographic And Racial Differences in Stroke) study cohort. Food intake was assessed with the use of a food frequency questionnaire. Weight status-metabolic health phenotypes were defined by using metabolic syndrome (MetS) and homeostasis model assessment of insulin resistance (HOMA-IR) criteria. Mean differences in food intake among weight status-metabolic health phenotypes were compared with the use of linear regression.

RESULTS

MetS-defined healthy obesity was present in 44% of white obese men and 58% of black obese men; the healthy obese phenotype, based on HOMA-IR, was equally prevalent in both white (20%) and black (21%) obese men. Among white men, MetS-defined healthy and unhealthy obesity were associated with lower wholegrain bread intake and higher consumption of red meat (P < 0.001), whereas HOMA-IR-defined healthy and unhealthy obesity were associated with lower red meat intake (P < 0.0001) compared with healthy normal weight in multivariable-adjusted analyses that adjusted for sociodemographic, lifestyle, and clinical confounders. However, results were attenuated and became nonsignificant after further adjustment for BMI. Healthy and unhealthy overweight, defined by both criteria, were associated with lower whole grain bread intake (P < 0.001) in all models. Among black men, weight status-metabolic health phenotypes were not associated with food intake in all models.

CONCLUSION

Healthy obesity in men is not associated with a healthier diet. Future studies need to consider dietary patterns, which may better inform the holistic effect of diet on healthy obesity, in prospective analyses.

Diet patterns and risk of sepsis in community-dwelling adults: a cohort study

Background

Sepsis is the syndrome of body-wide inflammation triggered by infection and is a major public health problem. Diet plays a vital role in immune health but its association with sepsis in humans is unclear.

Methods

We examined 21,404 participants with available dietary data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a national cohort of 30,239 black and white adults ≥45 years of age living in the US. The primary exposures of interest were five empirically derived diet patterns identified via factor analysis within REGARDS participants: “Convenience” (Chinese and Mexican foods, pasta, pizza, other mixed dishes), “Plant-based” (fruits, vegetables), “Southern” (added fats, fried foods, organ meats, sugar-sweetened beverages), “Sweets/Fats” (sugary foods) and “Alcohol/Salads” (alcohol, green-leafy vegetables, salad dressing). The main outcome of interest was investigator-adjudicated first hospitalized sepsis events.

Results

A total of 970 first sepsis events were observed over ~6 years of follow-up. In unadjusted analyses, greater adherence to Sweets/Fats and Southern patterns was associated with higher cumulative incidence of sepsis, whereas greater adherence to the Plant-based pattern was associated with lower incidence. After adjustment for sociodemographic, lifestyle and clinical factors, greater adherence to the Southern pattern remained associated with higher risk of sepsis (hazard ratio [HR] comparing the fourth to first quartile, HR 1.39, 95 % CI 1.11,1.73). Race modified the association of the Southern diet pattern with sepsis (P_interaction = 0.01), with the Southern pattern being associated with modestly higher adjusted risk of sepsis in black as compared to white participants (HR comparing fourth vs. first quartile HR 1.42, 95 % CI 0.75,2.67 vs. 1.21, 95 % CI 0.93,1.57, respectively).

Conclusion

A Southern pattern of eating was associated with higher risk of sepsis, particularly among black participants. Determining reasons for these findings may help to devise strategies to reduce sepsis risk.

Electronic supplementary material

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Sodium content in packaged foods by census division in the United States, 2009

Excess sodium intake correlates positively with high blood pressure. Blood pressure varies by region, but whether sodium content of foods sold varies across regions is unknown. We combined nutrition and sales data from 2009 to assess the regional variation of sodium in packaged food products sold in 3 of the 9 US census divisions. Although sodium density and concentration differed little by region, fewer than half of selected food products met Food and Drug Administration sodium-per-serving conditions for labeling as "healthy." Regional differences in hypertension were not reflected in differences in the sodium content of packaged foods from grocery stores.

