Sports injuries: emergency assessment and field-side care.
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Ambulatory Care↗
Biomedical subjects
A Luke
Publications and source records attributed to A Luke.
The quantitative trait locus on chromosome 2 for serum leptin levels is confirmed in African-Americans.
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Black or African American↗
Genetic and physiologic analysis of the role of uncoupling protein 3 in human energy homeostasis.
By virtue of its potential effects on rates of energy expenditure, uncoupling protein 3 (UCP3) is an obesity candidate gene. We identified nine sequence variants in UCP3, including Val9Met, Val102Ile, Arg282Cys, and a splice site mutation in the intron between exons 6 and 7. The splice mutation results in an inability to synthesize mRNA for the long isoform (UCP3L) of UCP3. Linkage (sib pair), association, and transmission disequilibrium testing studies on 942 African-Americans did not suggest a significant effect of UCP3 on body composition in this group. In vastus lateralis skeletal muscle of individuals homozygous for the splice mutation, no UCP3L mRNA was detectable; the short isoform (UCP3S) was present in an increased amount. In this muscle, we detected no alterations of in vitro mitochondrial coupling activity, mitochondrial respiratory enzyme activity, or systemic oxygen consumption or respiratory quotient at rest or during exercise. These genetic and physiologic data suggest the following possibilities: UCP3S has uncoupling capabilities equivalent to UCP3L; other UCPs may compensate for a deficiency of bioactive UCP3L; UCP3L does not function primarily as a mitochondrial uncoupling protein.
Alternative Splicing↗
Mortality and optimal body mass index in a sample of the US population.
In this paper, the authors model the nonmonotonic relation between body mass index (BMI) (weight (kg)/height2 (m2)) and mortality in 13,242 black and white participants in the NHANES I Epidemiologic Follow-up Study in order to estimate the BMI at which minimum mortality occurs. The BMI of minimum mortality was 27.1 for black men (95% confidence interval (CI) 24.8-29.4), 26.8 for black women (95% CI 24.7-28.9), 24.8 for white men (95% CI 23.8-25.9), and 24.3 for white women (95% CI 23.3-25.4). Each confidence interval included the group average. Analyses conducted by smoking status and after exclusion of persons with baseline illness and persons who died during the first 4 years of follow-up led to virtually identical estimates. The authors determined the range of values over which risk of all-cause mortality would increase no more than 20% in comparison with the minimum. This interval was nine BMI units wide, and it included 70% of the population. These results were confirmed by parallel analyses using quantiles. The model used allowed the estimation of parameters in the BMI-mortality relation. The resulting empirical findings from each of four race/sex groups, which are representative of the US population, demonstrate a wide range of BMIs consistent with minimum mortality and do not suggest that the optimal BMI is at the lower end of the distribution for any subgroup.
Adult↗
Mortality patterns among adult Hispanics: findings from the NHIS, 1986 to 1990.
OBJECTIVES: The purpose of this study was to assess the mortality pattern of the adult Hispanic population in the United States. METHODS: This was a cohort study using data from the National Health Interview Survey from 1986 through 1990. Deaths were ascertained by matching the National Death Index through 1991. RESULTS: This representative national sample included 297,640 non-Hispanic Whites, 53,552 Blacks, and 27,239 Hispanics, all aged 18 years or older at baseline. Different matching criteria resulted in modest differential estimates of the number of deaths by ethnic groups; these differences were quantitatively more important for Hispanics. Overall age-standardized mortality was lower among Hispanics. A prominent age by race interaction was apparent. The Hispanic: White mortality ratio was 1.33, 0.92, and 0.76 among men aged 18 through 44, 45 through 64, and 65 and older, respectively. Among women in the same age groups the Hispanic: White mortality ratio was 1.22, 0.75, and 0.70, respectively. CONCLUSIONS: Longitudinal cohorts provide an important source of health status information on Hispanics. These results suggest that overall mortality is lower among Hispanics than among non-Hispanic Whites, especially in the oldest age group. Among younger and middle-aged persons, the mortality of Hispanics is similar to or even higher than that of Whites.
Adult↗
Relation between body mass index and body fat in black population samples from Nigeria, Jamaica, and the United States.
