A study by researchers from the Harvard School of Public Health and Harvard Medical School shows that women who care for grandchildren more than nine hours a week have a 55 percent greater chance of developing coronary heart disease than those women who don’t provide such care. Though the study didn’t probe the reasons behind the findings, Sunmin Lee, research fellow at the School of Public Health and instructor in medicine at Harvard Medical School, said that providing care for children is physically and mentally demanding. Small children, in particular, require constant attention as well as frequent picking up and carrying. Looking after children also takes away grandmothers’ time to socialize, Lee said. This eliminates opportunities to relieve stress – both from caregiving and from other daily hassles – by interacting with friends and family members. The demands on caregiving grandmothers probably also results in less time caring for themselves. For example, they may have less time to sleep, rest, exercise, and get regular checkups, Lee said. Lee’s study, published in the November 2003 issue of the American Journal of Public Health, was conducted with Professor of Medicine Graham Colditz, Thomas D. Cabot Professor of Public Health Lisa Berkman, and Professor of Social Epidemiology Ichiro Kawachi.