Protocol for the Imagine HEALTH Study: Guided imagery lifestyle intervention to improve obesity-related behaviors and salivary cortisol patterns in predominantly Latino adolescents.

Innovative lifestyle interventions are needed to reduce type 2 diabetes risk in adolescents. This report describes the protocol of the Imagine HEALTH cluster randomized control trial, that tests an intervention based in Self-Determination Theory (SDT) and uses lifestyle education combined with the mind-body, complementary health modality of guided imagery (GI), to address obesity prevention and treatment in predominantly Latino adolescents. The primary aim is to determine the unique effects of each of the three major components of the 12-week lifestyle intervention (lifestyle education, stress reduction guided imagery, and lifestyle behavior guided imagery) compared to control on primary outcomes of physical activity (accelerometry), dietary intake (3-day recall), and stress biomarker levels (salivary cortisol). Secondary aims assess changes compared to controls in psychosocial outcomes (stress, well-being, depression), diabetes-related metabolic outcomes (adiposity, insulin resistance), maintenance of outcome changes for one year post-intervention, and SDT-based mediation of intervention effects. The development and rationale for each of the intervention components, study design, and outcome measurement processes are described. Adolescent participants recruited from four urban schools are cluster randomized by school into one of four arms of the 12-week (3-month) intervention, followed by 6 months of maintenance and 6 months of no contact. Outcome measures are assessed at the end of each period (3-, 9-, and 15-months). Results to date show successful recruitment of 97% of the target study population. Future results will demonstrate the effects of this integrative intervention on primary and secondary outcome measures in adolescents at risk for lifestyle-related metabolic disease.

Imagine HEALTH: results from a randomized pilot lifestyle intervention for obese Latino adolescents using Interactive Guided ImagerySM.

BACKGROUND: There is an urgent need for innovative and developmentally appropriate lifestyle interventions to promote healthy lifestyle behaviors and to prevent the early onset of type 2 diabetes and cardiovascular disease risk in obese Latino adolescents. Guided imagery offers promise to reduce stress and promote lifestyle behavior change to reduce disease risk in obese adolescents. Our objectives were: 1) To pilot test a new 12-wk lifestyle intervention using a randomized trial design in obese Latino adolescents, in order to determine the effects of the mind-body modality of Interactive Guided ImagerySM (IGI), over and above those of a didactic lifestyle education, on insulin resistance, eating and physical activity behaviors, stress and stress biomarkers; and 2) To explore the role of intervention-related changes in stress and stress biomarkers on changes in metabolic outcomes, particularly insulin resistance. METHODS: Obese (BMI > 95th percentile), Latino adolescents (n = 35, age 14-17) were randomized to receive either 12 weekly sessions of a lifestyle education plus guided imagery program (GI), or lifestyle education plus a digital storytelling computer program (DS). Between-group differences in behavioral, biological, and psychological outcomes were assessed using unpaired T-tests and ANCOVA in the 29 subjects who completed the intervention. RESULTS: The GI group demonstrated significant reductions in leisure sedentary behavior (p < .05) and increases in moderate physical activity (p < .05) compared to DS group, and a trend toward reduced caloric intake in GI vs DS (p = .09). Salivary cortisol was acutely reduced by stress-reduction guided imagery (p < .01). There were no group differences in adiposity, insulin resistance, perceived stress, or stress biomarkers across the 12-week intervention, though decrease in serum cortisol over the course of the intervention was associated with improved insulin sensitivity (p = .03) independent of intervention group and other relevant co-variates. CONCLUSIONS: The improvements in physical activity and stress biomarkers following this pilot intervention support the role of guided imagery in promoting healthy lifestyle behavior change and reducing metabolic disease risk in obese Latino adolescent populations. Future investigations will be needed to determine the full effects of the Imagine HEALTH intervention on insulin resistance, stress, and stress biomarkers. TRIAL REGISTRATION: Clinicaltrials.gov Registry #: NCT01895595.

Impaired glucose tolerance and reduced beta-cell function in overweight Latino children with a positive family history for type 2 diabetes.

The objective of this study was to examine relationships between impaired glucose tolerance (IGT) and body composition and insulin-related phenotypes in 150 overweight Latino children with a family history of type 2 diabetes. Glucose tolerance was assessed by an oral glucose challenge. Body composition was assessed by dual energy x-ray absorptiometry and magnetic resonance imaging. Insulin sensitivity, the acute insulin response, and the disposition index (DI), as an index of beta-cell function, were determined by an iv glucose tolerance test and compared between normal glucose-tolerant and IGT children. IGT was present in 28% of children, and was similar across obesity groups, but higher in children exposed to gestational diabetes mellitus (41% IGT). There were no significant differences in body composition, fat distribution, insulin sensitivity, or acute insulin response, but DI was significantly lower in IGT children by 16% (P < 0.02), and DI was inversely related to age. In conclusion, IGT is present in 28% of overweight Latino children with a family history of type 2 diabetes, is not influenced by obesity, is more prevalent in children exposed to gestational diabetes mellitus, and is related to poor beta-cell function, which shows signs of deterioration with age in this population.