Race specific altitude effects on blood pressure

Altitude affects blood pressure (BP) depending on duration and absolute altitude of exposure. Until now changes in BP during exposure to altitude were studied only in Caucasians. It is not known whether BP is affected differently in black and white people in response to altitude. During a 6-day climb on Kilimanjaro, BP was measured in five white and four black people. All participants (mean +/- s.d.: age 31 +/- 8 years, body mass index 22 +/- 2 kg/m2, BP 125 +/- 11/84 +/- 9 mm Hg) had previous similar experience of high-altitude mountaineering. In the base camp (3040 m) systolic BP (SBP) was similar in both groups (131 +/- 9 vs 119 +/- 8 mm Hg). During ascent until 4600 m SBP increased in all whites (6.5 +/- 2.2 mm Hg) and decreased in all blacks (-7.3 +/- 4.6 mm Hg; P = 0.02, blacks vs whites). During descent SBP returned to initial values in whites, whereas it decreased further in blacks. Diastolic BP (DBP) and heart rate remained constant in all participants. During ascent body weight increased in all whites (1.0 +/- 0.8 kg) and decreased in all blacks (-1.9 +/- 1.4 kg; P = 0.02, blacks vs whites) whereas it returned approximately to initial levels during descent: +0.8 +/- 0.4 kg in blacks and -1.0 +/- 1.3 kg in whites (P = 0.03, blacks vs whites). In this study changes in SBP and body weight during exposure to high altitudes varied between whites and blacks. Fluid balance, acclimatisation, physical fitness or genetics could explain these findings.     

Effect of administered potassium on the renin-aldosterone axis in young blacks compared with whites

BACKGROUND: We had observed previously that the aldosterone excretion rate and plasma aldosterone concentration were lower for black children than they were for white children. We did not know whether this was secondary to a lower intake of potassium or to suppression of the renin-angiotensin system in blacks. OBJECTIVE: To test the hypothesis that the secretion of aldosterone in response to potassium would be different in blacks than in a control group of whites. DESIGN: Black and white subjects were selected on the basis of their having aldosterone excretion rates that were in the lowest quartile for the entire original cohort. Since the blacks typically had lower aldosterone excretion rates than did the whites, the black participants were represented primarily by those with average rates of aldosterone production among blacks, whereas the whites were represented by those with the lowest aldosterone production rates among whites. The protocol consisted of a placebo-controlled, randomized cross-over study design. METHODS: Twelve blacks and 12 whites, aged 14.1 +/- 1.6 (mean +/- SD) and 15.4 +/- 2.1 years, respectively, were allocated randomly to double-blind treatment either with placebo or with 40 mmol/day potassium chloride for 7 days and then the alternate treatment Measurements of the plasma renin activity (PRA), plasma aldosterone concentration, and urinary aldosterone excretion were performed in an inpatient research unit at the end of the treatment. The blood pressure was monitored for 24 h. RESULTS: Treatment with potassium increased the plasma aldosterone concentration (P = 0.0006) and the urinary excretion of aldosterone (P = 0.0002) significantly both for blacks and for whites. There was no significant racial difference in the response to potassium. The PRA was overall 1.605-fold lower in the blacks than it was in the whites (P = 0.0124). The lowest PRA levels, such as those in the blacks when they were supine, tended to be increased with the potassium treatment. The blood pressure did not change significantly with the potassium supplement for either racial group. CONCLUSIONS: After we had supplemented the intake of potassium, aldosterone production increased in the blacks and in the control group of whites to the same extent The potassium treatment appeared to increase lower PRA levels. A lower intake of potassium could at least partially account for the suppression of the renin-aldosterone system in blacks.     

Racial differences in validity of employment tests: Reality or illusion?

Tested the fit of data on single-group validity of 19 employment tests to a statistical model assuming equal true validites for blacks and whites. For both subjective and objective criterion measures, observed frequencies of both kinds of single-group validity (significant for whites but not for blacks and vice versa) were not significantly different from those predicted by the null differences model. These findings cast serious doubt on the existence of single-group and differential validity as substantive phenomena. It is concluded that psychologists concerned with the applicability of employment tests to minority groups should direct their future efforts to the study and determination of test fairness rather than to the problem of racial differences in test validity. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Race-ethnic differences in stroke risk factors among hospitalized patients with cerebral infarction: the Northern Manhattan Stroke Study

