Biomedical subjects

Thomas O Obisesan

Publications and source records attributed to Thomas O Obisesan.

8 recordsLinked to original sources

PubMed2006

C-reactive protein genotype affects exercise training-induced changes in insulin sensitivity.

An etiologic role for chronic inflammation in the development of insulin resistance has been hypothesized. We determined whether the -732A/G and +219G/A C-reactive protein (CRP) gene variants affect insulin and glucose measures and whether these variants affect training-related changes in insulin sensitivity and glucose measures. Men and women 50 to 75 years old (n = 61) underwent baseline testing that included glucose tolerance, maximal oxygen consumption, body composition, CRP levels, and genotyping assessments. Tests were repeated after 24 weeks of aerobic exercise training. In bivariate analyses, CRP -732A/G G allele carriers had significantly lower baseline postprandial plasma glucose and after-training CRP levels. After exercise training, the -732A/G G allele carriers had approximately 28% increase in insulin sensitivity index (ISI) and approximately 26% reduction in insulin area under the curve (AUC), compared with the approximately 7% increase in ISI and approximately 15% reduction in insulin AUC in the A allele homozygotes (P = .03). The significant enhancement of ISI in -732A/G G allele carriers remained evident in analyses limited to those with normal glucose tolerance. Multivariate analyses adjusted for demographic and biologic variables confirmed the significant enhancement of training-induced improvement in ISI by the CRP gene variant. In addition, the CRP -732A/G and +219G/A haplotype significantly associated with training-induced improvements in ISI and insulin AUC in separate multivariate models. In conclusion, the CRP -732A/G variant modulates exercise training-related improvements in ISI and glucose AUC, and the haplotype of the CRP -732A/G and +219G/A variants significantly affected training-induced changes in ISI and insulin AUC.

Aged↗

PubMed2005

Ethnic and age-related fat free mass loss in older Americans: the Third National Health and Nutrition Examination Survey (NHANES III).

BACKGROUND: Although age-related loss of fat free mass (FFM) is well known, there is paucity of data on national estimates, and on the differential influence of ethnicity on the decline in FFM with increasing age. We determined whether age-related loss in FFM and fat free mass index (FFMI) vary by gender and or ethnicity, using representative data from the Third National Health and Nutrition Examination Survey (NHANES III). METHODS: Analyses were limited to 5,803 non-institutionalized, non-Hispanic Whites and African Americans (Blacks) over the age of 40 years. Body density was calculated from the sum of 3-skinfolds, and percent body fat estimated from body density. FFM was estimated by subtracting body fat from body weight, while FFMI was defined as FFM (kilograms) divided by the square of body height (meter2). RESULTS: Overall FFM and FFMI were significantly higher in black women than white women (P = 0.001; P = 0.001 respectively), but similar in black men compared to white men. Age-related decline in FFM reached significance level earlier in black men (at age 65-69) than white men (at age 70-74), and in black women (at age 70-74) than white women (at age 75-79). Similar decline in FFMI was noted in men and in women. In multivariate analyses, FFM significantly associated with ethnicity (p = 0.012) and with age (p < 0.001) in women, but only with age (p < 0.001) in men. In men and in women, FFMI significantly associated with ethnicity (p < 0.001; p = 0.003 respectively) and with age (p < 0.001; p = 0.004 respectively). CONCLUSION: Age-related loss and decline in FFM and FFMI in older Americans is higher for black men and women, than for white men and women. The development of focused population-based preventive strategies is likely to improve functional independence in the aged.

Adult↗

PubMed2004

Correlates of serum lipoprotein (A) in children and adolescents in the United States. The third National Health Nutrition and Examination Survey (NHANES-III).

