Recreational physical activity may be associated with breast tissue composition and oxidative stress levels in adolescent girls, independent of body fat percentages, according to research findings published in Breast Cancer Research.
“The importance and urgency of this research are underscored by the rising incidence of breast cancer in young women and the alarmingly low levels of recreational physical activity observed both in this study and among adolescents across the United States and globally,” said first study author Rebecca D. Kehm, PhD, Assistant Professor of Epidemiology at Columbia Mailman School of Public Health. “Our findings suggest that recreational physical activity is associated with breast tissue composition and stress biomarker changes in adolescent girls, independent of body fat, which could have important implications for breast cancer risk.”
Study Methods
Researchers explored associations between recreational physical activity and breast tissue composition, oxidative stress, and inflammation in adolescent girls to determine how recreational physical activity impacts breast cancer risks during adolescence. They gathered data from a population-based urban cohort of 191 Black/African-American and Hispanic girls between the ages of 11 and 20 years. All of the girls reported the total amount of hours of recreational physical activity that they had participated in for the past week.
“Our study population of urban Hispanic (Dominican) and non-Hispanic Black/African-American adolescent girls is critical to include in breast cancer research,” added Dr. Kehm, who is also affiliated with the Herbert Irving Comprehensive Cancer Center. “These groups not only have been historically underrepresented in studies, but they [also] face higher risks of developing breast cancer at younger ages and of experiencing more aggressive subtypes. At the same time, Black and Hispanic girls consistently report lower levels of recreational physical activity than their non-Hispanic White peers.”
Optical spectroscopy was used to measure breast tissue composition by determining the percent of water, collagen, and lipid content in the breast tissue. Researchers also looked at urinary concentrations of 15-F2t-isoprostane to measure oxidative stress and at markers of TNF-alpha, IL-6, and high-sensitivity C-reactive protein in the blood.
Key Findings
According to self-reporting, 51% of the girls had not engaged in any type of recreational physical activity in the past week, 73% had not participated in any organized physical activities, and 66% had not participated in any unorganized physical activities.
Lower water content rates were found in the breast tissue of girls who had participated in at least 2 hours of organized recreational physical activities in the past week compared with those who had not participated in any activities (β = –0.41; 95% confidence interval [CI] = –0.77 to –0.05), and this was not found to be impacted by body fat percentages. The girls with increased hours of participation in organized recreational physical activities in the past week also showed lower urinary concentrations of 15-F2t-isoprostane (β = –0.50; 95% CI = –0.95 to –0.05).
Higher markers of oxidative stress were associated with a higher collagen content percentage in the breast (β = 0.15; 95% CI = 0.00–0.31).
Recreational physical activity was not found to be associated with markers for inflammation, and when adjusting for percent body fat, inflammation markers were not associated with breast tissue composition either.
The study authors noted that additional longitudinal research is needed to further understand implications of these findings on breast cancer risk for adolescent girls.
DISCLOSURE: The study was supported by the National Institute of Environmental Health Sciences and the National Cancer Institute. The study authors reported no conflicts of interest.
