Passive smokers also gain from bans

A review of studies from 21 countries has found national smoking bans reduce the risk of heart disease for passive smokers.

National smoking bans reduce the harms of passive smoking, an updated review says. (AAP)

National smoking bans do reduce the harms of passive smoking, particularly risks from heart disease, says an updated review.

Since the first systematic review by the Irish researchers in 2010, more countries have introduced legislation banning smoking in public places and work places.

The authors of the updated review, published in the Cochrane Library, said it provided the most robust evidence yet bans lead to improved health outcomes through reducing second-hand smoke exposure.

The review included 77 studies from 21 countries and found evidence of a significant reduction in heart disease following the introduction of the bans.

The greatest reduction in admissions for heart disease following smoking laws were identified in populations of non-smokers.

The authors said cigarette smoking is one the greatest public health disasters of the 20th century, with over 20 million attributable deaths.

The World Health Organisation estimates that six million people die every year from tobacco-related diseases - 600,000 from the effects of passive smoking.