CHECK: A randomized trial evaluating the efficacy and cost-effectiveness of home visitation in pediatric weight loss treatment.

BACKGROUND: Socioeconomically-disadvantaged households have a high prevalence of pediatric overweight/obesity, and also face barriers to accessing weight loss treatment in healthcare settings. Delivering family-based pediatric weight loss treatment in the home setting may enhance its efficacy by facilitating treatment attendance, enabling more tailored treatment recommendations informed by observations of the home environment, and increasing accountability. This paper describes the design of the Creating Health Environments for Chicago Kids (CHECK) Trial, which evaluates the efficacy, cost-effectiveness, and mechanisms of home visitation in family-based pediatric weight loss treatment for children in low-income households. DESIGN: CHECK is a two-arm, parallel group, randomized controlled trial that is enrolling N = 266 children, ages 6-12 y, who have overweight/obesity (BMI percentile ≥85) and live in a low-income household. Participants are randomized in a 1:1 ratio to either standard of care family-based weight loss treatment delivered in the home, or the identical intervention delivered in an academic medical center. The primary outcome is change in child BMI z-score from baseline to 12 months. Program delivery costs are rigorously documented to enable cost-effectiveness analyses from the societal and payer perspectives. Objectively-documented changes to the home environment and aspects of intervention delivery (e.g., hours of in-person contact received, quantity of behavioral goals set per session) will be tested as hypothesized treatment mechanisms. IMPLICATIONS: Findings will inform the design of future interventions, and treatment dissemination decisions by public health agencies and third-party payers. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03195790.

Physical changes in the home environment to reduce television viewing and sugar-sweetened beverage consumption among 5- to 12-year-old children: a randomized pilot study.

This study evaluated the feasibility of a home-based intervention to reduce sugar-sweetened beverage intake and television viewing among children. Lower income parents of overweight children aged 5-12 years (n = 40) were randomized to a home environment intervention to reduce television viewing with locking devices and displace availability of sugar-sweetened beverages with home delivery of non-caloric beverages (n = 25), or to a no-intervention control group (n = 15) for 6 months. Data were collected at baseline and 6 months. After 6 months, television viewing hours per day was significantly lower in the intervention group compared with the control group (1.7 [SE = .02] vs. 2.6 [SE = .25] hours/day, respectively, P < .01). Sugar-sweetened beverage intake was marginally significantly lower among intervention group compared to control group children (0.21 [SE = .09] vs. 0.45 [SE = .10], respectively, P < .09). Body mass index (BMI) z-score was not significantly lower among intervention compared to control children. Among a lower income sample of children, a home-based intervention reduced television viewing, but not sugar-sweetened beverage intake or BMI z-score.

Unhealthy and healthy weight control behaviours among bus operators.

BACKGROUND: Urban bus operators are an occupational group with high rates of overweight and obesity. Understanding methods bus operators use for weight control may be important; there may be increased risk for these workers to engage in less healthy weight management behaviours due to stressful working conditions. AIMS: To examine the prevalence of unhealthy and healthy weight control behaviours used by bus operators and examine associations between use of unhealthy weight control behaviours and work-related and sociodemographic variables. METHODS: Bus operators from four different transit garages were invited to complete a self-administered survey; height and weight were measured by research staff. Unhealthy and healthy weight control behaviours, work hours, work schedule and social support were measured with self-report items on the employee survey. Logistic regression analysis was conducted to estimate associations. RESULTS: Nearly 60% of bus operators endorsed at least one unhealthy method; over 50% reported skipping meals, 30% fasted and 10% reported taking diet pills in the past year. Bus operator gender, race, body mass index status and hours worked per week showed significant associations with using at least one unhealthy weight control behaviour. CONCLUSIONS: Worksite interventions should emphasize the benefit of healthy eating and physical activity but should also address the use of less healthy methods for weight control for individuals employed in transportation occupations.

A computational modelling study of oxygen vacancies at LaCoO3 perovskite surfaces.

