Researchers at Columbia University have found that girls who engage in recreational physical activity may have lower breast density and reduced stress markers, both of which are associated with a lower risk of breast cancer later in life. The study, involving nearly 200 Black and Hispanic adolescent girls in New York, measured breast tissue composition and biomarkers of stress and inflammation.
The findings, published after assessments of girls recruited between 1998 and 2006, showed that those who reported at least two hours of recreational physical activity in the previous week had indicators of lower breast density and reduced concentrations of stress markers in their urine. The average age of participants was 16, and more than half identified as Hispanic.
“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,” said Dr Rebecca Kehm, assistant professor of epidemiology at Columbia Mailman School of Public Health.
More than half of the girls reported no recreational physical activity in the past week, and nearly three-quarters said they had not participated in any organised activities. The researchers noted that breast density, which forms during adolescence and is driven by hormones, is a key indicator of breast cancer risk. Dense breast tissue contains more fibrous and glandular tissue and less fatty tissue, making it harder to detect cancer on mammograms.
The study comes as breast cancer rates rise among women under 50 in the United States, with a notable spike between 2016 and 2019. Black and Hispanic women are disproportionately affected at younger ages. “At the same time, Black and Hispanic girls consistently report lower levels of recreational physical activity than their non-Hispanic white peers,” Dr Kehm added.
