Research
Hormonal
The association between weight gain and breast cancer risk is stronger in women who have never used postmenopausal hormones (PMH) compared to those who have ever used PMH.
For postmenopausal women who have never used hormone therapy, weight gain poses a significantly higher breast cancer risk than for those who have used it. This is because exogenous hormones mask the hormonal effects of body fat.
StrongQualifiesHIGH confidence
The association varied by PMH use; for women who had a 25.0-kg or more weight gain and who had ever used PMH, the multivariate-adjusted RR was 1.20 (95% CI, 1.01-1.43) vs 1.98 (95% CI, 1.55-2.53) among those who never used it (P <.001 for interaction).
Why this rating
Large prospective cohort study with long follow-up and rigorous adjustment for confounders.
Source
Adult Weight Change and Risk of Postmenopausal Breast Cancer
A. Heather Eliassen et al. · JAMA · 2006
DOI 10.1001/jama.296.2.193
cohort · n=87143Cited 650×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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- Postmenopausal weight loss of 10 kg or more, particularly when maintained, significantly decreases the risk of breast cancer in women who have never used postmenopausal hormones.Strong
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