The Physical Activity and Obesity Epidemiology Laboratory was established at Pennington Biomedical Research Center in August 2007. We have several completed and on-going collaborations on epidemiological and clinical investigations. The summaries below describe some of our recent research activities.
Obesity is a very common and serious medical and social condition, with Louisiana currently ranked among the states with the highest levels of obesity. Obesity is a condition that increases the risk of type 2 diabetes, heart disease, stroke, gallbladder disease, respiratory problems, quality of life, and several cancers. Obesity and its health problems greatly affect underserved populations, and Louisiana is characterized by high levels of poverty, low health literacy, and food insecurity, all of which may contribute to the high obesity levels in the State. PROPEL is a cluster-randomized, two-arm controlled trial in primary care settings. A total of 18 primary care clinics inclusive of low income populations with a high percentage of African Americans from urban and rural areas across Louisiana will be randomized to either: 1) intervention or 2) usual care. The sample includes 800 obese (BMI 30-45 kg/m2) patients (18 clinics, 60 patients / clinic). The primary aim of this trial is to develop and test the effectiveness of a 24 month, patient-centered, pragmatic and scalable obesity treatment program delivered within primary care in an underserved population. Trained health coaches embedded in the primary care clinic will deliver the active intervention - a comprehensive, “high-intensity" program, as recommended first-line therapy by the 2013 AHA/ACC/TOS Obesity Guidelines, and based on the Look AHEAD intensive lifestyle intervention which was an adaptation of the Diabetes Prevention Program (DPP). Patients in the intervention arm will attend weekly (15 in-person) sessions in the first six months, followed by monthly sessions for the remaining 18 months. Patients assigned to the usual care arm will continue to interact with their primary care practitioner (PCP) according to their usual schedule, and will be invited to attend a series of social meetings on topics of interest, including importance of sleep for health, household money management, family coping skills, smoking cessation, etc. PCPs in the usual care arm will receive a webinar describing the current CMS approach to reimbursing for obesity treatment, and a reminder informational brochure will be sent to the PCPs each year. Patients in both arms will be assessed on primary and secondary outcome measures at baseline, and at 6, 12, 18 and 24 months of intervention. PROPEL is funded by the Patient-Centered Outcomes Research Institute (PCORI).
REACHNet is one of 13 funded Clinical Data Research Networks funded by the Patient Centered Outcomes Research Institute. Pennington Biomedical has partnered with the Louisiana Public Health Institute (LPHI) to participate in the network. LPHI, Pennington Biomedical, Tulane University, Ochsner Health System, and Baylor Scott & White Healthare working together to build an infrastructure for clinical research that may add new partners from across the state and thereby benefit millions of patients in Louisiana. Additionally, the team is advancing the capacity to conduct efficient clinical research on two highly prevalent health conditions, obesity and diabetes, along with multiple associated comorbidities, sickle cell disease, and some rare cancers.
The PCLS draws its data from screening and study-specific information contained in the central PBRC clinic database and the bio-repository. These data have been collected over the last twenty years during the clinical research studies conducted at PBRC. The existing PCLS cross-sectional dataset represents an extract of the central clinic database that has undergone further data management to identify unique individuals and establish a baseline that maximizes the currently available data. The PCLS represents an effort to utilize the data collected on research volunteers to develop a cohort that can be used for cross-sectional analyses and can be followed prospectively for the development of a variety of health-related outcomes.
Anthropometric Assessment of Abdominal Obesity and Health Risk
in Children and Adolescents
Abdominal fat, in particular intra-abdominal visceral adipose tissue, is considered to be the most dyslipidemic and atherogenic fat depot in the human body. Intra-abdominal visceral adipose tissue and total body fat can be measured precisely and reliably in a laboratory setting using advanced imaging techniques; however, reliable clinical measurements of pediatric intra-abdominal visceral adipose tissue and total body fat are yet to be developed. Thus, the specific aims of this study are to 1) identify reliable landmarks and methodology for the measurement of pediatric waist circumference that are associated with intra-abdominal visceral adipose tissue and total body fat across the pediatric age, total body adiposity, and maturity range among African American and Caucasian children and adolescents, 2) determine if waist circumference in combination with other anthropometric indices is a better predictor of intra-abdominal visceral adipose tissue and total body fat than waist circumference alone across the pediatric age, total body adiposity, and maturation range, and 3) develop and determine the clinical utility of pediatric race-sex-specific waist circumference thresholds for the identification of elevated chronic disease risk factors across the pediatric age, total body adiposity, and maturation range. We will accomplish these aims by conducting a cross-sectional study of 100 African American boys, 100 Caucasian boys, 100 African American girls, and 100 Caucasian girls 5 to 18 years of age. Waist circumference will be measured at the four common anatomic sites used in pediatric research: 1) superior border of the iliac crest, 2) midpoint between the iliac crest and the lowest rib, 3) umbilicus, and 4) minimal waist. Additional body dimensions will be obtained in order to determine the clinical utility of combining waist circumference with other measurements in predicting intra-abdominal visceral adipose tissue and total body fat, which will be assessed using advanced imaging techniques. The identification of the most appropriate waist circumference landmarks and measurement techniques is important for the clinical identification of children at elevated obesity-related health risk and for the standardization of obesity surveillance strategies within and between countries. This study was funded by the U.S. National Institutes of Health.
