Based on findings of a recent study researchers say weight gain after age 18 can be a significant predictor of breast cancer risk for postmenopausal women who are not taking hormone replacement therapy.
In 1992, researchers sampled nearly 62,000 women, ages 50 to 74, by asking them about their weight at age 18 and their current weight. Since then, the women have been periodically asked to provide updates on their weight, in addition to any diagnosis of cancer. Research shows women who gained 20 to 30 pounds since age 18 were 40-percent more likely to develop breast cancer than those who had not gained more than five pounds. Women who gained more than 70 pounds doubled their risk.
This supports the theory that more body fat yields higher estrogenic levels, increasing the risk of breast cancer in women. Women with less body fat are reported to have lower estrogenic levels and lower risks of breast cancer. Thus researcehrs suggest , avoiding weight gain as one of the few ways to reduce the risk of breast cancer among postmenopausal women.