Home and neighbourhood built environment features in family-based treatment for childhood obesity.

BACKGROUND: Family-based behavioural weight loss treatment (FBT) for childhood obesity helps families develop strategies to facilitate healthy choices in their home and other environments (e.g. home neighbourhood). The current study examines how the home food environment, both pre-FBT and post-FBT, and the neighbourhoods in which families live are associated with child weight and weight-related outcomes in FBT. METHODS: Parent-child dyads (n = 181) completed a 16-session FBT programme and completed home environment, anthropometric and child dietary/activity assessments at pre-FBT and post-FBT. Parents reported on availability of food, electronics and physical activity equipment in the home. The neighbourhood food and recreation environments around each dyad's residence was characterized using existing data within a geographic information system. RESULTS: Families successfully made healthy home environment modifications during FBT. Regression models showed reducing RED (e.g. high-energy-dense and low-nutrient-dense) foods and electronics in the home during FBT had positive effects on child weight and weight-related outcomes. No neighbourhood food or recreation environment variables were significantly related to outcomes, although having a larger density of public recreation spaces was associated with increases in physical activity at the trend-level. CONCLUSIONS: Modifying the home environment, specifically reducing RED foods and electronics, may be particularly important for FBT success.

Delay discounting and utility for money or weight loss.

OBJECTIVE: Obesity is related to a bias towards smaller immediate over larger delayed rewards. This bias is typically examined by studying single commodity discounting. However, weight loss often involves choices among multiple commodities. To our knowledge, no research has examined delay discounting of delayed weight loss compared with other commodities. METHODS: We examined single commodity discounting of money and cross commodity discounting of money and weight loss in a sample of 84 adults with obesity or overweight statuses interested in weight loss. The exchange rate between money and weight loss was calculated, and participants completed two delay discounting tasks: money now versus money later and money now versus weight loss later. RESULTS: Participants discounted weight loss more than money (p < 0.001). When participants were divided into those who preferred weight loss (n = 61) versus money (n = 23), those who preferred money over weight loss discounted weight loss even more than individuals that preferred weight loss (p = 0.003). CONCLUSIONS: Greater discounting of weight loss for those who preferred money suggest that idiosyncratic preferences are related to multiple commodity discounting, and greater discounting of weight loss across all participants provide insight on important challenges for weight control.

Friends and social contexts as unshared environments: a discordant sibling analysis of obesity- and health-related behaviors in young adolescents.

OBJECTIVE: This study examines the contribution of best friends' weight and the peer social context (time spent alone versus with friends) as sources of unshared environment associated with variability in weight and health behaviors among weight-discordant siblings. METHODS: Pairs of same-sex biologic siblings (N=40 pairs; ages 13-17) were originally recruited as part of a study evaluating putative factors contributing to differences in adiposity among weight-discordant siblings. Siblings were asked to bring their best friends to the laboratory and siblings and friends' height and weight were objectively measured. Siblings also completed multi-pass dietary recalls to assess energy intake and sugar sweetened beverage (SSB) consumption. Siblings' physical activity was measured using accelerometry. Experience sampling methodology was used to assess sedentary behaviors/screen time and the number of occasions siblings spent alone and in the presence of friends. Multilevel models were used to estimate the relationships between predictors (best friends' zBMI, time spent alone or with friends) and outcomes (siblings' zBMI and obesity-related health behaviors). RESULTS: Best friends' zBMI was the best predictor of participants' zBMI, even when controlling for child's birth weight. Best friends' weight (zBMI) further predicted participants' SSB intake and time engaged in sedentary behaviors. Being active with friends was positively associated with participants' overall physical activity, whereas spending time alone was negatively associated with accelerometer counts regardless of siblings' adiposity. CONCLUSIONS: A friends' weight and the social context are unshared environmental factors associated with variability in adiposity among biologically-related weight-discordant siblings.

Sensitization of food reinforcement is related to weight status and baseline food reinforcement.

BACKGROUND: Food reinforcement is an empirical index of motivation to obtain food. Higher levels of food reinforcement are associated with increased energy intake and increased body weight. Food reinforcement can vary over repeated food presentations, as people may show reduced reinforcing value if they satiate to repeated reinforcers, or they may show sensitization, or an increase in reinforcing value with repeated presentations. Over the past few years, our laboratory has been studying the impact of repeated administration of large portions of high energy density snack foods on food reinforcement. We have shown in three separate studies that the majority of non-obese individuals become satiated after 2 weeks of the same snack food administration, but that a subset of obese individuals sensitize after this same manipulation. OBJECTIVE: The purpose of the study presented here was to identify predictors of reinforcer satiation or sensitization. SUBJECTS: For the analyses presented here, we combined data sets from three previous studies for a total of 67 adult participants. RESULTS: We found that higher body mass index (BMI) and higher baseline motivation to eat predicted sensitization, and baseline motivation to eat moderated the effects of BMI, such that higher baseline responding for food predicted sensitization in obese individuals, but satiation in non-obese individuals. CONCLUSIONS: These data suggest that repeated exposure to high energy density snack foods may result in sensitization to those foods, with similar effects as drugs of abuse in susceptible individuals, and that an individual's BMI and baseline responding act as predictors of this response.

Co-twin control designs for testing behavioral economic theories of child nutrition: methodological note.

OBJECTIVE: To illustrate the use and potential efficiency of the co-twin control design for testing behavioral economic theories of child nutrition. DESIGN: Co-twin control design, in which participating twins ate an ad libitum lunch on two laboratory visits. At visit 1, child food choices were not reinforced. On visit 2, twins were randomized to conditions such that one twin was reinforced for each fruit and vegetable serving consumed during lunch ('contingent') while his co-twin was reinforced irrespective of food intake ('non-contingent'). SUBJECTS: Six male twins, 5 years old, from three monozygotic twin pairs. MEASUREMENTS: Ad libitum intake of total energy (kcals), fat (kcals), and fruits and vegetables (servings) from the protocol test meals on the two visits. RESULTS: Compared to twins receiving non-contingent reinforcement, twins receiving contingent reinforcement increased fruit and vegetable intake by 2.0 servings, reduced fat intake 106.3 kcals, and reduced total energy intake by 112.7 kcals. The relative efficiency of the co-twin control design compared to a conventional between-groups design of unrelated children was most powerful for detecting 'substitution effects' (i.e., reduced total energy and fat intake) more so than for detecting increased fruit and vegetable intake. CONCLUSION: Genetically informative studies, including the co-twin control design, can provide conceptually elegant and efficient strategies for testing environmental theories of child nutrition and obesity.

Relationship between sex of parent and child on weight loss and maintenance in a family-based obesity treatment program.

OBJECTIVE: To determine if the sex of the participating parent/child pair is a contributing factor in initial weight loss and maintenance within a family-based obesity treatment program. DESIGN: A 2-year family-based obesity treatment program targeting one overweight parent and one overweight child. SUBJECTS: One overweight parent (body mass index (BMI) > or = 25) and child (> or = 85th BMI percentile) from 164 families. MEASUREMENTS: Parameters of body weight, including height, weight, BMI, z-BMI, percent overweight (BOV) at baseline and at 6-, 12- and 24-month follow-up time points. RESULTS: Children within the opposite-sex dyads had greater weight loss (P < 0.01) at 6- and 12-month time points compared with children in the same-sex dyads. Parents within opposite-sex dyads had significantly greater weight loss at 24 months (P < 0.05) compared with those in the same-sex dyads. When individual dyads were examined, the change in child z-BMI after 6 months was greater for the mother-son dyad as compared to the mother-daughter and father-son (P < 0.05). For parent z-BMI, the mother-daughter dyad consistently exhibited the poorest results. At 6- and 12-month time points, parents in the mother-daughter dyad lost significantly less weight than parents in all other dyads (P < 0.05), and at 24 months, parents in the mother-daughter dyad lost less weight than parents in the opposite-sex dyads (P < 0.05). CONCLUSION: These data reveal that child-parent sex interactions can strongly influence the outcome of obesity treatment when both parent and child are the target for weight loss. The reasons that underlie this effect remain to be determined.

