Exercise Capacity in Adult African-Americans Referred for Exercise Stress Testing

Exploring the role of blood pressure in the black-white disparity in cardiovascular disease mortality: a causal mediation analysis

BACKGROUND

Cardiovascular diseases (CVDs) are the leading cause of death in the USA, and high blood pressure is a major risk factor for CVD. Despite the overall declining rates of CVD mortality in the USA in recent years, marked disparities between racial and ethnic groups persist, with black adults having a higher mortality rate than white adults. We investigated the extent to which blood pressure mediated the black-white disparity in CVD mortality.

METHODS

Data came from the Multi-Ethnic Study of Atherosclerosis, a diverse longitudinal cohort. We included 1325 black and 2256 white community-based adults aged 45-80 years free of clinical CVD at baseline and followed for 14 years. We used causal mediation analysis to estimate the effect of race on CVD mortality that was mediated through blood pressure.

RESULTS

Black participants had a higher hazard of dying from CVD compared with white participants (adjusted hazard ratio (HR): 1.28 (95% CI 0.88, 1.88)), though estimates were imprecise. Systolic blood pressure mediated 27% (HR: 1.02, 95% CI 1.00, 1.06) and diastolic blood pressure mediated 55% (HR: 1.07, 95% CI 1.01, 1.10) of the racial disparities in CVD mortality between white and black participants. Mediation effects were present in men but not in women.

CONCLUSIONS

We found that black-white differences in blood pressure partially explain the observed black-white disparity in CVD mortality, particularly among men. Our findings suggest that public health interventions targeting high blood pressure prevention and management could be important strategies for reducing racial disparities in CVD mortality.

The Child Opportunity Index 2.0 and Disparities in Pediatric Cardiorespiratory Fitness

OBJECTIVE

To evaluate the effect of neighborhood-level characteristics on cardiorespiratory fitness (CRF) via peak oxygen consumption (VO2peak) for healthy pediatric patients.

STUDY DESIGN

The institutional cardiopulmonary exercise testing (CPET) database was analyzed retrospectively. All patients aged ≤ 18 years without a diagnosis of cardiac disease and with a maximal effort CPET were included. Patients were divided into three self-identified racial categories: White, Black, and Latinx. The Child Opportunity Index (COI) 2.0 was used to analyze social determinants of health. CRF was evaluated based on COI quintiles and race. Assessment of the effect of COI on racial disparities in CRF was performed using ANCOVA.

RESULTS

A total of 1753 CPETs met inclusion criteria. The mean VO2peak was 42.1 ± 9.8 mL/kg/min. The VO2peak increased from 39.1 ± 9.6 mL/kg/min for patients in the very low opportunity cohort to 43.9 ± 9.4 mL/kg/min for patients in the very high opportunity cohort. White patients had higher percent predicted VO2peak compared with both Black and Latinx patients (P < .01 for both comparisons). The racial differences in CRF were no longer significant when adjusting for COI.

CONCLUSION

In a large pediatric cohort, COI was associated with CRF. Racial disparities in CRF are reduced when accounting for modifiable risk factors.

The Association Between C24:0/C16:0 Ceramide Ratio and Cardiorespiratory Fitness is Robust to Effect Modifications by Age and Sex

Ceramides and cardiorespiratory (CR) fitness are both related to cardiovascular diseases. The associations of three blood plasma ceramides (C16:0, C22:0, and C24:0) with CR fitness in the population-based Study of Health in Pomerania (SHIP-START-1; n = 1,102; mean age 50.3 years, 51.5% women) are investigated. In addition, subgroup analysis according to age ( Collapse

Key Words

• cardiopulmonary exercise test
• cardiorespiratory fitness
• cardiovascular risk factors
• ceramides

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MESH Headings

• Humans
• Male
• Female
• Middle Aged
• Ceramides
• Cardiorespiratory Fitness
• Biomarkers
• Cardiovascular Diseases/epidemiology

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Grants

• P20 HL113444 NIH HHS
• P20 HL113444 NHLBI NIH HHS
• P30 DK020579 NIH HHS
• R33 HL155858 NHLBI NIH HHS
• P30 DK020579 NIDDK NIH HHS

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Affiliation(s)

Jule Zatloukal Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany
Stephanie Zylla German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, 17475, Greifswald, Germany
Marcello R P Markus Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany
Ralf Ewert Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany
Sven Gläser Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany Clinic for Internal Medicine, Vivantes Klinikum Spandau/Neukölln, 12351, Berlin, Germany
Henry Völzke German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany Institute of Community Medicine, University Medicine Greifswald, 17475, Greifswald, Germany
Diana Albrecht Institute of Community Medicine, University Medicine Greifswald, 17475, Greifswald, Germany Leibniz Institute for Plasma Science and Technology, 17489, Greifswald, Germany
Nele Friedrich German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, 17475, Greifswald, Germany
Matthias Nauck German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, 17475, Greifswald, Germany
Linda R Peterson Division of Cardiology, Department of Medicine, Washington University, St Louis, MO, 63110, USA
Xuntian Jiang Division of Cardiology, Department of Medicine, Washington University, St Louis, MO, 63110, USA
Jean E Schaffer Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA
Stephan B Felix Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany
Marcus Dörr Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany
Martin Bahls Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany
Stefan Gross Dept. of Internal Medicine B, University Medicine Greifswald, 17475, Greifswald, Germany German Centre for Cardiovascular Research (DZHK), 17475, Partner-site Greifswald, Germany

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Symptom-limited exercise capacity is associated with long-term survival