OBJECTIVE: To determine the correlates of serum lipoprotein (a) (Lp(a)) in children and adolescents in the United States. METHODS: Cross-sectional study using representative data from a US national sample for persons aged 4-19 years participating in The Third National Health Nutrition and Examination Survey (NHANES-III). RESULTS: We observed ethnicity-related differences in levels of Lp(a) > 30 mg/dl, with values being markedly higher in African American (black) than nonhispanic white (white) and Mexican American children in multivariate model (P < 0.001). Higher levels of Lp(a) > 30 mg/dl associated with parental history of body mass index and residence in metro compared to nonmetro in Blacks, and high birth weight in Mexican American children in the NHANES-III. In the entire group, total cholesterol (which included Lp(a)) and parental history of premature heart attack/angina before age 50 (P < 0.02) showed consistent, independent, positive association with Lp(a). In subgroup analysis, this association was only evident in white (P = 0.04) and black (P = 0.05) children. However, no such collective consistent associations of Lp(a) were found with age, gender, or birth weight. CONCLUSION: Ethnicity-related differences in mean Lp(a) exist among children and adolescents in the United States and parental history of premature heart attack/angina significantly associated with levels of Lp(a) in children. Further research on the associations of Lp(a) levels in childhood with subsequent risk of atherosclerosis is needed.

Journal Article↗

PubMed2004

C-reactive protein genotypes affect baseline, but not exercise training-induced changes, in C-reactive protein levels.

OBJECTIVE: The goal of this study is to determine whether C-reactive protein (CRP) gene variants affect baseline and training-induced changes in plasma CRP levels. METHODS AND RESULTS: Sixty-three sedentary men and women aged 50 to 75 years old underwent baseline testing (Vomax, body composition, CRP levels). They repeated these tests after 24 weeks of exercise training while on a low-fat diet. The CRP +219G/A variant significantly associated with CRP levels before and after training after accounting for the effects of demographic and biological variables. CRP -732A/G genotype was significantly related on a univariate basis to CRP levels after training. The CRP +29T/A variant did not affect CRP levels before or after training. In regression analyses, the +219 and -732 variants each had significant effects on CRP levels before and after training. Subjects homozygous for the common A/G -732/+219 haplotype exhibited the highest CRP levels, and having the rare allele at either site was associated with significantly lower CRP levels. CRP levels decreased significantly with training (-0.38+/-0.18 mg/L; P=0.03). However, none of the CRP variants was associated with the training-induced CRP changes. CONCLUSIONS: CRP +219G/A and -732A/G genotypes and haplotypes and exercise training appear to modulate CRP levels. However, training-induced CRP reductions appear to be independent of genotype at these loci.

Adenine↗

PubMed2004

Normal exercise blood pressure response in African-American women with parental history of hypertension.

BACKGROUND: Genetic and environmental hypotheses may explain why normotensive persons at high risk of developing hypertension often exhibit greater cardiovascular reactivity to stressors than those at low risk. METHODS: Pearson's correlation was used to evaluate reproducibility and independent t test to compare the cardiovascular responses to 30 W of exercise of normotensive young adult African-American women with positive and negative parental histories (PH) of hypertension (PH, n = 23; PH, n = 20). RESULTS: Correlations were significant for duplicate measurements. The effects of PH on blood pressure measured at rest and during exercise were not statistically significant (P > 0.1). A nearly significant trend for greater resting (.-)VO(2) (P = 0.08) was detected in the PH than in the PH group (3.67 +/- 0.18 versus 3.26 +/- 0.14 mL/kg/min). CONCLUSION: A hyper-reactive blood pressure response to exercise, characteristic of the evolution of hypertension, may not be present among the normotensive female offspring of hypertensive African Americans. The significance of an 11% intergroup difference in the mean resting (.-)VO(2) observed in this study is unclear.

Adolescent↗

PubMed2004

Obese African Americans: the prevalence of dyslipidemia, hypertension, and diabetes mellitus.

