Influence of Obesity on the Relationship of Cardiometabolic Risks Factors With Cardiovascular Disease in Older African and European Americans

PURPOSE

This study evaluated the impact of obesity on cardiometabolic risk factors (CRF) interrelationships and predictive efficiency of CVD development in older African (AA) and European Americans (EA).

DESIGN

A comparative research design evaluated CRF risk profile differences between participant groups.

SETTING

Seven neighborhoods in a southern US city.

SUBJECTS

A sample of 179 older AA (n = 128) and EA (n = 51) adults.

MEASURES

Non-fasting blood samples were evaluated for lipids and lipoproteins, glycosylated hemoglobin, systolic -(SBP) and diastolic blood pressure (DBP), body mass index (BMI), body fat percentage (BF%) and physical function.

ANALYSIS

Data were analysis with descriptive statistics, t-tests, and correlations.

RESULTS

AA were heavier than EA although all had above average age-appropriate fitness. Means and relationships between CRF and other variables were different (P < .05) based on race. Both AA (41.3 + 5.8) and EA (38.6 + 6.4) BF% were CRF risks. Holding BMI constant, CRF were generally not related, and the relationships were different for AA and EA. AA had a range of 13.0 to 27.2% more favorable values for cholesterol, HDL-C, and triglyceride. EA had favorable A1c (EA 5.8 vs AA 6.2%) values.

CONCLUSIONS

A limitation of this report is the small sample size. Although further research is warranted, these findings suggest population specific CRF selections would improve CVD prediction in AA.

Cardiometabolic risk factors and cardiovascular disease predictions in older African and European Americans

Cardiometabolic (CMO) risks factors do not provide similar cardiovascular disease (CVD) predictions in young African (AA) and European Americans (EA) adults. Whether CMO risk predictions contribute to this disparity in older adults is unclear. We hypothesize that older AA CMO clustering pattern will be different from EA clustering patterns when determine with non-fasting lipid and lipoproteins. The participants were 106 older adults (66 AA and 40 EA) from a working/middle class neighborhood (income $46,364 – $80,904) in an urban North Carolina community. The participants were evaluated for CMO risk factors (total cholesterol, high- (HDL) and low-density lipoproteins (LDL), triglyceride (TG), glycosylated hemoglobin (HbA1c), systolic –SBP- and diastolic blood pressures -DBP), body mass index (BMI), body fat % (BF%) and timed up and go test (assessed falls risk and physical function). The AA participants were heavier, had higher BMI, BF%, and timed up and go values (p < 0.01). The data were evaluated for differences (t-test) and Pearson correlations for relationships. If data differ by p < 0.05 the data were significantly different. The AA had a 17.6 % higher HDL (64.7 vs 55.1 mg/dL – p < 0.05) and 7.6 % higher HbA1c (5.8 vs 5.4 % – p < 0.01) than EA. Higher HDL values in EA indicate lower CVD risks. The HDL paradox for AA (AA had higher HDL values, but greater CVD risks) was observed and the HbA1c difference may be misleading, as similar glucose values in AA tend to have higher HbA1c values. Lipid, lipoprotein, and blood pressure was not different between the races. AA had higher body composition and HDL values. Although future research on this topic with larger samples, dietary data and detailed descriptions of participations medications is warranted to validate findings from this study. These data suggest older AA and EA adults with similar environmental conditions have similar CMO risks when measures with none fasting blood samples. Since AA have a greater prevalence of CVD, these finding suggests that population specific CMO risk factor clustering may be more effective predictors of CVD for AA.

Do the Same Central Anthropometric Variables that Best Predict Blood Pressure in European Americans also Best Predict Blood Pressure in African Americans?

Objective

The purpose of this study was to determine if central anthropometric variables that best estimate blood pressure risks in European Americans also best estimate blood pressure risks in African Americans.

Design

The participants were 357 normotensive African and European American volunteers with a mean age of 32.6 ± 12.4 years. Participants were evaluated for central adiposity with dual energy X-ray absorptiometry, abdomen and thigh skinfolds, waist and hip circumferences, waist/hip ratio, waist/height ratio, body mass index, and systolic and diastolic blood pressures. Descriptive statistics, partial correlations, ANOVA and stepwise regressions were used to analyze the data.