African-Americans have an unexplained increased incidence and mortality from stroke compared with whites, and little is known about stroke in Hispanics. To investigate cross-sectional differences in sociodemographic and stroke risk factors, we prospectively evaluated 430 patients hospitalized for acute ischemic stroke (black 35%. Hispanic 46%, white 19%) over the age of 39 from Northern Manhattan. Blacks and Hispanics were younger than whites (mean ages, blacks 70, Hispanics 67, whites 80; p < 0.001) and were more likely to have less than 12 years of education than whites. Hypertension was more prevalent in blacks and Hispanics with stroke than whites (blacks 76%, Hispanics 79%, whites 63%; p < 0.05) and was often untreated in blacks. Left ventricular hypertrophy by ECG was more frequent in blacks (blacks 20%, whites 9%; p = 0.02). History of cardiac disease (atrial fibrillation, myocardial infarction, angina, and congestive heart failure) was less prevalent in both blacks and Hispanics. Black women were significantly more obese than white women (mean Quetelet Index percent, blacks 3.9%, whites 3.6%; p < 0.05). Heavy alcohol use was more often reported by blacks and Hispanics; cigarette smoking was increased only in blacks. Moreover, blacks were less likely to have visited a physician 1 year after their stroke (blacks 85%, whites 98%; p < 0.05), and Hispanics less often lived alone compared with whites. These cross-sectional differences suggest that the burden of stroke risk factors is increased in both blacks and Hispanics with stroke. Further studies controlling for stroke risk factors are needed to establish whether race-ethnicity is an independent determinant of stroke risk.     

Racial differences in nitric oxide-mediated vasodilator response to mental stress in the forearm circulation

An abnormal hemodynamic response to stressful stimuli has been proposed as a mechanism involved in the higher prevalence of hypertension in blacks. Given the important role of nitric oxide (NO) in the regulation of cardiovascular homeostasis, we investigated the possibility of racial differences in vascular NO activity during mental stress. To test this hypothesis, we compared the forearm blood flow (FBF) response to mental stress in 14 white and 12 black healthy subjects during intra-arterial infusion of either saline or NO synthesis inhibitor N(G)-monomethyl-L-arginine (L-NMMA; 4 micromol/min). We also examined vascular responses of the two groups to intra-arterial infusion of sodium nitroprusside (0.8 to 3.2 microg/min), an exogenous NO donor. During saline infusion, the increase in FBF from baseline induced by mental stress was significantly higher in whites than in blacks (109+/-20% versus 58+/-8%; P=0.03). L-NMMA significantly reduced stress-induced increase in FBF in whites (from 109+/-20% to 54+/-11%; P=0.004) but not in blacks (from 58+/-8% to 42+/-10%; P=0.24); thus, the vasodilator effect of stress testing during L-NMMA was similar in whites and blacks (54+/-11% versus 42+/-10%; P=0.44). The vasodilator response to sodium nitroprusside was also lower in blacks than in whites (maximum flow, 6.9+/-2 versus 11.6+/-3.5 mL x min(-1) x dL(-1); P=0.001) and was not significantly modified by L-NMMA in either group. Our findings indicate that blacks have a reduced NO-dependent vasodilator activity during mental stress. This difference seems related to reduced sensitivity of smooth muscle to the vasodilator effect of NO and may play some role in the increased prevalence of hypertension and its complications in blacks.     

Effects of different levels of integration on advertising preference and intention to purchase.

90 black and 90 white male undergraduates evaluated 6 proposed advertisements in terms of attractiveness and likelihood of purchase of the product advertised. The advertisements differed in the degree of racial integration depicted, which was operationally defined by a 5-point continuum ranging from 0 whites and 4 blacks (0W-4B) to 4 whites and 0 blacks (4W-0B). The hypothesis that young blacks react negatively to integrated ads depicting tokenism (e.g., 3 whites to 1 black) and positively to ads depicting equality (e.g., 2 whites to 2 blacks) was supported with each of the dependent measures. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of the performance of matched groups of black children and white children on the Wechsler Preschool and Primary Scale of Intelligence.