Body mass index (BMI) is the most commonly used measure of obesity. Recently, some investigators have advocated direct measurement of adiposity rather than use of the BMI. This study was undertaken to determine the ability of BMI to predict body fat levels in three populations of West African heritage living in different environments. A total of 1,054 black men and women were examined in Nigeria, Jamaica, and the United States during 1994 and 1995. A standardized protocol was used to measure height, weight, waist and hip circumferences, and blood pressure at all sites; percentage of body fat was estimated using bioelectrical impedance analysis. Percentage of body fat and BMI were highly correlated within site- and sex-specific groups, and the resulting r2 ranged from 0.61 to 0.85. The relation was quadratic in all groups except Nigerian men, in whom it was linear. The regression coefficients were similar across sites, yet the mean body fat levels differed significantly (p < 0.001) as estimated by the intercept, making intersite comparison difficult. Compared with BMI, percentage of body fat was not a better predictor of blood pressure or waist or hip circumference.
Adult↗
Heritability of plasma leptin in a population sample of African-American families.
The aim of this study was to examine familial patterns of plasma leptin levels and the potential association with cardiovascular risk factors in a population sample of African-American families recruited from metropolitan Chicago. The study included 68 mothers, 31 fathers, 143 daughters, and 119 sons, for a total of 361 individuals from 118 families. Leptin levels were adjusted for the effect of age separately for mothers, fathers, daughters, and sons. Residuals were then standardized before estimating familial correlation using the maximum-likelihood method available in SEGPATH. With the exception of height, plasma leptin level was strongly correlated with all measured anthropometric variables. Familial effect (i.e., heritability) of leptin levels was estimated as 39% in this population at high risk for over weight. A significant sex difference was observed, and most of the estimated familial effect may be attributed to genetic influences since the spouse correlation was not statistically different from zero. A strong nonshared environmental effect is also suggested, however.
Anthropometry↗
One size fits all: implications for assessing dietary behavior.
Accurate assessment of dietary behavior is central to the design, implementation, and evaluation of intervention programs aimed at behavior change, and use of an Eating Behaviors Questionnaire (EBQ) has been suggested for measuring dimensions of dietary fat behavior. The EBQ has proven useful in characterizing fat-related dietary patterns among middle-class, highly educated, highly motivated white women. To investigate the generalizability of the instrument, we provide findings from a community-based sample of 235 African-Americans in Maywood, Illinois, a middle-class working community outside Chicago. The sample consisted of 159 women and 76 men with an average age of 47.4 +/- 13.8 years for women and 48.1 +/- 12.1 years for men (mean +/- standard deviation; range, 18 to 87 years). The EBQ is based on four broad behavioral domains (ie, avoidance, modification, substitution, and replacement) associated with fat-related eating patterns. These behavioral domains are composed of specific dietary behaviors (factors). Using a scoring system that allowed all participants to be included in all analyses, we identified a set of factors characterizing eating patterns in our sample that differed from those reported previously. When the factors were converted to scales using unit scoring, the average value suggested a tendency toward a higher fat eating pattern. Results indicate that although behavioral domains appear to be constant across populations, fat-related eating patterns are not. These observations have implications for understanding the diversity of fat-related dietary patterns across groups and for planning appropriate behavior change strategies.
Adult↗
Relative weight and mortality in U.S. blacks and whites: findings from representative national population samples.
PURPOSE: To examine the impact of relative weight on mortality in black and white men and women. METHODS: Two representative national populations samples were used: the NHANES-I Epidemiologic Follow-up Study (NHEFS), and the National Health Interview Survey (NHIS). The principal analysis focused on 13,242 participants in the NHEFS and 114,954 in the NHIS. Minimum mortality was estimated from both categorical analysis and a logistic model. RESULTS: Minimum mortality ranged from a body mass index (BMI) of 25 to 32 kg/m2. The model-estimated BMI of minimum mortality for NHEFS was 27.1 (24.8-29.4, 95% CI), 26.8 (24.7-28.9, 95% CI), 24.8 (23.8-25.9, 95% CI) and 24.3 (23.2-25.4, 95% CI); for black men, black women, white men and white women, respectively, whereas for NHIS the corresponding values were 30.2 (24.8-35.6, 95% CI) 26.4 (24.2-28.7, 95% CI), 27.1 (25.5-28.7, 95% CI), and 25.6 (24.2-27.0, 95% CI). In all groups the shape of the relative risk curve was virtually identical and a broad range of BMI values in the middle of the distribution was associated with low relative mortality risk. Averaging the results from both surveys, the observed BMI of minimum risk was 3.1 kg/m2 higher in black men and 1.5 kg/m2 higher in black women than in their white counterparts; when adjusted for covariates these differences were only of borderline statistical significance, however. CONCLUSIONS: Because of the wide range of BMI values associated with low risk, and the consistency of the point of the up-turn in risk, group specific definitions of optimal values do not appear to be warranted.