Results

Central adiposity anthropometric indices made different contributions to blood pressure in African and European American men and women. When weight was held constant, waist circumference shared stronger partial relationships with blood pressure in African Americans (r = .30 to .47) than in European Americans (r = .11 to .32). Waist circumference in combination with other indices was a predictor of systolic and diastolic blood pressures in European American men (P<.05) but only a predictor for diastolic blood pressure in African American men and women (P<.01). Hip circumference was the only predictor for systolic blood pressure (P<.01) in African American men and women.

Conclusions

Further research on the relative contributions of central anthropometric indices to blood pressure in African and European Americans is warranted. A better understanding of this relationship may help reduce hypertensive morbidity and mortality disparities between African and European Americans.

Inflammation and Healthy Lifestyle Choices Influence Cardiometabolic Risks in African American Women

OBJECTIVES

Individuals of African origin in Europe and the Caribbean have a lower prevalence of coronary heart disease (CHD) than do Europeans and European Americans; however, African Americans, especially women, do not possess the same low CHD prevalence as Africans. As such, this study was designed to determine whether highly sensitive C-reactive protein (hsCRP) and fitness (V˙O_2max) cluster with other cardiometabolic risks (CMRs) or whether their influence is independent of other CMRs in African American women.

METHODS

Fifty African American women were compared on fasting glucose, triglyceride, high-density lipoprotein cholesterol, blood pressure, and adiposity-based hsCRP classifications (low <1, group 1; moderate >1, group 2). Participants were obese but metabolically healthy.

RESULTS

Oxygen uptake (V˙O_2max) was correlated with systolic blood pressure, and percentage of fat in group 1. V˙O_2max was related to systolic blood pressure, diastolic blood pressure, low-density lipoprotein-cholesterol, and percentage of fat, and hsCRP was related to triglycerides, and percentage of fat was related to diastolic blood pressure in group 2. These data indicate that CMRs are inversely related to V˙O_2max at moderate hsCRP values in African American women. Inflammation and obesity are relatively independent of other CMRs.

CONCLUSIONS

Inflammation along with sedentary lifestyles may contribute to the disparity observed for CHD morbidity and mortality in African American women. Adding the CMR profile may improve the prediction of CHD in African American women.

Health Fitness Training Responses of Normotensive and Elevated Normotensive Children

The purpose of this study was to compare health fitness profiles of normotensive (blood pressure < 108/76) and elevated normotensive (blood pressure ≥ 108/76) children and to evaluate the health fitness training responses of children with higher and lower blood pressures to a regular program of exercise over an eight month period. The subjects were 386 fourth grade students (lower blood pressures = 305; higher blood pressures = 81). They were measured for height and weight and evaluated before and after an exercise intervention program for flexibility, muscular endurance, cardiovascular endurance, and body fat levels. The results show that children with higher blood pressures were fatter and had lower cardiovascular fitness levels before and after the intervention. They had health fitness profiles similar to hypertensive adults. Their rate of health fitness improvement, with training, was similar to children with lower blood pressures. Therefore, elevated normotensive children have an increased risk of cardiovascular disease but can change their risk profile with regular exercise.

Influence of obesity assessments on cardiometabolic risks in African and European American women

OBJECTIVES

African American women (AAW) have increased odds of developing cardiometabolic (CME) risks and cardiovascular diseases (CVD) compared with European American women (EAW). The influence of obesity on other CME risks and the CVD disparity is unclear. The purpose of our study was to develop a CME index and evaluate the obesity and CME risk index relationships based on race.

DESIGN

A comparative research design was employed in our study as 213 women (132 AAW; 81 EAW) from the Louisiana Delta were evaluated for CME risk clustering patterns by race, based on BMI, dual energy X-ray absorptiometry % body fat and waist conference. Fasting glucose, triglyceride (TC), high density lipoprotein cholesterol (HDL-C), systolic (SBP) and diastolic blood pressure (DBP) were the measured CME risks.

FINDINGS

In summary, when the CME indexes were evaluated by obesity classification categories the ones that were CVD risk or near risk for the AAW were SBP and TG. The trend of CME index risk for the EAW was SBP and glucose. The stepwise regression equations indicate that HDL-C and SBP/DBP were the best indicators of the effects of obesity on CME risks in AAW and that SBP/DBP and glucose were the best indicators of CME risks in EAW.

