Smoking bans in workplaces were associated with fewer deaths and hospitalizations due to heart attacks, strokes and respiratory diseases, a new review finds.

The introduction of smoke-free laws were followed by a 15 per cent decrease in hospitalizations for heart attacks, a 16 per cent decrease in stroke hospitalizations and a 24 per cent decrease in hospitalizations for diseases such as asthma and chronic obstructive pulmonary disease.

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Smoke-free policies should be expanded to include casinos, multiunit housing, motor vehicles and outdoors, doctors in California say. (Mel Evans/Associated Press)

More comprehensive smoke-free laws that covered workplaces, restaurants and bars were associated with larger declines, the researchers said after reviewing 43 studies on smoke-free laws in U.S. cities and states as well as countries ranging from Uruguay to New Zealand.

"The study provides strong evidence not only of the health benefits of smokefree laws but also of the need to enact comprehensive laws without exceptions," Stanton Glantz, the study's senior author and director of the Center for Tobacco Control Research and Education at the University of California, San Francisco and his co-authors concluded in this week's issue of the journal Circulation.

Passing smoke-free laws reflect changes in social norms that reduce smoking behaviour, they said.

Previous studies also found smoke-free laws were followed by decreases in hospital admissions for heart attacks and other heart problems.

The researchers cautioned that a cause-and-effect relationship can't be drawn from studies comparing  health effects before and after the introduction of smoking bans.

But one study in Helena, Mont. did observe a  rebound in heart attack admissions after the city suspended its smoke-free law during a lawsuit, which supports a causal link, they said.

Glantz's research was funded by the U.S. National Cancer Institute.

Another study published this week in the journal Archives of Internal Medicine also found a 33 per cent decline in heart attacks when they compared the incidence 18 months before and after the introduction of smoke-free laws in workplaces, including bars, in one county in Minnesota.

Smoke-free laws are also associated with fewer hospital admissions for asthma in children and improved quality of life, the editors of a journal commentary accompanying the Minnesota study said.

"Moving forward, we should prioritize the enforcement of smoke-free policies, eliminating loopholes in  existing policies as well as encouraging expansion of smoke-free policies to include multiunit housing, motor vehicles, casinos and outdoor locations," wrote Dr. Sara Kalkhoran and Dr. Pamela Ling of the University of California, San Francisco.