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At least 19 recordsLinked to original sources
PubMed1990

Hypertension: racial differences.

Racial differences in the prevalence, course, and pathophysiologic characteristics of hypertension in black and white populations are reviewed. Accumulated epidemiologic data indicate that the prevalence of hypertension among blacks is greater than that among whites in almost all age- and sex-matched groups. Hypertensive blacks have a higher incidence of left ventricular dysfunction, stroke, and renal damage, but a lower incidence of ischemic heart disease, than do hypertensive whites. A significant pathophysiologic difference between blacks and whites is salt sensitivity; normotensive, as well as hypertensive, blacks tend to be salt sensitive. Blacks also tend to have lower renin levels than do whites, while dopamine response to a salt load is diminished among blacks as compared with whites. These differences and others lead to the recommendation that hypertension among blacks should be managed initially with salt restriction; if dietary control is insufficient, administration of an antihypertensive agent with 24-hour efficacy, which lowers vascular peripheral resistance, promotes sodium excretion, and potentially improves renal hemodynamics, is recommended. A calcium channel blocker may satisfy these requirements.

Black People↗
PubMed1986

Breast cancer prognosis in three different racial groups in relation to steroid hormone receptor status.

Follow-up studies on 466 patients over a 5-year period showed Whites to have an overall significantly longer disease-free interval and survival than Blacks and Asians. No racial differences in prognosis were seen in patients with Stage II disease (p greater than 0.2) but in Stage III, White patients had significantly longer disease-free periods than Blacks or Asians; the same was not true of survival. Whites had a 67% incidence of cytoplasmic estrogen receptor (CER) positive tumors compared with only 49% in Blacks and 41% in Asians. When tumors were assayed for CER, nuclear estrogen receptor (NER), and cytoplasmic progesterone receptor (CPR), there were no racial differences in the proportions of tumors containing all 3 receptors, but significant variations were found in neoplasms with no receptors and in those with apparently defective receptors. In White patients receptor status had no influence on prognosis (p greater than 0.3). Black patients whose tumors contained both CER and NER had a significantly better time to recurrence than those whose tumors lacked these receptors, while in Asian women the presence of CER alone, or CER together with NER, or CER, NER, and CPR, was indicative of a significantly longer disease-free period.

Breast Neoplasms↗
PubMed1989

Cutaneous reactive hyperaemia: racial differences induced by corticoid application.

The postocclusive hyperaemic reaction before and after a single 1 h application of a potent corticoid (clobetasol 0.05% in ointment) was recorded by means of laser Doppler velocimetry in order to elucidate different racial responses in skin vasoconstriction. Fourteen young male subjects entered the study (eight Caucasians, six Blacks). Reactive hyperaemia was recorded after 4 min of occlusion of the forearm blood flow. The following parameters of the hyperaemic reaction were investigated: area under the curve response, peak response, rise of blood flow slope to peak and decay of blood flow slope after peak. Different responses were recorded in the Black subjects after the vasoconstrictive stimulus compared to the Caucasians, namely: decreased area under the curve response (P less than 0.04); decreased peak response (P less than 0.01); decreased decay slope after peak blood flow (P less than 0.04). These data are consistent with a different reactivity of blood vessels in black skin and possibly not related to the transcutaneous penetration of the chemical compound.

Adult↗
PubMed1992

Racial differences in propranolol pharmacokinetics.

Racial differences in the antihypertensive response to propranolol are well documented. This study was conducted to determine whether differences between black subjects and white subjects in propranolol enantiomer pharmacokinetics and protein binding exist that may contribute to the response differences. Twenty-six healthy men (13 black and 13 white subjects) took 80 mg propranolol orally three times daily for 16 doses. Serum samples were collected for 12 hours after the last dose for analysis by chiral HPLC. Protein binding was determined by equilibrium dialysis. Area under the serum concentration-time curve (AUC) for both propranolol enantiomers was lower in black subjects than in white subjects (e.g., l-propranolol AUC: 292 +/- 100 versus 394 +/- 121 ng.hr/ml, p less than 0.05) and apparent oral clearance was higher in black subjects than in white subjects (e.g., l-propranolol apparent oral clearance: 27.6 +/- 8.2 versus 20.6 +/- 7.0 ml/min/kg, p less than 0.05). Fraction unbound and unbound AUC were not statistically different between black subjects and white subjects for either enantiomer, although the lack of statistical significance may have been attributable to the small sample size. In summary, racial differences in unbound l-propranolol concentration probably do not explain the clinically observed differences in response to propranolol. However, the racial differences in apparent oral clearance suggest there may be racial differences in hepatic metabolism of propranolol.