Adult↗
Leptin concentration in women is influenced by regional distribution of adipose tissue.
Leptin concentrations in humans are increased with obesity, and women have higher leptin concentrations than men. This sex difference reflects the greater fat mass of women. However, there is evidence that factors other than the size of the adipose tissue mass contribute to serum leptin concentrations. This study was undertaken to determine whether anthropometric factors influenced leptin concentrations in our population. Leptin concentrations were measured in 375 persons from a population study of hypertension and diabetes for whom body-composition data (bio-electrical impedance analysis and anthropometry) were available. Serum leptin concentrations were more than four times higher in women than in men (18.5 +/- 13.9 compared with 3.8 +/- 3.6 ng/L, P < 0.0001). In individuals with comparable body mass indexes, these differences persisted after adjustment for either percentage fat (P < 0.05) or fat mass (P < 0.0001) by multivariate-regression analysis. After fat mass was adjusted for, the serum leptin concentration in both men and women was independent of waist circumference but in women was associated with hip circumference. Hip circumference is a proxy measure of peripheral fat and these results suggest that the larger hips of women may contribute to the sex difference in serum leptin concentration.
Adipose Tissue↗
Simultaneous monitoring of heart rate and motion to assess energy expenditure.
Measurement of energy expenditure in free-living individuals represents a methodologic challenge in epidemiologic research. Heart rate monitors, while closely tied to energy expenditure at high levels of energy output, provide much less predictive power at low levels; however, measurement of motion may improve the predictive ability. This study was undertaken to determine the usefulness of simultaneously monitoring heart rate and motion for the estimation of energy expenditure. Ten subjects were studied during simulated activities of daily living (ADLC) and submaximal treadmill tests. Compared to direct measurement, the motion sensor predicted oxygen consumption poorly (r2 = 0.53) for both tests. Heart rate measured simultaneously yielded an r2 of 0.81 for ADLC and 0.90 for the treadmill. Addition of motion data increased the r2 value for the ADLC for all but one individual and increased the group mean from 0.81 to 0.86. This improvement was not observed for the treadmill, confirming the hypothesis that the principle value of monitoring motion occurs at lower heart rates.
Activities of Daily Living↗
Relationship between blood pressure and body mass index in lean populations.
Associations between body mass index (BMI) and blood pressure (BP) have been consistently observed, but remain poorly understood. One unresolved question is whether there is a linear relationship across the entire BMI range. We investigated this question among 11,235 adult men and women from seven low-BMI populations in Africa and the Caribbean. We used kernel smoothing and multivariate linear and spline regression modeling to examine gender differences in the relationship and to test for a threshold. Age-adjusted slopes of BP on BMI were uniformly higher in men than women, with pooled slope ratios of 2.00 and 2.20 for systolic and diastolic BPs, respectively. Men displayed no evidence of age modification or nonlinearity in the relationship, and the age-adjusted slope of systolic BP on BMI was 0.90 (95% confidence interval [CI], 0.76 to 1.04). Women demonstrated both age modification and nonlinearity. For both younger (<45 years) and older (45+ years) women, the optimal change point for a single threshold model was found to be 21 kg/m2. Slopes of systolic BP on BMI above this threshold were positive and significant: 0.68 (95% CI, 0.54 to 0.81) and 0.53 (95% CI, 0.29 to 0.76) for younger and older women, respectively. Slopes below the threshold were essentially zero for both groups of women, and the difference between the slopes above and below the threshold was significant for younger women (P=.019). In summary, we observed a threshold at 21 kg/m2 in the relationship between BMI and BP for women but not for men. This contributes to the effort to identify the mechanisms that underlie this relationship and how they differ by gender.