Atomistic computational modelling of the surface structure of the catalytically-active perovskite LaCoO(3) has been undertaken in order to develop better models of the processes involved during catalytic oxidation processes. In particular, the energetics of creating oxygen ion vacancies at the surface have been investigated for the three low index faces (100), (110) and (111). Two mechanisms for vacancy creation have been considered involving dopant Sr(2+) cations at the La(3+) site and reduction of Co(3+) to Co(2+). For both mechanisms, there is a general tendency that the smaller the cation defect separation, the lower the energy of the cluster, as would be expected from simple electrostatic considerations. In addition, there are clear indications that oxygen vacancies are more easily created at the surface than in the bulk. The results also confirm that the presence of defects strongly influences crystal morphology and surface chemistry. The importance of individual crystal surfaces in catalysis is discussed in terms of the energetics for the creation of oxygen vacancies.

The nature of the oxidation states of gold on ZnO.

The interaction between gold in the 0, i, ii and iii oxidation states and the zinc-terminated ZnO(0001) surface is studied via the QM/MM electronic embedding method using density functional theory. The surface sites considered are the vacant zinc interstitial surface site (VZISS) and the bulk-terminated island site (BTIS). We find that on the VZISS, only Au(0) and Au(i) are stable oxidation states. However, all clusters of i to iii oxidation states are stable as substitutionals for Zn2+ in the bulk terminated island site. Au(OH)(x) complexes (x= 1-3) can adsorb exothermically onto the VZISS, indicating that higher oxidation states of gold can be stabilised at this site in the presence of hydroxyl groups. CO is used as a probe molecule to study the reactivity of Au in different oxidation states in VZISS and BTIS. In all cases, we find that the strongest binding of CO is to surface Au(i). Furthermore, CO binding onto Au(0) is stronger when the gold atom is adsorbed onto the VZISS compared to CO binding onto a gas phase neutral gold atom. These results indicate that the nature of the oxidation states of Au on ZnO(0001) will depend on the type of adsorption site. The role of ZnO in Au/ZnO catalysts is not, therefore, merely to disperse gold atoms/particles, but to also modify their electronic properties.

Computational approaches to the determination of active site structures and reaction mechanisms in heterogeneous catalysts.

We apply quantum chemical methods to the study of active site structures and reaction mechanisms in mesoporous silica and metal oxide catalysts. Our approach is based on the use of both molecular cluster and embedded cluster (QM/MM) techniques, where the active site and molecular complex are described using density functional theory (DFT) and the embedding matrix simulated by shell model potentials. We consider three case studies: alkene epoxidation over the microporous TS-1 catalyst; methanol synthesis on ZnO and Cu/ZnO and C-H bond activation over Li-doped MgO.

Factors associated with women's and children's body mass indices by income status.

OBJECTIVE: To describe associations between eating behaviors, dietary intake, physical activity, attitudes toward diet and health, sociodemographic variables and body mass index (BMI) among women and children, and differences by household income. DESIGN: Data from the 1994-1996 Continuing Survey of Food Intakes by Individuals (CSFII) and the Diet and Health Knowledge Survey (DHKS) were examined using multivariate regression to estimate the associations between BMI and behavioral and environmental variables among women and children. SUBJECTS: CSFII 1994-1996 is representative of the US population. DHKS surveyed CSFII respondents 20 y of age and over. Our samples consisted of 2419 adult women and 1651 school-age children. MEASUREMENTS: CSFII respondents reported 24 h recalls of all food intakes on 2 nonconsecutive days and their personal and household characteristics, including self-reported height and weight. DHKS collected data on knowledge and attitudes toward dietary guidance and health from CSFII adult respondents. RESULTS: Significant correlations between women's BMI and age, race, dietary patterns, TV watching, and smoking was observed among women from both low- and high-income households. Beverage consumption, eating out, the importance of maintaining healthy weight, and exercise were correlated with BMI only among women from high-income households. Among children, age, race, income, and mother's BMI were significantly correlated with child BMI. CONCLUSIONS: Among women, the associations between some behavioral and environmental factors and BMI differ by household income. Intervention programs need to target specific eating and physical activity behaviors to promote a healthy body weight.

Weight-related attitudes and behaviors of adolescent boys and girls who are encouraged to diet by their mothers.

