Women who gain weight as young adults have a greater risk of developing breast cancer after menopause than women who maintain or lose weight, a study says.

More than 87,000 female nurses were involved in the research that concluded women with more body fat after menopause produce more estrogen, which fuels the growth of most breast cancers.

Losing weight, even after menopause, reduces a woman's risk of breast cancer, said the study from Brigham and Women's Hospital and Harvard Medical School.

However, the researchers noted few women lose weight after menopause, so they recommend women "avoid weight gain throughout adult life" in order to reduce their risk of breast cancer.

The study appears in the July 12 issue of the Journal of the American Medical Association.

Copyright 2006 by United Press International