Dr lightwood analysed 13 published reports on heart attacks in countries or states where smoking bans have been introduced .
莱特伍德博士分析了十三份已发表的有关已实施禁烟的国家或州的心脏病发作报告。
" This study adds to the already strong evidence that secondhand smoke causes heart attacks , and that passing 100 % smoke-free laws in all work places and public places is something we can do to protect the public , " dr lightwood said .