Location: Children's Nutrition Research Center
2024 Annual Report
Objectives
(1) Examine the acute effects of sedentary behaviors on energy metabolism and cardiometabolic health in Latino adolescents, after adjusting diet.
(2. NEW) Removed to due investigator departure.
Approach
Researchers will utilize whole-room calorimetry to examine the effects of an acute bout of sedentary behaviors on cardiometabolic outcomes (glucose, insulin, lipids, arterial stiffness) and energy metabolism (energy expenditure, substrate utilization) in Latino adolescents (12-16 years old) with obesity (BMI% '95th) as compared to non-Latino white adolecents (12-16 years old) with obesity (BMI% '95th). Findings from this study will increase our understanding of the contributions of sedentary behaviors to the development of cardiometabolic diseases in high-risk youth. This information will inform future behavioral interventions aimed at reducing sedentariness to reduce disease risk and address health disparities in Latino youth.
Progress Report
Progress towards Objective 1 was made as we completed recruitment and data collection efforts. To improve our recruitment efforts this year, we collaborated with our community partner Baker Ripley, a community-based organization in predominantly Hispanic communities across Houston. We also continued to use the Children’s Nutrition Research Center (CNRC) Volunteer Database and made multiple efforts to contact and screen over 170 potential participants. These efforts yielded a sample size of 12 (n=4 males, n=8 females participants who completed the research protocol at the CNRC’s metabolic research unit. The mean age was 15.9 (SD=18.6) years and all youth were present with obesity (Mean BMI=38, SD=7). Youth included in the study were also late to post puberty according to a self-reported pubertal development scale. To answer the research question posed in Objective 1, youth completed a protocol for which they engaged in sedentary behaviors for 4 hours inside a whole-room calorimeter. Blood draws were taken every hour during the protocol to assess the impact of sedentary pursuits on cardiometabolic disease risk. Additionally, the calorimeter allowed for a rigorous assessment of energy expenditure. To investigate subobjectives to determine if there are differences in ‘active’ verses ‘passive’ sedentary activities, youth engaged in a mental activity (coloring books, word puzzles, books) for two hours and a passive activity, movie watching, for two hours during the four-hour protocol. To further progress towards Objective 1, all analysis of data collected has been completed. Blood samples collected have been processed at the Genomics core at the CNRC and a preliminary review has been conducted to check for abnormal values. To continue progress towards Objective 1, we compiled a database containing all blood markers, energetics, survey, DXA, and anthropometrics data. To fulfill Objective 1, this year we cleaned this data and began collaborating with CNRC statisticians to begin the statistical analyses to fulfill this objective. Our preliminary findings demonstrate that youth who started in the ‘active’ sedentary activities condition before crossing over to the ‘passive’ sedentary activities have slightly higher energy expenditure throughout the 4-hour period than those who started in the ‘passive’ sedentary activities (p = 0.0635, estimate (beta coefficient) = 0.1538). While we saw a more precipitous decrease in insulin in the ‘active’ sedentary condition compared to the ‘passive’ sedentary condition; however, this difference was not significant. None of the other risk factors including lipids and inflammatory markers were significantly different by condition. The four-hour protocol may not have been a long enough period of time to observe any effects on these factors. We will continue to work with our lead statistician to finalize our findings and complete all analyses in preparation for dissemination.
Accomplishments
1. Potential different metabolic consequences of active and passive sedentary behaviors. Excessive time spent in a sedentary behavior contributes to increased risk for obesity and cardiometabolic diseases; however, the underlying physiologic pathways by which sedentary pursuits contribute to metabolic disease in youth are unknown. Researchers at the Children's Nutrition Research Center in Houston, Texas conducted a study that demonstrate that an acute, four-hour bout of sedentary time, did not significantly impact energy metabolism or metabolic markers. We observed an increase in energy expenditure in youth when engaged in active sedentary behaviors (reading or doing a crossword puzzle) compared to youth engaged in passive sedentary behaviors (watching a movie), suggesting that more research is needed to understand the underlying pathways by which sedentary pursuits contribute to disease and if there are sedentary behaviors that are more harmful to metabolic health compared to others. This study advances the science by encouraging researchers to think more deeply about sedentary behaviors and to consider sedentary pursuits as more dynamic behaviors requiring more robust assessment methods.