Administration, Oral↗
PubMed1986

Racial differences in alcohol sensitivity.

The existence of racial differences in alcohol sensitivity between Oriental and Caucasian populations has been well documented. The primary manifestation is a highly visible facial flushing (47-85% in Orientals vs 3-29% in Caucasians) accompanied by other objective and subjective symptoms of discomfort. Even among different Oriental groups, subtle differences in the flushing response and alcohol consumption can exist. North and South American Indian populations differ in phenotypes for alcohol dehydrogenase and aldehyde dehydrogenase, but systematic studies comparing degree of flushing, alcohol elimination rates and blood acetaldehyde levels in these populations are lacking. Although flushing does not automatically 'immunize' an individual against alcohol use, those susceptible tend to consume less alcohol, at least in Orientals. However, the flushing phenomenon cannot be the sole explanation for differences in incidences of alcoholism among different racial groups. Socio-cultural, environmental and genetic factors also have to be considered. An increased incidence of flushing has been found to associate with a familial risk of development of future alcoholism in a Caucasian population. It remains to be determined whether the same is true in Orientals. Most biochemical investigations of the flushing phenomenon have focused on aspects of alcohol metabolism. Based on recent findings, a convincing mechanism is the higher accumulation of acetaldehyde in flushing subjects because they have an unusual, less-active liver aldehyde dehydrogenase isozyme (ALDHI). The possibility that an 'atypical' alcohol dehydrogenase, which is present in 85-90% of Oriental subjects, can contribute to increased blood acetaldehyde levels in flushing subjects cannot be ruled out. Based on results of a small number of pedigree studies which demonstrated familial resemblances in flushing, a pharmacogenetic defect in ALDHI has been proposed to be responsible for flushing. Other possible biochemical mechanisms (e.g. prostaglandins) and genetic defects need to be investigated.

Acetaldehyde↗
PubMed1992

Racial differences in lipid and lipoprotein levels in diabetes.

Racial differences in plasma lipid and lipoprotein levels were investigated in 145 patients with non-insulin-dependent diabetes mellitus (NIDDM). Black men had higher high-density lipoprotein (HDL) cholesterol levels, lower triglyceride levels, and an improved atherogenic index compared with white men. Premenopausal black women were also found to have higher HDL cholesterol levels, lower triglyceride levels, and a lower atherogenic index than their white counterparts. Adjustment for age, waist to hip ratio (WHR), hemoglobin A1c (HbA1c), and physical activity did not eliminate the significant differences found. There were no racial differences found regarding total and low-density lipoprotein (LDL) cholesterol. Metabolic control as measured by HbA1c was significantly correlated with the triglyceride level in black women. These data confirm that racial differences exist in plasma lipid levels among patients with NIDDM.

Adult↗
PubMed1991

Calcium, vitamin D, and parathyroid hormone status in young white and black women: association with racial differences in bone mass.