Coronary heart disease risk factors and outcomes in the twenty-first century: findings from the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

REasons for Geographic and Racial Differences in Stroke (REGARDS) is a longitudinal study supported by the National Institutes of Health to determine the disparities in stroke-related mortality across USA. REGARDS has published a body of work designed to understand the disparities in prevalence, awareness, treatment, and control of coronary heart disease (CHD) and its risk factors in a biracial national cohort. REGARDS has focused on racial and geographical disparities in the quality and access to health care, the influence of lack of medical insurance, and has attempted to contrast current guidelines in lipid lowering for secondary prevention in a nationwide cohort. It has described CHD risk from nontraditional risk factors such as chronic kidney disease, atrial fibrillation, and inflammation (i.e., high-sensitivity C-reactive protein) and has also assessed the role of depression, psychosocial, environmental, and lifestyle factors in CHD risk with emphasis on risk factor modification and ideal lifestyle factors. REGARDS has examined the utility of various methodologies, e.g., the process of medical record adjudication, proxy-based cause of death, and use of claim-based algorithms to determine CHD risk. Some valuable insight into less well-studied concepts such as the reliability of current troponin assays to identify "microsize infarcts," caregiving stress, and CHD, heart failure, and cognitive decline have also emerged. In this review, we discuss some of the most important findings from REGARDS in the context of the existing literature in an effort to identify gaps and directions for further research.

Inter- and independent effects of region and race/ethnicity on variety of fruit and vegetable consumption in the USA: 2011 Behavioral Risk Factor Surveillance System (BRFSS)

OBJECTIVE

(i) To estimate the independent and combined effects of race/ethnicity and region on the variety of fruits and vegetables consumed in the USA in 2011; and (ii) to assess whether and to what extent race/ethnicity and region may synergistically influence variety of fruit and vegetable consumption.

DESIGN

Cross-sectional analysis. Multivariate logistic regression predicted the likelihood of meeting fruit and vegetable variety indicators independently and in combination for each race/ethnicity and region. Interaction effects models were used to test for interaction effects between race/ethnicity and region on fruit and vegetable variety.

SETTING

The 2011 Behavioral Risk Factor Surveillance System (BRFSS).

SUBJECTS

The sample consisted of 275 864 adult respondents.

RESULTS

Fewer than half of respondents consumed fruit and all vegetable subcategories at least once weekly. The adjusted likelihood of meeting fruit and vegetable variety indicators varied significantly by race/ethnicity and region (P<0·05). Significant interactions between race/ethnicity and region were found for at least once weekly consumption of beans, orange vegetables, all vegetables, and fruit and all vegetables (P<0·05).

CONCLUSIONS

Our results reinforce previous findings that the variety of vegetable consumption is lacking and is particularly evident among some population subgroups, such as non-Hispanic blacks in the Midwest USA, who may benefit from targeted dietary interventions.

Dietary factors and higher blood pressure in African-Americans

Adverse blood pressure (BP) is a major independent risk factor for epidemic cardiovascular diseases affecting almost one third of the US adult population. This review synthesizes results from studies published over the past few years on BP differences and prevalent hypertension between US blacks and whites and their different intakes of foods (e.g., fruits, vegetables, and dairy products) and micronutrients (e.g., vitamin D, calcium, potassium, and phosphorus). Studies have consistently reported higher prevalence of adverse BP levels and hypertension and less favorable dietary intakes in blacks than in whites, but the influence of specific dietary factors on high BP risk for blacks remains unclear.

Dietary Patterns Derived Using Exploratory and Confirmatory Factor Analysis are Stable and Generalizable Across Race, Region, and Gender Subgroups in the REGARDS Study

Background: Examining diet as a whole using dietary patterns as exposures is a complementary method to using single food or nutrients in studies of diet and disease, but the generalizability of intake patterns across race, region, and gender in the United States has not been established.

Objective: To employ rigorous statistical analysis to empirically derive dietary patterns in a large bi-racial, geographically diverse population and examine whether results are stable across population subgroups.

Design: The present analysis utilized data from 21,636 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who completed the Block 98 food frequency questionnaire. We employed exploratory factor analysis and confirmatory factor analyses on 56 different food groups iteratively and examined differences by race, region, and sex to determine the optimal factor solution in our sample.

