Abstract 65: Exercise Mitigates Chronic Stress Effects on BMI Trajectories in Girls Aged 10 to 19: Longitudinal Findings from the NHLBI Growth and Health Study.
Introduction: Obesity is a leading cause of cardiovascular disease. Adolescence is a period when behavior changes consolidate, setting a trajectory towards obesity. Both poor health behaviors and psychological stress promote obesity. Studies have shown that ongoing stress is related to weight gain while maintaining physical activity mitigates obesity in children as they transition to adulthood. We hypothesized that during childhood, physical activity maintenance would moderate the relationship between chronic stress and BMI increase.
Methods: The NHLBI Growth and Health Study enrolled 2,379 Black and White girls aged 9-10 and assessed them annually over ten years. Perceived Stress was measured in years 2, 4, 6, 8, and 10 with the well-validated Perceived Stress Scale, simplified for use in children. The Physical Activity Patterns Questionnaire assessed duration and frequency of activities in and out of school at years 1, 3, 5, and 7-10. Body mass index (BMI; kg/m2) was available all years. Covariates included pubertal timing, race, parental income and education, and nutrient intake. Repeated measurement allows prediction of trajectories of BMI with growth curve modeling, i.e. rate of BMI change over time.
Results: On average, baseline BMI was 20.79 and increased 0.63 BMI units/year. Yet, BMI increase varied significantly as a function of stress and physical activity (p = .005). Even when reporting high stress, girls who maintained activity had lower BMI growth than girls who were fairly inactive between ages 10 and 19. An average of two units less in BMI was seen at age 19 in those highly stressed yet active versus highly stressed and less active - a likely clinically significant difference, as the girls in the latter category neared 30 kg/m2 (see Figure). The slowest increase in BMI between ages 10 and 19 was evidenced in girls more active and lower in stress.
Conclusion: This study adds to a converging literature showing that physical activity is a modifiable behavior that can limit the harmful health effects of ongoing stress.
Author Disclosures: E. Puterman: None. A.A. Prather: None. E.E. Epel: None. S. Loharuka: None. N.E. Adler: None. B. Laraia: None. A. Tomiyama: None.
- © 2014 by American Heart Association, Inc.