The longer a woman is overweight, the higher her risk of several cancers, researchers report. The study, which followed nearly 74,000 U.S. women, found that the longer a woman carried excess poundage, the greater her risk of breast, endometrial, colon and kidney cancers. "We've known for a long time that excess weight is important in cancer risk," said the vice president of epidemiology for the American Cancer Society.

The cancer society says excess weight contributes to as many as 20 percent of all cancer deaths. "This study is interesting because it suggests that the number of years you spend being overweight also matters," said an official who was not involved in the research. And that, she said, should provide further incentive to avoid excess weight gain in the first place. Currently, about 7 out of 10 adults in the United States are overweight, and more than one-third are o bese ,…