The effect of passive smoking with respect to cardiac disease³ was studied by Ichiro Kawachi of the Harvard School of Public Health, who followed 32046 healthy, non-smoking women enrolled in the nurses health study for a period of 10 years (Circulation 1997;95:2374-9). He found that healthy, non-smoking women who reported regular exposure to passive smoke at home or in the workplace had a 91% greater relative risk of heart attack than those who reported minimal passive smoke exposure. Those who reported occasional exposure had a 58% greater relative risk.