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Biomedical subjects

L H Epstein

Publications and source records attributed to L H Epstein.

At least 37 records · Page 2Linked to original sources
PubMed2000

Asthma and maternal body mass index are related to pediatric body mass index and obesity: results from the Third National Health and Nutrition Examination Survey.

OBJECTIVE: Clinical research has shown an increased prevalence of obesity in children with asthma. This study was designed to assess the relationship between asthma and pediatric body mass index (BMI) in a national database and to examine factors that may modify this relationship. DESIGN: The cross-sectional relationship between asthma and pediatric BMI and obesity (BMI > or = 85th percentile) was studied. Variables that may influence the relationship between asthma and pediatric BMI, such as race/ethnicity and television watching were included in the model for the total sample. A smaller sample of 3,009 white and African American youth were studied in regression models including maternal BMI. STUDY POPULATION: A nationally representative cross-sectional sample of 5154 children and adolescents of 6 to 16 years of age from the Third National Health And Nutrition Examination Survey. RESULTS: In the full sample, asthma and television watching were related to BMI, accounting for 3% of the variance in BMI. When maternal BMI was included in the non-Hispanic sample, television watching, maternal BMI, and the interaction of maternal BMI and asthma were related to youth BMI, accounting for 15% of the variance. The standardized BMI z-score for those youth without asthma and no maternal obesity was 0.06, which increased to 0.33 if the youth had asthma, to 0.70 if the youth did not have asthma but the mother was obese, and to 1.71 if the youth had asthma and the mother was obese. Asthma, television watching, and maternal BMI were independent predictors of youth obesity. CONCLUSIONS: BMI and prevalence of obesity is higher in youth with asthma. Pediatric BMI, but not obesity, is also related to the interaction of asthma and maternal BMI in white and African American youth. Comorbidity of asthma and obesity may complicate treatment of either condition, and prevention of obesity should be encouraged for asthmatic children.

Adolescent↗
PubMed2000

Open-loop feedback to increase physical activity in obese children.

OBJECTIVE: The present study investigated whether making access to sedentary activities contingent on physical activity would increase physical activity. DESIGN: Experimental. PARTICIPANTS: Thirty-four obese children aged 8-12 y were randomized to one of three groups in which children had to accumulate 750 or 1500 pedometer counts to earn 10 min of access to video games or movies, or to a control group in which access to sedentary behaviors was provided noncontingently. MEASUREMENTS: Physical activity in the 20 min experimental session was measured by electronic pedometer and triaxial accelerometer (ie TriTrac(R)). Activity liking was measured by visual analog scales. Anthropometric and demographic characteristics were also assessed. RESULTS: Children in the 750 and 1500 count contingency groups engaged in significantly more physical activity and spent more time in moderate intensity activity or higher compared with controls. Children in the Contingent 1500 group engaged in more activity and spent more time in moderate or greater intensity activity compared to children in the Contingent 750 group. CONCLUSION: Findings suggest that contingent access to sedentary activities can reinforce physical activity in obese children, and changes in physical activity level depend in part on the targeted physical activity goal.

Child↗
PubMed2000

Problem solving in the treatment of childhood obesity.

This study randomized obese children from 67 families to groups that received a 6-month family-based behavioral weight-control program plus parent and child problem solving, child problem solving, or standard treatment with no additional problem solving. The standard group showed larger body mass index (BMI) decreases than the parent + child group through 2 years, with significant differences in the percentage of children who showed large BMI changes. Significant statistical and clinical improvements were observed over time in child behavior problems and parental distress. Parent problem solving increased in the parent + child condition relative to the other conditions, whereas child problem solving increased equally in all conditions. The bulk of evidence suggests that problem solving did not add to treatment effectiveness beyond the standard family-based treatment.

Adult↗
PubMed1999

Providing sedentary adults with choices for meeting their walking goals.

BACKGROUND: This study was designed to test different ways of meeting the new ACSM/CDC recommendations for physical activity stating that all Americans at least 2 years of age should obtain 30 minutes of moderate intensity activity on most days of the week. METHODS: Thirty-two sedentary 18- to 55-year-old adults were randomly assigned to three groups of brisk walking/6 days per week: 30 continuous minutes, three 10-minute bouts, and 30 minutes in any combination of bouts as long as each bout was at least 5 minutes. Aerobic fitness, blood pressure, body composition, and physical activity were assessed at baseline, at end of program (16 weeks), and at follow-up (32 weeks). RESULTS: All groups significantly (P </= 0.05) improved their aerobic fitness and systolic blood pressure and increased their physical activity at the end of the program. At follow-up all groups maintained these changes, while additionally reducing their percentage body fat and diastolic blood pressure. CONCLUSION: These findings demonstrate that a walking prescription of 30 minutes per day on most days of the week with the choice to walk in as little as 5 minute bouts can improve cardiovascular health and body composition, as well as help sedentary people maintain those improvements over time. This is supported by all participants indicating that "making walking part of my lifestyle" was the most important factor in maintaining their walking habits.