The prognostic value of exercise capacity has been demonstrated in subjects with established cardiovascular diseases. We aim to evaluate the independence of exercise capacity measured by treadmill exercise test (TET) in predicting long-term outcomes among various comorbidities. This study was conducted from January 2003 to December 2012 in a tertiary medical center in Taiwan. Subjects referred for symptom-limited TET were recruited. Peak achieved metabolic equivalents (METs) were determined by treadmill grade and speed at peak exercise. The main outcomes were cardiovascular and all-cause mortality by linking to the National Death Registry. A total of 18,954 participants (57.8 ± 12.8 years, 62% men) achieved a mean peak METs of 9.2. Subjects in the lowest tertile of peak METs were older, had poorer renal function, lower hemoglobin, and more comorbidities. During a median follow-up of 4.3 years, there were 642 mortalities and 132 cardiovascular deaths. Peak METs significantly predicted cardiovascular death and all-cause mortality in the multivariable Cox regression models [hazard ratio (95% confidence intervals): 0.788 (0.660-0.940) and 0.835 (0.772-0.903), respectively]. The prognostic influence of peak METs consistently appeared in the subgroups, regardless of age, gender, body weight, comorbidities, use of beta-blockers, or the presence of exercise-induced ischemia. The fitness was more predictive of long-term outcomes in young or those with ischemic changes during TET (P for interaction: 0.035 and 0.018, respectively). The benefit of fitness was nonlinearly associated with long-term survival. The prognostic impacts of exercise capacity were universally observed in subjects with or without various comorbidities.

Korean vs. Western Exercise Capacity Nomograms for Korean Patients With Cardiovascular Disease

BACKGROUND

Exercise capacity is known to be an independent predictor of cardiovascular events and mortality. However, most previous studies were based on Western populations. Further study is warranted for Asian patients according to ethnic or national standards. We aimed to compare prognostic values of Korean and Western nomograms for exercise capacity in Korean patients with cardiovascular disease (CVD).

METHODS

In this retrospective cohort study, we enrolled 1,178 patients (62 ± 11 years; 78% male) between June 2015 and May 2020, who were referred for cardiopulmonary exercise testing in our cardiac rehabilitation program. The median follow-up period was 1.6 years. Exercise capacity was measured in metabolic equivalents by direct gas exchange method during the treadmill test. The nomogram for exercise capacity from healthy Korean individuals and a previous landmark Western study was used to determine the percentage of predicted exercise capacity. The primary endpoint was the composite of major adverse cardiovascular events (MACE; all-cause death, myocardial infarction, repeat revascularization, stroke and hospitalization for heart failure).

RESULTS

A multivariate analysis showed that the risk of primary endpoint was more than double (hazard ratio [HR], 2.20; 95% confidence interval [CI], 1.10-4.40) in the patients with lower exercise capacity (< 85% of predicted) by Korean nomogram. The lower exercise capacity was one of the strong independent predictors along with left ventricular ejection fraction, age, and level of hemoglobin. However, the lower exercise capacity by Western nomogram could not predict the primary endpoint (HR, 1.33; 95% CI, 0.85-2.10).

CONCLUSION

Korean patients with CVD with lower exercise capacity have higher risk of MACE. Considering inter-ethnic differences in cardiorespiratory fitness, the Korean nomogram provides more suitable reference values than the Western nomogram to determine lower exercise capacity and predict cardiovascular events in Korean patients with CVD.

Aerobic Capacity in Relation to Selected Elements of Body Posture

BACKGROUND

In the 21st century, with the rapid development of many human life areas, physical activity should be prevalent in health maintenance and promotion. Body posture is a motor habit characteristic of every individual. Its correctness depends on numerous aspects, e.g., physical activity, age, mental state, or eating habits. There are numerous reports in the literature on the impact of physical activity on body posture, correct foot arch development, and the level of aerobic capacity in children and adolescents, but there is a noticeable lack of assessments of these characteristics and their correlations in adults.

AIM

To evaluate aerobic capacity in males and females in relation to selected body posture elements.

METHODS

The study involved 45 females and 46 males aged 20-21 years. The inclusion criteria involved declared good health and no contraindications. Selected somatic traits, body posture, and physical capacity indicators were determined.

RESULTS

Physical capacity shows a significant relationship with body mass in both sexes (female: r = -0.346; p = 0.020; male: r = -0.321; p = 0.030). A significant correlation was observed between aerobic capacity and lean body mass in females (r = -0.428; p = 0.003) and body mass (r = -0.461; p = 0.001) and body fat percentage in males (r = -0.443; p = 0.002). A significant correlation was demonstrated between maximal oxygen uptake and Clarke's angle (r = -0.300; p = 0.045) in females, between maximal oxygen uptake and the loaded area of the right foot (r = -0.247; p = 0.098) in the male group, and between maximal oxygen uptake and spine lateral deviation (r = 0.352; p = 0.018) in females. There was no dimorphism between body posture elements and physical capacity except for the level of foot longitudinal arches, feet loading surface, spine lateral deviation, and the range of spine mobility in the sagittal and frontal planes. Aerobic capacity significantly influenced lean body mass (β = -0.379; p = 0.007) and spine deviation from the anatomical axis in the frontal plane in females (β = 0.287; p = 0.039) and body fat percentage in males (β = -0.443; p = 0.002).

CONCLUSIONS

Selected body posture elements demonstrate relationships with physical capacity in both sexes. The results should find wide practical applications, e.g., in promoting a comprehensive assessment of body posture and physical capacity as determinants of health maintenance.

Current state of unhealthy living characteristics in White, African American and Latinx populations

The United States (US) is similar to most industrialized countries in that it falls short on many of the basic metrics related to cardiovascular and overall health. These metrics include nutritional patterns, levels of physical activity (PA), cardiorespiratory fitness (CRF), and prevalence of overweight and obesity. These issues are even more apparent in underserved communities, among whom unhealthy living characteristics cluster and contribute to a disproportionate chronic disease burden. The reasons for these inequities are complex and include social and economic factors as well as reduced access to health care. CRF has been demonstrated to be a critically important risk factor that tends to be lower in disadvantaged groups. In this article we discuss the current state of health & lifestyle characteristics in the US, the impact of social inequality on health, and the particular role that CRF and PA patterns play in the current state of unhealthy living characteristics as they relate to underserved populations.

Racial disparity in sleep apnea-related mortality in the United States

BACKGROUND

Sleep apnea is one of the most common sleep disorders in the United States (US). Although the prevalence, risk factors, and clinical presentations of sleep apnea vary by racial groups, the racial disparity in sleep apnea-related mortality remains unclear.