Results: Five dietary patterns emerged: the “Convenience” pattern was characterized by mixed dishes; the “Plant-based” pattern by fruits, vegetables, and fish; the “Sweets/Fats” pattern by sweet snacks, desserts, and fats and oils; the “Southern” pattern by fried foods, organ meat, and sweetened beverages; and the “Alcohol/Salads” pattern by beer, wine, liquor, and salads. Differences were most pronounced in the Southern pattern with black participants, those residing in the Southeast, and participants not completing high school having the highest scores.

Conclusion: Five meaningful dietary patterns emerged in the REGARDS study and showed strong congruence across race, sex, and region. Future research will examine associations between these patterns and health outcomes to better understand racial disparities in disease and inform prevention efforts.

Comparison of prevalence of inadequate nutrient intake based on body weight status of adults in the United States: an analysis of NHANES 2001-2008

OBJECTIVE

To compare micronutrient intake status of those overweight and those obese with normal weight adults.

METHODS

Using total nutrient intake (from foods and supplements) from the National Health and Nutrition Examination Survey (NHANES) 2001-2008, we determined usual intakes for micronutrients using the National Cancer Institute methodology in adults (n = 18,177). Only subjects with reliable dietary records were included and pregnant and lactating females were excluded. Subjects were categorized by body weight status as either normal weight (body mass index [BMI] < 25), overweight (BMI ≥ 25 to < 30), or obese (BMI ≥ 30).

RESULTS

A substantial proportion of the adult population (over 40%) had inadequate intakes of vitamin A, vitamin C, vitamin D, vitamin E, calcium, and magnesium. Compared to normal weight adults, obese adults had about 5% to 12% lower (p < 0.05) intakes of micronutrients and higher (p < 0.01) prevalence of nutrient inadequacy.

CONCLUSION

We conclude that obese adults compared to normal weight adults have lower micronutrient intake and higher prevalence of micronutrient inadequacy.

Food intake does not differ between obese women who are metabolically healthy or abnormal

BACKGROUND

Metabolically healthy obesity may confer lower risk of adverse health outcomes compared with abnormal obesity. Diet and race are postulated to influence the phenotype, but their roles and their interrelations on healthy obesity are unclear.

OBJECTIVE

We evaluated food intakes of metabolically healthy obese women in comparison to intakes of their metabolically healthy normal-weight and metabolically abnormal obese counterparts.

METHODS

This was a cross-sectional study in 6964 women of the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Participants were aged 45-98 y with a body mass index (BMI; kg/m(2)) ≥18.5 and free of cardiovascular diseases, diabetes, and cancer. Food intake was collected by using a food-frequency questionnaire. BMI phenotypes were defined by using metabolic syndrome (MetS) and homeostasis model assessment of insulin resistance (HOMA-IR) criteria. Mean differences in food intakes among BMI phenotypes were compared by using ANCOVA.

RESULTS

Approximately one-half of obese women (white: 45%; black: 55%) as defined by MetS criteria and approximately one-quarter of obese women (white: 28%; black: 24%) defined on the basis of HOMA-IR values were metabolically healthy. In age-adjusted analyses, healthy obesity and normal weight as defined by both criteria were associated with lower intakes of sugar-sweetened beverages compared with abnormal obesity among both white and black women (P < 0.05). HOMA-IR-defined healthy obesity and normal weight were also associated with higher fruit and low-fat dairy intakes compared with abnormal obesity in white women (P < 0.05). Results were attenuated and became nonsignificant in multivariable-adjusted models that additionally adjusted for BMI, marital status, residential region, education, annual income, alcohol intake, multivitamin use, cigarette smoking status, physical activity, television viewing, high-sensitivity C-reactive protein, menopausal status, hormone therapy, and food intakes.

CONCLUSIONS

Healthy obesity was not associated with a healthier diet. Prospective studies on relations of dietary patterns, which may be a better indicator of usual diet, with the phenotype would be beneficial.

Dietary patterns and risk of death and progression to ESRD in individuals with CKD: a cohort study

BACKGROUND

Nutrition is linked strongly with health outcomes in chronic kidney disease (CKD). However, few studies have examined relationships between dietary patterns and health outcomes in persons with CKD.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

3,972 participants with CKD (defined as estimated glomerular filtration rate < 60 mL/min/1.73 m2 or albumin-creatinine ratio ≥ 30 mg/g at baseline) from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a prospective cohort study of 30,239 black and white adults at least 45 years of age.

