By Genevra Pittman
Reuters

Heart attacks dropped by one-third in one county in Minnesota after two smoke-free workplace ordinances went into place, a new study shows.

The lead researcher on the work said that decline was likely due to less secondhand smoke exposure in restaurants and bars, as smoke can trigger heart problems due to its effects on arteries and blood clotting.

But another tobacco expert questioned whether the drop in heart attacks could be clearly attributed to the two ordinances, 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 ordinance was enacted, the rate of heart attacks in Olmsted County was 151 for every 100,000 people. By the 18 months following the second ordinance, that fell to 101 per 100,000 people.

Dr. Richard Hurt said a few other studies, including one from Montana, have also suggested smoke-free workplace laws could impact heart attack rates.

But, he told Reuters Health, "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.

About 3,600 municipalities have laws on the books that restrict where people may smoke, according to the American Nonsmokers Rights Foundation, with more than 1,000 including a smoke-free provision of some kind.

According to Hurt, the findings also make sense biologically. Exposure to secondhand smoke can cause immediate changes in the lining of the aorta, and can make blood platelets stickier - so they're more likely to form a dangerous clot.

The study is in line with the Institute of Medicine, which advises the U.S. government and said in a 2009 statement that, "data consistently demonstrates that secondhand-smoke exposure increases the risk of coronary heart disease and heart attacks and that smoking bans reduce this risk."

Hurt's results are published in the Archives of Internal Medicine.

He and his colleagues tried to account for general changes in heart attack rates that might have happened regardless of smoke-free laws. They found heart attacks had been declining even in the years before the ordinances - but fell much faster once they were put in place.

But that analysis wasn't convincing enough for Dr. Michael Siegel, a tobacco control researcher from the Boston University School of Public Health.

"The main problem with this study is that there's no control group or comparison group. This is a look only at what happened before and after an ordinance went into effect in one particular county," Siegel, who wasn't involved in the research, told Reuters Health.

"We have no idea whether heart attacks may also have gone down in other counties in Minnesota that didn't have this smoke-free law. Without knowing that, I don't see how you can make the conclusion that this (decline) was due to the law."

Siegel said there is more-convincing evidence that smoke-free workplace laws can help protect against asthma attacks and other lung problems.

"We don't need to prove that they actually decrease heart attacks over a short period of time," he said. "There's lots of reasons to support (these laws)."

A study out Wednesday suggests that calcium supplements might increase the risk for heart attacks. But this research from Swiss scientists in the British journal Heart is just the type of experiment that often scares people unnecessarily and gives the science of epidemiology a bad name.

The Swiss scientists looked at a group of almost 24,000 people who participated in a European cancer and nutrition study over 11 years. There is the first tip that the research might be less than reliable. The study was set up to look at cancer risk and these scientists are “mining” the data to look for heart disease outcomes. What the researchers unearth is a confusing set of conclusions.  In some people calcium intake seems to protect against heart disease. Indeed in the entire population there was no increase in total heart disease. But among those taking large amounts of supplements, they observe an increased number of heart attacks.

There has been concern for some time that too much calcium supplementation might cause heart disease because heart disease can result from a buildup of calcium in the arteries.  Several studies of the issue have come to differing conclusions.  What is not in doubt is that calcium in the correct amounts is critical for bone heath, but too much can cause health problems, possibly heart disease but for sure a risk of kidney stones and other health problems.

The study, though, should remind people that even though calcium is critical for bone health too much can be a hazard.

As Dr. Ethel Siris of New York-Presbyterian Columbia puts it, "People think more is better in this case in this case more is not better. Enough is enough.”

Getting the right amount of calcium can be a challenge.  The government recommends that adults take 1000 mg a day of calcium and women over 50 take 1200.  But it says no one over 50 should be taking more than 2000 mg a day.

It is easy to get too much calcium -- 22 percent of the adult US population takes calcium supplements.

Many foods have calcium.  A cup of milk, a serving of cheese and a container of yogurt all have more than 300 mg. Some fortified breakfast cereals have as much as 1000 mg per serving.

But for bone health people do need calcium including a supplement. If they are not getting it from food or other sources they need a supplement – just not too much.