Genetic parameters of dermal patterns of ridge counts.

Dermatoglyphic traits including ridge counts and pattern type counts on fingers were studied in 711 families representing six racial groups in Hawaii. Heritability tesimates were derived from regressions of offspring on father, mother and mid-parent values as well as from full-sib correlations. These estimates varied from 0.23 for radial loops to 0.80 for total ridge count. The heritability estimates were lower for ridge counts of single hands or single digits.     

Racial differences in nasopharyngeal carcinoma in the United States

Background: Nasopharyngeal carcinoma (NPC) is a malignant neoplasm arising from the mucosal epithelium of the nasopharynx. Different races can have different etiology, presentation, and progression patterns. Methods: Data were analyzed on NPC patients in the United States reported to the SEER (Surveillance, Epidemiology, and End Results) database between 1973 and 2009. Racial groups studied included non-Hispanic whites, Hispanic whites, blacks, Asians, and others. Patient characteristics, age-adjusted incidence and mortality rates, treatment, and five-year relative survival rates were compared across races. Stratification by stage at diagnosis and histologic type was considered. Multivariate regression was conducted to evaluate the significance of racial differences. Results: Patient characteristics that were significantly different across races included age at diagnosis, histologic type, in situ/malignant tumors in lifetime, stage, grade, and regional nodes positive. Incidence and mortality rates were significantly different across races, with Asians having the highest rates overall and stratified by age and/or histologic type. Asians also had the highest rate of receiving radiation only. The racial differences in treatment were significant in the multivariate stratified analysis. When stratified by stage and histologic type, Asians had the best five-year survival rates. The survival experience of other races depended on stage and type. In the multivariate analysis, the racial differences were significant. Conclusions: Analysis of the SEER data shows that racial differences exist among NPC patients in the U.S. This result can be informative to cancer epidemiologists and clinicians.     

Sex differences in fingerprint ridge density in the Mataco-Mataguayo population

Ridge density (RD), the number of digital ridges per unit area, varies according to sex, age, and population origin. The main objective of this study was to determine the extent of sexual dimorphism in RD and to set the age at which it appears, in an Amerindian sample from the Mataco-Mataguayo population. The sample studied for this research consisted of 99 males and 110 females, between 6 and 25 years old, which amounts to a total of 2090 fingerprints. Ridge count was carried out on distal radial and distal ulnar and on proximal regions of each finger to explore the RD patterns in order to identify similarities and differences among samples, areas, age groups, and sexes. RD decreased with age and, at all ages, RD was higher on the distal (radial and ulnar) areas, followed by the proximal sides. Females were found to have higher RD than males when older than 12 years, but not when younger. In the radial area, the Mataco-Mataguayo population, in both sexes, presented the RD similar to Spanish samples, but higher than all other populations analysed to date using this method. Variations in RD in the Amerindian population based on sex, age, and topology were confirmed in this work, and it is postulated that these variations are due to developmental differences among individuals and populations. A comparison between the Mataco-Mataguayo and Spanish populations is presented.     

Racial differences in bumetanide-sensitive cotransport and N-ethylmaleimide-stimulated potassium efflux

Racial differences in erythrocyte potassium effluxes mediated by two loop-diuretic sensitive modes of cotransport were compared. In red cells loaded to contain approximately equimolar amounts of sodium and potassium, black subjects had lower bumetanide-sensitive sodium-dependent net potassium effluxes as compared to whites. In fresh, washed erythrocytes pretreated with N-ethylmaleimide (NEM), maximal net potassium efflux was greater in blacks than in whites. NEM-stimulated potassium efflux was partially inhibited by bumetanide but only at very high concentrations. The quantitative differences in these two modes of potassium efflux suggest that NEM-stimulated potassium efflux is not an altered mode of sodium-dependent potassium efflux.     