OBJECTIVE: To assess the relationships between mothers' reports of dieting and encouraging adolescents to diet and adolescents' reports of their own dieting practices and weight-related concerns. DESIGN: Cross-sectional study of parent interviews and adolescent surveys in an ethnically-diverse sample. SUBJECTS: A total of 810 adolescents (n=381 boys and n=429 girls) and their mothers. RESULTS: Mothers' dieting was associated with their adolescent girls' weight-related concerns and behaviors, but these associations were not significant after adjusting for girls' body mass index (BMI). In contrast, mothers' encouragement for sons to diet was associated with sons' binge eating, dieting and other weight-control behaviors, even after controlling for sons' BMI. Compared with mothers who did not encourage their child to diet, mothers who encouraged their child to diet were significantly heavier women and were more likely to view their child as overweight. Forty-three percent of boys and 46% of girls who were encouraged by their mothers to diet were classified as nonoverweight by federal guidelines. CONCLUSIONS: Boys who are encouraged by their mothers to diet may be at risk for health-compromising eating and dieting behaviors, particularly binge-eating, fasting, eating a little bit of food and skipping meals. Parents who are concerned about their children's weight should be educated to encourage healthy eating habits and physical activity to promote their children's health, including healthy weight control.

Prevalence and correlates of large weight gains and losses.

OBJECTIVE: To examine the prevalence and correlates of large weight gains and losses over a 3 y period in a heterogeneous population of participants in a study of weight gain prevention. DESIGN AND MEASURES: Analyses based on a cohort of 823 participants in a weight gain prevention study whose weight was measured on at least two of four annual examinations. RESULTS: Weight gains and losses of >or=5% body weight over 1 y were observed in 9.3 and 15% of the population, respectively. Weight gains among those initially losing weight were significantly greater (3.9 kg) than among those experiencing stable weight (0.8 kg) or a large weight gain (1.5 kg) over the following 2 y. Cumulative weight changes over 3 y were -2.6, 1.0 and 7.6 kg among large loss, weight stable and large gain groups, respectively. Large weight loss was more common in smokers, large gains were more common in younger people and in those with a more extensive weight loss history, and stable weight was observed more often in individuals with less extensive histories of weight loss. CONCLUSION: The high prevalence of large short-term weight gains and losses in this heterogeneous population, their apparent resistance to short-term reversal, and the strength of their relationship to longer-term weight trends suggest that rapid weight change over relatively short time intervals is a phenomenon that deserves more research attention. Short periods of rapid weight gain may contribute importantly to rapidly rising obesity rates.

Solubility of cerium in LaCoO3-influence on catalytic activity.

The recent interest in the catalytic properties of lanthanum perovskites for methane combustion and three way catalysis has led to considerable debate as to their structure and defect chemistry. We have investigated the doping of LaCoO3 with the tetravalent cerium cation using atomistic simulation techniques. We have compared three routes for cerium insertion and identified the favoured doping mechanism, which explain experimental observations relating to the effect of cerium on catalytic activity.

Simulation of cardiac work transitions, in vitro: effects of simultaneous Ca2+ and ATPase additions on isolated porcine heart mitochondria.

During increases in cardiac work there are net increases in cytosolic [Ca(2+)] and ATP hydrolysis by myofiliments and ion transport ATPases. However, it is still unclear what role Ca(2+)or the ATP hydrolysis products, ADP and Pi, have on the regulation of mitochondrial ATP production. In this study, work jumps were simulated by simultaneous additions of Ca(2+) and ATPase to porcine heart mitochondria. The net effects on the mitochondrial ATP production were monitored by simultaneously monitoring respiration (mVo2), [NADH], [ADP] and membrane potential (deltapsi) at 37 degrees C. Addition of exogenous ATPase (300 mlU.ml(-1))]ATP (3.4 mM) was used to generate a 'resting' background production of ADP. This resting metabolic rate was 200% higher than the quiescent rate while [NADH] and deltapsi were reduced. Subsequent ATPase additions (1.3IU.ml(-)) were made with varying amounts of Ca(2+)(0 to 535 nM) to simulate step increases in cardiac work. Ca(2+) additions increased mVo2 and depolarized deltapsi, and were consistent with an activation of Fo/F1)ATPase. In contrast, Ca(2+) reduced the [NADH] response to the ATPase addition, consistent with Ca(2+)-sensitive dehydrogenase activity (CaDH). The calculated free ADP response to ATPase decreased \2-fold in the presence of Ca(2+). The addition of 172nM free Ca(2+)] ATPase increased mVo2 by 300% (P<0.05, n=8) while deltapsi decreased by 14.9+/-0.1 mV without changes in [NADH] (P > or =0.05, n=8), consistent with working heart preparations. The addition of Ca(2+) and ATPase combined increased the mitochondrial ATP production rate with changes in deltapsi, NADH and [ADP], consistent with an activation of CaDH and F o /F(1)ATPase activity. These balancing effects of ATPase activity and [Ca(2+)] may explain several aspects of metabolic regulation in the heart during work transitions in vivo.