CONCLUSIONS

Our results indicate that CME risks as evaluated based on obesity categories are different for AAW than for EAW.

Skeletal muscle lipid peroxidation and insulin resistance in humans

OBJECTIVE

The relationships among skeletal muscle lipid peroxidation, intramyocellular lipid content (IMCL), and insulin sensitivity were evaluated in nine insulin-sensitive (IS), 13 insulin-resistant (IR), and 10 adults with type 2 diabetes (T2DM).

DESIGN

Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp [glucose disposal rate (GDR)]. Lipid peroxidation was assessed by 4-hydroxynonenal (HNE)-protein adducts and general oxidative stress by protein carbonyl content. All patients were sedentary.

RESULTS

Protein-HNE adducts were elevated 1.6-fold in T2DM compared with IS adults, whereas IR showed intermediate levels of HNE-modified proteins. Protein-HNE adducts correlated with GDR, waist circumference, and body mass index. IMCL was increased by 4.0- and 1.9-fold in T2DM and IR patients, respectively, compared with IS, and was correlated with GDR and waist circumference but not BMI. Protein carbonyls were not different among groups and did not correlate with any of the measured variables. Correlations were detected between IMCL and protein-HNE.

CONCLUSION

Our data show for the first time that skeletal muscle protein-HNE adducts are related to the severity of insulin resistance in sedentary adults. These results suggest that muscle lipid peroxidation could be involved in the development of insulin resistance.

Benefits of yoga for African American heart failure patients

BACKGROUND

The number of African American (AA) patients living with heart failure (HF) has been increasing, especially among the economically disadvantaged. Yoga therapy has been found to improve physical and psychological parameters among healthy individuals, but its effect in patients with HF remains unknown. The purpose of this study was to examine the effects of yoga therapy on cardiovascular endurance (VO2peak), flexibility, quality of life (QoL), and inflammatory markers on medically stable HF patients.

METHODS

Forty patients (38 AA, 1 Asian, and 1 Caucasian) with systolic or diastolic HF were randomized to the yoga group (YG, n = 21) or the control group (CG, n = 19). All patients were asked to follow a home walk program. Premeasurement and postmeasurement included a treadmill stress test to peak exertion, flexibility, interleukin-6 (IL-6), C-reactive protein (CRP), and extracellular superoxide dismutase (EC-SOD). QoL was assessed by the Minnesota Living with Heart Failure Questionnaire (MLwHFQ).

RESULTS

The statistical analyses (assessed by ANOVA and t-tests) were significant for favorable changes in the YG, compared with those in the CG, for flexibility (P = 0.012), treadmill time (P = 0.002), VO2peak (P = 0.003), and the biomarkers (IL-6, P = 0.004; CRP, P = 0.016; and EC-SOD, P = 0.012). Within the YG, pretest to posttest scores for the total (P = 0.02) and physical subscales (P < 0.001) of the MLwHFQ were improved.

CONCLUSIONS

Yoga therapy offered additional benefits to the standard medical care of predominantly AA HF patients by improving cardiovascular endurance, QoL, inflammatory markers, and flexibility.

Comparison of health perceptions and health status in African Americans and Caucasians

PURPOSE

This study was designed to compare the health perceptions of adults based on race (African American and Caucasian) and gender in the southern United States to determine if health perception contributed to health disparity between African Americans and Caucasians.

METHODS

A between-groups design was used in this study where African Americans and Caucasians completed an extensive health questionnaire and were compared for health perceptions and self-reported health status differences.

RESULTS

Fewer African Americans (p < .05; males, 55.8%; females, 68%) perceived their health to be good to excellent compared with Caucasians (males, 76.6%; females, 77.1%) and more had been diagnosed with 1 or more chronic diseases. Yet, more than three-quarters of all groups thought that their health care provider shared with them good to excellent information about their health, and 75.0% of the African American males and 71.5% of the Caucasian males and more than 62.0% of the African American and Caucasian females stated that medication cost was not a reason they did not take prescribed medications.

CONCLUSIONS

Health perceptions of African Americans are often not consistent with their actual health, and this is especially true for African American males. Their perceptions appear to influence the value they place on health behaviors which may result in a reduced health status.

