Scott B Going

PMID: 8325963;Abstract:

Dehydroepiandrosterone (DHEA) has an antiobesity effect in rodents, and elevated endogenous levels of its sulfate ester (DHEAS) are associated with reductions in risk for cardiovascular disease (CVD) in men. To examine the association of body fat and fat distribution, established correlates of CVD and CVD risk factors, with circulating DHEAS levels in women, we measured trunk and limb skinfold thicknesses and circumferences, total and regional body fat from dual energy x-ray absorptiometry (DXA), and serum levels of DHEAS in 96 healthy Caucasian females aged 28-39 yr. Body mass index, percentage fat from DXA and the waist-to-hip ratio were not significantly correlated (r ≤ 0.15, P ≥ 0.156) with serum DHEAS levels, regardless of statistical control for age, smoking behavior, and fasting status. However, the ratio of trunk/total skinfold thicknesses (r = 0.23, P = 0.030) and the percentage of total fat located on the trunk from DXA (r = 0.32, P = 0.002) were positively correlated with DHEAS, whereas the ratio of leg/total skinfold thicknesses (r = -0.25, P = 0.015) and the percentage of total fat located on the legs from DXA (r = -0.25, P = 0.015) were inversely correlated with DHEAS after adjusting for age, smoking, and fasting status. With the exception of the trunk/total skinfold thickness ratio, the correlations of DXA- and skinfold-derived estimates of fat distribution remained significant (P ≤ 0.033) even after further adjust ment for percentage fat or body mass index. It is concluded that increased amounts of total fat located on the trunk and decreased amounts of total fat located on the legs are associated with increased serum DHEAS concentrations in normally menstruating females.

This study characterized body composition profiles of elite American heptathletes and cross-validated skinfold (SKF) and bioelectrical impedance analysis (BIA) field method equations for estimation of percent body fat (%Fat) using dual energy x-ray absorptiometry (DXA) as the criterion. Weight, height, fat mass (FM), fat-free mass (FFM), bone mineral density (BMD), and %Fat were measured in 19 heptathletes using standard measurement protocols for DXA, SKFs and BIA. The ages, heights, and weights were respectively 25.5 +/- 3.5 years, 175.0 +/- 6.6 cm, 67.3 +/- 7.1 kg. DXA estimates of mean +/- SD values for body composition variables were 57.2 +/- 6.1 kg FFM, 10.1 +/- 2.6 kg FM, 114 +/- 7% BMD for age/racial reference group, and 15 +/- 3.0 %Fat. Ranges of bias values for %Fat (DXA minus SKF or BIA) were, respectively, -0.5 to 1.6% and -5.5 to -1.2%. Ranges for standard errors of estimate and total errors were, respectively, SKF 2.4-2.5%, 2.4 - 2.8% and BIA 3.0%, 5.0-6.5%. Regression analyses of the field methods on DXA were significant (p .05) for all SKF equations but not BIA equations. This study demonstrates that elite American heptathletes are lean, have high levels of BMD, and that SKF equations provide more accurate estimates of %Fat relative to DXA than estimates from BIA equations.

One aim of the Pathways study is to improve the knowledge, attitudes, and behaviors of American Indian children in grades 3-5 regarding physical activity and diet in. This article describes the development of a culturally sensitive, age-appropriate questionnaire to assess these variables. The questionnaire was designed to be administered in the classroom in two 30-min sessions. Questions were developed to assess 4 key areas: physical activity, diet, weight-related attitudes, and cultural identity. Potential questions were written after review of relevant literature and existing questionnaires. Numerous and extensive revisions were made in response to input from structured, semistructured, and informal data collection. Questions were pretested in 32 children in grades 3-5 by using semistructured interviews. Test-retest reliability and the internal consistency of scales were examined in 371 fourth-grade children and subsequently in 145 fourth-grade children. Questions were reviewed by American Indians from the communities involved in the Pathways study several times during the developmental process. The process described here serves as one model for the development of a culturally appropriate tool to assess knowledge, attitudes, and behaviors in American Indian children.

Abstract:

An understanding of body composition is crucial to understanding human health, disease, and function. Research in body composition has focused on the development of assessment methods, description of normal changes in body composition with growth and development and aging, and the changes that occur in body composition in response to challenges ranging from illness to planned interventions. Each focus is significant, and in a sense, they are interdependent, because technological advances allow more sophisticated questions to be addressed, which in turn drives the development of better methods. Significant advances have been made in each area, although perhaps surprisingly basic questions remain. For example, growth trajectories are often estimated from cross-sectional data, given the resources needed for long-term observational studies, and thus, longitudinal descriptive data are still needed. Along with advances in laboratory methods, development of field methods remains relevant for screening and clinical practice. Despite recognition of wide interindividual differences in intervention response, average outcomes continue to be emphasized. With technological advances, it is now possible to examine genetic along with nongenetic factors that underlie changes in body composition, and these techniques need to be applied in long-term, well-controlled trials. In this article, we review 10 key questions in related areas in which research is needed to continue to advance the field. Copyright © 2014 AAHPERD.

PMID: 18155996;Abstract:

Energy underreporting is a concern with dietary intake data; therefore, subject characteristics associated with underreporting energy intake should be elucidated. Baseline self-reported dietary intake and measures of diet and weight history, life status, weight-loss readiness, psychology, eating behavior, physical activity, and self-image of obese middle-aged women (mean body mass index [calculated as kg/m²]=31.0) enrolled in a lifestyle weight-loss program were evaluated. Of the 155 participating, 71 women were identified as underreporting energy intake using the Goldberg cutoff values. Comparison of means between psychosocial and behavioral measures from energy underreporters and energy accurate reporters were used to help develop logistic regression models that could predict likelihood to underreport energy intake based on baseline measures. Characteristics most predictive of energy underreporting included fewer years of education (P=0.01), less-realistic weight-loss goals (P=0.02), higher perceived exercise competence (P=0.07), more social support to exercise (P=0.04), more body-shape concern (P=0.01), and higher perception of physical condition (P=0.03). These results highlight distinct psychosocial and behavioral characteristics that, at baseline, can help identify the likelihood an overweight middle-aged woman entering a weight-loss intervention will underreport energy intake. These results can help provide a framework for screening study participants for probability of energy underreporting, based on baseline psychosocial and behavioral measures. This knowledge can help researchers target at-risk subjects and, through education and training, improve the accuracy of self-reported energy intake and, ultimately, the accuracy of energy and nutrient intake relationships with health and disease. © 2008 American Dietetic Association.