The relationship between restraint and weight and weight-related behaviors among individuals in a community weight gain prevention trial.

PURPOSE: The present study evaluated the cross-section and prospective associations between the Eating Inventory's (EI) total, flexible and rigid dietary restraint scales and changes in weight and behaviors in a community sample of adults enrolled in a 3 y weight gain prevention study. METHODS: Subjects were participants in the Pound of Prevention (POP) study, a community-based weight gain prevention trial. RESULTS: Higher levels of baseline total, flexible and rigid dietary restraint were related to lower weight and more weight-controlling behaviors at the baseline assessment. Baseline restraint measures positively predicted increases in weighing frequency over the 3 y follow-up. Increases in restraint over the follow-up period were related to decreases in weight, energy intake and television watching, and increases in self-weighing and physical activity. CONCLUSION: The EI's total, flexible and rigid restraint scales were not differently associated with weight and behaviors in this heterogeneous sample of adults who were attempting to lose weight. Developing methods to increase behavioral and cognitive strategies to control weight may help to prevent weight gain in clinical and community samples.

Environmental influences on eating and physical activity.

Obesity has increased dramatically over the past two decades and currently about 50% of US adults and 25% of US children are overweight. The current epidemic of obesity is caused largely by an environment that promotes excessive food intake and discourages physical activity. This chapter reviews what is known about environmental influences on physical activity and eating behaviors. Recent trends in food supply, eating out, physical activity, and inactivity are reviewed, as are the effects of advertising, promotion, and pricing on eating and physical activity. Public health interventions, opportunities, and potential strategies to combat the obesity epidemic by promoting an environment that supports healthy eating and physical activity are discussed.

Adolescent binge/purge and weight loss behaviors: associations with developmental assets.

PURPOSE: To study associations between binge/purge and weight loss behaviors and "developmental assets" among adolescent girls and boys. METHODS: The Search Institute's Profile of Student Life: Attitudes and Behaviors self-report questionnaire was administered to 48,264 girls and 47,131 boys in grades 6 through 12 at schools in 213 cities or towns across the United States. The 156-item questionnaire measured 40 "developmental assets," or protective factors associated with successful adolescent development. Developmental assets were examined using multiple logistic regression among students who reported binge/purge behaviors, weight loss behavior, both, or neither. RESULTS: Developmental assets related to positive identity were the strongest discriminators of binge/purge and weight loss behaviors in both girls and boys. Girls who reported binge/purge and weight loss behaviors were about half as likely to report feeling a sense of purpose [odds ratio (OR) = 0.45, 95% confidence interval (CI) = 0.40, 0.50] and high self-esteem (OR = 0.55, 95% CI = 0.49, 0.61), compared with girls not reporting either of these behaviors. Among boys the ORs were: sense of purpose OR = 0.53 (95% CI = 0.46, 0.61) and self-esteem OR = 0.76 (95% CI = 0.65, 0.88). Assets related to values about abstinence from alcohol, drugs, or sex ("restraint") were also significant correlates. Girls and boys who reported these values were less likely to report binge/purge and weight loss behaviors, compared with those who did not report these values (girls: OR = 0.56, 95% CI = 0.50, 0.63; boys: OR = 0.83, 95% CI = 0.70, 0.97). CONCLUSIONS: Internal assets such as self-esteem, sense of purpose, and values related to abstinence from alcohol and sex appear to be protective against unhealthy eating behaviors and may reflect a general resilience that buffers against a broad range of health risk behaviors.