Predicting oxygen uptake in older adults using lower-limb accelerometer measures

Assessing physical activity in older adults has proven to be difficult but important, because regular participation has a protective and rehabilitative effect against disability and morbidity. Commercially available physical activity monitors measure waist movements and have not been validated for older adults. This study developed a model for establishing prediction equations to estimate older adults physical activity levels based on lower-limb accelerometer measures. Oxygen uptake and lower-limb accelerometer data were simultaneously recorded from treadmill and stair-climbing exercises. The best stepwise regression equations were obtained when accelerometer and weight measures were regressed on oxygen uptake when subjects walked 1, 2, and 3 miles per hour (R = 0.69 with accelerometer on back of the heel) and for accelerometer measures and gender when subjects climbed stairs (R = 0.77 with accelerometer on mid-ankle). These findings illustrate that physical activity can be effectively predicted in older adults from lower-limb accelerometer measurements.

Walking, body composition, and blood pressure dose-response in African American and white women

PURPOSE

The purpose of this study was to evaluate body composition and blood pressure (BP) responses to a 16-week dose of brisk walking in sedentary and obese African American (AA) and White women.

METHODS

Seventy-five sedentary women (45 AA and 30 White) between the ages of 18 and 50 years and body fat > or =27% signed institutional approved informed consent forms and volunteered to participate in this study. The participants were divided into four groups (AA exercisers [AAE], AA control [AAC], White exercisers [WE], White controls [WC]). The exercisers walked three miles a day, three days a week. Body composition and BP were measured before and after the training intervention. Food records were collected before, during, and after the intervention.

RESULTS

Following training, only the WE experienced a reduction in body weight and body fat (P<.05). However, the energy intake of the AAE increased 4.7% during and 16% at the conclusion of the intervention and contributed to them neither losing nor gaining weight or fat. Both exercise groups experienced reductions (P<.05) in systolic (AAE 5.7 mm Hg, WE 11.3 mm Hg) and diastolic BPs (AAE 3.0 mm Hg, WE 3.6 mm Hg) following training, but the reductions for the WE were greater (P<.05) than for the AAE. There were no changes in body composition or BP for either AAC or WC.

CONCLUSIONS

These results indicate that a 16-week walking intervention provides body composition and BP benefits for both AA and White women, but the benefits are greater for White women.

Relationships and CHD risks of BMI, lipoproteins, lipids, and blood pressure in African-American men and women

BACKGROUND

Body mass index (BMI) is believed to be associated with coronary heart disease (CHD) risks. A major question is whether each BMI category provides independent risk information and whether the BMI categories provide similar results for African-American (AA) men and women relative to lipid, lipoproteins, and blood pressure.

METHODS

A descriptive research design was used to evaluate the effects of BMI categories on lipoproteins, lipids, and blood pressure, and to determine if similar CHD risks related to these variables were observed in AA men and women. The 358 (108 men and 250 women; 40-70 year of age) participants were recruited from churches in a southeastern metropolitan area.

RESULTS

The results indicate that BMI is positively associated with lipoproteins, lipids, and blood pressure in both AA men and women. Relative risks for CHD were higher for obese (BMI > 30 kg/m(2)) men and women, but the overweight (OW) category provided the same information as the normal weight (NW) category for men, but not for women.

CONCLUSIONS

This suggests that the same BMI standards provide different CHD risk information for AA men than for AA women and that gender-specific BMI standards may be warranted for more effective CHD risk stratification in AA adults.

Resistive training and long-term function in older adults

The purpose of this study was to evaluate the effects of a 24-month moderate-intensity resistive-training intervention on strength and function in older adults. A repeated-measures experimental research design was employed as a sample of 55 apparently healthy, older, community-dwelling volunteers (30 exercisers- 25 women and 5 men; 25 comparisons- 16 women and 9 men) were evaluated for strength of 5 muscle groups that influence lower extremity movement and physical function. Strength and function were evaluated at 6-month intervals. The findings from this study indicate that a moderate-intensity resistive-training program increases strength in older adults and that the strength benefits are retained for the duration of the intervention. Furthermore, a long-term strength-training program can increase independent-function skills in older adults and might therefore aid in prolonging functional independence.

Effects of long-term resistive training on mobility and strength in older adults with diabetes

BACKGROUND

Strength training has been shown to be beneficial in older adults. However, very little data exist on the effects of strength training in older diabetics.

