Theoretical Mediators of Diabetes Risk and Quality of Life Following a Diabetes Prevention Program for Latino Youth With Obesity.

PURPOSE: This study tested self-efficacy and social support for activity and dietary changes as mediators of changes in type 2 diabetes related outcomes following a lifestyle intervention among Latino youth. SETTING AND INTERVENTION: Latino adolescents (14-16 years) with obesity (BMI% = 98.1 ± 1.4) were randomized to a 3-month intervention (n = 67) that fostered self-efficacy and social support through weekly, family-centered sessions or a comparison condition (n = 69). MEASURES: Primary outcomes included insulin sensitivity and weight specific quality of life. Mediators included self-efficacy, friend, and family social support for health behaviors. Data was collected at baseline, 3-months, 6-months, and 12-months. ANALYSIS: Sequential path analysis was used to examine mediators as mechanisms by which the intervention influenced primary outcomes. RESULTS: The intervention had a direct effect on family (ß = 0.33, P < .01) and friend social support (ß = 0.22, P < .001) immediately following the intervention (3-months). Increased family social support mediated the intervention's effect on self-efficacy at 6-months (ß = 0.09, P < .01). However, social support and self-efficacy did not mediate long-term changes in primary outcomes (P > .05) at 12-months. CONCLUSIONS: Family social support may improve self-efficacy for health behaviors in high-risk Latino youth, highlighting the important role of family diabetes prevention. Fostering family social support is a critical intervention target and more research is needed to understand family-level factors that have the potential to lead to long-term metabolic and psychosocial outcome in vulnerable youth.

Yields and costs of recruitment methods with participant phenotypic characteristics for a diabetes prevention research study in an underrepresented pediatric population.

BACKGROUND/AIMS: Prediabetes and diabetes disproportionately impact Latino youth, yet few diabetes prevention programs have prioritized inclusion of this underrepresented population. This report describes the recruitment process, yields, associated costs, and phenotypic characteristics of Latino youth with obesity and prediabetes enrolled in a randomized controlled diabetes prevention study in the USA. METHODS: Recruitment efforts included referrals from clinics, community outlets, local media, and word of mouth with the goal of enrolling 120 Latino adolescents aged 12-16 with obesity (BMI > 95th percentile) and prediabetes. Prediabetes eligibility was determined by any of the following: HbA1c between 5.7 and 6.5%, fasting glucose between 100 and 125 mg/dL, or a 2-h glucose between 120 and 199 mg/dL following a 75-g oral glucose tolerance test (OGTT), but not meeting any of the diagnostic criteria for diabetes. Eligible participants were randomized 2:1 to either a 6-month community-based lifestyle intervention that included group nutrition and health education classes (1 day/week) and group exercise classes (2 days/week) or usual care control arm. Recruitment yields were determined by review of referral source in the study screening database. Recruitment costs were determined by an after-the-fact financial review of actual and in-kind costs. Participant phenotypic characteristics (i.e., demographics, anthropometrics, and biochemical data) were compared by recruitment strategy using a one-way ANOVA. RESULTS: Recruitment efforts covered 160 mile2 (414 km2) across 26 ZIP codes (postcode) in the Phoenix Metropolitan Area and yielded 655 referrals from clinics (n = 344), community (n = 143), media (n = 137), and word-of-mouth (n = 31). From this pool, 26% (n = 167) did not meet general, pre-screening eligibility criteria; 29% (n = 187) declined participation; and 10% (n = 64) were unable to be contacted. A total of 237 youth were invited to the clinical research unit to determine final eligibility. Following the OGTT, 52% (n = 122) met prediabetes criteria and 117 were subsequently randomized. Clinical recruitment yielded the highest number of referrals (53%; n = 344) while word-of-mouth yielded the highest proportion (35%; n = 11) of randomized participants per referred youth. There were no significant differences in anthropometric or biochemical measures among youth by recruitment strategy. Based upon final enrollment numbers, community recruitment was the costliest approach ($486/randomized participant) followed by clinical ($248/randomized participant) and media ($236/randomized participant). CONCLUSIONS: The ability to meet enrollment goals for a clinical trial of an underrepresented population required multiple recruitment strategies. Although strategies vary in yields and costs, it appears they produce similar phenotypical risk profiles of eligible youth. TRIAL REGISTRATION: ClinicalTrials.gov NCT02615353 . Registered on 26 November 2015.

