PubMed Health⌕ Search

Biomedical subjects

David B Allison

Publications and source records attributed to David B Allison.

At least 91 records · Page 5Linked to original sources
PubMed2003

Primary care physicians' attitudes about obesity and its treatment.

OBJECTIVE: This study was designed to assess physicians' attitudes toward obese patients and the causes and treatment of obesity. RESEARCH METHODS AND PROCEDURES: A questionnaire assessed attitudes in 2 geographically representative national random samples of 5000 primary care physicians. In one sample (N = 2500), obesity was defined as a BMI of 30 to 40 kg/m(2), and in the other (N = 2500), obesity was defined as a BMI > 40. RESULTS: Six hundred twenty physicians responded. They rated physical inactivity as significantly more important than any other cause of obesity (p < 0.0009). Two other behavioral factors-overeating and a high-fat diet-received the next highest mean ratings. More than 50% of physicians viewed obese patients as awkward, unattractive, ugly, and noncompliant. The treatment of obesity was rated as significantly less effective (p < 0.001) than therapies for 9 of 10 chronic conditions. Most respondents (75%), however, agreed with the consensus recommendations that a 10% reduction in weight is sufficient to improve obesity-related health complications and viewed a 14% weight loss (i.e., 78 +/- 5 kg from an initial weight of 91 kg) as an acceptable treatment outcome. More than one-half (54%) would spend more time working on weight management issues if their time was reimbursed appropriately. DISCUSSION: Primary care physicians view obesity as largely a behavioral problem and share our broader society's negative stereotypes about the personal attributes of obese persons. Practitioners are realistic about treatment outcomes but view obesity treatment as less effective than treatment of most other chronic conditions.

Adult↗
PubMed2003

A festschrift for Roland L. Weinsier: nutrition scientist, educator, and clinician.

Roland L. Weinsier, M.D., Dr.P.H., devoted himself to the fields of nutrition and obesity for more than 35 years. He contributed outstanding work related to the treatment of obesity through dietary and lifestyle change; metabolic/energetic influences on obesity, weight loss, and weight regain; body composition changes accompanying weight loss and regain; the health benefits and risks of weight loss; nutrition education for physicians; and nutrition support of sick patients. He served on the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) National Task Force on Prevention and Treatment of Obesity, as Chair of the University of Alabama at Birmingham's Department of Nutrition Sciences, and as Founder and Director of its NIDDK-funded Clinical Nutrition Research Center. He was a long-time and active member of NAASO, serving in the roles of Councilor, Publications Committee Chair, Continuing Medical Education Course Director, Public Relations Committee Chair, and Membership Committee Co-Chair, to name just a few. He was well respected as a staunch defender of NAASO's scientific integrity in these roles. Sadly, Roland Weinsier died on November 27, 2002. He will be missed and remembered by many as a revered and beloved teacher, mentor, healer, and scholar.

History, 20th Century↗
PubMed2003

Obesity and quality of life: mediating effects of pain and comorbidities.

OBJECTIVE: To estimate the association between body mass index (BMI) and health-related quality of life (HRQL) and examine whether joint pain and obesity-related comorbidities mediate the BMI-HRQL association. RESEARCH METHODS AND PROCEDURES: Population-based survey data from the 1999 Behavioral Risk Factor Surveillance Survey. Adults (N = 155,989) were classified according to BMI as underweight (<18.5 kg/m(2)), desirable weight (18.5 to 24.9 kg/m(2)), overweight (25 to 29.9 kg/m(2)), obese class I (30 to 34.9 kg/m(2)), obese class II (35 to 39.9 kg/m(2)), and obese class III (>/=40 kg/m(2)). Data including general health status, unhealthy days in the past 30 caused by physical problems and mental problems, and total unhealthy days in the past 30 were collected. RESULTS: After adjusting for age, sex, race, smoking, education, and income, we observed J-shaped associations between BMI and HRQL. Compared with desirable weight adults, underweight, overweight, and obesity classes I, II, and III adults [odds ratio (OR) = 1.57, 1.19, 1.95, 2.72, and 4.36, respectively] were significantly (p < 0.001) more likely to report fair/poor general health status. For unhealthy days caused by physical problems, the corresponding ORs were 1.51, 1.15, 1.66, 2.27, and 3.61 (p < 0.001). For unhealthy days caused by mental problems, the ORs were 1.35, 1.14 1.43, 1.57, and 2.25 (p < 0.001). For total unhealthy days, the corresponding ORs were 1.27, 1.09, 1.37, 1.73, and 2.46 (p < 0.01). Adding joint pain and obesity-related comorbidities into models attenuated BMI-HRQL associations. DISCUSSION: Associations between BMI and HRQL indices were J-shaped. Joint pain and comorbidities may mediate BMI-HRQL associations.

