New research shows national smoking bans reduce the harms of passive smoking.
A review of studies from around the world suggests that heart disease in non-smokers is less frequent in countries with smoking bans.
New Zealand became one of the first countries in the world to ban indoor smoking, starting with offices in 1990 and then all workplaces and licensed premises in 2003. Since then, a raft of countries, states and regions have adopted similar smoke-free legislation.
Now, a team of Irish researchers has pulled together 77 studies from populations of 21 countries to look into the effects of passive smoking, and the associated health risks including heart disease.
They found a significant reduction in heart disease following the introduction of these bans, but the greatest reduction in admissions for heart disease was identified in populations of non-smokers.
"The current evidence provides more robust support for the previous conclusions that the introduction of national legislative smoking bans does lead to improved health outcomes through a reduction in second-hand smoke exposure for countries and their populations," says review author Professor Cecily Kelleher, from University College, Dublin.
Cigarette smoking is identified as one the greatest public health disasters of the 20th century, with over 20 million attributable deaths.
The World Health Organization estimates 6 million people die every year from tobacco-related diseases, 600,000 from the effects of passive smoking.