METHODS

Sleep apnea-related mortality for 1999-2019 was obtained from the National Center for Health Statistics provided by the Centers for Disease Control and Prevention. We examined the mortality trends for sleep apnea using Joinpoint regression analysis and compared the associated outcomes and multiple causes of death between Blacks and Whites.

RESULTS

For 1999-2019, sleep apnea was documented as the underlying cause of death in 17,053 decedents, with 2593 Blacks and 14,127 Whites. The overall age-adjusted mortality rates in all population, Blacks, and Whites were 2.5, 3.5, and 2.4 per 1,000,000 population, respectively (P < 0.001). Both Blacks and Whites had the highest mortality rates in the Midwest and the lowest in the Northeast. Despite the flattened mortality trend in the last decade overall, Black males had a continuous mortality increase over the study period (Annual Percentage Change 2.7%, 95% CI: 1.2-4.2). For both genders of sleep apnea decedents, Blacks were more likely to have multiple cause of death of Cardiac Arrest, Hypertension, Obesity, and Chronic Renal Failure, but Arrhythmia was more common in Whites (P < 0.05).

CONCLUSIONS

There is a significant racial disparity in sleep apnea-related mortality in the US. The uptrend in mortality in Black males and associated outcomes related to cardiovascular disease should raise concerns specifically in Blacks with sleep apnea.

Safety of Exercise Testing in the Clinical Chinese Population

This 18-year cross-sectional study was conducted to provide data on the safety of exercise testing in the clinical Chinese population. We retrospectively identified exercise tests completed at Xiangya Hospital of Central South University from January 1, 2002 to December 31, 2019. From 43,130 unique individuals (50.9% female), a total of consecutive 50,142 tests (standard exercise testing 29,466; cardiopulmonary exercise testing 20,696) were retrieved. Demographics, patients' medical history, exercise testing characteristics, and exercise testing-related adverse events were described. Safety data is expressed as the number of adverse events per 10,000 tests, with 95% confidence interval. The average patients' age was 51 ± 13 years. The majority of patients were diagnosed with at least one disease (N = 44,941, 89.6%). Tests were maximal or symptom-limited. Common clinical symptoms included dizziness (6,822, 13.6%), chest pain or distress (2,760, 5.5%), and musculoskeletal limitations (2,507, 5.0%). Out of 50,142 tests, three adverse events occurred, including one sustained ventricular tachycardia, one sinus arrest with junctional escape rhythm at a rate of 28 bpm, and one syncopal event with fecal and urinary incontinence. The rate of adverse events was 0.8 events per 10,000 tests (95% confidence interval, 0.2–3.0) in men, 0.4 per 10,000 tests (0.7–2.2) in women, and 0.6 per 10,000 tests (0.21.8) total. This study represents the largest dataset analysis of exercise testing in the clinical Chinese population. Our results demonstrate that clinical exercise testing is safe, and the low rate of adverse events related to exercise testing might be due to the overall changes in clinical practice over time.

Trends in cardiorespiratory fitness among apparently healthy adults from the Ball State Adult Fitness Longitudinal Lifestyle STudy (BALL ST) cohort from 1970-2019

Introduction

Cardiorespiratory fitness (CRF) is a strong independent predictor of cardiovascular disease (CVD) and CVD mortality. However, little is known in regards to how CRF has trended in apparently healthy adults over the past several decades.

Purpose

To analyze trends in CRF and CVD risk factors over the last 50 years in a population of apparently healthy adult men and women.

Methods

Participants were 4,214 apparently healthy adults (2,390 men and 1,824 women) from the Ball State Adult Fitness Longitudinal Lifestyle STudy (BALL ST) that performed maximal cardiopulmonary exercise testing between 1970–2019 for the assessment of CRF defined as VO_2max (ml/kg/min). Participants were self-referred either to a community-based exercise program, fitness testing, or were research subjects in exercise related studies and were placed into groups by decade based on testing date.

Results

CRF showed a general trend to decline (P<0.05) from the 1970s to the 2000s with an increase (P<0.05) from the 2000s to the 2010s for both men and women. This pattern persisted for age and sex-adjusted CRF level, determined by Fitness Registry and the Importance of Exercise: A National Data Base (FRIEND). For both women and men, CRF across the decades was associated (P<0.05) with the prevalence of physical inactivity, smoking, obesity, dyslipidemia and hypertension, and with diabetes in men only.

Conclusion

CRF declined from 1970 through the 2000s in a cohort of apparently healthy men and women which was associated with worsening CVD risk profiles. However, the decline in CRF was attenuated over the past decade which may have a positive impact on future CVD in the population. Promoting physical activity to increase CRF should be a primary aspect of CVD prevention programs.

Gender and racial/ethnic differences in physiologic responses in the Stimulant Reduction Intervention using Dosed Exercise Study

Exercise may be beneficial for individuals in substance use disorder (SUD) treatment given the higher rates of both medical and psychiatric comorbidity, namely mood and anxiety disorders, compared to the general population. Gender and/or racial/ethnic differences in health benefits and response to prescribed exercise have been reported and may have implications for designing exercise interventions in SUD programs.

METHOD

Data are from the National Drug Abuse Treatment Clinical Trials Network (NIDA/CTN) Stimulant Reduction Intervention using Dosed Exercise (STRIDE) trial. Gender differences across racial/ethnic groups in physiological responses and stimulant withdrawal severity across time were analyzed using linear mixed effects models.

RESULTS

Males completed significantly more exercise sessions than females and were more adherent to the prescribed exercise dose of 12 Kcal/Kg/Week. Controlling for age, race/ethnicity, treatment group and stimulant withdrawal severity, there was a significant gender by time interaction for body mass index (BMI) (p < 0.001), waist circumference (p < 0.001) and heart rate measured prior to exercise sessions (p < 0.01). For females, body mass index (BMI) and waist circumference increased over time while for males BMI and waist circumference stayed unchanged or slightly decreased with time. Heart rate over time significantly increased for females at a higher rate than in males. Stimulant withdrawal severity was similar in males and females at baseline but males exhibited a significant decrease over time while females did not. Although baseline differences were observed, there were no time by race/ethnicity differences in physiologic responses.