Pricing and promotion effects on low-fat vending snack purchases: the CHIPS Study.

OBJECTIVES: This study examined the effects of pricing and promotion strategies on purchases of low-fat snacks from vending machines. METHODS: Low-fat snacks were added to 55 vending machines in a convenience sample of 12 secondary schools and 12 worksites. Four pricing levels (equal price, 10% reduction, 25% reduction, 50% reduction) and 3 promotional conditions (none, low-fat label, low-fat label plus promotional sign) were crossed in a Latin square design. Sales of low-fat vending snacks were measured continuously for the 12-month intervention. RESULTS: Price reductions of 10%, 25%, and 50% on low-fat snacks were associated with significant increases in low-fat snack sales; percentages of low-fat snack sales increased by 9%, 39%, and 93%, respectively. Promotional signage was independently but weakly associated with increases in low-fat snack sales. Average profits per machine were not affected by the vending interventions. CONCLUSIONS: Reducing relative prices on low-fat snacks was effective in promoting lower-fat snack purchases from vending machines in both adult and adolescent populations.

Calcium activation of heart mitochondrial oxidative phosphorylation: rapid kinetics of mVO2, NADH, AND light scattering.

Parallel activation of heart mitochondria NADH and ATP production by Ca(2+) has been shown to involve the Ca(2+)-sensitive dehydrogenases and the F(0)F(1)-ATPase. In the current study we hypothesize that the response time of Ca(2+)-activated ATP production is rapid enough to support step changes in myocardial workload ( approximately 100 ms). To test this hypothesis, the rapid kinetics of Ca(2+) activation of mV(O(2)), [NADH], and light scattering were evaluated in isolated porcine heart mitochondria at 37 degrees C using a variety of optical techniques. The addition of Ca(2+) was associated with an initial response time (IRT) of mV(O(2)) that was dose-dependent with a minimum IRT of 0.27 +/- 0.02 s (n = 41) at 535 nm Ca(2+). The IRTs for NADH fluorescence and light scattering in response to Ca(2+) additions were similar to mV(O(2)). The Ca(2+) IRT for mV(O(2)) was significantly shorter than 1.6 mm ADP (2.36 +/- 0.47 s; p < or = 0.001, n = 13), 2.2 mm P(i) (2.32 +/- 0.29, p < or = 0.001, n = 13), or 10 mm creatine (15.6.+/-1.18 s, p < or = 0.001, n = 18) under similar experimental conditions. Calcium effects were inhibited with 8 microm ruthenium red (2.4 +/- 0.31 s; p < or = 0.001, n = 16) and reversed with EGTA (1.6 +/- 0.44; p < or = 0.01, n = 6). Estimates of Ca(2+) uptake into mitochondria using optical Ca(2+) indicators trapped in the matrix revealed a sufficiently rapid uptake to cause the metabolic effects observed. These data are consistent with the notion that extramitochondrial Ca(2+) can modify ATP production, via an increase in matrix Ca(2+) content, rapidly enough to support cardiac work transitions in vivo.

Fast food restaurant use among adolescents: associations with nutrient intake, food choices and behavioral and psychosocial variables.

OBJECTIVE: To examine demographic, behavioral and dietary correlates of frequency of fast food restaurant use in a community-based sample of 4746 adolescent students. DESIGN: A survey was administered to students in classrooms at 31 secondary schools in a large metropolitan area in Minnesota, United States. Height and body weight were measured. SUBJECTS: Students in grades 7-12 who were enrolled in participating schools, had parental consent and were in attendance on the day of data collection. MEASUREMENTS: Frequency of fast food restaurant use (FFFRU), dietary intake, and demographic and behavioral measures were self-reported. Dietary intake was assessed using a semi-quantitative food frequency questionnaire. Height and body weight were directly measured. RESULTS: FFFRU was positively associated with intake of total energy, percent energy from fat, daily servings of soft drinks, cheeseburgers, french fries and pizza, and was inversely associated with daily servings of fruit, vegetables and milk. FFFRU was positively associated with student employment, television viewing, home availability of unhealthy foods, and perceived barriers to healthy eating, and was inversely associated with students' own and perceived maternal and peer concerns about healthy eating. FFFRU was not associated with overweight status. CONCLUSIONS: FFFRU is associated with higher energy and fat intake among adolescents. Interventions to reduce reliance on fast food restaurants may need to address perceived importance of healthy eating as well as time and convenience barriers.

