Why might a higher BMI at 20 be linked to lower breast cancer risk later in life?
 

A large UK cohort study found that higher BMI at age 20 was associated with lower postmenopausal breast cancer risk, while higher BMI in later adulthood was linked to increased risk. Lower VAS percentage mammographic density appeared to explain part of the early-adulthood association, while fibroglandular volume showed a different relationship with life-course adiposity.

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