Familism, Self-Esteem, and Weight-Specific Quality of Life Among Latinx Adolescents With Obesity.

OBJECTIVE: Obesity is a critical public health condition affecting Latinx adolescents and contributes to health disparities across the lifespan. Childhood and adolescent obesity is associated with reduced quality of life (QoL) and decreased self-esteem. The purpose of this study is to examine the role of cultural (e.g., familism) and psychosocial (e.g., self-esteem) factors as predictors of weight-specific QoL among Latinx adolescents with obesity. METHODS: Baseline data from 160 Latinx adolescents (ages 14-16 years) with obesity (BMI > 95th percentile for age and sex) who were recruited for a diabetes prevention intervention were used. Structural equation modeling tested the relationships between four latent constructs (familism, positive self-esteem, self-deprecation, and weight-specific QoL). RESULTS: The model tested paths from familism to positive self-esteem, self-deprecation, and weight-specific QoL, and paths from positive self-esteem and self-deprecation to weight-specific QoL. Higher familism was positively associated with positive self-esteem but not self-deprecation. In turn, positive self-esteem was positively associated with higher weight-specific QoL, whereas self-deprecation was negatively associated. Furthermore, there was an indirect effect of familism on QoL via positive self-esteem. CONCLUSIONS: These data shed light into specific cultural and psychosocial constructs that influence QoL among Latinx adolescents with obesity. This study suggests that familism and positive self-esteem can operate as protective factors associated with higher weight-specific QoL in Latinx adolescents with obesity; whereas self-deprecation may operate as a risk factor for lower weight-specific QoL.

Sex as a moderator of body composition following a randomized controlled lifestyle intervention among Latino youth with obesity.

BACKGROUND: Body composition differences between males and females emerge during adolescence and continue throughout adulthood; however, whether sex moderates body composition changes in adolescents with obesity after an intervention is unknown. OBJECTIVE: To examine sex as a moderator of changes in adiposity following lifestyle intervention. METHODS: A total of 136 Latino youth with obesity (BMI% 98.2 ± 1.3) aged 14 to 16 years old were randomized to either a 12-week lifestyle intervention (27 males/40 females) or control (35 males/34 females) group. The intervention included nutrition education (1 h/wk) and moderate-to-vigorous physical activity (3 h/wk). Anthropometric data (body mass index [BMI], BMI%, waist circumference, total body fat, and fat-free mass) were obtained pre- and post-intervention. Sex differences were examined by general linear models with significance determined at P < .05 for the F-statistic. RESULTS: Sex did not moderate changes in BMI (F1,115 = 0.01, P = .9), BMI% (F1,115 = 0.14, P = .7), or waist circumference (F1,117 = 1.1, P = .3). Sex significantly moderated changes in body fat percent (F1,117 = 5.3, P = .02), fat mass (F1,116 = 4.5, P = .04), and fat-free mass (F1,116 = 4.3, P = .04). Intervention males compared with females had greater relative reductions in fat percent (-4.1 ± 0.8% vs -1.2 ± 0.7%, P = .02) and fat mass (-5.0 ± 1.1 kg vs -1.5 ± 0.9 kg, P = .02) and gained more fat free mass (3.6 ± 0.9 kg vs 0.5 ± 0.8 kg, P = .02) when compared with same sex controls. CONCLUSION: Males and females exhibited a differential response to lifestyle intervention for percent fat, fat mass, and fat-free mass indicating that sex-specific improvements in body composition favours males over females.

Decreased GlycA after lifestyle intervention among obese, prediabetic adolescent Latinos.