Racial and cultural differences in sensitivity to flickering light

Latin America has been registering a fast decrease in fertility rates since the mid-twentieth century. This change can be linked to the modernization process these populations have been undergoing. However, research with Latin American indigenous populations, which are undergoing relatively similar lifestyle changes, shows very different trends in fertility. The aim of this study was to analyze fertility patterns in the indigenous Toba community of Cacique Sombrero Negro, which is experiencing a rapid process of economic and social Westernization. Fertility patterns were analyzed between 1981 and 1999, the period for which the most accurate records were found. Results showed an overall increase in fertility rates and changes in the age of peak fertility across time periods. It is hypothesized that the lifestyle transition this population is experiencing leads to better access to resources that, in the absence of contraception, allow for a higher number of offspring. Nevertheless, this higher resource availability would be differential, affecting mostly the fertility of younger mothers.     

Racial differences in alcohol sensitivity: A new hypothesis

Summary Cocultivation of fibroblast cells from a male patient with Bloom syndrome (BS) and a female control reduced the rate of sister chromatid exchanges in the BS cells from a mean of 54 SCE per metaphase (range 42–65) to 41 (range 24–59). Medium used to culture control cells for 48 h also reduced the rate of SCE (from 40–65 to 33–54), whereas medium used for only 24h altered the SCE rate only slightly (to 39–61). Dialyzed medium concentrate with molecular cutoff at 15,000 did not alter the SCE rate. These initial studies suggest that normal cells produce an agent, presumably lacking in BS cells, that is capable of mitigating the chromosomal manifestation of the BS mutation (bl) in bl/bl cells.     

Racial differences in lipid metabolism in women with abdominal obesity

We evaluated palmitate rate of appearance (R(a)) in plasma during basal conditions and during a four-stage epinephrine infusion plus pancreatic hormonal clamp in nine white and nine black women with abdominal obesity, who were matched on fat-free mass, total and percent body fat, and waist-to-hip circumference ratio. On the basis of single-slice magnetic resonance imaging analysis, black women had the same amount of subcutaneous abdominal fat but less intra-abdominal fat than white women (68 +/- 9 vs. 170 +/- 14 cm(2), P < 0.05). Basal palmitate R(a) was lower in black than in white women (1.95 +/- 0.26 vs. 2.88 +/- 0.23 micromol. kg fat-free mass(-1). min(-1), P < 0.005), even though plasma insulin and catecholamine concentrations were the same in both groups. Palmitate R(a) across a physiological range of plasma epinephrine concentrations remained lower in black women, because the increase in palmitate R(a) during epinephrine infusion was the same in both groups. We conclude that basal and epinephrine-stimulated palmitate R(a) is lower in black than in white women with abdominal obesity. The differences in basal palmitate kinetics are not caused by alterations in plasma insulin or catecholamine concentrations or lipolytic sensitivity to epinephrine. The lower rate of whole body fatty acid flux and smaller intra-abdominal fat mass may have clinical benefits because of the relationship between excessive fatty acid availability and metabolic diseases.     

Demographic differences in diet breadth of Canada lynx during a fluctuation in prey availability

Population dynamics of specialist carnivores are closely linked to prey availability, but the extent of variability in diet breadth of individual carnivores relative to natural variability in the abundance of their primary prey is not well understood. Canada lynx (Lynx canadensis) specialize on snowshoe hares (Lepus americanus) and exhibit cyclic fluctuations in abundance that lag 1–2 years behind those of snowshoe hares. Declining hare densities spur demographic changes in lynx, but it is unclear whether a corresponding increase in diet breadth occurs: (1) broadly across a lynx population; (2) only among individuals who are able to effectively switch to alternative prey; or (3) only among individuals who cannot capture sufficient primary prey. We measured stable isotope ratios of lynx muscle tissue spanning a cyclic increase and decline in hare density (1998–2001) in Fort Providence, NT, Canada. We found that lynx cohorts responded differently to hare population change, with yearling animals having broader diets at low hare densities, while adults and dependent juveniles maintained a constant diet through the initial decline in hare density. This result was consistent irrespective of lynx sex and indicates that yearling lynx likely are forced to adopt a broader diet when primary prey densities decline. Our results imply that select cohorts of specialist carnivores can exhibit high dietary plasticity in response to changes in primary prey abundance, prompting the need to determine whether increased diet breadth in young lynx is a successful strategy for surviving through periods of snowshoe hare scarcity. In this way, cohort‐specific niche expansion could strongly affect the dynamics of organisms exhibiting population cycles.     