Compared the Wechsler Preschool and Primary Scale of Intelligence Verbal, Performance, and Full Scale IQs of blacks and whites who were matched on age, sex, geographic region, father's occupation, and urban-rural residence. A group of 132 4-61/2 yr old pairs was obtained from the standardization sample of 1,044 whites and 156 blacks. The whites had significantly higher Verbal and Full Scale IQs at all age levels. Performance IQ, however, was significantly higher for the whites in the youngest group (ages 4-41/2) but not for those aged 5-51/2 and 6-61/2. Results are compared to previous findings, and implications are discussed in term of perceptual experiences. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blacks supervising whites: A study of interracial difficulties in working together in a simulated organization.

Investigated interracial difficulties of blacks and whites working together, when blacks are in a supervisory position over whites. 45 groups of male undergraduates were supervised by blacks, and 45 were supervised by whites. In each group, 2 subordinates played a business game with either a black or a white supervisor and were observed by 2 white Os. Results indicate that (a) the performance ratings of black supervisors were significantly poorer than those of white supervisors; (b) subordinates supervised by blacks behaved differently than subordinates supervised by whites, and some of these behaviors appeared to hinder the effectiveness of the black supervisor; and (c) subordinates with negative racial bias gave poorer ratings to black supervisors than subordinates with liberal racial attitudes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human immunodeficiency virus and resistance]

CONTEXT: Racial differences in tobacco-related diseases are not fully explained by cigarette-smoking behavior. Despite smoking fewer cigarettes per day, blacks have higher levels of serum cotinine, the proximate metabolite of nicotine. OBJECTIVE: To compare the rates of metabolism and the daily intake of nicotine in black smokers and white smokers. DESIGN: Participants received simultaneous infusions of deuterium-labeled nicotine and cotinine. Urine was collected for determination of total clearance of nicotine and cotinine, fractional conversion of nicotine to cotinine, and cotinine elimination rate. Using cotinine levels during ad libitum smoking and clearance data, the daily intake of nicotine from smoking was estimated. SETTING: Metabolic ward of a university-affiliated public hospital. PARTICIPANTS: A total of 40 black and 39 white smokers, average consumption of 14 and 14.7 cigarettes per day, respectively, of similar age (mean, 32.5 and 32.3 years, respectively) and body weight (mean, 73.3 and 68.8 kg, respectively). MAIN OUTCOME MEASURES: Clearance (renal and nonrenal), half-life, and volume of distribution of nicotine and cotinine and the calculated daily intake of nicotine. RESULTS: The total and nonrenal clearances of nicotine were not significantly different, respectively, in blacks (17.7 and 17.2 mL x min(-1) x kg(-1)) compared with whites (19.6 and 18.9 mL x min(-1) x kg(-1)) (P=.11 and .20). However, the total and nonrenal clearances of cotinine were significantly lower, respectively, in blacks (0.56 and 0.47 mL x min(-1) x kg(-1)) than in whites (0.68 vs 0.61 mL x min(-1) x kg(-1); P=.009 for each comparison). The nicotine intake per cigarette was 30% greater in blacks compared with whites (1.41 vs 1.09 mg per cigarette, respectively; P=.02). Volume of distribution did not differ for the 2 groups, but cotinine half-life was higher in blacks than in whites (1064 vs 950 minutes, respectively; P = .07). CONCLUSIONS: Higher levels of cotinine per cigarette smoked by blacks compared with whites can be explained by both slower clearance of cotinine and higher intake of nicotine per cigarette in blacks. Greater nicotine and therefore greater tobacco smoke intake per cigarette could, in part, explain some of the ethnic differences in smoking-related disease risks.     

Human mammary cancer cell lines and other epithelial cells cultured as organoid tissue in lenticular pouches of reinforced collagen membranes

Incidence and mortality rates for lung cancer in the United States are significantly greater in blacks than in whites. This disparity cannot be explained by differences in smoking behavior. We hypothesize that the observed racial differences in risk may be due to differences in the metabolic activation or detoxification of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). To test this, different biomarkers of NNK exposure and metabolism, including the urinary metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and the presumed detoxification product [4-(methylnitrosamino)-1-(3-pyridyl)but-1-yl]-beta-O-D-glucosiduronic acid (NNAL-Gluc), were examined along with questionnaire data on lifestyle habits and diet in a metabolic epidemiological study of 34 black and 27 white healthy smokers. Results demonstrated that urinary NNAL-Gluc:NNAL ratios, a likely indicator of NNAL glucuronidation and detoxification, were significantly greater in whites than in blacks (P < 0.02). In addition, two phenotypes were apparent by probit analysis representing poor (ratio < 6) and extensive (ratio > or = 6) glucuronidation groups. The proportion of blacks falling into the former, potentially high-risk group was significantly greater than that of whites (P < 0.05). The absolute levels of urinary NNAL, NNAL-Gluc, and cotinine were also greater in blacks than in whites when adjusted for the number of cigarettes smoked. None of the observed racial differences could be explained by dissimilarities in exposure or other sociodemographic or dietary factors. Also, it is unlikely that the dissimilarities are due to racial differences in preference for mentholated cigarettes, because chronic administration of menthol to NNK-treated rats did not result in either increases in urinary total NNAL or decreases in NNAL-Gluc:NNAL ratios. Altogether, these results suggest that racial differences in NNAL glucuronidation, a putative detoxification pathway for NNK, may explain in part the observed differences in cancer risk.     

Trends in alcohol consumption patterns among whites, blacks and Hispanics: 1984 and 1995

OBJECTIVE: To report national trends in alcohol consumption patterns among whites, blacks and Hispanics between 1984 and 1995, in relation to the recent decline in per capita consumption in the United States. METHOD: Data were obtained from two nationwide probability samples of U.S. households, the first conducted in 1984 and the second in 1995. The 1984 sample consisted of 1,777 whites, 1,947 blacks and 1,453 Hispanics; the 1995 sample consisted of 1,636 whites, 1,582 blacks and 1,585 Hispanics. On both occasions, interviews averaging 1 hour in length were conducted in respondents' homes by trained interviewers. RESULTS: Between 1984 and 1995, the rate of abstention remained stable among whites but increased among blacks and Hispanics. Frequent heavy drinking decreased among white men (from 20% to 12%), but remained stable among black (15% in both surveys) and Hispanic men (17% and 18%). Frequent heavy drinking decreased among white women (from 5% to 2%), but remained stable among black (5% in both surveys) and Hispanic women (2% and 3%). White men and women were two times more likely to be frequent heavy drinkers in 1984 than in 1995. CONCLUSIONS: The reduction in per capita consumption in the U.S. is differentially influencing white, black and Hispanic ethnic groups. The stability of rates of frequent heavy drinking places blacks and Hispanics at a higher risk for problem development than whites. This finding is, therefore, a concern to public health professionals and others interested in the prevention of alcohol-related problems among ethnic groups in the United States.     

Differences in Lp[a] concentrations and apo[a] polymorphs between black and white Americans

Lp[a] concentrations in nmol/L and apo[a] size isoforms, expressed in terms of the relative number of apo[a] kringle 4 (K4) repeats, were determined in 3959 whites and blacks from four U.S. communities. Plasma Lp[a] analyses were performed by an ELISA method insensitive to apo[a] size heterogeneity and apo[a] size isoforms were determined by high resolution agarose gel electrophoresis. Allele frequencies were estimated by maximum likelihood methods in order to account for the presence of null alleles and coalescence of hands on gels. The apo[a] allele frequencies and phenotype distributions differed significantly between blacks and whites (P < 0.0001). Blacks had a higher relative frequency of the intermediate alleles K4(22) through K4(28) whereas whites had a higher relative frequency of the small alleles K4(17) through K4(24) and large alleles K4(29) through K4(33). The estimated frequency of the null allele was low in both blacks (1.0%) and whites (6.7%). The Lp[a] distribution was less skewed and Lp[a] concentrations were higher in blacks than whites (mean 94 nmol/L and 48 nmol/L, median 74 nmol/L and 20 nmol/L for blacks and whites, respectively). The relationship between apo[a] size and Lp[a] concentration also differed significantly between these two racial groups. For the large polymorphs (> 31 K4 repeats) both blacks and whites exhibited uniformly low Lp[a] values. For the intermediate isoforms K4(20) through K4(30), a considerable range of Lp[a] values was evident in blacks; the median Lp[a] for each isoform increased nearly linearly as the apo[a] size decreased. In contrast in whites there was little change in median Lp[a] concentrations for isoforms K4(20) through K4(30). For the small apo[a] size (< 20 K4) both blacks and whites exhibited high median Lp[a] levels and a wide variation of Lp[a] levels. The major difference in Lp[a] levels between the two racial groups occurred in the intermediate size isoform range of K4(20) through K4(25). In conclusion, whites and blacks differ significantly in Lp[a] concentrations, allele and phenotype frequencies, and in the relationship between apo[a] size isoform and Lp[a] concentration.     

Comprehensive analysis of risk factors for acquisition of Pseudomonas aeruginosa in young children with cystic fibrosis

Racial differences in insulin secretion and insulin sensitivity in healthy children were studied by administering a 2-hour hyperglycemic clamp (225 mg/dL) to 14 black and 16 white healthy adolescents (Tanner II-V), and 12 black and 11 white prepubertal children, matched for age, body mass index, and Tanner I pubertal development. In prepubertal children, fasting and first-phase insulin concentrations were higher in blacks compared with whites (14.7+/-1.3 vs 10.4+/-1.2, P=0.02, and 76.9+/-6.8 vs 52.1+/-6.4 microu/mL, P=0.016). There were no differences in second-phase insulin levels and insulin sensitivity index. In pubertal adolescents, first-phase and second-phase insulin concentrations were higher in blacks compared with whites (first-phase: 157.3+/-18.3 vs 77.0+/-8.7 microu/mL, P=0.0003; second-phase: 175.0+/-24.3 vs 108.7+/-8.8 microu/mL, P=0.012). Insulin sensitivity index was 35% lower in black adolescents compared with whites (P=0.02). These findings indicate that significant differences in insulin secretion and sensitivity are detectable early in childhood in healthy African-American vs American whites. However, genetic (race) vs environmental factors (physical activity/fitness, energy balance) should be carefully scrutinized as potential factors responsible for such differences.     

Social dominance and cerebral hemisphericity: discriminating race, socioeconomic status, and sex groups by performance on two lateralized tests

A neurosociological argument is presented which hypothesizes that persons in positions of social subdominance--black racial status, low and middle socioeconomic status (SES), and female sexual status will, in comparison to persons in positions of dominance--white, high SES, and male, be right-hemispheric, i.e., will perform best on a test lateralized to the right cerebral hemisphere and its appositional mode of thought as opposed to a test lateralized to the left hemisphere and its propositional mode of thought. Data from 1058 adults from two probability samples (excluding left-handers, housewives and unemployed persons) are analyzed. Appositional performance is measured by the Street Gestalt-Completion Test (A), propositional performance by the WAIS Similarities Subtest (P), and right-hemisphericity by (A-P)/(A+P). Multigroup discriminant function analysis and three-way analyses of variance produced the following results: (1) blacks are more right-hemispheric than are whites, with lower similarities performance and higher Street performance; (2) SES varies directly with Similarities performance, but not with Street performance; (3) there is a two way interaction between race and SES such that middle SES groups are most right-hemispheric for whites, and low SES groups, most right-hemispheric for blacks; (4) females are more right hemispheric than are males among blacks and lower SES whites, reflecting in part the superior performance of black females on the Street test.     

Pathophysiology of carbohydrate-deficient glycoprotein syndrome--neuroradiological and neurophysiological study

We examined the cross-sectional relation of dietary vitamin C intake to serum lipids in 1,825 preadolescent black and white girls. Dietary vitamin C intake exclusive of supplement use, determined by 3-day diet record, appeared unrelated to total serum cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and triglyceride levels. Because other investigators have demonstrated an inverse association between vitamin C and total serum cholesterol in individuals with elevated total serum cholesterol levels, we analyzed the subgroup of 285 girls (142 blacks and 143 whites) with total serum cholesterol levels > or = 200 mg per dl. Multivariate analyses of this subgroup, which adjusted for saturated fat, polyunsaturated fat, monounsaturated fat, cholesterol, fiber, and energy intake and for body mass index, demonstrated negative association between vitamin C intake and total serum cholesterol. In girls with total serum cholesterol levels > or = 200 mg per dl, each 100 mg per day increase in dietary vitamin C intake (ranges 13-373 and 14-242 mg per day for blacks and whites, respectively) was associated with a total serum cholesterol decrease of 4 mg per dl (95% confidence limits = -10.34, 2.77) in blacks and 13 mg per dl (95% confidence limits = -22.99, -2.68) in whites. If the observed association is causal and generalizable, our results suggest that increased vitamin C intake could play an important role in the cholesterol homeostasis of females with elevated total cholesterol levels.     

White norms and black MMPIs: A prescription for discrimination?

