New Delhi | A new study has linked recreational physical activity in teenage girls with a lower water content in breasts, indicating a lower breast density, and lower levels of stress-related biomarkers.
Findings published in the journal Breast Cancer Research shed light on how physical activity during adolescence -- a critical period for breast development -- can impact biological pathways related to breast cancer risk in the future, researchers said.
"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," first author Rebecca Kehm, assistant professor of epidemiology at the University of Columbia's School of Public Health, said.
"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," Kehm said.
Studies have shown higher levels of recreational physical activity -- being physically active during leisure time such as through sports, gym or dance -- are consistently linked with a lower risk of breast cancer among adult women.
However, the biological processes behind the link have remained poorly understood, the researchers said.
They added that the study is among the first to provide evidence linking recreational physical activity to breast tissue composition and stress-related biomarkers in teenage girls.
About 200 adolescent girls were surveyed for the number of hours they engaged in recreational physical activity during the week prior to the survey. Blood and urine samples were collected from the participants, who also underwent breast tissue assessments.
Fifty one per cent of the participants reported not having engaged in physical activity in the week prior.
"Girls who engaged in (more than) two hours of organised RPA (recreational physical activity) in the past week, compared to none, had lower per cent water content in the breast, and this association was not modified by percent body fat; they also had lower urinary concentrations of 15-F2t-isoprostane (biomarker for oxidative stress)," the authors wrote.
They noted that more long-term studies are required to understand how biomarkers during teenage may translate into breast cancer risk later in life.
The team added that the findings underscore the potential importance of promoting physical activity early in development.
