Research

Hormonal

In postmenopausal women, higher baseline BMI (specifically ≥35.0) is associated with a significantly increased risk of invasive breast cancer, particularly estrogen receptor-positive subtypes, and is linked to more advanced disease characteristics and higher mortality.

For postmenopausal women, maintaining a healthy weight (BMI < 25) is critical for reducing invasive breast cancer risk, especially estrogen receptor-positive types. While weight loss after becoming obese may not reverse the elevated risk established by high BMI, preventing obesity in the first place is the most effective strategy. Regular screening is essential, as obesity is also linked to more advanced disease stages.

StrongSupportsVERY_HIGH confidence
Women who were overweight; obese, grade 1; and obese, grade 2 plus 3 had an increased invasive breast cancer risk relative to women of normal weight... The HRs increased as BMI increased and displayed a dose-response effect with the greatest risk for women with grade 2 plus 3 obesity (HR, 1.58; 95% CI, 1.40-1.79; P < .001 for trend).
Marian L. Neuhouser et al. · JAMA Oncology · 2015

Why this rating

Large-scale randomized clinical trial (WHI) with 67,142 participants and 13 years of follow-up.

Source

Overweight, Obesity, and Postmenopausal Invasive Breast Cancer Risk

Marian L. Neuhouser et al. · JAMA Oncology · 2015

DOI 10.1001/jamaoncol.2015.1546

rct · n=67142Cited 629×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →