Hospital admissions for patients with heart and respiratory problems have dropped by around a third in Canada since anti-smoking laws were introduced in 2001, a new study showed Monday.

The 10-year study was carried out in the city of Toronto and aimed to measure the effects of banning smoking in restaurants and bars.

"Research delineating the impact of smoke-free legislation on cardiovascular and respiratory outcomes could have an immense impact on public health, given that an estimated one billion people are expected to die during the 21st century as a result of tobacco-related disease," wrote lead author Alisa Naiman from the University of Toronto.

Since smoking was banned nine years ago, hospital admissions for cardiovascular and respiratory conditions dropped 39 percent and 33 percent respectively, according to the article published in the Canadian Medical Association Journal.

It recalled that tobacco is the leading cause of preventable death in the world, and that second-hand smoke is the third leading cause of preventable poor health and premature death in the developed world.

The authors added their findings were "consistent with the evidence that exposure to second-hand smoke is detrimental to health and legitimizes legislative efforts to further reduce exposure."

Additional research should be carried out to determine in which public places smoking bans are most effective, they concluded.