White KK et al. – The findings emphasize the significance of maintaining a healthy weight throughout adulthood for the prevention of postmenopausal breast cancer.

• Of the 82,971 White, African American, Native Hawaiian, Japanese and Latina women included in this analysis, 3,030 were diagnosed with invasive breast cancer.
• Body mass index (BMI), height, weight and adulthood weight gain were associated with a significantly higher risk and, with the exception of height, were found to vary across ethnic groups.

• Native Hawaiians and Japanese with a BMI ≥30.0 compared to 20.0–24.9kg/m² had the highest risk (hazard ratio=1.82, 95% confidence interval: 1.31, 2.54, p-trend=0.001, and hazard ratio=1.59, 95% confidence interval: 1.24, 2.05, p-trend<0.0001, respectively).
• Current hormone replacement therapy use modified the impact of a high BMI, as non- and former users had a significantly higher risk compared to current users.
• BMI also had a more pronounced risk for advanced tumors compared to localized tumors.
• When both BMI and adult weight gain were analyzed simultaneously, adult weight gain, rather than BMI, was a significant risk factor overall.