DISCUSSION

Gender differences in response to exercise may have implications for developing gender specific exercise interventions in SUD programs.

The Effects of Social and Behavioral Determinants of Health on the Relationship Between Race and Health Status in U.S. Breast Cancer Survivors

Background: To examine the association between race and health outcomes among U.S. breast cancer (BC) survivors and explore to what extent do social and behavioral factors contribute to racial disparities for these associations. Materials and Methods: Four hundred forty-one female participants diagnosed with BC in the National Health and Nutrition Examination Survey from 2007 to 2016 were included in this study. Poisson regression with robust variance was used to estimate the prevalence ratio (PrR) and 95% confidence intervals for the associations between race, diabetes, hypertension, and other cancers. Results: The PrR for co-occurrence of diabetes and hypertension was 2.21 (p < 0.001) and 1.62 (p < 0.001) times, respectively, among African Americans (AA) compared with non-Hispanic whites. Body mass index (BMI) explained 17.5% of the association between AA race and diabetes prevalence; a smaller reduction (7.8%) was observed adjusting for type of health insurance coverage, only. A 23.5% reduction was observed in the association between AA race and diabetes prevalence with adjustment for BMI and insurance. The association between AA race and hypertension prevalence was reduced by <6% with addition of individual risk factors, including education, insurance, poverty, obesity, smoking, and physical activity, and with adjustment of the combination of these factors. Conclusions: The association between AA race and diabetes prevalence among BC survivors may be partially explained by BMI and insurance coverage to a lesser extent. Interventions to improve outcomes among AA survivors should focus on weight management strategies.

Comparative Cardiorespiratory Fitness in Children: Racial Disparity May Begin Early in Childhood

African American (AA) adults are reported to have lower levels of cardiorespiratory fitness (CRF) as compared to Caucasian adults. CRF is linked to cardiovascular morbidity and mortality. We hypothesized that the disparities start early in childhood. This was a retrospective analysis of the cardiopulmonary exercise test (CPET). We included normal healthy children, ≤ 18 years of age, who had normal electrocardiograms and normal cardiac function. We excluded patients with congenital heart disease, obesity and suboptimal exercise test. The entire cohort was divided into two groups based on race (Caucasian vs. AA) and then further subcategorized by gender. The cohort of 248 patients had a mean ± SD age of 14.4 ± 2.1 years. 158 (60.8%) were males and 158 (60.8%) were Caucasians. Oxygen consumption was higher among Caucasian children when compared to the AA children (48.7 ± 7.9 vs. 45.4 ± 7 mL/kg/min, p = 0.01). This racial disparity continued to persist when comparisons were performed separately for girls and boys. Upon comparing the four groups, the AA females were found to have the lowest values of VO_2max, exercise time and METS (p = 0.001). Thus, in conclusion, the AA children have significantly lower level of CRF, as measured by VO_2max and exercise time. The racial disparity is independent of gender. African American females show the lowest level of aerobic capacity. The findings of our study suggest that the racial disparity in the CRF levels seen in the adult population may begin early in childhood.

Cardiorespiratory fitness and cardiovascular disease - The past, present, and future

The importance of cardiorespiratory fitness (CRF) is now well established and it is increasingly being recognized as an essential variable which should be assessed in health screenings. The key findings that have established the clinical significance of CRF are reviewed in this report, along with an overview of the current relevance of exercise as a form of medicine that can provide a number of positive health outcomes, including increasing CRF. Current assessment options for assessing CRF are also reviewed, including the direct measurement via cardiopulmonary exercise testing which now can be interpreted with age and sex-specific reference values. Future directions for the use of CRF and related measures are presented.

Racial Differences in the Association Between Nonexercise Estimated Cardiorespiratory Fitness and Incident Stroke

OBJECTIVE

To examine the association between estimated cardiorespiratory fitness (eCRF) and incident stroke by black and white race.

PARTICIPANTS AND METHODS

A total of 24,162 participants from the REasons for Geographic And Racial Differences in Stroke study (13,232 [54.8%] women; 9543 [39.5%] blacks; mean age, 64.6±9.3 years) without stroke at enrollment between January 15, 2003, and October 30, 2007, were followed for incident stroke through March 31, 2016. Baseline eCRF in maximal metabolic equivalents was determined using nonexercise sex-specific algorithms and further grouped into age- and sex-specific tertiles.

RESULTS

Over a mean of 8.3±3.2 years of follow-up, 945 (3.9%) incident strokes occurred (377 in blacks and 568 in whites). The association between eCRF and stroke risk differed significantly by race (PInteraction<.001). In whites, after adjustment for stroke risk factors and physical functioning score, the hazard ratio of stroke was 0.82 (95% CI, 0.67-1.00) times lower in the middle tertile of eCRF than in the lowest tertile and was 0.54 (95% CI, 0.43-0.69) times lower in the highest tertile of eCRF. The protective effect of higher levels of eCRF on stroke incidence was more pronounced in those 60 years or older among whites. No association between eCRF and stroke risk was observed in blacks.

CONCLUSION

Estimated cardiorespiratory fitness measured using nonexercise equations is a useful predictor of stroke in whites. The lack of an overall association between eCRF and stroke risk in blacks suggests that the assessment of eCRF in blacks may not be helpful in primary stroke prevention.

Cardiorespiratory Fitness Change and Mortality Risk Among Black and White Patients: Henry Ford Exercise Testing (FIT) Project

BACKGROUND

Little is known about the relationship of change in cardiorespiratory fitness and mortality risk in Black patients. This study assessed change in cardiorespiratory fitness and its association with all-cause mortality risk in Black and White patients.

METHODS

This is a retrospective, longitudinal, observational cohort study of 13,345 patients (age = 55 ± 11 years; 39% women; 26% black) who completed 2 exercise tests, at least 12 months apart at Henry Ford Hospital, Detroit, Mich. All-cause mortality was identified through April 2013. Data were analyzed in 2015-2016 using Cox regression to calculate hazard ratios (HR) for risk of mortality associated with change in sex-specific cardiorespiratory fitness.