Indicates distinctive differences between the MMPI scores of blacks and whites. Differences in social desirability ratings of items and disproportionate representation of black-favored items on the key scales partially account for these findings. Education, residence, and cultural separation influence the degree of difference found. However, whether normal or institutionalized, blacks generally obtain higher scores than whites on the Validity, Schizophrenia, and Hypomania scales. Item and factor analyses reveal that these differences represent differences between blacks and whites in values, perceptions, and expectations, rather than differences in level of adjustment. The principal value exhibited by blacks has been labeled distrust of society or social cynicism. Preliminary data is presented from the author's study of white (n = 300) and black (n = 487) job applicants and psychiatric patients. Results suggest that (a) prospective black policemen and hospital attendents are disadvantaged when the MMPI is used for screening and (b) black psychiatric patients are less likely than whites to be diagnosed accurately by the MMPI. Various solutions to this problem are discussed; the most satisfactory approach appears to be construction of an MMPI based on black norms. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task-relevant information, social reinforcement, and race as factors affecting performance.

Hypothesized that lower-class blacks, who have been found to have an external control orientation to their environment, would be more responsive to social reinforcements in a skill task than in a chance task situation. Conversely, it was expected that middle-class whites, who have been shown typically to maintain interval control orientations, would be more responsive to social reinforcements in a chance task than in a skill task situation. 48 male 5th and 6th graders (24 lower-class blacks and 24 middle-class whites) were assigned to social reinforcement and control conditions. The independent variables, social reinforcement, type of task, and ethnic group of Ss were used in a 3 * 2 * 2 analysis of variance. Results confirm the original hypotheses. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acetylator phenotype, aminobiphenyl-hemoglobin adduct levels, and bladder cancer risk in white, black, and Asian men in Los Angeles, California

BACKGROUND: There is a large body of epidemiologic and experimental data that have identified a number of arylamines as human bladder carcinogens. Metabolic activation is required to biotransform these arylamines into their carcinogenic forms, and N-hydroxylation, which is catalyzed by the hepatic cytochrome P4501A2 isoenzyme, is generally viewed as the first critical step. On the other hand, the N-acetylation reaction, catalyzed by the hepatic N-acetyltransferase enzyme, represents a detoxification pathway for such compounds. The N-acetyltransferase enzyme is coded by a single gene displaying two phenotypes, slow and rapid acetylators. In the United States, cigarette smoking is a major cause of bladder cancer in men, and carcinogenic arylamines present in cigarette smoke are believed to be responsible for inducing bladder cancer in smokers. PURPOSE: Our purpose was to test the differences in three ethnic/racial groups for the prevalence of acetylator phenotypes and to ascertain whether slow acetylators actually have higher levels of activated arylamines in comparison with rapid acetylators. METHODS: One hundred thirty-three male residents of Los Angeles County who were either white, black, or Asian (Chinese or Japanese) and over the age of 35 years were assessed for their acetylator phenotype and levels of 3- and 4-aminobiphenyl (ABP) hemoglobin adducts. Subjects were either lifetime nonsmokers (n = 72) or current cigarette smokers of varying intensity (n = 61). RESULTS: The proportion of slow acetylators was highest among whites (54%), intermediate among blacks (34%), and lowest among Asians (14%). Similarly, geometric mean levels of both 3- and 4-ABP-hemoglobin adducts were highest in whites (1.80 and 49.2 pg/g hemoglobin [Hb], respectively), intermediate in blacks (1.54 and 38.5 pg/g Hb), and lowest in Asians (0.73 and 36.0 pg/g Hb). As expected, cigarette smokers had significantly higher mean levels of both 3- and 4-ABP-hemoglobin adducts relative to nonsmokers, and the levels increased with the number of cigarettes smoked per day (P < .0005 for both adducts). Slow acetylators consistently exhibited higher mean levels of ABP-hemoglobin adducts relative to rapid acetylators, independent of race and level of smoking. CONCLUSION: The present cross-sectional survey supports acetylation phenotype as an important determinant of bladder cancer risk and a possible major factor in the varying bladder cancer risk among whites, blacks, and Asians.     

Stool weight and faecal pH in two South African populations with a dissimilar colon cancer risk

Bowel diseases (appendicitis, diverticulitis and colon cancer) in South African whites and populations of prosperous Western countries are similar. Among rural South African blacks with a traditional lifestyle these diseases are very uncommon or almost unknown. A study was undertaken to measure stool weight and faecal pH in South African urban blacks and whites. There was no difference in stool weight, but the faecal pH was significantly higher in whites (P = 0.002).