Pubertal alterations in growth and body composition. VI. Pubertal insulin resistance: relation to adiposity, body fat distribution and hormone release.

OBJECTIVE: To investigate the independent influence of alterations in fat mass, body fat distribution and hormone release on pubertal increases in fasting serum insulin concentrations and on insulin resistance assessed by the homeostasis model (HOMA). DESIGN AND SUBJECTS: Cross-sectional investigation of pre- (n=11, n=8), mid- (n=10, n=11), and late-pubertal (n=10, n=11) boys and girls with normal body weight and growth velocity. MEASUREMENTS: Body composition (by a four-compartment model), abdominal fat distribution and mid-thigh interfascicular plus intermuscle (extramyocellular) fat (by magnetic resonance imaging), total body subcutaneous fat (by skinfolds), mean nocturnal growth hormone (GH) release and 06:00 h samples of serum insulin, sex steroids, leptin and insulin-like growth factor-I (IGF-I). RESULTS: Pubertal insulin resistance was suggested by greater (P<0.001) fasting serum insulin concentrations in the late-pubertal than pre- and mid-pubertal groups while serum glucose concentrations were unchanged and greater (P<0.001) HOMA values in late-pubertal than pre- and mid-pubertal youth. From univariate correlation fat mass was most related to HOMA (r=0.59, P<0.001). Two hierarchical regression models were developed to predict HOMA. In one approach, subject differences in sex, pubertal maturation, height and weight were held constant by adding these variables as a block in the first step of the model (r(2)=0.36). Sequential addition of fat mass (FM) increased r(2) (r(2)((inc)remental)=0.08, r(2)=0.44, P<0.05) as did the subsequent addition of a block of fat distribution variables (extramyocellular fat, abdominal visceral fat, and sum of skinfolds; r(2)(inc)=0.11, r(2)=0.55, P<0.05). Sequential addition of a block of hormone variables (serum IGF-I and log((10)) leptin concentrations; r(2)(inc)=0.04, P>0.05) did not reliably improve r(2) beyond the physical characteristic and adiposity variables. In a second model, differences in sex and pubertal maturation were again held constant (r(2)=0.25), but body size differences were accounted for using percentage fat data. Sequential addition of percentage body fat (r(2)((inc)remental)=0.11, r(2)=0.36, P<0.05), then a block of fat distribution variables (percentage extramyocellular fat, percentage abdominal visceral fat, and percentage abdominal subcutaneous fat; r(2)(inc)=0.08, r(2)=0.44, P=0.058), and then a block of serum IGF-I and log((10)) leptin concentrations (r(2)(inc)=0.07, r(2)=0.51, P<0.05) increased r(2). Mean nocturnal GH release was not related to HOMA (r=-0.04, P=0.75) and therefore was not included in the hierarchical regression models. CONCLUSION: Increases in insulin resistance at puberty were most related to FM. Accumulation of fat in the abdominal visceral, subcutaneous and muscular compartments may increase insulin resistance at puberty beyond that due to total body fat. Serum concentrations of leptin and IGF-I may further modulate HOMA beyond the effects of adiposity and fat distribution. However, the results are limited by the cross-sectional design and the use of HOMA rather than a criterion measure of insulin resistance.

Sex differences in obese children and siblings in family-based obesity treatment.