RESULTS

Mean time between the tests was 3.4 years (interquartile range 1.9-5.6 years). During 9.1 years (interquartile range 6.3-11.6 years) of follow-up, there were 1931 (14%) deaths (16.5% black, 13.7% white). For both races, change in fitness from Low to the Intermediate/High category resulted in a significant reduction of death risk (HR 0.65 [95% confidence interval (CI), 0.49-0.87] for Black; HR 0.41 [95% CI, 0.34-0.51] for White). Each 1-metabolic-equivalent-of-task increase was associated with a reduced mortality risk in black (HR 0.84 [95% CI, 0.81-0.89]) and white (HR 0.87 [95% CI, 0.82-0.86]) patients. There was no interaction by race.

CONCLUSIONS

Among black and white patients, change in cardiorespiratory fitness from Low to Intermediate/High fitness was associated with a 35% and 59% lower risk of all-cause mortality, respectively.

Association among sickle cell trait, fitness, and cardiovascular risk factors in CARDIA

The contribution of sickle cell trait (SCT) to racial disparities in cardiopulmonary fitness is not known, despite concerns that SCT is associated with exertion-related sudden death. We evaluated the association of SCT status with cross-sectional and longitudinal changes in fitness and risk for hypertension, diabetes, and metabolic syndrome over the course of 25 years among 1995 African Americans (56% women, 18-30 years old) in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Overall, the prevalence of SCT was 6.8% (136/1995) in CARDIA, and over the course of 25 years, 46% (738/1590), 18% (288/1631), and 40% (645/1,611) of all participants developed hypertension, diabetes, and metabolic syndrome, respectively. Compared with participants without SCT, participants with SCT had similar baseline measures of fitness in cross-section, including exercise duration (535 vs 540 seconds; P = .62), estimated metabolic equivalent of tasks (METs; 11.6 vs 11.7; P = .80), maximum heart rate (174 vs 175 beats/min; P = .41), and heart rate at 2 minutes recovery (44 vs 43 beats/min; P = .28). In our secondary analysis, there was neither an association of SCT status with longitudinal changes in fitness nor an association with development of hypertension, diabetes, or metabolic syndrome after adjustment for sex, baseline age, body mass index, fitness, and physical activity. SCT is not associated with reduced fitness in this longitudinal study of young African American adults, suggesting the increased risk for exertion-related sudden death in SCT carriers is unlikely related to fitness. SCT status also is not an independent risk factor for developing hypertension, diabetes, or metabolic syndrome.

Racial Differences in the Prognostic Value of Cardiorespiratory Fitness (Results from the Henry Ford Exercise Testing Project)

The aim of this analysis was to determine whether racial differences exist in the prognostic value of cardiorespiratory fitness (CRF) in black and white patients undergoing stress testing. We included 53,876 patients (mean age 53 ± 13, 49% women) from the Henry Ford Exercise Testing project free of established coronary disease or heart failure who completed a maximal exercise test from 1991 to 2009. Patients were followed for a mean duration of 11.5 years for all-cause mortality, ascertained by linkage with the Death Master File. Follow-up over mean 6.2 years was also available for incident myocardial infarction. Multivariate Cox proportional hazards regression models were used adjusting for demographic variables, risk factors, medications, and reason for stress test referral, including formal interaction testing by race (black vs white). Black patients (n = 16,725) were younger (54 ± 13 vs 52 ± 13, p <0.001) but had higher prevalence of hypertension (73% vs 57%, p <0.001) and obesity (28% vs 21%, p <0.001). On average, black patients achieved a lower CRF compared with whites (8.4 vs 9.5 metabolic equivalents, p <0.0001). A graded increase in mortality risk was noted with decreasing CRF for both black and white patients. In multivariate Cox regression, CRF was a predictor of both myocardial infarction and mortality, with no significant interaction between race, fitness, and outcomes (all interaction terms p >0.10). CRF is a strong predictor of all-cause mortality in both white and black patients, with no significant interaction observed between race, fitness, and outcomes.

Disparities and genetic risk factors in obstructive sleep apnea

Obstructive sleep apnea (OSA) is an increasingly prevalent condition. A growing body of literature supports substantial racial disparities in the prevalence, risk factors, presentation, diagnosis, and treatment of this disease. Craniofacial structure among Asians appears to confer an elevated risk of OSA despite lower rates of obesity. Among African Americans, Native Americans, and Hispanics, OSA prevalence is increased, likely due in part to obesity. The burden of symptoms, particularly excessive daytime sleepiness, is higher among African Americans, although Hispanics more often report snoring. Limited data suggest that African Americans may be more susceptible to hypertension in the setting of OSA. While differences in genetic risk factors may explain disparities in OSA burden, no definitive genetic differences have yet been identified. In addition to disparities in OSA development, disparities in OSA diagnosis and treatment have also been identified. Increased severity of disease at diagnosis among African Americans suggests a delay in diagnosis. Treatment outcomes are also suboptimal among African Americans. In children, tonsillectomy is less likely to cure OSA and more commonly associated with complications in this group. Among adults, adherence to continuous positive airway pressure (CPAP) is substantially lower in African Americans. The reasons for these disparities, particularly in outcomes, are not well understood and should be a research priority.

Cardiac rehabilitation in African Americans: evidence for poorer outcomes compared with whites, especially in women and diabetic participants

BACKGROUND

Cardiac rehabilitation (CR) improves coronary artery disease risk factors and mortality. Outcomes after CR in African Americans (AAs) compared with whites have not been studied extensively.

METHODS

A total of 1,096 patients (169 AAs, 927 whites) were enrolled in a 36-session CR program for ischemic heart disease or postcardiac surgery. The program consisted of exercise, lifestyle modification, and pharmacotherapy.

