Taking care of grandchildren can give women more than a headache -- it can raise their risk of heart attack, researchers report.
The study of more than 54,000 nurses found that those who cared for grandchildren at least nine hours a week had a 55% increased risk of heart attack.
It's probably the stress, said Sunmin Lee of Brigham and Women's Hospital, who led the study, published in the American Journal of Public Health.
Lee's team at the Harvard School of Public Health and Harvard Medical School said that about one in seven U.S. women have raised a grandchild for six months or more.
Eight or nine homes were destroyed.