Adult↗
PubMed2003

Is percentage body fat differentially related to body mass index in Hispanic Americans, African Americans, and European Americans?

BACKGROUND: Limited research has been done to explore differences between ethnic groups, including Hispanic Americans (HAs), in the association between percentage body fat (PBF) and body mass index (BMI; in kg/m(2)); the numbers of HAs are increasing in the US population. OBJECTIVE: We investigated whether the relation between PBF and BMI in adult HAs differed from that of African Americans (AAs) and European Americans (EAs). DESIGN: We used a multiple regression model in which PBF measured with dual energy X-ray absorptiometry was predicted by the reciprocal of BMI (1/BMI; in m(2)/kg) in a sample of 487 men (n(EA) = 192, n(AA) = 148, and n(HA) = 147) and 933 women (n(EA) = 448, n(AA) = 304, and n(HA) = 181). RESULTS: For men, our results showed no significant differences between HAs and EAs, AAs and EAs, or HAs and AAs in the slope of the line relating 1/BMI to PBF. In women, there were significant differences in PBF as predicted by BMI between HAs and EAs (P < 0.002) and AAs and HAs (P = 0.020), but not between AAs and EAs. When PBF was estimated on the basis of predicting equations, the trend of the predicted PBF value in women differed according to ethnic group and BMI category. At a BMI < 30, HAs tended to have more body fat than did EAs and AAs, and at a BMI > 35, EAs tended to have more body fat than did the other groups. CONCLUSIONS: Our results show that the relation between PBF and BMI in HA women differs from that of EA and AA women.

Absorptiometry, Photon↗
PubMed2003

Carbohydrate intake and biomarkers of glycemic control among US adults: the third National Health and Nutrition Examination Survey (NHANES III).

BACKGROUND: Recommendations for preventing and treating type 2 diabetes include consuming carbohydrates, predominantly from whole grains, fruit, vegetables, and low-fat milk. However, the quantity and type of carbohydrates consumed may contribute to disorders of glycemic control. OBJECTIVE: We evaluated the association between carbohydrate intakes and biomarkers of glycemic control in a nationally representative sample of healthy US adults who participated in a cross-sectional study, the third National Health and Nutrition Examination Survey. DESIGN: The sample (5730 men and 6125 women aged > or = 20 y) was divided into quintiles of carbohydrate intake (as a percentage of energy). Carbohydrate intakes were examined in relation to glycated hemoglobin (Hb A(1c)), plasma glucose, serum C-peptide, and serum insulin concentrations by using logistic regression. RESULTS: Carbohydrate intakes were not associated with Hb A(1c), plasma glucose, or serum insulin concentrations in men or women after adjustment for confounding variables. Carbohydrate intakes were inversely associated with serum C-peptide concentrations in men and women. Odds ratios for elevated serum C-peptide concentrations for increasing quintiles of carbohydrate intake were 1.00, 0.88, 0.57, 0.39, and 0.75 (P for trend = 0.016) in men, and 1.00, 0.69, 0.57, 0.36, and 0.41 (P for trend = 0.007) in women. When carbohydrate intakes were further adjusted for intakes of total and added sugar, the association of serum C-peptide with carbohydrate intakes was strengthened in men. CONCLUSIONS: Carbohydrate intakes were not associated with Hb A(1c), plasma glucose, or serum insulin concentrations but were inversely associated with the risk of elevated serum C-peptide; this supports current recommendations regarding carbohydrate intake in healthy adults.