RESULTS

After CR, quality of life, blood pressure, and low-density lipoprotein cholesterol improved significantly in both AAs and whites, although to a lesser degree in AAs. Whites also had significant improvements in weight and triglyceride concentrations. Overall, mean peak exercise capacity, measured in metabolic equivalents (METs), improved by only 1.6 (95% CI 1.3-1.8) in AAs compared with 2.4 (2.3-2.6) in CCs (P< .001 for AAs vs CCs). African American women had the least improvement in METs, but changes were still significant (1.1 [CI 0.9-1.4]). The subgroup with the least improvement in METs was AA diabetic patients (1.4 (CI 1.1-1.7]).

CONCLUSION

African Americans derive a significant benefit from CR, but not to the same degree as whites, based on changes in risk factors and in exercise capacity. Within both ethnic groups, both women and diabetic patients appeared to have markedly less improvement.

Depressive Symptoms and Walking in African-Americans

OBJECTIVE

Although increased frequency of physical activity is associated with fewer depressive symptoms in African-Americans, most studies do not focus on a specific type of activity. Identifying the activity can provide helpful information for designing interventions that focus on depressive symptoms. The objective of this study was to examine the odds of depressive symptoms in relation to walking in African-Americans.

DESIGN AND SAMPLE

A secondary analysis was performed on the National Survey of American Life. The sample was made up of community-dwelling African-American women (n = 1,903) and men (n = 1,075) who did not meet the DSM-IV-TR criteria for depression.

MEASURES

Walking was measured by self-reported frequency (i.e., never, rarely, sometimes, often). Depressive symptoms were measured with the Center for Epidemiologic Studies Depression scale. Logistic regression for complex samples was used to examine the odds of depressive symptoms in relation to walking.

RESULTS

Women who reported often walking had lower odds for depressive symptoms than women who reported never walking (OR = 0.56, 95% CI = 0.38-0.82). Walking frequency was not related to depressive symptoms in men.

CONCLUSIONS

Walking frequency is a modifiable risk factor for elevated depressive symptoms in African-American women.

The impact of race and higher socioeconomic status on cardiorespiratory fitness

PURPOSE

Previous studies suggest that African Americans (AA) have lower levels of cardiorespiratory fitness (CRF) than their Caucasian (C) counterparts. However, the association between CRF and race/ethnicity in the context of higher socioeconomic status (SES) has not been explored.

METHODS

We evaluated 589 AA (309 men and 203 women) and 33,015 C (19,399 men and 8753 women) enrolled in the Cooper Center Longitudinal Study. Education years and access to a preventive health care examination were used as a proxy for higher SES. Data were collected from a questionnaire, maximal treadmill exercise stress test, and other clinical measures. The outcome variable was CRF, which was stratified into low fit (quintile 1 of CRF) and fit (quintiles 2-5). Multivariable regression was used to compare adjusted mean CRF between groups. P values were adjusted for unbalanced sample size and unequal variance between groups.

RESULTS

The mean education years were similar for AA and C men at 16 yr; however, AA women had more years of education than C (15.8 vs 15.2 yr, P = 0.0062). AA men and women had a significantly higher prevalence of being unfit compared with their C counterparts (men 26.7% vs 12.6%, P < 0.0001; women 21.3% vs 8.4%, P < 0.0001). The adjusted mean estimated maximal METs were 10.9 vs 11.7 and 8.8 vs 9.8 for AA and C men and women, respectively. Fully adjusted odds ratios revealed that AA men had more than twice the risk of being unfit compared with C men. A trend persisted for AA women to have a lower MET value than their counterparts.

CONCLUSIONS

Despite comparable higher SES, lower CRF existed among AA men versus C men. These results suggest that CRF may not be mediated strictly by environmental factors related to SES.

Low cardiorespiratory fitness in African Americans: a health disparity risk factor?

Low cardiorespiratory fitness (CRF) is a well-established risk factor for all-cause and cardiovascular disease mortality. African Americans have higher rates of cardiovascular disease compared with their Caucasian counterparts. However, the extent to which lower CRF levels contribute to the excess risk in African Americans has not been fully explored. The purpose of this review is to: (i) explore the literature evaluating the relationship between CRF and mortality specifically in African American populations; and (ii) critically evaluate the studies which have compared CRF between African American and Caucasians in epidemiological studies and clinical trials. We have further discussed several potential mechanisms that may contribute to the observation of lower CRF levels in African American compared with Caucasian adults, including potential racial differences in physical activity levels, muscle fiber type distribution, and hemoglobin levels. If lower CRF is generally present in African Americans compared with Caucasians, and is of a clinically meaningful difference, this may represent an important public health concern.

Low fitness partially explains resting metabolic rate differences between African American and white women

BACKGROUND

High levels of obesity among African American women have been hypothesized to be partially resultant from a lower resting metabolic rate compared with white women. The aim of the current study was to determine if differences in cardiorespiratory fitness and moderate-to-vigorous physical activity are associated with differences in resting metabolic rate among free-living young adult African American women and white women.

METHODS

Participants were 179 women (white women n = 141, African American women n = 38, mean age = 27.7 years). Resting metabolic rate was measured using indirect calorimetry, body composition using dual energy x-ray absorptiometry, cardiorespiratory fitness via maximal treadmill test, and moderate-to-vigorous physical activity using an activity monitor.

RESULTS

African American women had higher body mass index, fat mass, and fat-free mass compared with white women but lower levels of cardiorespiratory fitness. No differences were observed between African American and white women in resting metabolic rate when expressed as kcal/day (1390.8 ± 197.5 vs 1375.7 ± 173.6 kcal/day, P = .64), but African American women had a lower resting metabolic rate when expressed relative to body weight (2.56 ± 0.30 vs 2.95 ± 0.33 mL/kg/min, P < .001). After statistical adjustment for differences in body composition between groups using linear regression models, African American women had a lower resting metabolic rate compared with white women (1299.4 ± 19.2 vs 1400.4 ± 9.2 kcal/day, P < .001). The addition of cardiorespiratory fitness reduced the differences among groups by 25%. The addition of moderate-to-vigorous physical activity did not improve the model.