Racial differences in cardiac structure and function in essential hypertension.

OBJECTIVE--To assess racial differences in cardiac structure and function in patients presenting with previously untreated hypertension. DESIGN--Untreated black patients with hypertension were compared with untreated white patients matched for age and sex. Both groups had similar body mass indices, blood pressures, and reported duration of hypertension. SETTING--Cardiovascular risk factor clinic for outpatients. SUBJECTS--36 men and 22 women with untreated essential hypertension. MAIN OUTCOME MEASURES--Variables of heart structure and function on cross sectional and Doppler echocardiography. RESULTS--The black patients had a significantly greater interventricular septal thickness (mean 1.23 (95% confidence interval 1.14 to 1.33) v 1.09 (1.02 to 1.16) cm; P = 0.02) and posterior wall thickness (mean 1.14 (1.07 to 1.22) v 0.96 (0.88 to 1.03) cm; P = 0.001) than the white patients, although left ventricular internal diameter was not significantly different (mean 4.90 (4.68 to 5.12) v 4.82 (4.64 to 5.01) cm; P = 0.59). This resulted in a significantly greater left ventricular mass index (mean 151 (137 to 164) v 120 (107 to 133) g/m2; P = 0.001) and relative wall thickness (mean 0.47 (0.43 to 0.51) v 0.40 (0.37 to 0.42) cm; P = 0.004) in the black patients. Comparison of Doppler measures of left ventricular diastolic function showed a significantly longer isovolumic relaxation time in black patients (mean 107 (98 to 116) v 92 (83 to 101) ms; P = 0.02) compared with white patients, although peak early to atrial filling ratios were similar in both groups (mean 1.14 (0.95 to 1.32) v 1.04 (0.94 to 1.15); P = 0.37). CONCLUSION--Among previously untreated hypertensive patients, black subjects compared with white subjects have significantly higher left ventricular mass index and relative wall thickness, as well as more impairment of left ventricular function during diastole.     

Effect of prenatal exposure to anticonvulsant drugs on dermal ridge patterns of fingers

BACKGROUND: An altered frequency of specific dermal ridge patterns on fingertips, such as an increased number of arches, has been observed in children exposed in utero to anticonvulsants and other teratogens. Asymmetry of the distribution of dermal ridge patterns has been attributed to environmental exposures and genetic factors. METHODS: We evaluated all of the dermal ridge patterns of 66 children who had been exposed to either the anticonvulsant phenytoin alone or phenytoin and phenobarbital. We determined the frequency of each pattern, concordance between the fingers on the left and right hands, sex differences and total ridge counts in the drug-exposed children and compared them to the findings in 716 unexposed comparison children. The frequency of each pattern was established in comparison to the most common type of pattern (ulnar loop), which showed that there were alterations in the frequency of arches, radial loops and whorls on specific fingers. RESULTS: Eight (12.1%) of 66 children had three or more arch patterns, with all but one having been exposed to phenytoin and phenobarbital. Only one of these eight children was considered by the masked examiner to have fingernail hypoplasia. There was no evidence of asymmetry in the anticonvulsant-exposed children. There were minor differences in the distribution of total ridge count. CONCLUSIONS: Subtle differences in several dermal ridge patterns, not just arch patterns, were present in anticonvulsant-exposed children, primarily in those exposed to polytherapy: phenytoin and phenobarbital.     