BACKGROUND: Obese youth with prediabetes are at increased risk for premature morbidity and mortality through multiple mechanisms, including increased systemic inflammation. GlycA is a novel measure of systemic inflammation that predicts type II diabetes, cardiovascular events, and all-cause mortality in adults. OBJECTIVE: The purpose of the present study was to examine changes in GlycA after lifestyle intervention among obese, prediabetic Latino youth. METHODS: Obese, prediabetic Latino youth (n = 27; 15.5 ± 1.1 years, 13 males/14 females) completed a 12-week lifestyle intervention that included weekly nutrition education and 3 d/wk of moderate to vigorous physical activity. Prediabetes was characterized by an expanded definition of impaired glucose tolerance, using 2-hour glucose ≥120 mg/dL after an oral glucose tolerance test. GlycA was assessed at baseline and 12 weeks using nuclear magnetic resonance spectroscopy. RESULTS: After the lifestyle intervention, GlycA was significantly reduced (445.3 ± 51.3 µmol/L to 419.0 ± 50.0 µmol/L, P = .01) (mean ± standard deviation). Additional improvements were observed in multiple cardiovascular risk factors, including body mass index (BMI; 34.8 ± 5.0 kg/m2 to 34.0 ± 5.1 kg/m2, P < .001), total cholesterol (154.1 ± 30.3 mg/dL to 143.3 ± 29.1 mg/dL, P = .003), and 2-hour glucose (141.0 ± 13.2 mg/dL to 115.9 ± 31.4 mg/dL, P < .001). Decreases in GlycA were associated with decreases in 2-hour glucose (r = 0.49, P = .008) and BMI (r = 0.41, P = .03). CONCLUSION: These data are consistent with the hypothesis that lifestyle intervention might improve GlycA levels in obese, prediabetic adolescent Latinos, but randomized trial evidence is needed. Healthy lifestyle modifications among high-risk youth may decrease future risk of cardiometabolic disease through reducing systemic inflammation, in addition to improving traditional cardiovascular risk factors.

Effects of a Community-Based Diabetes Prevention Program for Latino Youth with Obesity: A Randomized Controlled Trial.

OBJECTIVE: This study examined the short- and long-term effects of a community-based lifestyle intervention among Latino youth with obesity. METHODS: Latino adolescents (14-16 years old) were randomized to a 3-month lifestyle intervention (n = 67) or comparison control (n = 69) and followed for 12 months. The intervention included weekly nutrition and health classes delivered to groups of families and exercise sessions (3 days/week) delivered to groups of adolescents. Comparison youth received laboratory results and general health information. Primary outcomes included insulin sensitivity and weight-specific quality of life (QoL) with secondary outcomes of BMI percentile (BMI%), waist circumference, and percent body fat. RESULTS: At 3 months, youth in the intervention group exhibited significant increases in insulin sensitivity (P < 0.05) and weight-specific QoL (P < 0.001), as well as reductions in BMI%, waist circumference, and percent body fat compared with controls. Increases in weight-specific QoL and reductions in BMI% and percent body fat remained significant at 12 months (P < 0.001), while changes in insulin sensitivity did not. In a subsample of youth with prediabetes at baseline, insulin sensitivity (P = 0.01), weight-specific QoL (P < 0.001), and BMI% (P < 0.001) significantly improved at 3 months. CONCLUSIONS: Lifestyle intervention can improve cardiometabolic and psychosocial health in a vulnerable population of Latino adolescents at high risk for developing type 2 diabetes.

Preventing diabetes in obese Latino youth with prediabetes: a study protocol for a randomized controlled trial.