CONCLUSIONS

The present study confirms that African American women have a lower resting metabolic rate compared with their white peers, and low cardiorespiratory fitness explained 25% of this difference. Variables associated with resting metabolic rate, such as cardiorespiratory fitness, represent possible points of tailored interventions designed to address high levels of obesity seen in certain demographic groups.

Improving prediction of outcomes in African Americans with normal stress echocardiograms using a risk scoring system

Cardiovascular mortality is high in African Americans, and those with normal results on stress echocardiography remain at increased risk. The aim of this study was to develop a risk scoring system to improve the prediction of cardiovascular events in African Americans with normal results on stress echocardiography. Clinical data and rest echocardiographic measurements were obtained in 548 consecutive African Americans with normal results on rest and stress echocardiography and ejection fractions ≥50%. Patients were followed for myocardial infarction and death for 3 years. Predictors of cardiovascular events were determined with Cox regression, and hazard ratios were used to determine the number of points in the risk score attributed to each independent predictor. During follow-up of 3 years, 47 patients (8.6%) had events. Five variables-age (≥45 years in men, ≥55 years in women), history of coronary disease, history of smoking, left ventricular hypertrophy, and exercise intolerance (<7 METs in men, <5 METs in women, or need for dobutamine stress)-were independent predictors of events. A risk score was derived for each patient (ranging from 0 to 8 risk points). The area under the curve for the risk score was 0.82 with the optimum cut-off risk score of 6. Among patients with risk scores ≥6, 30% had events, compared with 3% with risk score <6 (p <0.001). In conclusion, African Americans with normal results on stress echocardiography remain at significant risk for cardiovascular events. A risk score can be derived from clinical and echocardiographic variables, which can accurately distinguish high- and low-risk patients.

Racial differences in the response of cardiorespiratory fitness to aerobic exercise training in Caucasian and African American postmenopausal women

African American (AA) women have an elevated risk of cardiovascular disease and have been reported to have lower cardiorespiratory fitness (CRF) compared with Caucasian American (CA) women. However, little data exist that evaluate racial differences in the change in CRF following aerobic exercise training. CA (n = 264) and AA (n = 122) postmenopausal women from the Dose-Response to Exercise in Women study were randomized to 4, 8, and 12 kcal·kg body wt(-1)·wk(-13) (KKW) of aerobic training or the control group for 6 mo. CRF was evaluated using a cycle ergometer. A greater increase in relative CRF was observed in CA compared with AA women in the 4 (CA: 1.00 vs. AA: 0.35 ml O2·kg(-1)·min (-1), P = 0.034), 8 (CA: 1.59 vs. AA: 0.82 ml O2·kg(-1)·min (-1), P = 0.041), and 12 (CA: 1.98 vs. AA: 0.50 ml O2·kg(-1)·min (-1), P = 0.001) KKW groups. Similar effects were found in absolute CRF, with the exception of the 4-KKW (CA: 0.04 vs. AA: 0.02 l O2/min, P = 0.147) group. However, in categorical analyses, the percentages of women who improved in both relative (>0 ml O2·kg(-1)·min (-1)) and absolute (>0 l O2/min) CRF were not significantly different for CA and AA women in all exercise groups (all P > 0.05). AA postmenopausal women, in general, had an attenuated increase in CRF (both relative and absolute) following exercise training, but had similar response rates compared with CA women. Future studies should investigate the physiologic mechanisms responsible for this attenuated response.

Obesity and african americans: physiologic and behavioral pathways

Although progress has been made to understand the association between physiological and lifestyle behaviors with regard to obesity, ethnic differences in markers of obesity and pathways towards obesity remain somewhat unexplained. However, obesity remains a serious growing concern. This paper highlights ethnic differences in African Americans and Caucasians that may contribute to the higher prevalence of obesity among African Americans. Understanding ethnic differences in metabolic syndrome criteria, functioning of the hypothalamic pituitary adrenal axis, variations in glucocorticoid sensitivity and insulin resistance, and physical activity and cardiovascular fitness levels may help to inform practical clinical and public health interventions and reduce obesity disparities.

Willingness to pay for obesity pharmacotherapy

Several treatments for obesity have received regulatory approval, but health insurers and other payers typically refuse to support access to them. Thus, patients are left to bear significant out-of-pocket costs for obesity pharmacotherapy. This study aimed to assess preferences and willingness to pay (WTP) for obesity medications among people seeking weight loss in the United States and United Kingdom. An online survey was developed based on literature review, clinician interviews, and profiles of available therapies. Participants indicated their preference for hypothetical treatments which varied by seven attributes: percentage of weight loss, long-term health risk reduction, time to noticeable weight loss, delivery mode, side effects, lifestyle modification, and cost; 502 obese participants completed the survey (mean BMI 37.12 kg/m(2) (±4.63); 73.5% female; 47.7 (±12.9) years of age). The participants deemed weight loss of >21 kg (United Kingdom) and >28 kg (United State) as "acceptable". All treatment attributes were important (P < 0.001) except "time to noticeable weight loss." The survey found that percentage weight loss was the most important factor for patients and a reduction in long-term health risk was relatively less important. Patients were willing to pay £6.51/$10.49 per month per percentage point of weight loss that a pharmacotherapy could provide. Participants also highly valued therapies that did not require substantial lifestyle modifications and were willing to pay £17.78/$30.77 more per month for a one-pill-per-day treatment vs. a weekly injectable. Participants placed a high value on weight loss and avoiding changes to their lifestyle, and less value on reducing long-term risks to health.