The etiology of the racial disparity in bone mass and fracture rate is unknown. Since the PTH-vitamin D endocrine system is a major regulator of calcium metabolism and bone turnover, this cross-sectional study examined the relationship of radial and lumbar bone density to vitamin D metabolite and PTH concentrations and to calcium intake and excretion in 67 white and 70 black highly comparable, healthy, premenopausal women. Bone density at both radial and lumbar sites was higher in blacks than in whites. Serum 25-hydroxyvitamin D was slightly but not statistically significantly (P = 0.08), lower in blacks than in whites, but there were no racial differences in 1,25-dihydroxyvitamin D, PTH, or renal tubular maximum for reabsorption of phosphate. The mean 25-hydroxyvitamin D concentration in blacks was well within the normal range and was not associated with evidence of secondary hyperparathyroidism. There were no correlations of bone density to vitamin D or PTH concentrations. Although there were no racial differences in dietary intake of calcium and vitamin D or in sodium excretion, 24-h urinary calcium excretion was significantly lower in blacks than in whites, and calcium excretion was inversely associated with radial bone density. In contrast to previous reports, in healthy, normal weight, premenopausal black women there is no evidence of vitamin D deficiency or secondary hyperparathyroidism, suggesting that factors other than the vitamin D-PTH axis are responsible for racial differences in bone mass.

Adult↗
PubMed1976

Alcohol metabolism in American Indians and whites. Lack of racial differences in metabolic rate and liver alcohol dehydrogenase.

To investigate alleged racial differences in alcohol tolerance, we measured the rate of ethanol metabolism in 30 American Indians and 30 whites. The mean rates of alcohol metabolism were virtually identical in the two groups: 92 +/- 3 mg of ethanol metabolized per kilogram of body weight per hour for the Indians versus 93 +/- 3 for the whites (mean +/- S.E.M.). Similarly, a comparison of liver alcohol dehydrogenase specific activity and isoenzyme pattern in biopsy specimens from seven American Indians and six whites revealed no racial differences. Biopsy specimens from the Indians demonstrated a mean specific enzymatic activity of 0.073 +/- 0.004 mumoles of ethanol oxidized per minute per milligram of soluble protein and from the whites, 0.082 +/- 0.009. These findings make it unlikely that alleged racial differences in response to alcohol can be explained on the basis of racial differences in the rate of alcohol metabolism.

Adolescent↗
PubMed1992

Racial differences in coagulation studies in stroke.

Racial differences in stroke are known to exist with persons in the black race having a higher morbidity, mortality and incidence of stroke compared to whites. We evaluated coagulation factors in black and white stroke patients and compared the results between races. D-dimer was elevated more frequently in blacks than whites to a statistically significant degree. There were non-significant trends for blacks to have a positive lupus anticoagulant, low protein C and protein S, higher platelet factor 4, and hyporesponsive platelets to 10 microM epinephrine. The significance of these findings in understanding racial differences in stroke is discussed.

Aged↗
PubMed1990

Racial differences in baseline cyclic adenosine monophosphate concentrations per million T-lymphocytes and protein concentrations.

beta-Adrenergic blockers are less efficacious as monotherapy for the treatment of hypertension in blacks as compared with whites. Because beta-adrenergic stimulation and blockade differ between racial groups, biochemical differences in the beta-adrenergic pathway may exist. It is the intent of this report to show underlying similarities and differences, at least in part, in the beta-adrenergic pathway (e.g., baseline cAMP and protein concentrations) using the T-lymphocyte as the model system. A total of 20 (n = 10 black, n = 10 white) normotensive male volunteers were recruited, begun on a low-sodium diet to normalize serum catecholamines, and blood was collected for lymphocyte beta-receptor isotherm binding experiments and cAMP determination. There were no differences in Bmax, sites per cell, or kd. Basal cAMP concentrations were significantly higher in the black group (16.0 +/- 9.8 pmol/10(6) cells) compared with the white group (7.0 +/- 1.8 pmol/10(6) cells) (p less than 0.05). Protein levels from the lymphocyte suspension were also higher in the black group (1,081.0 +/- 367.7 micrograms/ml) compared with the white group (766.8 +/- 220.4 micrograms/ml) (p less than 0.05). Normalization of cAMP for protein yielded 83.2 +/- 55.4 fmol/micrograms protein in the black group and 56.6 +/- 29.8 fmol/micrograms protein in the white group (p = 0.11). Altered protein levels may be a confounding variable in studies of this type. Further work is necessary to identify the nature and significance of this protein elevation, its relationship to the adenylate cyclase system in lymphocytes, and the source of the cAMP elevation noted herein.

