Research

Hormonal

In postmenopausal women, the increased risk of breast cancer associated with higher body mass index (BMI) is largely mediated by elevated serum concentrations of bioavailable estrogens, particularly free estradiol.

For postmenopausal women, maintaining a healthy weight is critical not just for general health, but specifically to keep estrogen levels lower, as higher body fat leads to higher bioavailable estrogen, which significantly increases breast cancer risk. Weight management strategies should focus on reducing adipose tissue to lower endogenous estrogen production.

GoodQualifiesHIGH confidence
The results are compatible with the hypothesis that the increase in breast cancer risk with increasing BMI among postmenopausal women is largely the result of the associated increase in estrogens, particularly bioavailable estradiol.
Endogenous Hormones Breast Cancer Collaborative Group · JNCI Journal of the National Cancer Institute · 2003

Why this rating

Large pooled analysis of 8 prospective studies with prospective blood collection, though limited by self-reported BMI in some cohorts and lack of hormone data for all subjects.

Source

Body Mass Index, Serum Sex Hormones, and Breast Cancer Risk in Postmenopausal Women

Endogenous Hormones Breast Cancer Collaborative Group · JNCI Journal of the National Cancer Institute · 2003

DOI 10.1093/jnci/djg022

cohort · n=2293Cited 1,091×
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DOI resolved against Crossref · corpus check 2026-06-10

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