OBJECTIVE: The primary goal was to evaluate sex differences in child weight control programs that targeted increasing physical activity (increase) or the combination of reducing sedentary behavior and increasing physical activity (combined). A second goal was to evaluate the benefits of family-based interventions on nontargeted siblings. RESEARCH METHODS AND PROCEDURES: Sixty-seven families with obese children and 89 siblings were randomized to interventions that targeted increasing physical activity (increase) or the combination of reducing sedentary behavior and increasing physical activity (combined). Targeted participants and nontargeted siblings were followed for 1 year. RESULTS: At 12 months, boys showed significantly better percentages of overweight changes (-15.8%) for the combined treatment than girls (-1.0%), with no significant differences for the increase intervention for boys (-9.3%) or girls (-7.6%). Boys adhered to treatment better than girls (p < 0.01). Adherence and predilection for physical activity were significant predictors of targeted child weight loss at 1 year in multiple regression analysis. Predictors of sibling weight loss included age, number of siblings, targeted child percentage of overweight change, and the interaction of group assignment by same sex of treated sibling. DISCUSSION: Gender may influence response to programs that attempt to decrease sedentary behavior, and generalization of treatment effects to siblings may depend on the intervention and characteristics of the siblings.

Attention-Deficit Hyperactivity Disorder (ADHD) symptoms and smoking patterns among participants in a smoking-cessation program.

Previous research has suggested an increased liability to smoking among individuals with Attention-Deficit Hyperactivity Disorder (ADHD). This link is thought to be attributable, in part, to nicotine's beneficial effects on attention and performance. In the present study, we examined the association of ADHD symptoms of inattention and hyperactivity with smoking behavior in a sample of 226 male and female smokers ages 18 and older who were enrolled in a smoking-cessation program. Prior to treatment, they completed measures of ADHD symptoms and standardized measures of smoking patterns. Hierarchical linear regression models were used to characterize the smoking patterns associated with ADHD inattention and hyperactivity symptoms, controlling for potential confounder variables. Smoking for stimulation purposes and the urge to smoke to minimize withdrawal symptoms were the primary patterns associated with ADHD inattention symptoms, while hyperactivity symptoms were not associated with smoking patterns. Consistent with a self-medication hypothesis, these results suggest that smokers with frequent symptoms of inattention may use nicotine as a stimulant drug to help manage these symptoms. Future studies of the role of inattention symptoms in response to smoking treatment are warranted.

How much activity do youth get? A quantitative review of heart-rate measured activity.

OBJECTIVE: Recommendations for adult physical activity have shifted from 20 to 60 minutes of continuous vigorous activity 3 to 5 times a week to accumulation of 30 minutes of moderate to vigorous physical activity most days of the week. Variations of these guidelines also have been suggested for children, based on the idea of accumulating moderate to vigorous physical activity throughout the day, rather than attaining vigorous physical activity in continuous blocks. The goal of this study was to assess accumulated amounts of physical activity at different intensities in children. METHODS: We reviewed 26 studies (n = 1883) in youth aged 3 to 17 years that used heart-rate recording to measure physical activity in children to determine accumulated daily activity. Included were studies that provided time being active for at least 2 heart rate intensities at or above 120 beats/minute. Descriptive characteristics of the study groups were determined, and the influence of age, gender, and hours and days of observation on the slope of activity time as a function of percentage of heart rate reserve (HRR) was determined using hierarchical linear regression. RESULTS: Youth attained 128.0 +/- 45.6, 47.1 +/- 14.9, 29.3 +/- 13.7, and 14.7 +/- 6.0 minutes/day between 20% to 40%, 40% to 50%, 50% to 60%, and greater than 60% HRR, respectively. Age was a significant predictor of the intercept and slope of the physical activity and %HRR relationship. CONCLUSION: Youth of all ages attain >60 minutes/day of low-intensity physical activity and approximately 30 minutes/day of activity at traditional cardiovascular fitness training levels of 50% or more of HRR. Recommendations for youth activity are discussed.

Parental activity as a determinant of activity level and patterns of activity in obese children.

The purposes of this study were to measure the level and pattern of moderate-to-vigorous physical activity (MVPA = > 4.5 METs) and examine predictors of activity in obese children. Fifty-one 8-12-year-old children seeking obesity treatment wore accelerometers for 3 or 4 days. Children averaged 12.2 bouts of MVPA per day that lasted an average of 4.2 min, while parents engaged in 3.9 bouts of MVPA that lasted 4.2 min. Hierarchical regression models showed parent activity improved the prediction of obese children's activity levels and the number of bouts of MVPA but not the duration of MVPA. These results suggest that programs to increase physical activity in obese children should structure the activity in short bouts and attempt to increase parental physical activity.