PREDICTORS

5 empirically derived dietary patterns identified by factor analysis: "convenience" (Chinese and Mexican foods, pizza, and other mixed dishes), "plant-based" (fruits and vegetables), "sweets/fats" (sugary foods), "Southern" (fried foods, organ meats, and sweetened beverages), and "alcohol/salads" (alcohol, green-leafy vegetables, and salad dressing).

OUTCOMES

All-cause mortality and end-stage renal disease (ESRD).

RESULTS

816 deaths and 141 ESRD events were observed over approximately 6 years of follow-up. There were no statistically significant associations of convenience, sweets/fats, or alcohol/salads pattern scores with all-cause mortality after multivariable adjustment. In Cox regression models adjusted for sociodemographic factors, energy intake, comorbid conditions, and baseline kidney function, higher plant-based pattern scores (indicating greater consistency with the pattern) were associated with lower risk of mortality (HR comparing fourth to first quartile, 0.77; 95% CI, 0.61-0.97), whereas higher Southern pattern scores were associated with greater risk of mortality (HR comparing fourth to first quartile, 1.51; 95% CI, 1.19-1.92). There were no associations of dietary patterns with incident ESRD in multivariable-adjusted models.

LIMITATIONS

Missing dietary pattern data, potential residual confounding from lifestyle factors.

CONCLUSIONS

A Southern dietary pattern rich in processed and fried foods was associated independently with mortality in persons with CKD. In contrast, a diet rich in fruits and vegetables appeared to be protective.

Intake of trans fat and incidence of stroke in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

BACKGROUND

Whether elevated intakes of trans fatty acids (TFAs) increase the risk of stroke remains unclear. Except for the Women's Health Initiative-Observational Study, most studies that directly assessed the association between TFA intake and stroke yielded null results.

OBJECTIVE

The aim of this study was to investigate the association between TFA intake and stroke incidence.

DESIGN

We prospectively investigated the association between TFA intake and stroke incidence in black and white men and women (n = 17,107) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Participants were recruited between 2003 and 2007 from the continental United States and followed for incident stroke. Diet was assessed by using the Block 1998 food-frequency questionnaire. Cox regression was used to test whether energy-adjusted TFA intake in 1-SD increments was associated with incident stroke.

RESULTS

During a median follow-up of 7 y, 479 strokes were identified, including 401 ischemic strokes. Sex modified the association between TFA intake and stroke (P-interaction = 0.06), and thus the results were stratified by sex. In fully adjusted models, a 1-SD (2-g/d) increase in TFA intake was associated with an increased risk of any stroke in men (HR: 1.14; 95% CI: 1.02, 1.28) but not in women (HR: 0.93; 95% CI: 0.79, 1.11). Similarly, our results showed an increased risk of ischemic stroke in men (HR: 1.13; 95% CI: 1.00, 1.28) but not in women (HR: 0.93; 95% CI: 0.77, 1.12).

CONCLUSIONS

We show that sex modifies the association between TFA intake and stroke; for every 2-g/d increase in TFA intake, there was a 14% increase in the risk of stroke in men but not in women. Our findings provide further evidence to support the concerted effort to minimize TFAs in the diet.

Non-traditional risk factors are important contributors to the racial disparity in diabetes risk: the atherosclerosis risk in communities study

BACKGROUND

Traditional risk factors, particularly obesity, do not completely explain the excess risk of diabetes among African Americans compared to whites.

OBJECTIVE

We sought to quantify the impact of recently identified, non-traditional risk factors on the racial disparity in diabetes risk.

DESIGN

Prospective cohort study.

PARTICIPANTS

We analyzed data from 2,322 African-American and 8,840 white participants without diabetes at baseline from the Atherosclerosis Risk in Communities (ARIC) Study.

MAIN MEASURES

We used Cox regression to quantify the association of incident diabetes by race over 9 years of in-person and 17 years of telephone follow-up, adjusting for traditional and non-traditional risk factors based on literature search. We calculated the mediation effect of a covariate as the percent change in the coefficient of race in multivariate models without and with the covariate of interest; 95 % confidence intervals (95 % CI) were calculated using boot-strapping.