Crossvalidation of two heart rate-based equations for predicting VO2max in white and black men

The purpose of this investigation was to crossvalidate 2 equations that use the ratio of maximal heart rate (HRmax) to resting HR (HRrest) for predicting maximal oxygen consumption (VO2max) in white and black men. One hundred and nine white (n = 51) and black (n = 58) men completed a maximal exercise test on a treadmill to determine VO2max. The HRrest and HRmax were used to predict VO2max via the HRindex and HRratio equations. Validity statistics were done to compare the criterion versus predicted VO2max values across the entire cohort and within each race separately. For the entire group, VO2max was significantly overestimated with the HRindex equation, but the HRratio equation yielded no significant difference compared with the criterion. In addition, there were no significant differences shown between VO2max and either HR-based prediction equation for the white subgroup. However, both equations significantly overestimated VO2max in the black group. Furthermore, large standard error of estimates (ranging from 6.92 to 7.90 ml·kg(-1)·min(-1)), total errors (ranging from 8.30 to 8.62 ml·kg(-1)·min(-1)), and limits of agreement (ranging from upper limits of 16.65 to lower limits of -18.25 ml·kg(-1)·min(-1)) were revealed when comparing the predicted to criterion VO2max for both the groups. Considering the results of this investigation, the HRratio and HRindex methods appear to crossvalidate and prove useful for estimating the mean VO2max in white men as a group but not for an age-matched group of black men. However, because of inflated values for error, caution should be exercised when using these methods to predict individual VO2max.

Association of BMI and cardiovascular risk stratification in the elderly African-American females

We aimed to estimate the association of BMI and risk of systemic hypertension in African-American females aged 65 years and older. In this retrospective, cross-sectional study, medical charts were randomly reviewed after obtaining institutional review board approval and data collection was conducted for height, weight, BMI, age, ethnicity, gender, and hypertension. A multivariable logistic regression analysis was performed. The mean BMI was significantly higher in hypertensive subjects than normotensives (30.3 vs. 29 kg/m2; P = 0.003). A higher proportion of hypertensive subjects had a BMI >23 kg/m2 as compared to normotensives (88.9% vs. 83.5%; P = 0.023). When the log odds of having a history of hypertension was plotted against BMI as a continuous variable, we found that the odds showed an increasing trend with increasing BMI and a steep increase after a BMI of 23 kg/m2. When BMI was analyzed as a categorical variable, a BMI of 23-30 kg/m2 was found to have an odds ratio of 1.43 (95% confidence interval 1.01-2.13; P = 0.05) and a BMI of >30 kg/m2 had an odds ratio of 1.76 (95% confidence interval 1.17-2.65; P = 0.007) when compared to a BMI of <23 kg/m2. This association remained significant in both univariate and multivariate analysis. We conclude that BMI is an independent predictor of hypertension in elderly African-American females. Our results indicate that the risk of hypertension increased significantly at BMI of >23 kg/m2 in this ethnic group. Weight reduction to a greater extent than previously indicated could play an integral role in prevention and control of high blood pressure in this particular population.

Relationship between Depressive Symptoms and Cardiovascular Disease Risk Factors in African American Individuals

Objective. To examine the relationship between depressive symptoms and cardiovascular disease (CVD) risk factors in a group of African American individuals. Design. A nonrandom sample of 253 (age 43.7 ± 11.6 years; 37% male) African American individuals was recruited by advertisements. Data were obtained by validated questionnaires, anthropometric, blood pressure, and blood sample measurements. Results. Regression analyses were performed to assess the relationship between depressive symptoms and CVD risk factors controlling for socioeconomic status indicators. These analyses demonstrated that those with higher levels of depressive symptoms had larger waist-to-hip ratios, higher percent body fat, higher triglycerides, and were more likely to be smokers. Conclusions. It has been well documented that higher levels of depressive symptoms are associated with higher CVD risk. However, this evidence is derived primarily from samples of predominantly Caucasian individuals. The present investigation demonstrates that depressive symptoms are related to CVD risk factors in African American individuals.

Prognostic characteristics of cardiopulmonary exercise testing in caucasian and African American patients with heart failure

Peak oxygen consumption (VO(2)) and ventilatory efficiency (minute ventilation/carbon dioxide output [VE/VCO(2)] slope) are prognostically important in heart failure (HF). The purpose of the present study was to compare the prognostic characteristics of these variables between Caucasian and African American patients. A total of 662 HF patients (455 Caucasian/207 African American) underwent cardiopulmonary exercise testing and were tracked for major cardiac events. The VE/VCO(2) slope was the strongest prognostic marker (chi-square >or=18.9, P<.001), irrespective of race. While peak VO(2) was a significant univariate predictor in both Caucasian (chi-square 42.0, P<.001) and African American (5.2, P=.02) subgroups, it was only retained in the Caucasian multivariate regression. The lack of predictive value of peak VO(2) in the African American subgroup was due to its lack of prognostic significance in female patients. While the VE/VCO(2) slope was the most robust prognostic marker in both Caucasian and African American patients, the predictive ability of peak VO(2) seems to be influenced by race and sex.

Correlates of depression at baseline among African Americans enrolled in cardiac rehabilitation

PURPOSE

To compare baseline psychosocial characteristics of African Americans entering phase 2 cardiac rehabilitation who have depression symptoms at or above threshold (Center for Epidemiological Studies Depression Scale [CES-D] score >or=16) with those who do not (CES-D score <16).

METHODS

A nonrandom sample of 112 men and women (n = 78 without depression, n = 34 with depression) was recruited through local phase 2 cardiac rehabilitation programs. Data were obtained by a structured interview and brief physical examination using several reliable and valid instruments. Chi-square tests, Kruskal-Wallis 2-sample tests, Spearman rank correlation coefficients, and logistic regression models were used for analyses.

RESULTS

We found that 30% of the participants were above the depression symptom threshold. Demographic characteristics were not significantly different between individuals at or above threshold and those below threshold. However, depressed individuals above threshold were more likely to be dissatisfied with their neighborhoods (P = .01) and had lower optimism scores (P < .0001), higher stress scores (P < .0001), lower adaptive coping scores (P = .05), and higher problematic coping scores (P < .01) than their counterparts who were below threshold. In the logistic regression model, the odds of being above the depression symptom threshold increased with stress (P < .001) and decreased with optimism (P = .03); none of the other psychosocial characteristics had an independent effect on depression symptoms.

CONCLUSIONS

At baseline, African Americans starting phase 2 cardiac rehabilitation with depression symptoms at or above threshold had more stress and fewer stress resilience factors. Assessing depression and stress resilience factors is important and may lead to more active participation in cardiac rehabilitation once enrolled, as well as optimal cardiovascular health outcomes.