Smoke can trigger heart problems due to its effects on arteries and blood clotting, leading the researchers to believe the decline was likely due to less secondhand smoke exposure in restaurants and bars.

However, another tobacco expert questioned whether the drop in heart attacks could be clearly ascribed to the regulations, which banned smoking in restaurants starting in 2002 and then in all workplaces, including bars, in 2007.

Researchers from the Mayo Clinic in Rochester, Minnesota, found that in the 18 months before the first regulations was enacted, the rate of heart attacks in Olmsted County was 151 for every 100 000 people. Eighteen months after the second regulations were implemented, that number fell to 101 per 100 000 people.

In a Reuters Health report, Dr Richard Hurt said a few other studies have also suggested smoke-free workplace laws could impact heart attack rates.

“There have been lingering doubts among some people about whether or not this was a real finding. We think we have produced the most definitive results that anyone can produce related to smoke-free laws and heart attacks.”

Hurt, who led the research, said other predictors of heart attacks – including cholesterol levels, blood pressure and diabetes and obesity rates – all held steady or increased in Olmsted County over the study period.

“The only thing that really changed here was the smoke-free workplace laws,” he said.

The findings also make sense biologically, said Hurt. Exposure to secondhand smoke can cause immediate changes in the lining of the aorta, and can increase platelet adhesiveness.

The study was published in the Archives of Internal Medicine.

Source: Reuters Health