KEY RESULTS

African American race was independently associated with incident diabetes. Body mass index (BMI), forced vital capacity (FVC), systolic blood pressure, and serum potassium had the greatest explanatory effects for the difference in diabetes risk between races, with mediation effects (95 % CI) of 22.0 % (11.7 %, 42.2 %), 21.7 %(9.5 %, 43.1 %), 17.9 % (10.2 %, 37.4 %) and 17.7 % (8.2 %, 39.4 %), respectively, during 9 years of in-person follow-up, with continued effect over 17 years of telephone follow-up.

CONCLUSIONS

Non-traditional risk factors, particularly FVC and serum potassium, are potential mediators of the association between race and diabetes risk. They should be studied further to verify their importance and to determine if they mark causal relationships that can be addressed to reduce the racial disparity in diabetes risk.

Population ancestry and genetic risk for diabetes and kidney, cardiovascular, and bone disease: modifiable environmental factors may produce the cures

Variable rates of disease observed between members of different continental population groups may be mediated by inherited factors, environmental exposures, or their combination. This article provides evidence in support of differential allele frequency distributions that underlie the higher rates of nondiabetic kidney disease in the focal segmental glomerulosclerosis spectrum of disease and lower rates of coronary artery calcified atherosclerotic plaque and osteoporosis in populations of African ancestry. With recognition that these and other common complex diseases are affected by biological factors comes the realization that targeted manipulation of environmental exposures and pharmacologic treatments will have different effects based on genotype. The present era of precision medicine will couple one's genetic makeup with specific therapies to reduce rates of disease based on the presence of disease-specific alleles.

High sodium:potassium intake ratio increases the risk for all-cause mortality: the REasons for Geographic And Racial Differences in Stroke (REGARDS) study

Increased dietary Na intake and decreased dietary K intake are associated with higher blood pressure. It is not known whether the dietary Na:K ratio is associated with all-cause mortality or stroke incidence and whether this relationship varies according to race. Between 2003 and 2007, the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort enrolled 30 239 black and white Americans aged 45 years or older. Diet was assessed using the Block 98 FFQ and was available on 21 374 participants. The Na:K ratio was modelled in race- and sex-specific quintiles for all analyses, with the lowest quintile (Q1) as the reference group. Data on other covariates were collected using both an in-home assessment and telephone interviews. We identified 1779 deaths and 363 strokes over a mean of 4·9 years. We used Cox proportional hazards models to obtain multivariable-adjusted hazard ratios (HR). In the highest quintile (Q5), a high Na:K ratio was associated with all-cause mortality (Q5 v. Q1 for whites: HR 1·22; 95 % CI 1·00, 1·47, P for trend = 0·084; for blacks: HR 1·36; 95 % CI 1·04, 1·77, P for trend = 0·028). A high Na:K ratio was not significantly associated with stroke in whites (HR 1·29; 95 % CI 0·88, 1·90) or blacks (HR 1·39; 95 % CI 0·78, 2·48), partly because of the low number of stroke events. In the REGARDS study, a high Na:K ratio was associated with all-cause mortality and there was a suggestive association between the Na:K ratio and stroke. These data support the policies targeted at reduction of Na from the food supply and recommendations to increase K intake.

Protective effects of low calcium intake and low calcium absorption vitamin D receptor genotype in the California Collaborative Prostate Cancer Study

BACKGROUND

High calcium intake is consistently associated with increased prostate cancer risk in epidemiologic studies. We previously reported that the positive association between calcium intake and risk of aggressive prostate cancer was modified by the single-nucleotide polymorphism (SNP) in the CDX-2 binding site of the vitamin D receptor (VDR) gene, among African American men.

METHODS

We expanded our previous study to include White men, a population with a higher calcium intake and a higher prevalence of the low absorption allele. We also examined VDR polymorphisms at other loci unrelated to calcium absorption. The study included 1,857 prostate cancer cases (1,140 with advanced stage at diagnosis, 717 with localized stage) and 1,096 controls. OR were estimated using conditional logistic regression.