Adrenergic beta-Antagonists↗
PubMed1990

Essential hypertension in blacks: epidemiology, characteristics, and possible roles of racial differences in sodium, potassium, and calcium regulation.

Racial differences in the regulation of Na+, K+, and Ca2+ have been shown both at the systemic and cellular levels. These include a higher incidence of "salt sensitivity," lower urinary K+ excretion, lower plasma renin activity, and higher circulating levels of immunoreactive parathyroid hormone and 1.25 dihydroxyvitamin D in blacks than in whites. Blacks exhibit a higher erythrocyte Na+ concentration, coupled with a lower maximal initial reaction velocity of erythrocyte Na,K-ATPase. Blacks also appear to differ from whites in erythrocyte Na+, K+ cotransport and Na-Li countertransport. Moreover, they show a higher activity of the Na(+)-H+ antiport in skin fibroblasts and a greater response of cellular Ca2+ signaling to agonists in serum. Mechanisms linking some of these racial differences in ionic metabolism to the increased propensity of blacks to develop essential hypertension are proposed, and the epidemiology and characteristics of this disease in blacks are reviewed.

Antihypertensive Agents↗
PubMedDate not supplied

Intermediate determinants of racial differences in 1980 U.S. nonmarital fertility rates.

There are four major determinants of racial differences in nonmarital fertility rates in the U.S.: differential sexual activity (exposure to risk); differential in spontaneous and induced abortion; differential contraceptive use (including method efficacy); and differential legitimation, through marriage, of births conceived out of wedlock. Racial differences in all four indicators encourage higher black than white nonmarital fertility rates in every age-group examined; however, the relative contribution of each determinant to differences in nonmarital fertility varies according to age. The gap between whites and blacks in contraceptive use is of greatest concern to policy-makers, because family planning effectiveness can, at least theoretically, be changed by program effort. However, even if black women and white women had equivalent levels of contraceptive use, sexual activity and recourse to abortion, there would still be substantial racial differences in nonmarital fertility rates because of the greater propensity among whites to legitimate premaritally conceived births.

Abortion, Induced↗
PubMed1992

Racial differences in left ventricular structure in healthy young adults.

Racial differences in cardiac structure and function were evaluated in 62 black and 71 white healthy young adults. Left ventricular (LV) mass index, relative wall thickness, fractional shortening, resting cardiac index and resting systemic vascular resistance index were estimated using M-mode echocardiography. Pulsed Doppler interrogation of transmitral flow was used to characterize LV filling. Average daytime blood pressure (BP) was determined by ambulatory monitoring during a typical work or school day. Ambulatory daytime BP averaged 127 +/- 12/80 +/- 7 mm Hg in black subjects, and 127 +/- 9/80 +/- 6 mm Hg in white subjects (p = not significant). The 2 groups were also similar in resting BP, age and gender composition. Relative wall thickness was significantly greater in black than in white subjects (0.37 +/- 0.06 vs 0.34 +/- 0.05; p less than 0.01). This difference was found in both men and women. Black subjects also had a higher resting systemic vascular resistance index (2,110 +/- 570 vs 1,920 +/- 500 dynes.s.cm-5.m2; p less than 0.05) and lower resting cardiac index (3.14 +/- 0.84 vs 3.46 +/- 0.85 L/min/m2; p less than 0.05). There were no significant differences between black and white subjects in LV mass index, fractional shortening and normalized peak filling velocity. These results suggest that racial differences in LV structure and systemic hemodynamics exist even in patients without sustained hypertension. In our study population, the greater relative wall thickness in black subjects was not accompanied by significant differences in LV systolic function or diastolic filling.

Adolescent↗
PubMedDate not supplied

Racial differences in prostate-specific antigen levels in patients with local-regional prostate cancer.