BACKGROUND: Obese Latino adolescents are disproportionately impacted by insulin resistance and type 2 diabetes. Prediabetes is an intermediate stage in the pathogenesis of type 2 diabetes and represents a critical opportunity for intervention. However, to date, no diabetes prevention studies have been conducted in obese Latino youth with prediabetes, a highly vulnerable and underserved group. Therefore, we propose a randomized-controlled trial to test the short-term (6-month) and long-term (12-month) efficacy of a culturally-grounded, lifestyle intervention, as compared to usual care, for improving glucose tolerance and reducing diabetes risk in 120 obese Latino adolescents with prediabetes. METHODS: Participants will be randomized to a lifestyle intervention or usual care group. Participants in the intervention group will attend weekly nutrition and wellness sessions and physical activity sessions twice a week for six months, followed by three months of booster sessions. The overall approach of the intervention is framed within a multilevel Ecodevelopmental model that leverages community, family, peer, and individual factors during the critical transition period of adolescence. The intervention is also guided by Social Cognitive Theory and employs key behavioral modification strategies to enhance self-efficacy and foster social support for making and sustaining healthy behavior changes. We will test intervention effects on quality of life, explore the potential mediating effects of changes in body composition, total, regional, and organ fat on improving glucose tolerance and increasing insulin sensitivity, and estimate the initial incremental cost effectiveness of the intervention as compared with usual care for improving glucose tolerance. DISCUSSION: The proposed trial builds upon extant collaborations of a transdisciplinary team of investigators working in concert with local community agencies to address critical gaps in how diabetes prevention interventions for obese Latino youth are developed, implemented and evaluated. This innovative approach is an essential step in the development of scalable, cost-effective, solution oriented programs to prevent type 2 diabetes in this and other populations of high-risk youth. TRIAL REGISTRATION: NCT02615353, registered on June 8, 2016.

Culturally-grounded diabetes prevention program for obese Latino youth: Rationale, design, and methods.

BACKGROUND: Type 2 diabetes (T2D) disproportionately impacts Latino youth yet few diabetes prevention programs address this important source of health disparities. OBJECTIVES: To address this knowledge gap, we describe the rationale, design, and methodology underpinning a culturally-grounded T2D prevention program for obese Latino youth. The study aims to: 1) to test the efficacy of the intervention for reducing T2D risk, 2) explore potential mediators and moderators of changes in health behaviors and health outcomes and, 3) examine the incremental cost-effectiveness for reducing T2D risk. Latino adolescents (N=160, age 14-16) will be randomized to either a 3-month intensive lifestyle intervention or a control condition. The intervention consists of weekly health education delivered by bilingual/bicultural promotores and 3 moderate-to-vigorous physical activity (PA) sessions/week. Control youth receive health information and results from their laboratory testing. Insulin sensitivity, glucose tolerance, and weight-specific quality of life are assessed at baseline, 3-months, 6-months, and 12-months. We will explore whether enhanced self-efficacy and/or social support mediate improvements in nutrition/PA behaviors and T2D outcomes. We will also explore whether effects are moderated by sex and/or acculturation. Cost-effectiveness from the health system perspective will be estimated by the incremental cost-effectiveness ratio using changes in insulin sensitivity at 12-months. CONCLUSIONS: The results of this study will provide much needed information on how T2D prevention interventions for obese Latino youth are developed, implemented and evaluated. This innovative approach is an essential step in the development of scalable, cost-effective, solution oriented programs to prevent T2D in this and other high-risk populations.

Diabetes Prevention for Latino Youth: Unraveling the Intervention "Black Box".

The translation of research findings into sustainable health promotion and disease prevention programs in community settings remains a challenge. This report describes the process of substantiating a community-developed diabetes prevention program for Latino youth through research. Included are design considerations, measurement strategies, and the context through which the project is culturally grounded for relevance and fit within a local community. The process included (1) refining the program to include salient, stakeholder-identified behavioral components; (2) refining the collaborative effort to embrace the capacity for facilitating relevant behavior change on targeted health-related outcomes to enhance intervention effectiveness; and (3) including the accurate assessment of intervention efficacy via precise assessment of diabetes-related health outcomes. We explain the process of collaborating with community partners to enhance the cultural relevance and sustainability of intervention effects on both individuals and communities. We discuss the rationale for empirical support for academic-community collaborations that function in both a "top-down" and a "bottom-up" manner to advance the science and practice of sustainable and efficacious community health promotion.

Use of the Stanford Brief Activity Survey for physical activity assessment in postpartum Latinas: a validation study of a linguistically translated Spanish version.

