Novel measures of inflammation and insulin resistance are related to obesity and fitness in a diverse sample of 11-14 year olds: The HEALTHY Study.

BACKGROUND: GlycA is a novel serum marker of systemic inflammation. There is no information on GlycA in pediatric populations, how it differs by gender or its association with body mass index (BMI) or fitness. Lipoprotein insulin resistance index (LP-IR) is a serum measure of insulin resistance, which is related to changes in BMI group in adolescents, but its relationship with fitness is unknown. The current study examined the independent associations between fitness and BMI with GlycA and LP-IR among US adolescents. METHODS: Participants were 1664 US adolescents from the HEALTHY study with complete 6th and 8th grade BMI, fitness and blood data. GlycA and LP-IR were measured by nuclear magnetic resonance spectroscopy. Three BMI groups and three fitness groups were created. Linear mixed models examined associations between GlycA, LP-IR, fitness and BMI. RESULTS: LP-IR decreased between 6th and 8th grade. GlycA increased among girls but decreased among boys. At 8th grade, median GlycA values were 27 (7.6%) µmol l(-1) higher (381 versus 354) for girls than boys. Median GlycA 6th grade values were 9% higher in obese girls than healthy weight girls. Overall, there was strong evidence (P<0.001) that GlycA was higher in higher BMI groups. Fitness was negatively associated with GlycA (r=-0.37 and -0.35) and LP-IR (r=-0.34 and -0.18) at the 6th and 8th grade assessments. As BMI category increased and fitness category decreased, GlycA and LP-IR levels increased. Lowest GlycA was found in the low BMI/high fitness group. CONCLUSIONS: GlycA was associated with BMI and fitness among in US adolescents. These findings suggest that there are independent effects for BMI and fitness group with both GlycA and LP-IR. Future studies should validate the role of GlycA and LP-IR to evaluate the effects of interventions to modify obesity and fitness to improve systemic inflammation and insulin resistance.

Recruitment and retention strategies and methods in the HEALTHY study.

HEALTHY was a 3-year middle school-based primary prevention trial to reduce modifiable risk factors for type 2 diabetes in youth. The study was conducted at seven centers across the country. This paper describes the recruitment and retention activities employed in the study. Schools and students were the focus of recruitment and retention. Each center was responsible for the recruitment of six schools; eligibility was based on ability to enroll a sufficient number of predominately minority and lower socioeconomic status students. Study staff met with district superintendents and school principals to verify the eligibility of schools, and to ascertain how appropriate the school would be for conducting the trial. Sixth grade students were recruited employing a variety of techniques; students and their parents did not know whether their school was randomized to the intervention or control arm. This cohort was followed through sixth, seventh and eighth grades. In the eighth grade, an additional sample of students who were not originally enrolled in the study was recruited in a similar manner to participate in data collection to allow for cross-sectional and dose-response secondary analyses. Parents signed informed consent forms and children signed informed assent forms, as per the needs of the local Institutional Review Board. Parents received a letter describing the results of the health screening for their children after data collection in sixth and eighth grades. Retention of schools and students was critical for the success of the study and was encouraged through the use of financial incentives and other strategies. To a large extent, student withdrawal due to out-migration (transfer and geographical relocation) was beyond the ability of the study to control. A multi-level approach that proactively addressed school and parent concerns was crucial for the success of recruitment and retention in the HEALTHY study.

Social marketing-based communications to integrate and support the HEALTHY study intervention.

The HEALTHY study was a randomized, controlled, multicenter, middle school-based, multifaceted intervention designed to reduce risk factors for the development of type 2 diabetes. The study randomized 42 middle schools to intervention or control, and followed students from the sixth to the eighth grades. Participants were a racially, ethnically and geographically diverse cohort from across the United States. Here, we describe the conceptual underpinnings and design of the social marketing-based communications component of the HEALTHY study intervention that combined changes in the school nutrition and physical education (PE) environment with behavior change initiatives. The communications intervention component coordinated multiple elements to deliver campaigns that served to integrate and support all aspects of the HEALTHY intervention. The campaigns unfolded across five semesters of middle school, each targeting a specific theme related to the HEALTHY objectives. Communications campaigns comprised (1) core elements such as branding, posters, banners and visual and verbal messaging, (2) student events supporting the nutrition, PE and behavior intervention components through the application of social marketing and communications strategies, including the incorporation of student-generated media and (3) distribution of premiums and theme enhancers to extend the visibility of the study beyond the intervention environment. Formative research conducted with students, parents and school administrators was used to refine the communications strategy. Student peer communicators selected from the student body were involved to influence the normative student environment. Marketing and creative design experts developed a brand, logo, activities and materials. In the latter half of the study, student-generated messages and media were used to reflect local interests and culture and enhance peer influence. The HEALTHY intervention delivery and impact were strengthened by the communications strategies. The HEALTHY experience provides practical considerations for systematically incorporating a social marketing-based communications approach within future school-based health behavior interventions.