Behavioral therapy in the treatment of pediatric obesity.

This article was designed to make a strong case for the importance of studying behavior and using behavioral therapy in the treatment of pediatric obesity. Behavioral treatments have been the most studied approaches to pediatric obesity, with great success. Six studies that provided long-term results are presented, and ideas for translating behavioral therapy into common pediatric practice are presented. Additional progress is needed to incorporate new findings in learning and behavioral neuroscience into clinical interventions and to integrate behavioral therapy with pharmacologic interventions and genetic predispositions and new advances in nutrition and exercise science.

Reducing sedentary behavior: role in modifying physical activity.

Decreased physical activity is associated with the increased incidence of obesity. Behavioral economic research demonstrates that reducing sedentary behaviors in children increases physical activity. Understanding how people choose physical or sedentary activities can aid in developing public health initiatives that increase access to physical activity, while reducing access to sedentary behaviors.

Changes in eating disorder symptoms with pediatric obesity treatment.

OBJECTIVE: To evaluate the effects of behavioral, family-based treatment on disordered eating and child behavior problems for obese 8- to 12-year-old children. STUDY DESIGN: We examined disordered eating in children and parents using the Kids' Eating Disorder Survey (KEDS) and the Binge Eating Scale, respectively; and psychologic problems in children and their parents using the Child Behavior Checklist and Symptom Checklist-90, respectively, in 47 families who participated in a family-based obesity treatment program. RESULTS: Obese children showed significant decreases (-12.5 +/- 13.5) in percent overweight, internalizing problems (-7.0 +/- 7.3), and total behavior problems (-4.8 +/- 6.6) and increases in behavioral competence (3.7 +/- 5.0) over 2 years of measurement; and their parents showed significant decreases in weight (-5.0 +/- 8.3 kg) and reductions in parental distress (-2.3 +/- 7.6) and in disturbed eating and weight-related cognition (-3.2 +/- 5.3). No significant changes were observed in total KEDS (-0.2 +/- 1.9), weight dissatisfaction (-0.3 +/- 1.7), or purging/restricting (0.2 +/- 0.6) scores. Decreases in total KEDS were related to decreases in total behavior problems and externalizing behavior problems. CONCLUSIONS: These results document improvements in child behavior problems and competence and no change in symptoms of disordered eating in a standardized behavioral weight control program.

Dietary variety, energy regulation, and obesity.

Increased variety in the food supply may contribute to the development and maintenance of obesity. Thirty-nine studies examining dietary variety, energy intake, and body composition are reviewed. Animal and human studies show that food consumption increases when there is more variety in a meal or diet and that greater dietary variety is associated with increased body weight and fat. A hypothesized mechanism for these findings is sensory-specific satiety, a phenomenon demonstrating greater reductions in hedonic ratings or intake of foods consumed compared with foods not consumed. Nineteen studies documenting change in preference, intake, and hedonic ratings of food after a food has been eaten to satiation in animals and humans are reviewed, and the theory of sensory-specific satiety is examined. The review concludes with the relevance of oral habituation theory as a unifying construct for the effects of variety and sensory-specific satiety, clinical implications of dietary variety and sensory-specific satiety on energy regulation, and suggestions for future research.

Effects of contingent television on physical activity and television viewing in obese children.