RESULTS

Among both Blacks and Whites, we observed a threshold for calcium intake (604 mg/d) below which prostate cancer risk declined sharply. Low calcium intake was most strongly associated with decreased risk among men with the VDR Cdx2 low calcium absorption genotype (P for interaction = 0.001 and P = 0.06 for Whites and African Americans, respectively). Among all men with this genotype, those in the lowest quartile of calcium intake (≤604 mg/d) had a 50% reduction in risk as compared with those in the upper three quartiles [OR = 0.49; 95% confidence interval (CI), 0.36-0.67]. The association between calcium intake and prostate cancer risk was not modified by genotype at other VDR loci.

CONCLUSIONS

Our findings support the hypothesis that genetic determinants of calcium absorption influence prostate cancer risk.

IMPACT

The differences between African Americans and Whites in calcium absorption and dietary calcium intake may contribute to racial disparities in prostate cancer incidence and mortality rates.

Favorite foods of older adults living in the Black Belt Region of the United States. Influences of ethnicity, gender, and education

The purpose of this study was to examine food preferences of older adults living in the Black Belt Region of the Southeastern United States and the extent to which food preferences vary according to ethnicity, gender, and educational level. 270 older adults who were receiving home health services were interviewed in their home and were queried regarding their favorite foods. Descriptive statistics were used to characterize the sample. Chi-square analysis or one-way analyses of variance was used, where appropriate, in bivariate analyses, and logistic regression models were used in multivariate analyses. A total of 1,857 favorite foods were reported (mean per person=6.88). The top ten favorite foods reported included: (1) chicken (of any kind), (2) collard greens, (3) cornbread, (4) green or string beans, (5) fish (fried catfish is implied), (6) turnip greens, (7) potatoes, (8) apples, (9) tomatoes, fried chicken, and eggs tied, and (10) steak and ice cream tied. African Americans and those with lower levels of education were more likely to report traditional Southern foods among their favorite foods and had a more limited repertoire of favorite foods. Findings have implications for understanding health disparities that may be associated with diet and development of culturally-appropriate nutrition interventions.

The cardiovascular health of urban African Americans: diet-related results from the Genes, Nutrition, Exercise, Wellness, and Spiritual Growth (GoodNEWS) trial

African Americans have a higher incidence of cardiovascular disease (CVD) than Americans in general and are thus prime targets for efforts to reduce CVD risk. Dietary intake data were obtained from African Americans participating in the Genes, Nutrition, Exercise, Wellness, and Spiritual Growth (GoodNEWS) Trial. The 286 women and 75 men who participated had a mean age of 49 years; 53% had hypertension, 65% had dyslipidemia, and 51% met criteria for metabolic syndrome. Their dietary intakes were compared with American Heart Association and National Heart, Lung, and Blood Institute nutrition parameters to identify areas for improvement to reduce CVD risk in this group of urban church members in Dallas, TX. Results from administration of the Dietary History Questionnaire indicated median daily intakes of 33.6% of energy from total fat, 10.3% of energy from saturated fat, 171 mg cholesterol, 16.3 g dietary fiber, and 2,453 mg sodium. A beneficial median intake of 2.9 cups fruits and vegetables per day was coupled with only 2.7 oz fish/week and an excessive intake of 13 tsp added sugar/day. These data indicate several changes needed to bring the diets of these individuals--and likely many other urban African Americans--in line with national recommendations, including reduction of saturated fat, sodium, and sugar intake, in addition to increased intake of fatty fish and whole grains. The frequent inclusion of vegetables should be encouraged in ways that promote achievement of recommended intakes of energy, fat, fiber, and sodium.

Association of dietary magnesium intake with radiographic knee osteoarthritis: results from a population-based study

OBJECTIVE

To examine the cross-sectional association between dietary magnesium intake and radiographic knee osteoarthritis (OA) among African American and white men and women.

METHODS

The presence of radiographic knee OA was examined among participants from the Johnston County Osteoarthritis Project and was defined as a Kellgren/Lawrence grade of at least 2 in at least 1 knee. The Block Food Frequency Questionnaire was used to assess magnesium intake. Effect modifiers were explored by testing interactions of magnesium intake and selected factors based on previous studies. The multivariable logistic regression model with standard energy adjustment method was used to estimate the relationship between magnesium intake and radiographic knee OA.