Adolescent↗
PubMed1999

Mecamylamine blocks the development of tolerance to nicotine in rats: implications for the mechanisms of tolerance.

Chronic injections of nicotine in rats produce upregulation of nicotinic cholinergic receptors. It has been proposed that this upregulation is a reflection of receptor desensitization and is the basis of functional tolerance. Mecamylamine, a non-competitive antagonist that blocks activation of nicotinic receptors, does not prevent upregulation produced by nicotine injections. This suggests that receptor activation is not a prerequisite for nicotine-induced receptor upregulation. Therefore, the present experiments tested whether mecamylamine would also fail to prevent the development of tolerance to nicotine. Six daily pairings of mecamylamine (1 mg/kg SC) with nicotine did block the development of tolerance to nicotine-induced antinociception (0.35 mg/kg) and to the ability of nicotine to suppress milk intake (0.66 mg/kg). In another experiment, six daily injections of mecamylamine, when given alone, did not alter the effects of a subsequent, acute injection of nicotine (0.35 mg/kg) in inducing antinociception in rats. There was no evidence that after six pairings of mecamylamine with nicotine, the cues associated with mecamylamine delivery took on conditioned antagonistic properties. These findings suggest that, unlike the receptor upregulation that results from either continuous or repeated nicotine administration, the tolerance following a short series of intermittent nicotine injections is dependent on receptor activation.

Analgesics↗
PubMed1999

Work and leisure time physical activity and mortality in men and women from a general population sample.

PURPOSE: The purpose of this study was to examine the long-term relationships between total physical activity and mortality from all causes and coronary heart disease (CHD) in the general population. METHODS: A prospective design was used, following participants for 29 years, beginning in 1960. The study population consisted of a randomly selected sample of white male (n = 698) and female (n = 763) residents of Buffalo, New York with a 79.0% participation rate and follow-up rates of 96.0% and 90.2% in males and females, respectively. At baseline, comprehensive information was obtained regarding participants' usual physical activity at work and during leisure time. RESULTS: As of December 31, 1989, three hundred and two (43.3%) men and 276 (41.0%) women died, 109 (15.6%) and 81 (10.6%) from CHD, respectively. In men, a significant interaction was found between activity and body mass index (BMI) for both outcomes. In women, a significant activity by age interaction was observed. In non-obese men (BMI<27.02), activity was inversely associated with all-cause [relative risk (RR) = 0.59; 95% confidence interval (CI), 0.39-0.89] and CHD mortality (RR = 0.39; 95% CI, 0.18-0.83), independent from the effects of age and education. No such associations were found in obese men and increased risks could not be ruled out. Among women, younger participants (age <60 years) had a significantly reduced risk of CHD death with increased activity (RR = 0.26; 95% CI, 0.07-0.99). No other significant associations were observed. CONCLUSIONS: Physical activity favorably influences mortality risks in non-obese men and younger women. Gender-specific factors should be considered for potential effect modification.

Adolescent↗
PubMed1999

The rate of sedentary activities determines the reinforcing value of physical activity.

In this study, the authors examined whether the reinforcing efficacy of sedentary behaviors was related to their base rates. Base rates of 3 sedentary and 1 physical activity were determined for 40 sedentary adults. Participants were randomized to groups in which either high-rate, moderate-rate, low-rate, or no sedentary activity was contingent on being physically active. Noncontingent sedentary activities remained freely available. Contingent high- or moderate-rate sedentary activities increased physical activity, whereas no increases in physical activity were observed for contingent low-rate or control conditions. Thus, sedentary behaviors can be used to reinforce physical activity, their reinforcing efficacy depends in part on their base rates, and they are not completely substitutable.

Adolescent↗
PubMed1999

Physical activity in the treatment of childhood overweight and obesity: current evidence and research issues.

