Research

Hormonal

In postmenopausal women with a normal body mass index (BMI 18.5–24.9), higher levels of body fat (specifically whole-body and trunk fat) are associated with a significantly elevated risk of invasive breast cancer, particularly estrogen receptor-positive (ER+) subtypes.

If you are a postmenopausal woman with a normal BMI, your body fat percentage still matters for breast cancer risk. High body fat, especially around the trunk, is linked to a significantly higher risk of ER-positive breast cancer, even if your weight is healthy. Focus on maintaining healthy body fat levels through diet and exercise, rather than just focusing on BMI.

GoodQualifiesHIGH confidence
In postmenopausal women with normal BMI, relatively high body fat levels were associated with an elevated risk of invasive breast cancer and altered levels of circulating metabolic and inflammatory factors. Normal BMI categorization may be an inadequate proxy for the risk of breast cancer in postmenopausal women.
Neil M. Iyengar et al. · JAMA Oncology · 2018

Why this rating

Large prospective cohort (WHI), long follow-up (median 16 years), precise body fat measurement (DXA), and multivariable adjustment, though observational in nature.

Source

Association of Body Fat and Risk of Breast Cancer in Postmenopausal Women With Normal Body Mass Index

Neil M. Iyengar et al. · JAMA Oncology · 2018

DOI 10.1001/jamaoncol.2018.5327

cohort · n=3460Cited 225×
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DOI resolved against Crossref · corpus check 2026-06-10

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