CONTEXT: The prevalence of the cardiovascular disease risk factors, dyslipidemia, hypertension, and diabetes mellitus, is increased in the setting of obesity. OBJECTIVE: To determine whether the prevalence of these risk factors increases with increasing body mass index in an obese cohort, or whether there is a threshold for their appearance. DESIGN AND SETTING: Individuals with body mass index > or = 30 kg/m2 joined a weight reduction program in the Howard University General Clinical Research Center. PARTICIPANTS: Five hundred fifteen African Americans (aged 12-74 years, mean body mass index of 42.8 +/- 8.5 kg/m2). OUTCOME MEASURES: The cohort was divided by incremental increases in body mass index of 4.99 kg/m2, and the prevalence rates of hypertension (blood pressure > or = 140/90 mm Hg), dyslipidemia (total cholesterol > 200 mg/dL, or low-density lipoprotein > 130 mg/dL, or elevated ratio of total or low-density to high-density lipoprotein cholesterol) and diabetes mellitus (fasting blood glucose > or = 126 mg/dL or random blood glucose > 200 mg/dL) were determined for each group. RESULTS: The cohort prevalence rates were: dyslipidemia, 27.0%; hypertension, 56.9%; and diabetes mellitus, 24.1%. These rates are higher than those found in the African-American population by the third National Health and Nutrition Examination Survey. After adjusting for age and sex, there were no significant differences in the prevalence rates of these risk factors according to increasing body mass index, suggesting a threshold of between 30 kg/m2-34.99 kg/m2 for maximal appearance of these risk factors. CONCLUSION: The incidence rates of dyslipidemia, hypertension, and diabetes mellitus do not increase with a greater degree of obesity above a body mass index of 34.99 kg/m2.

Adolescent↗

PubMed2003

Predictors of hospital admissions in the elderly: analysis of data from the Longitudinal Study on Aging.

Healthcare for the elderly population presents enormous challenges, which are further complicated by ethnicity-related socioeconomic disparities in the United States. We set out to determine the predictors of hospital admissions in the elderly by conducting a retrospective cohort analysis of a nationally representative sample of community-dwelling individuals aged 70 and older in 1984 (n = 7541). Multivariate logistic regression analysis of data from the Longitudinal Study on Aging revealed that race, health status, type of family relationship, and activities of daily living (ADL) are significant predictors of hospitalization among the elderly. Older blacks are less likely to be admitted into the hospital, compared to their white counterparts (OR 0.68, 95%CI 0.52-0.89). Elderly persons who perceive their health status as being fair or poor are three times as likely to be hospitalized than those who perceived their health status as excellent (OR 2.99, 95%CI 2.15-4.15). Those with impairment in activities of daily living are twice as likely to be confined to the hospital than those without impairment (OR 1.78, 95%CI 1.64-1.96). Elderly persons living with nonrelatives are three times as likely to be admitted for short hospital stays than those living with spouses (OR 2.90, 95%CI 1.44-5.82). Future identification of predictors of hospital admissions in the elderly may help characterize those at risk and perhaps allow for focused and timely intervention.

Activities of Daily Living↗

PubMed2002

Aerobic exercise attenuates an exaggerated exercise blood pressure response in normotensive young adult African-American men.

An exaggerated exercise blood pressure response (EEBPR) may be associated with an increased risk of hypertension. We hypothesized that aerobic exercise training can decrease EEBPR and the risk for hypertension by decreasing arterial resistance. We studied the effects of aerobic training on the submaximal exercise blood pressure (BP) of eight normotensive young adult African-American men with an EEBPR. Subjects were trained on a stationary bicycle at an intensity of 70% peak oxygen uptake (VO2peak), for 30 min, three times per week, for 8 weeks. BP, heart rate, cardiac output (CO), stroke volume (SV) and total peripheral vascular resistance (TPR) were measured at rest and during submaximal exercise at a work intensity of 50% VO2peak. Significance of the training effects were evaluated by comparing the pre- and post-training measures (t-test, p < 0.05). A 15% post-training increase in VO2peak (34.6 +/- 1.4 to 40 +/- 1.4 ml/kg/min) and a 9.5 ml post-training increase in mean resting stroke volume were found. A 16.2 mmHg decrement in mean systolic BP, an 11.5 mmHg decrement in mean diastolic BP, a 120 dyne/s/cm5 decrement in TPR and a 1.2 l/min increase in CO were detected during the post-training submaximal exercise tests. These results suggest that reductions in TPR may attenuate the EEBPR of normotensive African-American males following an 8-week training regimen of stationary bicycling at 70% VO2peak. Aerobic exercise training may, therefore, reduce the risk of hypertension in normotensive African-American males by the mechanism of a reduction in TPR. Because of the limited number of subjects, the results of this study should be interpreted cautiously pending confirmation by a larger controlled trial.

Adolescent↗