Childhood Adiposity and Risk for Breast Cancer

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Investigators have uncovered that a higher adiposity in childhood may lead to less dense tissue formation and decrease the risk of breast cancer, according to a recent study published by Vabistsevits et al in Nature Communications.


As a result of the rising incidence of breast cancer, there is an urgent need to identify new modifiable risk factors.

Higher breast density—measured using a mammogram—is an established risk factor for breast cancer and is known to be influenced by body size. When a mammogram shows dense breast tissue, there is a higher proportion of glandular or fibrous tissue compared with fatty tissue. Conversely, when breast tissue is less dense, there is more fatty tissue relative to glandular or fibrous tissue.

Previous studies have demonstrated that childhood adiposity may lead to various diseases in adulthood. However, observational epidemiologic studies and those using genetic data have recently shown that higher body size in childhood may decrease the risk of breast cancer.

Study Methods and Results

In the recent study, the investigators used data from genome-wide association studies and Mendelian randomization analyses to explore the connections between body size in pediatric and adult patients, higher childhood adiposity, timing of the onset of puberty, breast tissue density, and the risk of breast cancer.

The investigators discovered that more than 50% of the protective effect higher childhood body size may have on breast cancer risk could be explained by changes in dense breast tissue. They hypothesized that a higher body size in childhood, especially near the onset of puberty, may lead to less formation of dense breast tissue in which breast cancer typically develops—thereby decreasing the risk of breast cancer in adulthood.


Despite these findings, the investigators emphasized that the biological pathway may be more complex, and determining smaller steps in this process using genetic data could help uncover the basis of this unexplained causal relationship. Further research may be needed to understand the mechanism behind the overall protective effects of childhood adiposity and identify new targets to mitigate the risk of breast cancer.

“Studying the mechanism of childhood adiposity protective effects is important, as weight gain in childhood cannot be considered to be a preventative measure for breast cancer,” underscored lead study author Marina Vabistsevits, PhD, MSc, BSc, of the MRC Integrative Unit and the Bristol Medical School: Population Health Sciences at the University of Bristol. “Investigating how this overall ‘protection’ works is crucial to understand the underlying mechanisms leading to and preventing cancer, as it might help identify new targets for intervention and prevention,” she concluded.

Disclosure: The research in this study was supported by a Cancer Research UK program grant. For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.