RESULTS

The prevalence of knee OA was 36.27% among the 2,112 participants. The relationship between magnesium intake and radiographic knee OA was found to be modified by race (P for interaction = 0.03). An inverse threshold association was observed among whites. Compared to participants in the lowest quintile, the relative odds of radiographic knee OA were cut by one-half for participants in the second quintile of magnesium intake (odds ratio 0.52, 95% confidence interval 0.34-0.79); further magnesium intake did not provide further benefits (P for trend = 0.51). A statistically significant association was not observed among African Americans.

CONCLUSION

A modest inverse threshold association was found between dietary magnesium intake and knee OA in whites, but not in African Americans. Further studies are needed to confirm these results and to elucidate the possible mechanisms of action for the racial modification.

Effect of race and genetics on vitamin D metabolism, bone and vascular health

The pathophysiology of chronic kidney disease-mineral and bone disorder accounts for an inverse relationship between bone mineralization and vascular calcification in progressive nephropathy. Inverse associations between bone mineral density (BMD) and calcified atherosclerotic plaque are also observed in individuals of European and African ancestry without nephropathy, suggesting a mechanistic link between these processes that is independent of kidney disease. Despite lower dietary calcium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, African Americans have higher BMD and develop osteoporosis less frequently than do European Americans. Moreover, despite having more risk factors for cardiovascular disease, African Americans have a lower incidence and severity of calcified atherosclerotic plaque formation than do European Americans. Strikingly, evidence is now revealing that serum 25(OH)D and/or 1,25 dihydroxyvitamin D levels associate positively with atherosclerosis but negatively with BMD in African Americans; by contrast, vitamin D levels associate negatively with atherosclerosis and positively with BMD in individuals of European ancestry. Biologic phenomena, therefore, seem to contribute to population-specific differences in vitamin D metabolism, bone and vascular health. Genetic and mechanistic approaches used to explore these differences should further our understanding of bone-blood vessel relationships and explain how African ancestry protects from osteoporosis and calcified atherosclerotic plaque, provided that access of African Americans to health care is equivalent to individuals of European ethnic origin. Ultimately, in our opinion, a new mechanistic understanding of the relationships between bone mineralization and vascular calcification will produce novel approaches for disease prevention in aging populations.

Race and region have independent and synergistic effects on dietary intakes in black and white women

BACKGROUND

Few studies have examined the effects of race and region on dietary intakes and the evidence on racial and regional disparities among women is limited. We aimed to examine whether race and region were associated with nutrient intakes among black and white women living in the Stroke Belt, Stroke Buckle, and Other regions in the United States. We hypothesized that significant differences would be observed among population sub-groups and that the effects of race on dietary intakes would vary across regions.

METHODS

This study included dietary data from 12,105 women from the Reasons for Geographic and Racial Differences in Stroke study (United States). Dietary data were collected using the Block 98 food frequency questionnaire.

RESULTS

Blacks consumed 1.05% lower energy from saturated fat (95% CI: -0.95, -1.16), and intakes were also lower in the Buckle (β = -0.20; 95% CI: -0.08, -0.32) and Belt (β = -0.35; 95% CI: -0.24, -0.46) compared to the Other regions. Within each region, sodium, potassium, and magnesium intakes were all lower among black women compared to white women (P <0.05 for all); intakes were significantly lower among blacks living in the Belt and Buckle compared to those in the Other regions. Significant interactions between race and region were detected for trans fat, calcium, and cholesterol (P <0.05 for all), where black women in the Other regions consumed the lowest dietary cholesterol and calcium while black women in the Belt consumed the lowest trans fat.

CONCLUSIONS

Race and region were significantly associated with nutrient intakes in a large study of black and non-Hispanic white women in the United States. Intakes of trans fat, calcium, and cholesterol among black and white women differed across regions. Race and region thus interact to impact dietary intakes, and their effects may be mediated by such factors as the broader food environment and food availability as well as food customs and culture. Race, region, and their correlates should therefore be considered together when examining diet and disease associations and planning dietary advice for population sub-groups.