Adult↗
PubMed2003

Stochastic search variable selection for identifying multiple quantitative trait loci.

In this article, we utilize stochastic search variable selection methodology to develop a Bayesian method for identifying multiple quantitative trait loci (QTL) for complex traits in experimental designs. The proposed procedure entails embedding multiple regression in a hierarchical normal mixture model, where latent indicators for all markers are used to identify the multiple markers. The markers with significant effects can be identified as those with higher posterior probability included in the model. A simple and easy-to-use Gibbs sampler is employed to generate samples from the joint posterior distribution of all unknowns including the latent indicators, genetic effects for all markers, and other model parameters. The proposed method was evaluated using simulated data and illustrated using a real data set. The results demonstrate that the proposed method works well under typical situations of most QTL studies in terms of number of markers and marker density.

Bayes Theorem↗
PubMed2003

Bayesian model choice and search strategies for mapping interacting quantitative trait Loci.

Most complex traits of animals, plants, and humans are influenced by multiple genetic and environmental factors. Interactions among multiple genes play fundamental roles in the genetic control and evolution of complex traits. Statistical modeling of interaction effects in quantitative trait loci (QTL) analysis must accommodate a very large number of potential genetic effects, which presents a major challenge to determining the genetic model with respect to the number of QTL, their positions, and their genetic effects. In this study, we use the methodology of Bayesian model and variable selection to develop strategies for identifying multiple QTL with complex epistatic patterns in experimental designs with two segregating genotypes. Specifically, we develop a reversible jump Markov chain Monte Carlo algorithm to determine the number of QTL and to select main and epistatic effects. With the proposed method, we can jointly infer the genetic model of a complex trait and the associated genetic parameters, including the number, positions, and main and epistatic effects of the identified QTL. Our method can map a large number of QTL with any combination of main and epistatic effects. Utility and flexibility of the method are demonstrated using both simulated data and a real data set. Sensitivity of posterior inference to prior specifications of the number and genetic effects of QTL is investigated.

Bayes Theorem↗
PubMed2003

Dietary restriction and beta-cell sensitivity to glucose in adult male rhesus monkeys.

We examined the effects of dietary restriction (DR) and age on ss-cell function and peripheral insulin sensitivity in rhesus monkeys. A semipurified diet was provided either ad libitum for approximately 8 hours/day to controls (C) or as approximately 70% of baseline intake to restricted (R) animals for 10 years. The minimal model of C-peptide secretion and kinetics and the labeled 2-compartment minimal model of glucose kinetics were identified using plasma glucose, C-peptide, and insulin concentrations during an intravenous glucose tolerance test. R monkeys had less body fat, lower basal ss-cell sensitivity to glucose (Ø(b)), greater insulin sensitivity, and lower first-phase plasma insulin response. DR did not significantly affect first-phase and second-phase ss-cell sensitivity to glucose. Indices of body fatness were highly predictive of the effect of DR on Ø(b), fasting insulin concentration and insulin responses to glucose. Enhanced peripheral insulin sensitivity among R monkeys was strongly correlated with lower Ø(b).

Adipose Tissue↗
PubMed2003

Nonreplication in genetic association studies of obesity and diabetes research.

The objective of this article is to provide an overview of the existing literature concerning the identification of genetic markers associated with obesity and diabetes. Specifically, this article will review recent association studies of diabetes and obesity with an emphasis on the need for the replication of findings. Unfortunately, a substantial number of the published associations between genetic markers and phenotypes, including diabetes and obesity, have not been replicated. Literature that addresses the potential reasons for the nonreplication of association studies (population stratification, publication bias, effect heterogeneity, Type I errors and lack of statistical power) is summarized. Recommendations to improve future association studies are presented.