Prostate cancer is a significant health problem for blacks. The incidence and mortality rates are higher in blacks than in whites; blacks often present with a higher stage. Prostate-specific antigen (PSA) is a very useful serum marker in prostate cancer. We analyzed data from a cohort of 161 patients to determine whether there were any racial differences in PSA levels prior to treatment in local-regional prostate cancer. The immunoradiometric method was used to determine the PSA values. The mean PSA levels were significantly higher in blacks than in whites (P = 0.022), and the difference remained significant in multivariate analysis after adjusting for stage and grade (P = 0.020). However, when analyzed further, the difference was statistically significant in one hospital (P = 0.001) and not in another (P = 0.493). Thus, our results are not unequivocal, but our data do suggest that racial differences in PSA levels not accounted for by tumor stage or grade may exist. Assuming that the data truly reflect a racial difference, the cause(s) of this difference remains to be determined. It may exist because, within each clinical stage, blacks are presenting with a higher tumor cell burden, or it may be indicative of more aggressive biological behavior. The possibility that racial differences are due to socioeconomic factors was considered by estimating median income level from zip code of residence; although a correlation between socioeconomic status and PSA level was found, racial differences remained borderline significant (P = 0.055) after adjusting for income level (in addition to stage and grade).

Black or African American↗
PubMed1988

Genetic basis of racial differences.

The purpose of this paper is (a) to present brief historical notes on the concept of race, (b) to define race in the context of evolutionary biology, (c) to quantify the extent of human genetic variation, (d) to estimate genetic differences within and between races, and (e) to comment on the implications of these concepts for racial differences in sport performance. Research shows that genetic variation in gene products and in the non-coding sequence of DNA is quite extensive in humans. Variation is found more frequently in non-coding DNA sequences than in coding exons, and while this variation does not influence the primary structure of the proteins, it may have considerable impact on gene expression. However, much of that genetic variation is shared by all human beings, and only about 10% is specific to races or populations within races. At this time, it is not possible to conclude satisfactorily the significance of these modest racial differences in genetic variation for racial differences in performance. It may turn out that this low level of genetic heterogeneity may have considerable implication for performance.

Genetic Variation↗
PubMed1989

Racial differences in drug response. Altered sensitivity to and clearance of propranolol in men of Chinese descent as compared with American whites.

To determine whether the pharmacokinetics and pharmacodynamics of beta-blockade differ among racial groups, we gave 10 men of Chinese descent and 10 American white men 10, 20, 40, and 80 mg of propranolol every eight hours; the dosages were given in random order, and each dose was given for one day. The degree of beta-blockade was measured as the reduction in the heart rate and blood pressure in the supine and upright positions and during treadmill exercise testing. The Chinese subjects had at least a twofold greater sensitivity to the beta-blocking effects of propranolol than the white subjects, as indicated by the mean (+/- SEM) plasma concentrations producing a 20 percent reduction in the heart rate in both the supine position (197 +/- 31 vs. 536 +/- 58 nmol per liter; P less than 0.05) and the upright position (131 +/- 27 vs. 343 +/- 39 nmol per liter; P less than 0.05) and after exercise testing (96 +/- 12 vs. 185 +/- 23 nmol per liter; P less than 0.05). In addition, the Chinese subjects had much greater sensitivity to the hypotensive effects of propranolol, as shown by the concentrations that reduced blood pressure by 10 percent in the supine position (73 +/- 5 vs. 748 +/- 7 nmol per liter; P less than 0.01) and in the upright position (89 +/- 5 vs. 401 +/- 6 nmol per liter; P less than 0.01). No difference in beta-receptor density or affinity of lymphocytes was found between the groups. The Chinese group had a 45 percent higher free fraction of propranolol in plasma, which may have contributed to the increased drug effect but cannot explain it entirely. This group metabolized propranolol more rapidly than the white group, which resulted in a 76 percent higher clearance of an oral dose (3740 +/- 737 vs. 2125 +/- 214 ml per minute; P less than 0.05) because of increased metabolism through multiple metabolic pathways. We conclude that Chinese men have greater sensitivity than white men to the effects of propranolol on heart rate and blood pressure. Decreased protein binding may be responsible in part, but most of the effect remains to be explained.

Adult↗