This study assessed the concurrent validity of the English and a linguistic Spanish translation of the Stanford Brief Activity Survey (SBAS) with pedometer-measured physical activity (PA) among postpartum Latinas. Latinas (n 97) completed the SBAS in either English (n 47) or Spanish (n 50) and wore pedometers 7 days at three different assessment periods. The English version demonstrated significant trends (p .01) for differentiating aerobic walking steps (AWS) and aerobic walking time (AWT) across SBAS intensity categories at two of the three assessment periods. The Spanish version showed marginally significant trends for differentiating AWS (p .048) and AWT (p .052) across SBAS intensity categories at only one assessment period. The English version of the SBAS is effective in assessing PA status among Latinas; however, the Spanish version indicates a need for research to further explore cultural and linguistic adaptations of the SBAS.

Addressing the demand for cultural relevance in intervention design.

This article describes the development of a model to promote physical activity in Hispanic women that embeds a life course perspective and culture to enhance comparative effectiveness in intervention design. When working with diverse cultural groups, researchers often struggle with intervention designs and strategies to enhance cultural relevance; they do so based on the assumption that this will enhance efficacy and make interventions more sustainable. In this article, the authors discuss how the model was used in two interventions designed for younger and older Hispanic women. These interventions were guided by a life course perspective, incorporated social support, and included salient elements from the women's culture. Three considerations underpinned the development of the model: (a) infusing concepts and values of a culture and tradition into the interventions, (b) viewing participants through a life course perspective to assess how an intervention can build on developmental transitions, and (c) determining how social support operates within two groups that, although sharing history and thus some cultural practices, diverge widely in those practices. The authors propose that by incorporating elements of this model into their interventions, researchers can increase program efficacy and effectiveness.

A randomized controlled trial of an office-based physical activity and physical fitness intervention for older adults.

This primary care-based study aimed to evaluate the efficacy and feasibility of a 24-week intervention on physical activity and physical fitness in a group of community-dwelling older adults. Secondary aims were to determine the effect of the intervention on self-efficacy and barriers to physical activity. Intervention participants (n = 36) received an exercise prescription based on physical fitness test results and personal choice. Comparison participants (n = 36) received a nutrition intervention. Both groups received 10 follow-up telephone calls. Repeated measures ANOVA analyses showed no direct effects of the intervention on the primary outcomes of physical activity or physical fitness in the intervention group (p > 0.05). Secondary analyses with ANCOVA that included potential moderating variables of age, gender, income, BMI, and support for physical activity showed that the intervention group significantly increased frequency of all physical activity (F = 3.50, p < 0.05) as well as the fitness outcomes of lower body strength (F = 3.63, p < 0.05) and aerobic endurance (F = 4.03, p < 0.05). This is one of the first studies to evaluate the use of fitness measures to increase physical activity and fitness in the primary care setting. The intervention improved some aspects of physical activity and fitness for selected participants.

Effects of a culturally grounded community-based diabetes prevention program for obese Latino adolescents.

PURPOSE: The purpose of this study was to test the feasibility and preliminary effects of a culturally grounded, community-based diabetes prevention program among obese Latino adolescents. METHODS: Fifteen obese Latino adolescents (body mass index [BMI] percentile = 96.3 ± 1.1, age = 15.0 ± 0.9 years) completed a 12-week intervention that included weekly lifestyle education classes delivered by bilingual/bicultural promotoras and three, 60-minute physical activity sessions per week. Participants were assessed for anthropometrics (height, weight, BMI, and waist circumference), cardiorespiratory fitness, physical activity/inactivity, nutrition behaviors, and insulin sensitivity and glucose tolerance by a 2-hour oral glucose tolerance test. RESULTS: The intervention resulted in significant decreases in BMI z score, BMI percentile, and waist circumference; increases in cardiorespiratory fitness; and decreases in physical inactivity and dietary fat consumption. In addition to these changes, the intervention led to significant improvements in insulin sensitivity and reductions in 2-hour glucose levels. CONCLUSIONS: These results support the feasibility and efficacy of a community-based diabetes prevention program for high-risk Latino youth. Translational approaches that are both culturally grounded and biologically meaningful represent a novel and innovative strategy for closing the obesity-related health disparities gap.

Camina por Salud: walking in Mexican-American women.

Forty-six percent of older Mexican-American women report that they do not engage in leisure time physical activity (PA); 38.1% of them are obese. This study (1) evaluated a PA intervention for coronary heart disease risk reduction and (2) determined which variables affect adherence to PA. For 36 weeks, Group I members walked for 3 days a week and Group II members walked for 5 days a week. We measured the participants' total body fat, regional fat, blood lipids, and adherence to PA The walking interventions favorably affected body fat, with significant differences in body mass index reduction, F(2, 16) = 12.86, p = .001. No statistical difference was noted in the anthropometric and blood lipid results between the baseline and 36-week measures.

Factors related to overweight and risk for overweight status among low-income Hispanic children.

The purpose of this research was to investigate the agent, host, and environmental factors that are related to overweight status in a sample of low-income Hispanic toddlers who were enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children in a large southwestern city in the United States. Among children at risk for overweight status, the mothers' body mass index (BMI) and the number of servings of fat in the children's daily diet were positively associated with their weight/height percentiles whereas servings of protein in the daily diet and the children's reporting of hunger were negatively associated with their weight/height percentiles. Among overweight children, age was positively associated with their weight/height percentiles. No other variable in the ecological model was associated with normal weight or overweight children and their weight/height percentiles. Different approaches to dietary counseling and health promotion may be indicated based on a child's weight/height percentile or BMI.

Retention of minority participants in clinical research studies.

Recruitment of minority participants for clinical research studies has been the topic of several analytical works. Yet retention of participants, most notably minority and underserved populations, is less reported and understood, even though these populations have elevated health risks. This article describes two related, intervention-based formative research projects in which researchers used treatment theory to address issues of recruitment and retention of minority women participants in an exercise program to reduce obesity. Treatment theory incorporates a model of health promotion that allows investigators to identify and control sources of extraneous variables. The authors' research demonstrates that treatment theory can improve retention of minority women participants by considering critical inputs, mediating processes, and substantive participant characteristics in intervention design.

Comparison of two walking frequencies in African American postmenopausal women.

Despite the known benefits of exercise, 60% of African American women are sedentary. The efficacy and dose-response effects of low intensity exercise performed in community settings by overweight sedentary women have not been established. The purpose of this study was to examine the effects of two intensities of walking on level of exercise maintenance and on cardiovascular risk factors in sedentary, obese African American women. A two group, randomized experimental approach was used to test 45-70 year old postmenopausal obese African American women, measuring age, self reported ethnic affiliation, height, weight, socioeconomic status, diet history, menopausal status, exercise volume, dietary restrictions, medication use, and medical conditions precluding participation. Group one walked three days/week; group 2 walked 5 days/week; both groups walked at 65% of their target heart rate reserve.

Evaluation of Selected Behavior Change Theoretical Models Used in Weight Management Interventions.

Purpose: This paper evaluates selected behavior change theoretical models used in weight reduction interventions and presents recommendations for the use of theory in weight reduction research. Overweight and obesity are complex problems, requiring long-term behavioral change. Behavioral treatments for overweight and obesity are as varied as the elements of behavior, and the long-term efficacy of most approaches is poor. Because of the complexity of both the problem and its treatment, investigations must target the development of cause-effect explanations. CONCLUSIONS: Many of the behavioral change intervention studies reviewed lacked external validity, primarily due to the failure to consider salient moderators. The theoretical models reviewed in this paper were primarily tested on white, employed populations. These and other data suggest that extant theoretical approaches may not be salient in certain groups. IMPLICATIONS: Practice implications include: 1) assess indicators for readiness to engage in weight reduction efforts; 2) base interventions on multiple theories; and 3) develop context-based interventions. Future research should include a focus on innovative methods in theory development, development of theory acknowledging mediator/moderator interactions, development of theory in context, and development of theory reflecting cultural meaning and diversity.