Biomedical subjects

Leonard H Epstein

Publications and source records attributed to Leonard H Epstein.

44 records · Page 3Linked to original sources

PubMed2003

Comparison between two measures of delay discounting in smokers.

Agreement between computer and questionnaire measures of delay discounting in smokers was compared. Correlations between measures for small, medium, or large rewards were significant. Log k values decreased as the reward delay increased, with values lower for the computer task than the questionnaire, with significant differences for small rewards. The 2 measures were related to smoking rate but not to age, gender, or obesity. The Bland-Altman test of agreement indicated large within-subject differences in k values between the 2 measures. The size of the difference between the log k values and magnitude of the log k values were positively related. Results suggest k values from the 2 measures are related but may not be used interchangeably.

Adolescent↗

PubMed2003

Influence of an interpersonal laboratory stressor on youths' choice to be physically active.

OBJECTIVE: To determine whether interpersonal stress reduces youths' motivation to exercise in a laboratory setting. RESEARCH METHODS AND PROCEDURES: Physical activity and sedentary behavior were measured in boys and girls across a control day, after reading children's magazines, and on a stress day, after giving a videotaped speech. For one analysis, children were divided into low (n = 12) and high (n = 13) heart-rate reactivity groups based on changes in heart rate to stress. In a second analysis, children were divided into low and high perceived level of stress based on changes in perceived stress. To determine differences in choice of exercise or sedentary behavior across the control and stress conditions, subjects chose either to exercise for progressively longer periods to earn a monetary reinforcer or to engage in a high-rated sedentary behavior. RESULTS: The choice to exercise was influenced by stress reactivity differently in the stress and control conditions. Low heart-rate reactive children participated in similar (p > 0.50) amounts of exercise on the stress and control days, but high heart-rate reactive children participated in less (p < 0.01) exercise (22.0 +/- 2.5 vs. 26.3 +/- 2.2 minutes) on the stress than control days. When grouped by change in perceived stress, there were no group differences, but subjects exercised longer (p < 0.01) on the control day than the stress day. DISCUSSION: Interpersonal stress decreased exercise in children susceptible to interpersonal stress. Stress-induced alterations in health behaviors may lead to weight gain in children.

Analysis of Variance↗

PubMed2002

Habituation of responding for food in humans.

Habituation to repeated food stimuli has been demonstrated in various response systems across animals and humans. Patterns of responding to obtain food demonstrate many empirical characteristics of habituation, and the purpose of the present study was to determine whether motivated responding for food in humans follows an habituation pattern. Thirty-five nonobese men were randomized to groups in which they responded to gain access to repeated presentations of the same food or presentations of a variety of isocaloric food. Subjective ratings of food liking and hunger were assessed. Consistent with habituation theory, participants working for one type of food demonstrated a more rapid decrease in responding for food and in ratings of liking of the repeatedly presented food than participants working for varied foods. All participants showed similar reductions of hunger and resumed responding for a novel food stimulus. This study documents that motivated responding for food in human shares characteristics of an habituation process.

Adult↗

PubMed2002

A cost-analysis of adopting a healthful diet in a family-based obesity treatment program.

OBJECTIVE: To assess dietary costs during a family-based pediatric obesity intervention. DESIGN: Families were randomized to one of two groups. Dietary and cost data were collected from a parent or child using three 24-hour recalls: at baseline, 6 months, and 12 months. SUBJECTS: Thirty-one families with an obese 8- to 12-year-old child entered treatment, with complete dietary data provided from 20 families. INTERVENTION: The 20-week behavior modification intervention emphasized increasing diet nutrient-density. Families attended group and individual sessions or group sessions. MAIN OUTCOME MEASURES: Energy intake; percent of energy from protein, fat, and carbohydrate; servings and percent servings from food groups classified by nutrient density; and daily food costs. STATISTICAL ANALYSES PERFORMED: Mixed analyses of variance, with group as the between-subject factor, and time as the within-subject factor. RESULTS: No significant effect of group was found in any analyses. Significant decreases in percent overweight were observed at 6 and 12 months for children (-10.0+/-8.7 and -8.0+/-10.3, respectively) (mean+/-standard deviation) and parents (-6.7+/-10.3 and -5.3+/-14.1). Energy intake for parents and children combined significantly decreased from baseline (1,881+/-462) to 6 months (1,412+/-284), and 1 year (1,338+/-444). Servings from low-nutrient-dense foods significantly decreased from baseline (34.7+/-16.2) to 6 months (16.0+/-8.6) and 1 year (18.6+/-9.2), causing a significant increase in diet nutrient density. Dietary cost did not change at 6 months, but significantly decreased from baseline to 1 year ($6.77+/-2.41 to $5.04+/-1.80). Cost per 1,000 kcal did not significantly change. APPLICATIONS/CONCLUSIONS: Adopting a lower-energy, nutrient-dense diet did not increase dietary costs over time. Consequently, cost should not be a barrier in the adoption of a healthful diet.