Adult↗
Nutritional status in rural Nigerians.
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Body Mass Index↗
Nutrient intake and obesity in prepubescent children with Down syndrome.
OBJECTIVE: The aim of this study was to measure nutrient intake and body composition in prepubescent children with Down syndrome to understand dietary barriers involved in the prevention and treatment of obesity. DESIGN: Dietary intake was determined from parent-reported 3-day diet records for children with Down syndrome and control subjects. Energy intake was compared with energy expenditure measured by the doubly labeled water method. Body composition was determined by deuterium dilution, bioelectrical impedance analysis, and skinfold thickness measurements. SUBJECTS/SETTING: Ten prepubescent children with Down syndrome and 10 control subjects were recruited from the hospital community. The study was conducted in the Clinical Research Center of the University of Chicago Medical Center. MAIN OUTCOME MEASURES: Nutrient intakes were compared with the Recommended Dietary Allowances (RDAs) to estimate risk for nutrient deficiency. Fat-free mass values determined by bioelectrical impedance analysis and measurement of skinfold thicknesses were compared with values determined using the deuterium dilution method. STATISTICAL ANALYSES PERFORMED: Unpaired t tests were used for comparisons between subjects groups and the Wilcoxon signed-rank test was used for comparison of nutrient intakes with RDAs. RESULTS: The subjects with Down syndrome were significantly shorter (P < .01) than control subjects; however, body composition did not differ between the groups. Reported energy intake was lower in subjects with Down syndrome. In addition, several micronutrients were consumed, especially among nonobese subjects with Down syndrome, at less than 80% of the RDA. APPLICATIONS: To avoid lowering already inadequate intakes of several vitamins and minerals, we suggest that treatment of obesity in children with Down syndrome combine a balanced diet without energy restriction, vitamin and mineral supplementation, and increased physical activity.
Body Composition↗
Prenatal diagnosis and fetopathological findings in five fetuses with trisomy 9.
Five male fetuses with trisomy 9 are discussed. Three were detected prenatally and terminated, 1 aborted spontaneously, and the fifth delivered prematurely and died soon after. Multiple congenital abnormalities characteristic of trisomy 9 were detected in all 5 cases and are compared to those of previous reports.
Abnormalities, Multiple↗
Techniques for measurement of resting energy expenditure in children.
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Basal Metabolism↗
Energy expenditure in children with Down syndrome: correcting metabolic rate for movement.
Children with Down syndrome (DS) have a high prevalence of obesity. To investigate the relation between energy expenditure and obesity, we measured body composition, resting metabolic rate (RMR), and total energy expenditure in 13 prepubescent children with DS and in 10 control subjects matched for age, weight, and percentage of fat, using indirect calorimetry and the doubly labeled water method. Measurement of RMR was complicated by excessive movement by both the DS and control subjects. We therefore developed a method of subtracting the energy expended in movement and calculated the corrected RMR. The corrected RMR was significantly lower in those with DS than in control subjects when expressed as a percentage of the basal metabolic rate, predicted by the World Health Organization: 79.5% +/- 10.4% and 96.8% +/- 7.8%, respectively (p < 0.001). No significant differences were detected in total daily energy expenditure or non-RMR expenditure between the subject groups. In the DS group, 60% of the variability in fat mass could be accounted for by non-RMR expenditure expressed per kilogram of body weight (p < 0.02). No relation was detected between fat mass and non-RMR expenditure in control subjects, nor were any measures of energy expenditure predictive of changes in fatness among the subjects with DS during a 1-year follow-up. The results of this study indicate that prepubescent children with DS have decreased RMR compared with control children.
Body Composition↗
dUTP pyrophosphatase and uracil-DNA glycosylase in rat liver and hepatomas.
1. The activity of dUTP pyrophosphatase (dUTPase) was similar in rat liver and hepatomas of slow or moderate growth rate but was increased several fold in three rapidly growing hepatomas. 2. There was an approx three-fold increase in the activity of uracil-DNA glycosylase in Morris hepatoma 7800 but there was little change in activity in other hepatomas that were examined. 3. The activities of dUTPase and uracil-DNA glycosylase were not significantly affected by two diets that may be promotional for hepatocarcinogenesis, a high orotate diet and an arginine-deficient diet.
Animals↗