Preventing diabetes in Latino families: A protocol for a randomized control trial.

BACKGROUND: Latino families are disproportionately affected by type 2 diabetes (T2D) and lifestyle intervention is the first-line approach for preventing T2D. The purpose of this study is to test the efficacy of a culturally-grounded lifestyle intervention that prioritizes health promotion and diabetes prevention for Latino families. The intervention is guided by a novel Family Diabetes Prevention Model, leveraging the family processes of engagement, empowerment, resilience, and cohesion to orient the family system towards health. METHOD: Latino families (N = 132) will be recruited and assessed for glucose tolerance as measured by an Oral Glucose Tolerance Test (OGTT) and General and Weight-Specific Quality of Life (QoL) at baseline, four months, and 12 months. All members of the household age 10 and over will be invited to participate. Families will be randomized to the intervention group or a control group (2:1). The 16-week intervention includes weekly nutrition and wellness classes delivered by bilingual, bicultural Registered Dietitians and community health educators at a local YMCA along with two days/week of supervised physical activity classes and a third day of unsupervised physical activity. Control families will meet with a physician and a Registered Dietitian to discuss the results of their metabolic testing and recommend lifestyle changes. We will test the efficacy of a family-focused diabetes prevention intervention for improving glucose tolerance and increasing QoL and test for mediators and moderators of long-term changes. CONCLUSION: This study will provide much needed data on the efficacy of a family-focused Diabetes Prevention Program among high-risk Latino families.

Changes in OGTT-derived biomarkers in response to lifestyle intervention among Latino adolescents with obesity.

BACKGROUND: Glucose concentrations during an oral glucose tolerance test (OGTT) have been used as biomarkers to differentiate type 2 diabetes risk phenotypes. No studies have examined changes in OGTT-glucose phenotypes following lifestyle intervention among high-risk youth. OBJECTIVE: To examine changes in OGTT-glucose phenotypes following lifestyle intervention and to explore differences in insulin sensitivity and ß-cell function among post-intervention phenotypes. METHODS: Latino adolescents with obesity (n = 48, age 15.4 ± 1.0, BMI% 98.2 ± 1.4, female 56.3%) completed a 12-week lifestyle intervention that included weekly nutrition education and physical activity. At baseline and 12 weeks, youth completed a 2-h OGTT with glucose and insulin concentrations assessed at 0', 30', 60', 90' and 120'. Glucose concentrations during the OGTT were used to identify biomarkers, 1-h glucose, glucose response curve and time to glucose peak. Using these respective biomarkers, high-risk (1-h glucose ≥ 155 mg/dl, Monophasic, Late Peak) and lower-risk phenotypes (1-h glucose < 155 mg/dl, Biphasic, Early Peak) were categorized. Insulin sensitivity was estimated by whole-body insulin sensitivity index (WBISI) and ß-cell function by oral disposition index (oDI). RESULTS: Following intervention, the prevalence of Monophasic phenotypes decreased from 81% to 67% (p = 0.048) and 1-h glucose ≥ 155 mg/dl from 38% to 10% (p = 0.054). Although Late Peak phenotypes did not significantly change (from 58% to 29%, p = 0.200), Early Peak phenotypes at post-intervention demonstrated significantly higher WBISI compared to Late Peak (2.3 ± 0.1 vs 1.7 ± 0.2, p = 0.023). CONCLUSIONS: OGTT-glucose phenotypes improve following lifestyle intervention among high-risk youth. These findings further support their potential utility as clinical biomarkers to identify diabetes risk and risk reduction in youth.

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.

Response heterogeneity to lifestyle intervention among Latino adolescents.

OBJECTIVE: To characterize the heterogeneity in response to lifestyle intervention among Latino adolescents with obesity. METHODS: We conducted secondary data analysis of 90 Latino adolescents (age 15.4 ± 0.9 y, female 56.7%) with obesity (BMI% 98.1 ± 1.5%) that were enrolled in a 3 month lifestyle intervention and were followed for a year. Covariance pattern mixture models identified response phenotypes defined by changes in insulin sensitivity as measured using a 2 hour oral glucose tolerance test. Baseline characteristics were compared across response phenotypes using one-way ANOVA and chi-square test. RESULTS: Three distinct response phenotypes (PH1, PH2, PH3) were identified. PH1 exhibited the most robust response defined by the greatest increase in insulin sensitivity over time (ß ± SE, linear 0.52 ± 0.17, P < .001; quadratic -0.03 ± 0.01, P = .001). PH2 showed non-significant changes, while PH3 demonstrated modest short-term increases in insulin sensitivity which were not sustained over time (linear 0.08 ± 0.03, P = .002; quadratic -0.01 ± 0.002, P = .003). At baseline, PH3 (1.1 ± 0.4) was the most insulin resistant phenotype and exhibited the highest BMI% (98.5 ± 1.1%), 2 hours glucose concentrations (144.0 ± 27.5 mg/dL), and lowest beta-cell function as estimated by the oral disposition index (4.5 ± 2.8). CONCLUSION: Response to lifestyle intervention varies among Latino youth with obesity and suggests that precision approaches are warranted to meet the prevention needs of high risk 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 lifestyle intervention on markers of cardiometabolic risk and oxidized lipoproteins among obese adolescents with prediabetes.