Anthropometry↗

PubMed2002

Dietary restraint and stress-induced snacking in youth.

OBJECTIVE: To determine whether dietary restraint modifies stress-induced eating in youth. RESEARCH METHODS AND PROCEDURES: Snacking was measured in boys (9.5 +/- 0.3 years) and girls (9.0 +/- 0.3 years), with and without dietary restraint, across a control day after reading children's magazines and/or coloring, and on a stress day after giving a videotaped speech, with order of conditions counterbalanced. Children were divided into four groups based on dietary restraint and changes in perceived stress: low-restraint/low-reactive (n = 9), low-restraint/high-reactive (n = 13), high-restraint/low-reactive (n = 10), and high-restraint/high-reactive (n = 8). Body composition was estimated by skinfolds. RESULTS: Energy intake of snack foods was influenced differently by dietary restraint and stress reactivity in the stress and control conditions (p < 0.01). After being stressed, low-restraint/low-reactive children ate fewer snacks and high-restraint/high-reactive children ate more snacks compared with the control condition. After covarying for percentage of body fat, the interactions remained (p < 0.01). Girls ate less than boys (p < 0.001), but sex did not influence eating in control and stress conditions. DISCUSSION: Dietary restraint occurs in children and may influence the effect of stress on eating. Interpersonal stress decreases snacking in low dietary restrained youth but increases snacking in high dietary restrained children, perhaps because of stress-induced disinhibition.

Body Mass Index↗

PubMed2002

Dopamine transporter genotype as a risk factor for obesity in African-American smokers.

OBJECTIVE: To assess the association between a polymorphism related to dopamine function, dopamine transport (SLC6A3), and obesity in smokers. RESEARCH METHODS AND PROCEDURES: Logistic regression was used to assess the relationship between this genetic polymorphism and obesity (body mass index > or = 30 kg/m(2)) from a sample of 510 smokers who smoked at least 10 cigarettes per day and who were participating in a study designed to examine genetic and nongenetic predictors of response to a pharmacological treatment. RESULTS: The likelihood of obesity in African Americans (N = 90) with the 10/10 SLC6A3 genotype was 5.16 times that of African Americans with 9/9 or 9/10 SLC6A3 genotypes (odds ratio = 5.16, confidence interval = 1.60 to 16.65). There was no association of the SLC6A3 genotype with obesity for non-Hispanic whites (N = 420). DISCUSSION: These results suggest that variants of the dopamine transporter gene may be related to obesity in African-American smokers. Possible mechanisms responsible for the association between dopamine transport and obesity in African-American smokers are discussed.

Adolescent↗

PubMed2002

Effects of manipulating sedentary behavior on physical activity and food intake.

OBJECTIVES: Sedentary behaviors have been correlated with obesity. We investigated whether changes in sedentary behaviors relate to changes in energy intake and/or physical activity. STUDY DESIGN: Experimental within-subject crossover design in which children participated in three 3-week phases: baseline and increased and decreased targeted sedentary behaviors. PARTICIPANTS: Thirteen 8- to 12-year-old, nonobese children. MEASUREMENTS: Sedentary behaviors were measured through the use of daily activity logs, physical activity measured with accelerometers, and energy intake measured by means of repeated 24-hour recalls collected during each phase. Energy intake, energy expenditure, and energy balance per day were calculated. RESULTS: Children showed significant (P <.001) increases of 50% and decreases of 53% in targeted sedentary behaviors from baseline during the increase and decrease phases, respectively. There was a significant (P =.05) increase in energy balance per day (+350.7 kcal) when sedentary behaviors were increased, as the result of an increase in energy intake per day (+250.9 kcal) and a decrease in energy expenditure (-99.8 kcal). No significant changes in energy balance were observed when sedentary behaviors were decreased. CONCLUSIONS: Increasing sedentary behaviors had a greater influence on physical activity and energy intake than reducing sedentary behavior in nonobese youth. In some children, changes in sedentary behaviors may be important to modify energy balance and prevent obesity.

Child↗

PubMed2002

Can fruits and vegetables and activities substitute for snack foods?

This study investigated the choice of snack foods versus fruits and vegetables and enjoyable sedentary behaviors using a computerized behavioral choice task. Thirty-nine participants were provided the choice of earning points for snack foods or fruits and vegetables (Condition 1) or snack foods or enjoyable sedentary behaviors (Condition 2). The behavioral cost to gain access to snacks increased across trials, whereas the behavioral costs to obtain alternatives to snack foods remained constant across trials. Results showed that when costs for snack foods and alternatives were equal, participants chose snack foods, but as the behavioral costs increased, participants shifted choice to the alternatives. The switch point for both alternatives was equal. Results suggest that fruits and vegetables and sedentary activities can substitute for snack foods when the behavioral cost for snack foods is increased.

Adult↗