Diabetes Mellitus↗
PubMed2003

Major histocompatibility complex class I alleles associated with slow simian immunodeficiency virus disease progression bind epitopes recognized by dominant acute-phase cytotoxic-T-lymphocyte responses.

Certain major histocompatibility complex class I (MHC-I) alleles are associated with delayed disease progression in individuals infected with human immunodeficiency virus (HIV) and in macaques infected with simian immunodeficiency virus (SIV). However, little is known about the influence of these MHC alleles on acute-phase cellular immune responses. Here we follow 51 animals infected with SIV(mac)239 and demonstrate a dramatic association between Mamu-A*01 and -B*17 expression and slowed disease progression. We show that the dominant acute-phase cytotoxic T lymphocyte (CTL) responses in animals expressing these alleles are largely directed against two epitopes restricted by Mamu-A*01 and one epitope restricted by Mamu-B*17. One Mamu-A*01-restricted response (Tat(28-35)SL8) and the Mamu-B*17-restricted response (Nef(165-173)IW9) typically select for viral escape variants in early SIV(mac)239 infection. Interestingly, animals expressing Mamu-A*1 and -B*17 have less variation in the Tat(28-35)SL8 epitope during chronic infection than animals that express only Mamu-A*01. Our results show that MHC-I alleles that are associated with slow progression to AIDS bind epitopes recognized by dominant CTL responses during acute infection and underscore the importance of understanding CTL responses during primary HIV infection.

Alleles↗
PubMed2003

Multispecific vaccine-induced mucosal cytotoxic T lymphocytes reduce acute-phase viral replication but fail in long-term control of simian immunodeficiency virus SIVmac239.

Given the current difficulties generating vaccine-induced neutralizing antibodies to human immunodeficiency virus (HIV), the focus of the vaccine community has shifted toward creating cytotoxic-T-lymphocyte (CTL)-based vaccines. Recent reports of CTL-based vaccine trials in macaques challenged with simian/human immunodeficiency virus SHIV-89.6P have supported the notion that such vaccines can ameliorate the course of disease. However, almost all of these studies included Env as an immunogen and since SHIV-89.6P is sensitive to neutralizing antibodies it is difficult to determine the mechanism(s) of protection. Consequently, SHIV-89.6P challenge of macaques may be a poor model for determining vaccine efficacy in humans. To ascertain the effect of vaccine-induced multispecific mucosal CTL, in the absence of Env-specific antibody, on the control of an immunodeficiency virus challenge, we vaccinated Mamu-A*01(+) macaques with constructs encoding a combination of CTL epitopes and full-length proteins (Tat, Rev, and Nef) by using a DNA prime/recombinant modified vaccinia virus Ankara (rMVA) boost regimen. The vaccination induced virus-specific CTL and CD4(+) helper T lymphocytes with CTL frequencies as high as 20,000/million peripheral blood mononuclear cells. The final rMVA vaccination, delivered intravenously, engendered long-lived mucosal CTL. At 16 weeks after the final rMVA vaccination, the vaccinees and naive, Mamu-A*01(+) controls were challenged intrarectally with SIVmac239. Massive early anamnestic cellular immune responses controlled acute-phase viral replication; however, the three vaccinees were unable to control virus replication in the chronic phase. The present study suggests that multispecific mucosal CTL, in the absence of neutralizing antibodies, can achieve a modicum of control over early viral replication but are unable to control chronic-phase viral replication after a high-dose mucosal challenge with a pathogenic simian immunodeficiency virus.

Acute Disease↗
PubMed2003

Expression of the major histocompatibility complex class I molecule Mamu-A*01 is associated with control of simian immunodeficiency virus SIVmac239 replication.

Several HLA alleles are associated with attenuated human immunodeficiency virus disease progression. We explored the relationship between the expression of particular major histocompatibility complex (MHC) class I alleles and viremia in simian immunodeficiency virus SIV(mac)239-infected macaques. Of the common MHC class I alleles, animals that expressed Mamu-A*01 exhibited the best control of viral replication.

Alleles↗
PubMed2003

Do allelic variants of SLC6A14 predispose to obesity?

