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Biomedical subjects

A E Long

Publications and source records attributed to A E Long.

9 recordsLinked to original sources

Weight-height relationships among eight populations of West African origin: the case against constant BMI standards.

OBJECTIVE: To ascertain whether constant body mass index (BMI) standards are appropriate in genetically similar populations. DESIGN: Data are taken from the International Collaborative Study of Hypertension in Blacks (ICSHIB), an observational study. SUBJECTS: Individuals of African descent who were included in ICSHIB. Subjects lived in eight different sites: Barbados; Cameroon (urban and rural); Jamaica; Manchester, UK; Maywood, IL; urban Nigeria; and St Lucia. MEASUREMENTS: Weight and height. RESULTS: Constant BMI standards effectively argue for the constancy of slope of the linear regression equations of In(weight) on In(height) across populations. Linear regression results indicate that the height/weight relationship implied by the use of constant BMI standards, is not found in these populations and that there is much variation across groups. CONCLUSION: The use of constant BMI standards in classifying individuals prognostically may be unwise, even in genetically similar populations.

Africa, Western↗

Leptin and body composition of Nigerians, Jamaicans, and US blacks.

The role of leptin in humans remains controversial. Leptin concentrations are highly correlated with body fat stores. We tested whether or not this relation was consistent across the range of body composition encompassing the lean as well as the obese. Individuals participating in community-based comparative research in Nigeria (n = 363), Jamaica (n = 372), and the United States (Maywood, IL; n = 699) had their plasma leptin concentrations and body compositions (with bioelectrical impedance analysis) measured. All participants identified themselves as being black. Body mass index (in kg/m2) ranged from 14 to 62. Large differences in mean plasma leptin were noted across populations for both men and women in Nigeria, Jamaica, and the United States, respectively (men: 2.8, 3.9, and 6.8 microg/L; women: 10.3, 18.6, and 27.7 microg/L). An exponential function fit the relation between percentage body fat or total fat mass and leptin for men and women at each site. For women and men the exponential function with either percentage body fat or total fat mass was of the same shape, but increased by a constant in women, yielding higher leptin concentrations than in men at every level of body fat. On the basis of this broad distribution of body composition, the data suggest an exponential response of leptin to increases in body fat stores, consistent with the development of leptin resistance in individuals developing obesity. These findings likewise confirm that men and women exhibit different set points in terms of leptin production.

Adipose Tissue↗

The relation between income and mortality in U.S. blacks and whites.

Differential mortality exists in the United States both between racial/ethnic groups and along gradients of socioeconomic status. The specification of statistical models for processes underlying these observed disparities has been hindered by the fact that social and economic quantities are distributed in a highly nonrandom manner throughout the population. We sought to provide a substantive foundation for model development by representing the shape of the income-mortality relation by racial/ethnic group. We used data on black and white men and women from the longitudinal component of the National Health Interview Survey (NHIS), 1986-1990, which provided 1,191,824 person-years of follow-up and 12,165 mortal events. To account for family size when considering income, we used the ratio of annual family income to the federal poverty line for a family of similar composition. To avoid unnecessary categorizations and prior assumptions about model form, we employed kernel smoothing techniques and calculated the continuous mortality surface across dimensions of adjusted income and age for each of the gender and racial/ethnic groups. Representing regions of equal mortality density with contour plots, we observed interactions that need to be accommodated by any subsequent statistical models. We propose two general theories that provide a foundation for more elaborate and testable hypotheses in the future.

Adolescent↗

Mortality from coronary heart disease and cardiovascular disease among adult U.S. Hispanics: findings from the National Health Interview Survey (1986 to 1994).

OBJECTIVES: We sought to estimate the coronary heart disease (CHD) and cardiovascular disease (CVD) mortality experience of U.S. Hispanics. BACKGROUND: Limited information is available concerning the mortality from CHD among U.S. Hispanics, the nation's second largest minority group. METHODS: The study used data from the National Health Interview Survey (1986 to 1994), including representative national samples of 246,239 non-Hispanic whites, 38,042 blacks and 14,965 Hispanics who were > or = 45 years old at baseline. Mean follow-up of mortality was 5 years (range 1 to 10). RESULTS: During the follow-up period, 27,702 whites (11%), 4,976 blacks (13%) and 1,061 Hispanics (7%) died. Among men, the age-adjusted total mortality per 100,000 person-years was 3,089 in whites and 2,466 in Hispanics, and among women, it was 1,897 and 1,581 in whites and Hispanics, respectively. The Hispanic/white mortality rate ratio for CHD was 0.77 (95% confidence interval [CI] 0.64 to 0.93) and 0.82 (95% CI 0.66 to 1.01) for men and women, respectively. The rate ratio was 0.79 (95% CI 0.68 to 0.91) and 0.80 (95% CI 0.69 to 0.94), respectively, for mortality from cardiovascular diseases. Given the lower all-cause mortality in Hispanics, the proportion of total deaths due to CHD and CVD was similar between the two populations for the same gender and were, respectively, 29.7% and 44.7% in white men, 28.1% and 44.3% in Hispanic men, 24.9% and 43.2% in white women and 24.1% and 41% in Hispanic women. CONCLUSIONS: These data from a cohort of a large national sample are consistent with vital statistics that show that all-cause, CHD and CVD mortality is approximately 20% lower among adult Hispanics than among whites in the United States.

Aged↗

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↗

Radiographic decision-making by the emergency physician.

To assist emergency clinicians in appropriately requesting x-ray examinations of their patients, this article looks at the factors that affect the decision to order a radiograph, describes methods of determining the efficacy of a radiograph, discusses several radiographic studies frequently requested by emergency physicians and when they are most efficacious, and reviews the ways physician decision-making may be influenced to decrease radiographic wastage.

Abdominal Injuries↗

Esophageal carcinosarcoma.

Carcinosarcoma is an uncommon malignancy of the esophagus that presents as a bulky intraluminal polypoid lesion of the esophagus. Histologically, both carcinomatous and sarcomatous components are seen. Because of accelerated intraluminal growth, esophageal carcinosarcoma often presents relatively early. This report describes a 64-year-old man with carcinosarcoma who was successfully treated with an esophagectomy. As in typical squamous cell carcinoma, early detection and treatment by surgical resection are needed to produce significant long-term survival.

Carcinosarcoma↗