Weight Gain Predicts Breast Cancer Risk, Study Finds

Gaining weight may be a serious risk factor for breast cancer, the American Cancer Society said on Wednesday.

A cancer society study found that women who gained 21 to 30 pounds after the age of 18 were forty percent more likely to get breast cancer than women who gained five pounds or less. Women who gained more than 70 pounds had twice the risk of cancer of women who stayed within five pounds of what they weighed at 18. “These findings further illustrate the importance of maintaining a healthy body weight throughout life,” said Heather Spencer Feigelson, a senior epidemiologist at the American Cancer Society who led the study. “Even modest weight gain since age 18 was associated with increased risk of post-menopausal breast cancer.” The researchers based their study on a survey begun in 1992, when women aged 50 to 74 were asked their current weight, as well as their weight at age 18. They were followed for several years. Women who used hormone replacement therapy did not show the same effects, the researchers said. This supports the idea that body fat increases breast cancer risk by increasing levels of the hormone estrogen, the cancer society said. “Lean women not using HRT have the lowest levels of circulating estrogens, and the lowest risk of breast cancer,” the cancer society said in a statement. “HRT users, both lean and fat, have high levels of circulating hormones, masking any additional estrogenic effect from fat cells.” Being overweight was already known to put a woman at higher risk of breast cancer, but the study offers additional details of how and why. “Avoiding weight gain is one of the few ways we know of to reduce the risk of breast cancer among post-menopausal women,” Feigelson said. The study will be published in the February issue of Cancer Epidemiology, Biomarkers and Prevention. (Source: Reuters Health News: February 2004)