Exercise reduces cancer risk

Researchers Grace Wyshak and Rose Frisch estimate that exposing women to physical activity during their college years or earlier may decrease the risk of breast cancer in women of all ages by 17 percent. That would reduce the 180,000 new cases reported in the United States each year by 30,600. For women under age 45, the proportion of breast cancers that might be prevented is even greater. "The effect was more marked among women younger than 45 years," said Wyshak, an associate professor at the Harvard School of Public Health and the Harvard Medical School. The findings came from a 15-year follow-up of 3,940 female athletes and nonathletes. Most of those in the study were graduates of Radcliffe College.