PURPOSE: This paper reviews the utility of exercise as a treatment for overweight and obese children and adolescents. METHODS: Computer database searches identified 13 studies that met the following criteria for inclusion: 1) obese children or adolescents were provided either different types of exercise programs or an exercise program compared with a no-exercise control, 2) subjects were randomly assigned to groups or assigned by matching on demographic and anthropometric variables, and 3) the exercise program was at least 2 months in duration. RESULTS: The only area in which there were a sufficient number of studies to make a quantitative analysis was the comparison of diet versus diet plus exercise programs, which suggested that exercise adds to the effect of diet in the short-term treatment of pediatric obesity. There was not enough research to evaluate the effects of exercise alone. The majority of findings indicate fitness changes are greater for subjects provided exercise alone or exercise combined with diet in comparison with subjects provided no exercise (control) or diet alone. CONCLUSIONS: Research on effects of exercise or physical activity in pediatric obesity treatments are encouraging and may be important for improving treatment outcome for obesity and comorbid conditions. Recommendations for future research are presented.

Child↗
PubMed1999

Reinforcing value of physical activity as a determinant of child activity level.

This study examined whether the relative reinforcing value of physical activity (RRVPA) measured in the laboratory predicted physical activity measured in the natural environment in 32 6-11-year-old children. RRVPA correlated with physical activity level (r = .42, p < .05), and contributed to the prediction of physical activity level along with child obesity. RRVPA was related to the number of moderate to vigorous physical activity exercise bouts (r = .35, p < .05), not to the duration of those bouts. These results suggest that RRVPA is a determinant of child physical activity level, and that it may be naturally more reinforcing for children to engage in multiple, short exercise bouts than fewer, more extended bouts.

Child↗
PubMed1998

The relationship between asthma and obesity in urban minority children and adolescents.

OBJECTIVE: To investigate the relationship between asthma and obesity in children and adolescents. DESIGN: Medical record review. SETTING: Urban community health center. PARTICIPANTS: One hundred seventy-one children aged 4 to 16 years, 85 with asthma and 86 nonasthmatic controls. MAIN OUTCOME MEASURES: Diagnosis of asthma, age, and sex-adjusted body mass index (weight in kilograms divided by the square of the height in meters). RESULTS: Seventy-eight percent of the sample was Hispanic, 17% was African American, 2% were white, and 3% were other minorities. There were significantly more children with asthma (30.6%) who were very obese (> or =95th body mass index percentile) compared with controls (11.6%) (P=.004). Children with asthma were also significantly more overweight than controls (mean+/-SD, 22.5%+/-28.3% vs 12.0%+/-19.6% overweight; P=.004). The difference in obesity between children with asthma and controls was significant for both sexes and across the 4.5 to 10.9 years and 11 to 16 years age groups. Asthma severity was not related to obesity. CONCLUSION: Asthma is a risk factor for obesity in children and adolescents.

Adolescent↗
PubMed1998

Predictors of child psychological changes during family-based treatment for obesity.

OBJECTIVE: To explore the influence of 1-year changes in child obesity and maternal psychopathology on changes in child psychological problems. DESIGN: Hierarchical regression models were used to predict child psychological change, with demographic variables, maternal psychological change, and child percentage overweight change as predictors. SETTING: Pediatric obesity research clinic. PARTICIPANTS: Clinic sample of 116 obese 8- to 12-year-old children and their mothers. INTERVENTIONS: Family-based behavioral weight-control program. MAIN OUTCOME MEASURES: Child psychopathology was assessed via mother-reported Child Behavior Checklists and maternal psychopathology was determined by standardizing scores on the Cornell Medical Index and the Symptoms Checklist-90-Revised. RESULTS: Significant improvements were observed in child percentage overweight (-20.1% overweight), and child and maternal psychopathology. Improved maternal psychopathology accounted for a significant amount of variance in improvements in the Child Behavior Checklist total Problems Scale and internalizing and externalizing problems subscales. Decreased obesity accounted for a significant amount of variance in improvements in the Total Competence scale and, somatic complaints, social problems and social competence subscales of the Child Behavior Checklist. Significant interactions of child obesity change by sex were found for Total Problems and externalizing scores. The interactions were due to girls with greater obesity reduction showing greater improvement in Total Problems, whereas boys with greater obesity reduction showed less improvement in externalizing problems. CONCLUSIONS: These results highlight the multidimensional nature of psychosocial functioning in obese children and call attention to multiple avenues for intervention to improve their psychosocial functioning.

Adult↗
PubMed1998

The role of corticosteroids in nicotine's physiological and behavioral effects.