Racial/ethnic differences in body fatness among children and adolescents

Background: Although the BMI is widely used as a measure of adiposity, it is a measure of excess weight, and its association with body fatness may differ across racial or ethnic groups. Objective: To determine whether differences in body fatness between white, black, Hispanic, and Asian children vary by BMI‐for‐age, and whether the accuracy of overweight (BMI‐for‐age ≥ Centers for Disease Control and Prevention (CDC) 95th percentile) as an indicator of excess adiposity varies by race/ethnicity. Methods and Procedures: Total body dual‐energy X‐ray absorptiometry (DXA) provided estimates of %body fat among 1,104 healthy 5‐ to 18‐year‐olds. Results: At equivalent levels of BMI‐for‐age, black children had less (mean, 3%) body fatness than white children, and Asian girls had slightly higher (1%) levels of %body fat than white girls. These differences, however, varied by BMI‐for‐age, with the excess body fatness of Asians evident only among relatively thin children. The ability of overweight to identify girls with excess body fatness also varied by race/ethnicity. Of the girls with excess body fatness, 89% (24/27) of black girls, but only 50% (8/16) of Asian girls, were overweight (P = 0.03). Furthermore, the proportion of overweight girls who had excess body fatness varied from 62% (8/13) among Asians to 100% (13/13) among whites. Discussion: There are racial or ethnic differences in body fatness among children, but these differences vary by BMI‐for‐age. If race/ethnicity differences in body fatness among adults also vary by BMI, it may be difficult to develop race‐specific BMI cut points to identify equivalent levels of %body fat.     

Racial differences in measures of obesity and risk of colon adenoma

Obesity is an established risk factor for several malignancies. However, the specific measurement of obesity most relevant to colon neoplasia is still debated, and evidence has suggested gender and racial differences in this measurement. In this study, we sought to compare which measurement--BMI, waist circumference (WC), waist-to-hip ratio (WHR) or waist-to-height ratio (WHtR)--is most strongly associated with development of colon adenomas, a precursor of colon cancer, and to investigate differences in this association between racial groups. We confirmed the strong association between WHR, as a measure of central obesity, and development of colon neoplasia. In our overall analysis, patients in the highest WHR quartile showed a substantial increase in risk of colon adenomas compared to patients in the lowest WHR quartile (odds ratio (OR) = 1.82, 95% confidence interval (CI): 1.12-2.71, P(trend) = 0.0017). In stratified analyses, we noted that strongly associated obesity measures in European Americans were WC (OR = 2.38, 95% CI = 1.45-3.92, P(trend) = 0.0004) and BMI (OR = 2.18, 95% CI = 1.37-3.49, P(trend) = 0.0015), whereas in African Americans, WHR was the strongest and the only obesity measure statistically significantly associated with adenoma risk (OR = 2.12, 95% CI = 1.05-4.30, P(trend) = 0.025). Our data highlight the importance of obesity in the development of early colon neoplasia and suggest substantial racial differences in the measures of obesity most strongly associated with risk of colon adenomas.     

Racial differences in colorectal cancer survival at a safety net hospital

BackgroundWhile racial disparity in colorectal cancer survival have previously been studied, whether this disparity exists in patients with metastatic colorectal cancer receiving care at safety net hospitals (and therefore of similar socioeconomic status) is poorly understood.MethodsWe examined racial differences in survival in a cohort of patients with stage IV colorectal cancer treated at the largest safety net hospital in the New England region, which serves a population with a majority (65%) of non-Caucasian patients. Data was extracted from the hospital’s electronic medical record. Survival differences among different racial and ethnic groups were examined graphically using Kaplan-Meier analysis. A univariate cox proportional hazards model and a multivariable adjusted model were generated.ResultsBlack patients had significantly lower overall survival compared to White patients, with median overall survival of 1.9 years and 2.5 years respectively. In a multivariate analysis, Black race posed a significant hazard (HR 1.70, CI 1.01–2.90, p = 0.0467) for death. Though response to therapy emerged as a strong predictor of survival (HR = 0.4, CI = 0.2-0.7, p = 0.0021), it was comparable between Blacks and Whites.ConclusionsDespite presumed equal access to healthcare and socioeconomic status within a safety-net hospital system, our results reinforce findings from previous studies showing lower colorectal cancer survival in Black patients, and also point to the importance of investigating other factors such as genetic and pathologic differences.