Impact of motivational interviewing on engagement in a parent-exclusive paediatric obesity intervention: randomized controlled trial of NOURISH+MI.

BACKGROUND: Attrition and treatment adherence are notorious challenges in paediatric obesity interventions. OBJECTIVE: To evaluate if brief, pretreatment motivational interviewing (MI) can improve retention (at baseline, post-assessment and follow-up assessment) and adherence (i.e. attendance) in a parent-exclusive paediatric obesity intervention. METHODS: MI was implemented with parents as an adjunct to a larger randomized controlled trial of Nourishing Our Understanding of Role-modeling to Improve Support and Health (NOURISH+ ), a parent intervention for children with overweight ages 5-11 years. Parents (N = 112) were randomized to receive two MI sessions (one telephone and one in person) or reminder calls. RESULTS: Parents (91% women; 52% African American) who completed one telephone MI session were more likely to attend baseline (74%) compared with parents who received reminder calls only (53%, p < .001). After a second MI session, there were no group differences in treatment initiation (p > .05). Treatment attendance, post or 4-month follow-up assessment completion did not differ between conditions (p > .05). CONCLUSION: One MI session implemented prior to treatment can improve baseline attendance; a second MI session did not enhance these effects. A single-session telephone-based MI pretreatment might be a cost and time-effective strategy to enhance recruitment efforts. Further strategies to address retention and treatment attendance are needed.

Impact of motivational interviewing on outcomes of an adolescent obesity treatment: results from the MI Values randomized controlled pilot trial.

The aim of this study is to examine outcomes from MI Values, a motivational interviewing (MI) intervention implemented adjunctive to obesity treatment. Adolescents (n = 99; 73% African American; 74% female; mean body mass index [BMI] percentile = 98.9 ± 1.2) were randomized to receive two MI sessions or education control. All adolescents participated in structured behavioural weight management treatment. Baseline, 3- and 6-month assessments of anthropometrics, dietary intake and physical activity were obtained. Both groups had significant reductions in BMI z-scores and energy intake and increased physical activity at 3 and 6 months (P < 0.05). MI participants reported greater reductions in 3-month energy intake compared with controls. Participation in MI is associated with reduction in energy intake, consistent with better adherence to dietitian visits previously reported from MI Values. MI might be an effective adjunct to adolescent obesity treatment; future research is needed to determine if motivational interviewing can enhance BMI outcomes, via greater adherence to behavioural intervention.

Motivational interviewing targeting diet and physical activity improves adherence to paediatric obesity treatment: results from the MI†Values randomized controlled trial.

BACKGROUND: Adherence is a challenge in obesity treatment. Motivational interviewing (MI) may promote patient adherence. MI Values is a randomized controlled trial of MI implemented as an adjunct to an adolescent obesity treatment [Teaching Encouragement Exercise Nutrition Support (T.E.E.N.S.)]. OBJECTIVE: Assess effects of MI Values on T.E.E.N.S. attrition and adherence. METHODS: Participants were randomized to MI (n = 58) or control (n = 41). At weeks 1 and 10, MI participants had brief MI sessions; controls viewed health education videos. All participants continued with T.E.E.N.S. (biweekly dietitian and behavioural support visits; 3 times per week supervised physical activity). Assessments were repeated at baseline, 3 and 6 months. T-tests and chi-square analyses examined T.E.E.N.S. attrition and adherence by group. RESULTS: Adolescents (N = 99) were primarily African-American (73%) females (74%); age = 13.8 ± 1.8 years, body mass index percentile = 98.0 ± 1.2. Compared with controls, MI participants had greater 3-month adherence overall (89.2% vs. 81.0%, P = 0.040), and to dietitian (91.3% vs. 84.0%; P = 0.046) and behavioural support (92.9% vs. 85.2%; P = 0.041) visits, and greater 6-month adherence overall (84.4% vs. 76.2%, P = 0.026) and to behavioural support visits (87.5% vs. 78.8%, P = 0.011). CONCLUSIONS: MI enhanced adherence to this obesity intervention. MI Values is the first study to examine the impact of MI on treatment adherence among obese, primarily African-American adolescents.

An exploration of body dissatisfaction and perceptions of Black and White girls enrolled in an intervention for overweight children.