This paper reviews evidence indicating that adrenal corticosteroids modulate the responsiveness of mice and rats to nicotine. Adrenalectomy increases, and both acute and chronic corticosteroid administration decrease, some of the physiological and behavioral effects of nicotine. One function of adrenal steroids may be to regulate stress-induced changes in nicotine sensitivity. Another is to mediate the development of chronic tolerance when nicotine is given intermittently, and when the resulting tolerance has a learned component. A role of glucocorticoids in the development of tolerance to nicotine is suggested by the findings that a conditioned elevation of plasma corticosterone, which anticipates nicotine delivery, accompanies the development of chronic tolerance and that environmental cues evoke a conditioned corticosterone response, but only after they have become associated with nicotine delivery. The mechanisms by which adrenal steroids modulate nicotine sensitivity are not known, although recent in vitro evidence suggests that steroids can rapidly and reversibly reduce nicotinic receptor function. While most of the data are consistent with the hypothesis that corticosteroids reduce nicotine responsiveness, and thus promote a learned form of tolerance, there are new findings that corticosteroids increase the development of sensitization to the locomotor-activating effects of nicotine. These data suggest that formulations postulating a unidirectional effect of corticosteroids on nicotine's actions (e.g. decreased sensitivity) must be revised to take into account interacting variables such as the specific nicotine effect being studied and whether that effect normally exhibits tolerance or sensitization. Finally, research is presented which indicates that the corticosterone-elevating effects of nicotine, previously reported for experimenter-administered drug, are also produced when nicotine administration is contingent on an operant response, and at a dose which sustains the development of nicotine self-administration in rats. These findings highlight the feasibility of using self-administration models in future explorations of the relationship between adrenal steroids and nicotine function.

Adrenal Cortex Hormones↗
PubMed1998

Integrating theoretical approaches to promote physical activity.

CONTEXT: Research on the promotion of physical activity has been based on a variety of conceptual models. These models generally target one level of analysis, such as the individual, community, or the environment, and differ in their relative contact with basic or applied science. There have been limited attempts to develop approaches that target multiple levels of analysis and can stimulate basic and applied research. OBJECTIVE: Theoretical integration in a multidiscliplinary field such as promotion of physical activity should take into account that social, behavioral, and biomedical colleagues may use different explanatory models, and use different approaches to the development of scientific knowledge. This essay argues for the development of integration of theory across multiple domains that can incorporate methods and findings of basic and applied scientists, and that uses language and methods common to social, behavioral, and biomedical scientists. METHOD: Behavioral choice theory is presented as an example of one theoretical approach that bridges different approaches to physical activity intervention, and that can stimulate both basic and applied research on physical activity. Behavioral research on choice was discussed in relationship to basic research, human laboratory research, and community and clinical research. CONCLUSIONS: Implications of behavioral choice theory for community and environmental change was discussed. The essay ends with ideas for future directions in integration of theory for physical activity research.

Choice Behavior↗
PubMed1998

Behavioral engineering of activity choice in obese children.

This laboratory study examined whether making sedentary activities contingent upon being physically active would increase obese children's physical activity. Fourteen obese children aged 8-12 y participated in a baseline session in which they had free choice among a variety of sedentary activities and riding a stationary bicycle. Children were then randomized to either a contingent group in which watching video cassette recorder (VCR) movies and playing video games were contingent upon riding the bicycle or a control group in which all physical and sedentary activities remained freely available. Contingent group children increased physical activity and decreased television activities in comparison to the control, even though other sedentary activities remained freely available. Findings suggest that highly valued sedentary activities can reinforce physical activities and that sedentary activities do not completely substitute amongst themselves. The automated system used to make television activities contingent upon physical activity has potential for modifying activity in the treatment of obesity.

Child↗
PubMed1998

Treatment of pediatric obesity.

The primary goal of childhood obesity interventions is regulation of body weight and fat with adequate nutrition for growth and development. Ideally, these interventions are associated with positive changes in the physiologic and psychological sequelae of obesity. To contribute to long-term weight maintenance, interventions should modify eating and exercise behaviors such that new, healthier behaviors develop and replace unhealthy behaviors, thereby allowing healthier behaviors to persist throughout development and into adulthood. This overview of pediatric obesity treatment, using predominantly randomized, controlled studies, highlights important contributions and developments in primarily dietary, activity, and behavior change interventions, and identifies characteristics of successful treatment and maintenance interventions. Potential positive (eg, reduction in blood pressure, serum lipids, and insulin resistance) and negative (eg, development of disordered eating patterns) side effects of treatment also are described. Recommendations for improving implementation of childhood obesity treatments, including application of behavioral choice theory, improving knowledge of response extinction and recovery in regards to behavior relapse, individualization of treatment, and integration of basic science with clinical outcome research, are discussed.

Adolescent↗