METHODS

31 community-dwelling older adults with diabetes (mean age = 66.1 years) were randomly assigned to either an exercise (EX) or control (CO) group. The EX group trained the plantar flexors, knee extensors, knee flexors, hip extensors, and hip flexors muscle groups at 50%, 60%, and 70% of 1-repetition maximum, 2.6 days a week, for 24 months. Mobility tests included the timed up and go, 50-foot walk, and walking up and down 8 stairs. Strength and mobility for both groups were evaluated at 6-month intervals.

RESULTS

There was a group and time effect as the EX group increased 31.4% (p <.001) in strength for all muscle groups after the first 6 months of training, and the strength gains were retained for the duration of the training intervention. There was also a group and time effect for mobility as performance increased 8.6% and 9.8% (p =.032 and p = 0.031) for the first 6 and 12 months, respectively, but decreased to 4.6% above baseline at the end of the intervention. There were essentially no changes from baseline strength or mobility values for the CO group.

CONCLUSION

In conclusion, these data suggest that a moderate-intensity resistive-training program can improve mobility and strength for the duration of a 24-month intervention in older adults with diabetes, thus potentially reducing the rate of mobility loss during aging.

Comparison of obesity assessment procedures in obese African-American and white women

The purpose of this study was to compare the accuracy of dual energy X-ray absorptiometry (DEXA) to field-based procedures for the estimation of obesity in 27 sedentary and obese African-American (AA) (34.8, +/- 7.7 yr) and 25 sedentary and obese White women (41.1, +/- 8.3 yr). Body fat was estimated by DEXA and skinfolds equations. Obesity was also estimated from BMI and percent of ideal body weight (greater than 120% of ideal body weight based on height and weight tables). All of the procedures classified the subjects as obese. Results from each procedure were compared with minimal obesity standards to determine the percentage by which each mean exceeded the minimal standard (percent difference). The percent difference was smaller for BMI and percent ideal body weight than for the 2 body fat assessment procedures. Although DEXA percent body fat did not differ by race, BMI and percent ideal body weight tended to be greater in AA women compared to White women, and more AA women were classified as obese. Therefore, field-based procedures that do not include percent body fat assessments are not as accurate for AA women. This finding suggests that obesity can be more effectively assessed in AA women if the standards for classifications are population-specific.

The thermic effect of food and obesity: discrepant results and methodological variations

Studies have yielded discrepant results concerning whether the thermic effect of food (TEF) is reduced in obesity. Methodological variations among published studies make understanding the discrepant results very difficult. Although methodological differences are often noted as contributing to the discrepant results, little work has been done to address these differences and standardize experimental protocols. This paper reviews 50 studies that have investigated TEF in obesity and focuses on factors related to experimental protocol and subject control that reportedly affect measurements of resting energy expenditure, postprandial energy expenditure, and the calculation of TEF.

Personal characteristics that influence exercise behavior of older adults

Long-term exercise participation among older adults will result in healthier lifestyles and reduced need for health care. A better understanding, therefore, of what influences older individuals to start and maintain exercise plans would be beneficial. The twofold purpose of this study was (1) to create a knowledge base of determinants that influence exercise behavior in older adults and (2) to have health professionals prioritize determinants that affect exercise initiation and adherence in older adults. The expert panel examined nine determinants within the category of personal characteristics: age, gender, ethnicity, occupation, educational level, socioeconomic status, biomedical status, smoking status, and past exercise participation. The experts rated the determinants on importance for influencing exercise behavior of older adults. This expert panel concluded that older adults who are in good health and have a history of exercise activity might be more likely to participate in long-term exercise programs.

Are practical methods of evaluating body fat in African-American women accurate?

Sixteen African American females were evaluated for body fat to assess the accuracy of several practical methods of estimation: near-infrared interactance, bioelectrical impedance, and Sloan and Jackson skinfold equations. Most methods produced different results from hydrostatic weighing and produced different body fat values from each other suggesting that practical methods do not provide accurate measurements.

