What is the relationship between obesity and breast cancer risk?

The relationship between obesity and breast cancer risk is significant, particularly in postmenopausal women. Obesity increases estrogen levels, which can promote the growth of certain types of breast cancer. After menopause, the ovaries produce less estrogen, and the fat tissue becomes a major source of estrogen production. Thus, women who are obese may experience higher levels of circulating estrogen, which has been linked to an increased incidence of breast cancer.

Moreover, obesity is associated with a more complex interplay of factors, including insulin resistance and inflammation, both of which may contribute to tumor development and progression. Research indicates that postmenopausal women who are overweight or obese have a higher risk of developing breast cancer than their normal-weight counterparts.

In contrast, options suggesting that obesity decreases the risk or has no effect do not align with established research findings regarding hormonal influences and cancer risk. The idea that only underweight women are at risk oversimplifies the issue and ignores the considerable body of evidence linking higher body mass index (BMI) to increased risks of breast cancer, underscoring the importance of maintaining a healthy weight for cancer prevention.