OBJECTIVE: Obesity and hyperglycaemia contribute to the atherosclerotic process in part through oxidative modifications to lipoprotein particles. The present study aimed to evaluate the effects of a lifestyle intervention on markers of oxidized lipoproteins in obese Latino adolescents with prediabetes. DESIGN: Pre-post design. SETTING: Participants were enrolled into a 12-week lifestyle intervention. Measurements pre- and post-intervention included anthropometrics and body composition, lipid panel, oxidized LDL (oxLDL), oxidized HDL (oxHDL), intake of fresh fruits and vegetables, and cardiorespiratory fitness. PARTICIPANTS: Thirty-five obese Latino adolescents (seventeen females, eighteen males; mean age 15·5 (sd 1·0) years; mean BMI percentile 98·5 (sd 1·2)) with prediabetes. RESULTS: Intervention participation resulted in significant reductions in weight (-1·2 %, P = 0·042), BMI and BMI percentile (-2·0 and -0·4 %, respectively, P < 0·001), body fat (-7·0 %, P = 0·025), TAG (-11·8 %, P = 0·032), total cholesterol (-5·0 %, P = 0·002), VLDL-cholesterol (-12·5 %, P = 0·029), and non-HDL-cholesterol (-6·7 %, P = 0·007). Additionally, fitness (6·4 %, P < 0·001) and intake of fruits and vegetables (42·4 %, P = 0·025) increased significantly. OxLDL decreased significantly after the intervention (51·0 (sd 14·0) v. 48·7 (sd 12·8) U/l, P = 0·022), while oxHDL trended towards a significant increase (395·2 (sd 94·6) v. 416·1 (sd 98·4) ng/ml, P = 0·056). CONCLUSIONS: These data support the utility of lifestyle intervention to improve the atherogenic phenotype of Latino adolescents who are at high risk for developing premature CVD and type 2 diabetes.

¡Viva Maryvale!: A Multilevel, Multisector Model to Community-Based Diabetes Prevention.

INTRODUCTION: Latino communities are disproportionately affected by type 2 diabetes and experience disparities in access to diabetes prevention programs. The purpose of this study was to test the preliminary efficacy of a culturally grounded, diabetes prevention program for high-risk Latino families delivered through an integrated research-practice partnership. STUDY DESIGN: The integrated research-practice partnership was established in a predominantly Latino community and consisted of a Federally Qualified Health Center, a YMCA, an accredited diabetes education program, and an academic research center. Data were collected and analyzed from 2015 to 2018. SETTING/PARTICIPANTS: Latino families consisting of a parent with an obese child between age 8 and 12 years. INTERVENTION: The 12-week lifestyle intervention included nutrition education and behavioral skills training (60 minutes, once/week) and physical activity classes (60 minutes, three times/week) delivered at a YMCA. MAIN OUTCOME MEASURES: Outcomes included measures of adiposity (BMI, waist circumference, and body fat); HbA1c; and weight-specific quality of life. RESULTS: Over the course of the 2-year project period, 58 families (parents n=59, children n=68) were enrolled with 36% of parents and 29% of children meeting the criteria for prediabetes at baseline. Feasibility and acceptability were high, with 83% of enrolled families completing the program, 91% of the intervention sessions attended, and 100% of families stating they would recommend the program. The intervention led to significant decreases in percentage body fat among parents (46.4% [SD=10.8] to 43.5% [SD=10.5], p=0.001) as well as children (43.1% [SD=8.0] to 41.8% [SD=7.2], p=0.03). Additionally, HbA1c was significantly reduced in parents (5.6% [SD=0.4] to 5.5% [SD=0.3], p=0.03), and remained stable in children (5.5% [SD=0.3] vs 5.5% [SD=0.3], p>0.05). Significant improvements in quality of life were reported in parents (64.6 [SD=15.8] to 71.0 [SD=13.7], p=0.001) and children (69.7 [SD=15.8] to 72.6 [SD=13.7], p=0.05). CONCLUSIONS: These findings support the preliminary efficacy of an integrated research-practice partnership to meet the diabetes prevention needs of high-risk Latino families within a vulnerable community.

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.