Obesity is arguably the world's most prevalent nutritional disorder and is a substantial contributor to morbidity and early mortality. Obesity is known to have a strong genetic component, but the specific influential genes in humans are largely unknown. A new paper describes a genetic variant that appears as though it may cause some people to be fatter or thinner than others (see the related article beginning on page 1762). This commentary considers the strength of the evidence in support of this finding and discusses additional research questions that should be addressed in further evaluations of this genetic variant as a putative contributor to human obesity.

Alleles↗
PubMed2003

The impact of weight gain on quality of life among persons with schizophrenia.

Weight gain has been associated with the use of antipsychotic medications, and research has linked obesity with reduced quality of life. This study sought to assess the impact of weight gain on persons with schizophrenia who are taking antipsychotic medications. The Psychological Well-Being Index, a measure of quality of life, was distributed to individuals with schizophrenia who belonged to mental health associations. Among 286 respondents, 56 percent gained no weight over a six-month period while taking antipsychotic medications, 19 percent gained one to ten pounds, 12 percent gained 11 to 20 pounds, and 14 percent gained more than 20 pounds. When gender and use of antipsychotics were controlled for, weight gain was related to poorer quality of life and reduced well-being and vitality. Clinicians should consider the effect of weight gain on quality of life when prescribing antipsychotics and should help patients adopt weight maintenance behaviors.

Adult↗
PubMed2003

Understanding racial differences in obesity and metabolic syndrome traits.

Epidemiologic data demonstrate a positive association between obesity and certain measures related to the metabolic syndrome that differ among individuals of different ethnic/racial backgrounds. The effect of genetic and environmental factors on these differences is not completely understood; however, insightful information can be obtained by taking into account the degree of ancestral admixture in populations.

Humans↗
PubMed2002

Transcriptional profiles associated with aging and middle age-onset caloric restriction in mouse hearts.

To provide a global analysis of gene expression in the aging heart, we monitored the expression of 9,977 genes simultaneously in 5- and 30-month-old male B6C3F(1) mice by using high-density oligonucleotide microarrays and several statistical techniques. Aging was associated with transcriptional alterations consistent with a metabolic shift from fatty acid to carbohydrate metabolism, increased expression of extracellular matrix genes, and reduced protein synthesis. Caloric restriction (CR) started at 14 months of age resulted in a 19% global inhibition of age-related changes in gene expression. Interestingly, CR also resulted in alterations in gene expression consistent with preserved fatty acid metabolism, reduced endogenous DNA damage, decreased innate immune activity, apoptosis modulation, and a marked cytoskeletal reorganization. These observations provide evidence that aging of the heart is associated with specific transcriptional alterations, and that CR initiated in middle age may retard heart aging by inducing a profound transcriptional reprogramming.

Aging↗
PubMed2002

Changes in body mass index for individuals with and without schizophrenia, 1987-1996.

The advent of the novel or atypical antipsychotic drugs has improved the treatment and quality of life for many individuals. However, many of these newer agents confer a degree of weight gain that is both greater than conventional antipsychotics and of a clinically meaningful magnitude. To better place this issue into perspective, we evaluated body mass index (BMI; kg/m2) levels and the prevalence of overweight and obesity among schizophrenic versus non-schizophrenic individuals among nationally representative samples of the US adult population and evaluated whether there were changes in these rates during the decade from 1987 to 1996, a period in which use of novel/atypical agents increased. Results showed that mean BMI for individuals with schizophrenia is significantly higher than individuals who are not schizophrenic. The non-schizophrenic population shows steady and significant gains in BMI from 1987 to 1996 both as a whole and when stratified by gender and age. In contrast, time trends among the population of schizophrenic individuals show a more complex pattern. Specifically, for most groups, there is little evidence of a general trend in BMI over time. However, among females with schizophrenia ages 18-30, BMI has increased dramatically and significantly causing a much higher obesity rate among young women with schizophrenia in recent years relative to their non-schizophrenic counterparts. The mechanism that underlies this weight age and sex specific time trend is unclear.

Adult↗