OBJECTIVE: Elevated television (TV) viewing and physical inactivity promote obesity in children. Thus, changes in physical activity and sedentary behavior seem critical to treating childhood obesity. PRESENT STUDY: Using a randomized, 2-arm design, this pilot study tested the effects of contingent TV on physical activity and TV viewing in 10 obese children. TV viewing was contingent on pedaling a stationary cycle ergometer for experimental participants but was not contingent on pedaling for control participants. The study was conducted over 12 weeks, including a 2-week baseline period. RESULTS: Multivariate analyses indicated that the intervention significantly increased pedaling and reduced TV-viewing time. During the treatment phase, the experimental group pedaled 64.4 minutes per week on average, compared with 8.3 minutes by controls. The experimental group watched 1.6 hours of TV per week on average, compared with 21.0 hours per week on average by controls during this phase. Secondary analyses indicated that the experimental group showed significantly greater reductions in total body fat and percent leg fat. Total pedaling time during intervention correlated with greater reductions in percent body fat (r = -0.68). CONCLUSIONS: Contingencies in the home environment can be arranged to modify physical activity and TV viewing and may have a role in treating childhood obesity. Contingent TV may be one method to help achieve this goal.

Increasing fruit and vegetable intake and decreasing fat and sugar intake in families at risk for childhood obesity.

OBJECTIVE: The goal of this study was to evaluate the effect of a parent-focused behavioral intervention on parent and child eating changes and on percentage of overweight changes in families that contain at least one obese parent and a non-obese child. RESEARCH METHODS AND PROCEDURES: Families with obese parents and non-obese children were randomized to groups in which parents were provided a comprehensive behavioral weight-control program and were encouraged to increase fruit and vegetable intake or decrease intake of high-fat/high-sugar foods. Child materials targeted the same dietary changes as their parents without caloric restriction. RESULTS: Changes over 1 year showed that treatment influenced targeted parent and child fruit and vegetable intake and high-fat/high-sugar intake, with the Increase Fruit and Vegetable group also decreasing their consumption of high-fat/high-sugar foods. Parents in the increased fruit and vegetable group showed significantly greater decreases in percentage of overweight than parents in the decreased high-fat/high-sugar group. DISCUSSION: These results suggest that focusing on increasing intake of healthy foods may be a useful approach for nutritional change in obese parents and their children.

Cost-effectiveness of group and mixed family-based treatment for childhood obesity.

OBJECTIVE: Family-based, behavioral treatment has been shown to be an effective intervention for the management of pediatric obesity. The goal of this study was to compare the cost-effectiveness of two protocols for the delivery of family-based behavioral treatment. RESEARCH METHODS AND PROCEDURES: Thirty-one families with obese children were randomized to groups in which families were provided mixed treatment incorporating both group and individualized treatment vs group treatment only. Cost-effectiveness of treatment was defined as the magnitude of reduction in standardized BMI and percentage overweight per dollar spent for recruitment and treatment. Anthropometric data were assessed at baseline, 6 months and 12 months post-randomization. RESULTS: Results for the 24 families with complete data showed the group intervention was significantly more cost-effective than the mixed treatment. This was due to the similarity between the two groups in Z-BMI or percentage overweight change for children and their parents, while the mixed treatment was significantly more expensive to deliver than the group treatment. DISCUSSION: These findings suggest that a family-based, behavioral intervention employing group treatment alone is a more cost-effective approach to treating pediatric obesity than a mixed group plus individual format.

Effects of sensory stimulation and post-ingestive consequences on satiation.

This study investigated the influence of sensory stimulation, with and without post-ingestive consequences, on satiation by varying the form of a preload and the timing of a mixed meal presented after the preload. Twenty-four, normal-weight, non-dieting, college-aged women were randomized to different preload groups: water preload (Water), sip-and-spit energy-dense preload (Taste), or energy-dense preload (Taste/kcal). Volume of fluid consumed prior to the meal was controlled. All participants had sessions in which a meal was provided immediately (0 min) or 30 min after the preload. Results showed equal suppression of intake for participants receiving sensory stimulation from an energy-dense preload (Taste and Taste/kcal groups) in comparison to a water preload (Water group). No effect of time from preload to food consumption was found; the suppression of intake was similar whether the meal immediately followed the preload or was 30 min after the preload. These findings suggest that sensory aspects of food can influence satiation, and in the conditions of this study, had a larger influence on satiation than post-ingestive consequences.