The Challenge for a Healthier Louisiana was funded by the Blue Cross and Blue Shield of Louisiana Foundation, and was an obesity prevention effort that supported communities as they developed partnerships and collaborations to plan and implement activities effecting policies, norms, practices, social supports, and the physical environment, to support healthy eating and active living for children and families across Louisiana. The Challenge for a Healthier Louisiana Program funded 12 projects throughout the state. The Physical Activity and Obesity Epidemiology Laboratory worked in partnership with Blue Cross and Blue Shield of Louisiana Foundation to develop the project, provide project management, capacity building, project specific evaluation and overall multi-site outcome evaluation.
InSight
Dietary intervention and other strategies to prevent unhealthy weight gain and the development of obesity should be based on knowledge of dietary, physiological, genetic, and behavioral determinants and their contributing interactions. Identifying these determinants is difficult because physiological susceptibility to specific dietary and behavioral factors implicated in unhealthy weight gain differs between populations and among individuals within populations. The research challenge is identifying specific determinants in a free-living, U.S. adult population. InSight is a prospective longitudinal study of free-living normal weight adults aged 20-35 at baseline. The primary aim of InSight is to identify the most important determinants of weight gain and the development of overweight and obesity. As a secondary aim, we will identify a single parsimonious collection of factors and develop strategies to mitigate the risks of developing obesity. The participants underwent a series of assessments in the domains of diet, physiology, genetics, and behavior at baseline and return for two yearly visits. Advanced longitudinal and multivariate statistical and epidemiologic techniques will be used to identify and model underlying correlation structures among the measurements collected by the research team pertaining to diet (dietary intake of fat, sugar-sweetened beverages, calcium, and fiber, and portion size) physiological factors (energy expenditure, insulin sensitivity and secretion, detailed body composition, skeletal muscle metabolism, adipocyte factors), genetic factors (sensory perception and candidate genes), behavioral factors (dietary restraint, disinhibition, food neophobia, sedentary behavior, and physical activity), demographics, and other possible contributing factors to unhealthy weight gain over time.
International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE)
Childhood obesity remains a major public health concern, and key questions about lifestyle and childhood obesity remain to be answered. Large multi-country studies of childhood obesity have not been truly global and are rare outside of Europe. Given that each country has limited variability in obesity and potentially modifying factors, an international study is able to maximize variability in these factors. The primary aim of ISCOLE is to determine the relationships between lifestyle behaviours and obesity in a multi-national study of children, and to investigate the influence of higher-order characteristics such as behavioral settings, and the physical, social and policy environments, on the observed relationships within and between countries. The study involved the collection of dietary, physical activity, and obesity data using a rigorous, standardized protocol across all countries. The final sample includes more than 7000 children from 12 countries on every inhabited continent. ISCOLE represents a multi-national collaboration among all world regions, and represents a global effort to increase research understanding, capacity and infrastructure in childhood physical activity and obesity. More than 240 people have worked on ISCOLE to date, including junior and senior scientists, post-doctoral fellows, students and staff. ISCOLE was funded by The Coca-Cola Company.
Delta Obesity Prevention Research Unit
Reducing the high and increasing prevalence of obesity is a federal priority. The current high levels of obesity are taking a staggering toll on public and personal health in the USA. The Pennington Biomedical Research Center is part of a research consortium that includes multiple universities in Louisiana, Mississippi, and Arkansas. The mission of this consortium is to conduct nutrition research to prevent obesity in at-risk, rural populations in the Lower Mississippi Delta of Arkansas, Louisiana, and Mississippi. The Agricultural Research Service (ARS) is coordinating this major research endeavor that brings together the talents of ARS and other research cooperators in the tri-state region with the ultimate goal of promoting optimal health and reducing the burden of obesity in this population. USDA funding for this research initiative at PBRC has been continuous since 1998. The partner institutions include the Pennington Biomedical Research Center, Southern University and A&M College, Baton Rouge, LA; University of Southern Mississippi, Alcorn State University, MS; University of Arkansas Pine Bluff, Arkansas Children’s Hospital Research Institute, AR; Delta NIRI Executive Office, AR. The current USDA funded project at PBRC is TigerKids which is establishing a prospective pediatric cohort to identify intervention targets based on the location, timing, barriers, and facilitators of current physical activity and sedentary behavior in a child’s day. The project will be a prospective examination of 340 African American and White girls and boys aged 10 to 16 years, including 50% who are classified as severely obese. We will use state-of-the-art technology including accelerometry to quantify physical activity, magnetic resonance imaging to quantify fat accumulation, and geographic position system and ecological momentary assessment to identify environmental and socio-emotional barriers and facilitators.