Silhouette measures are one approach to assessing body dissatisfaction in children, although little is known about their use among racially diverse, overweight girls seeking weight-loss treatment. This study assessed racial differences in body dissatisfaction and body size perceptions of 58 girls (ages 6-11, 66% Black, 34% White) participating in a randomized trial for pediatric overweight. Body dissatisfaction did not differ between races; 99% of girls reported an ideal figure smaller than their current one. Black girls selected a larger silhouette to represent their ideal body size, and most girls in both racial groups underestimated their actual size. Outcomes strengthen the argument that, despite an overall preference for a larger body size, obesity might mitigate cultural factors that protect Black girls from body dissatisfaction. Additional research is needed to enhance understanding of children's body size perceptions and dissatisfaction to inform assessment and treatment of pediatric obesity and associated disordered eating symptoms.

Binge eating disorder: a symptom-level investigation of genetic and environmental influences on liability.

BACKGROUND: Recent behavioral genetic studies have emphasized the importance of investigating eating disorders at the level of individual symptoms, rather than as overall diagnoses. We examined the heritability of binge eating disorder (BED) using an item-factor analytic approach, which estimates contributions of additive genetic (A), common environmental (C), and unique environmental (E) influences on liability to BED as well as individual symptoms. METHOD: Participants were 614 monozygotic and 410 dizygotic same-sex female twins from the Mid-Atlantic Twin Registry who completed a self-report measure of BED symptoms based upon DSM-IV criteria. Genetic and environmental contributions to BED liability were assessed at the diagnostic and symptom levels, using an item-factor approach. RESULTS: Liability to BED was moderately heritable; 45% of the variance was due to A, with smaller proportions due to C (13%), and E (42%). Additive genetic effects accounted for 29-43% of the variance in individual items, while only 8-14% was due to C. CONCLUSIONS: Results highlight the relevance of examining eating disorders at the symptom level, rather than focusing on aggregate diagnoses.

A twin study of specific bulimia nervosa symptoms.

BACKGROUND: Twin studies have suggested that additive genetic factors significantly contribute to liability to bulimia nervosa (BN). However, the diagnostic criteria for BN remain controversial. In this study, an item-factor model was used to examine the BN diagnostic criteria and the genetic and environmental contributions to BN in a population-based twin sample. The validity of the equal environment assumption (EEA) for BN was also tested. METHOD: Participants were 1024 female twins (MZ n=614, DZ n=410) from the population-based Mid-Atlantic Twin Registry. BN was assessed using symptom-level (self-report) items consistent with DSM-IV and ICD-10 diagnostic criteria. Items assessing BN were included in an item-factor model. The EEA was measured by items assessing similarity of childhood and adolescent environment, which have demonstrated construct validity. Scores on the EEA factor were used to specify the degree to which twins shared environmental experiences in this model. RESULTS: The EEA was not violated for BN. Modeling results indicated that the majority of the variance in BN was due to additive genetic factors. There was substantial variability in additive genetic and environmental contributions to specific BN symptoms. Most notably, vomiting was very strongly influenced by additive genetic factors, while other symptoms were much less heritable, including the influence of weight on self-evaluation. These results highlight the importance of assessing eating disorders at the symptom level. CONCLUSIONS: Refinement of eating disorder phenotypes could ultimately lead to improvements in treatment and targeted prevention, by clarifying sources of variation for specific components of symptomatology.

Assessing the heritability of anorexia nervosa symptoms using a marginal maximal likelihood approach.

BACKGROUND: Assessment of eating disorders at the symptom level can facilitate the refinement of phenotypes. We examined genetic and environmental contributions to liability to anorexia nervosa (AN) symptoms in a population-based twin sample using a genetic common pathway model. METHOD: Participants were from the Norwegian Institute of Public Health Twin Panel (NIPHTP) and included all female monozygotic (MZ; 448 complete pairs and four singletons) and dizygotic (DZ; 263 complete pairs and four singletons) twins who completed the Composite International Diagnostic Interview (CIDI) assessing DSM-IV Axis I and ICD-10 criteria. Responses to items assessing AN symptoms were included in a model fitted using the marginal maximum likelihood (MML) approach. RESULTS: Heritability of the overall AN diagnosis was moderate [a2=0.22, 95% confidence interval (CI) 0.0-0.50] whereas heritabilities of the specific items varied. Heritability estimates for weight loss items were moderate (a2=0.31-0.34) and items assessing weight concern when at a low weight were smaller (0.18-0.29). Additive genetic factors contributed little to the variance of amenorrhea, which was most strongly influenced by unshared environment (a2=0.16, e2=0.71). CONCLUSIONS: AN symptoms are differentially heritable. Specific criteria such as those related to body weight and weight loss history represent more biologically driven potential endophenotypes or liability indices. The results regarding weight concern differ somewhat from those of previous studies, highlighting the importance of assessing genetic and environmental influences on variance of traits within specific subgroups of interest.