Comparison of existing skinfold equations for estimating body fat in African American and white women

The purpose of this study was to compare seven skinfold equations with underwater weighing (UWW) for estimating body fat in 39 African American [age: 22.8 +/- 3.6 y (x +/- SD); weight: 59.6 +/- 8.3 kg) and 39 white (age: 22.1 +/- 2.9 y; weight: 61.7 +/- 7.3 kg) women. The hypothesis examined was that the equations would produce more accurate body fat estimates in white women, but would be appropriate for use in African American women. Body fat estimated from two quadratic, three linear, and two logarithmic skinfold equations was compared with body fat estimated from UWW; the same procedures were used to evaluate the results in both African Americans and whites. The data were analyzed by using t tests, analysis of variance, Scheffé's honestly significant difference tests, correlations, error assessments, and agreement. The results showed that total error, SEE, and SD values were larger in the African American women than in the white women and were not within acceptable limits listed in the literature. The correlation coefficients were lower in the African American women than in the white women. Agreement between the skinfold equations and UWW, based on deviations from mean differences, was better in the white women. In conclusion, the skinfold prediction equations evaluated in this study were more variable and produced more error when used in African American women. Therefore, population-specific equations for African American women should be used to estimate body fat because they will probably yield more accurate estimates.

Exercise adherence for a strength training program in older adults

The first purpose of the present investigation was to examine initiation of a moderate intensity strength training and flexibility program in older adults. The second purpose was to assess adherence to training six months after conclusion of the initiation period. Forty-six apparently healthy older adults (mean age = 71.3; 33 women; 13 men) trained one hour, three days a week, for 4 months on a Nautilus Multi-Station Unit. The subjects trained on five upper extremity, three trunk, and three lower extremity stations. Training sessions consisted of 50 minutes of strength training and 10 minutes of flexibility exercises. Baseline exercise habits were obtained from the subjects using the Physical Exercise Profile (PEP). Subjects also completed portions of the PEP immediately following the conclusion of the 4-month intervention and 6 months later. The data were analyzed by chi square contingency tables. The subjects had over a 95% initiation rate during the study. Exercise leadership and program organization were found to be the most important reasons for the high initiation rate. Two determinants that influenced older adults to continue training were identified: satisfaction with the exercise routine and body image. These results indicate that exercise programs designed for older adults should emphasize exercise leadership to facilitate program initiation and subsequent exercise adherence.

A follow-up study on the effects of strength training with older adults

This study was designed to evaluate changes in strength, and functional ability in older adults after completion of a 4-month strength training intervention. The follow-up sample consisted of 30 older adults (12 men and 18 women, 100% Caucasian; mean age = 71.8) who were evaluated an average of 15 months after completion of the training intervention. At the follow-up testing, 45% of the subjects reported that they continued strength training on their own after the conclusion of the strength training intervention. The data were evaluated for pre-, post-training, and follow-up differences via repeated measures ANOVA and Scheffé HSD tests. After the intervention, the subjects showed significant improvement in muscular strength and one of the functional tasks measuring coordination. From post- to the 15 month follow-up, the subjects declined in muscular strength and functional ability (mobility). However, at follow-up the subjects were stronger and had better coordination than before they entered the strength training intervention. These results suggest benefits were retained 15 months after the strength training intervention in a sample of relatively healthy older adults.

Effects of resistive training on strength gains in older adults

This study was designed to evaluate the effects of a moderate intensity, 16-week resistive strength training program on the rate and pattern of strength changes in trunk, upper, and lower extremity muscle groups. This study was also designed to determine the importance of muscle mass on strength gains during a training intervention with older adults. A repeated measures experimental design was employed with 43 experimental (ES) and 42 comparison subjects (CS). The active older sample had a relatively high level of strength for their age (72.1 yr) and had no contraindications for strength training. The ES trained five upper, three trunk, and three lower extremity muscle groups. Both ES and CS received pre- and post-testing assessments for muscle strength, muscle morphology, body composition, flexibility, and balance. The ES also received intermittent testing for one repetition maximum (1RM). ANOVA and Scheffé HSD tests were used to evaluate the data. The ES experienced significant strength gains (over 41% for each body segment) following the intervention. The rate of gain in this study was less than but the absolute strength gain was reasonably similar to values reported by studies in the literature [1,2]. There was no change in muscle mass (p>.05) following training. These results suggests that stronger active older adults have a muscle mass sufficient for greater strength and that training enables them to use available muscle mass more effectively. These results further suggest that muscle hypertrophy may be possible following strength training but it is not always necessary for strength improvement in older adults.