Fast food restaurant use among women in the Pound of Prevention study: dietary, behavioral and demographic correlates.

OBJECTIVE: To examine demographic, behavioral and dietary correlates of frequency of fast food restaurant use in a community-based sample of 891 adult women. DESIGN: A survey was administered at baseline and 3 y later as part of a randomized, prospective intervention trial on weight gain prevention. SUBJECTS: Women (n = 891) aged 20-45 y who enrolled in the Pound of Prevention study. MEASUREMENTS: Frequency of fast food restaurant use, dietary intake, demographic and behavioral measures were self-reported. Dietary intake was measured using the 60-item Block Food Frequency Questionnaire. Body weight and height were directly measured. RESULTS: Twenty-one percent of the sample reported eating > or = 3 fast food meals per week. Frequency of fast food restaurant use was associated with higher total energy intake, higher percentage fat energy, more frequent consumption of hamburgers, French fries and soft drinks, and less frequent consumption of fiber and fruit. Frequency of fast food restaurant use was higher among younger women, those with lower income, non-White ethnicity, greater body weight, lower dietary restraint, fewer low-fat eating behaviors, and greater television viewing. Over 3 y, increases in frequency of fast food restaurant use were associated with increases in body weight, total energy intake, percentage fat intake, intake of hamburgers, French fries and soft drinks, and with decreases in physical activity, dietary restraint and low-fat eating behaviors. Intake of several other foods, including fruits and vegetables, did not differ by frequency of fast food restaurant use. CONCLUSION: Frequency of fast food restaurant use is associated with higher energy and fat intake and greater body weight, and could be an important risk factor for excess weight gain in the population.

Can anyone successfully control their weight? Findings of a three year community-based study of men and women.

This study examined the prevalence, distribution and correlates of successful weight loss and successful weight maintenance over three years in a community-based sample of 854 subjects aged 20-45 at baseline. More than half (53.7%) of the participants in the study gained weight within the first twelve months, only one in four (24.5%) successfully avoided weight gain over three years, and less than one in twenty (4.6%) lost and maintained weight successfully. The findings underscore the importance of current public health efforts to prevent weight gain, and suggest that without much greater efforts to promote and support weight control the prevalence of obesity will continue to rise.

Predictors of weight gain in the Pound of Prevention study.

OBJECTIVES: This study examined cross-sectional and prospective relationships between macronutrient intake, behaviors intended to limit fat intake, physical activity and body weight. DESIGN: The overall goal was to identify diet and exercise behaviors that predict and/or accompany weight gain or loss over time. Specific questions addressed included: (a) are habitual levels of diet or exercise predictive of weight change; (b) are habitual diet and exercise levels associated cross-sectionally with body weight; and (c) are changes in diet and exercise associated with changes in body weight over time? PARTICIPANTS: Subjects were a sample of community volunteers (n=826 women, n=218 men) taking part in a weight gain prevention project over a 3-year period. MEASURES: Body weight was measured at baseline and annually over the study period. Self-report measures of diet and exercise behavior were also measured annually. RESULTS: Among both men and women, the most consistent results were the positive association between dietary fat intake and weight gain and an inverse association between frequency of physical activity and weight gain. Individuals who weighed more both ate more and exercised less than those who weighed less. Individuals who increased their physical activity level and decreased their food intake over time were protected from weight gain compared to those who did not. Frequency of high-intensity physical activity was particularly important for both men and women. Additionally, women who consistently engaged in higher levels of moderate physical activity gained weight at a slower rate compared to women who were less active. CONCLUSIONS: Overall results indicated that both cross-sectionally and prospectively, the determinants of weight and weight change are multifactorial. Attention to exercise, fat intake and total energy intake all appear important for successful long term control of body weight.