Bans on smoking in public places reduce heart attack rates. That's the conclusion of a new report from the Institute of Medicine. The institute is an independent group of experts that advises the U.S. government. The experts looked at 11 studies from the United States, Canada, Italy and Scotland. They found that heart attack rates dropped after smoking bans in restaurants and other public places took effect. The reduction ranged from 6% to 47%. Smoking and secondhand smoke release tiny particles of air pollution. Smoke can damage blood vessels and promote formation of blood clots that cause heart attacks. The Associated Press wrote about the report October 15.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Secondhand smoke is even more dangerous than we thought. A new report from the Institute of Medicine leaves no doubt about the positive health effects of banning smoking in public places.

The report compares rates of illness, especially heart attacks, before and after smoking bans were put in place. Heart attack rates fell, though the rate of decline varied.

The report also compares towns that imposed smoking bans with other towns that did not. In some areas without a ban, the heart attack rate actually increased compared with prior years. These comparisons add support to the overall findings.

The authors of the report acknowledge that the health improvements could have been caused by factors other than reducing secondhand smoke. For example, it is quite likely that smokers used fewer cigarettes per day once the smoking bans were in place.

The amount of secondhand smoke within a confined area matters. The greater the smoke density, the higher the risk. However, no level of secondhand smoke can be considered safe at this time.

The adverse health effects of secondhand smoke can be immediate and long term. The increased rate of heart attacks is primarily an immediate effect.

One longer-term effect is connected to the buildup of a fatty substance called plaque in coronary arteries. People may or may not know that they have the problem.

The chemicals in tobacco smoke can cause the plaque to crack. The ruptured plaque releases substances in the blood that promote formation of a blood clot at that spot. In addition to that danger, inhaling the tobacco smoke makes blood clot faster.

What Changes Can I Make Now?

You can't always avoid tobacco smoke. But you are in control of most of the factors that increase the risk of heart attacks.

Here are the ones you can change and how to do it:

• High blood levels of LDL cholesterol -- Make fruits and vegetables your priority. Avoid saturated and trans fats. Take medicine to lower your cholesterol if your doctor prescribes it.
• Low levels of HDL -- Exercise is the best way to raise your HDL.
• Type 2 diabetes -- You may not be able to completely avoid diabetes. However, you can postpone it by exercising regularly and maintaining a healthy body weight.
• High blood pressure -- Make sure your diet is loaded with fruits and vegetables and low in salt. Take your blood pressure medicines daily.
• Depression and/or persistent stress -- These are relatively new risk factors, but just as important as all the others. Treating depression and lowering stress levels decreases your heart attack risk.
• Social isolation -- People who stay connected to family and friends are less likely to have a heart attack.

What Can I Expect Looking to the Future?

Researchers will find it more difficult to measure the contribution of secondhand smoke to other health problems. These may include lung cancer, emphysema and chronic bronchitis. This report from the Institute of Medicine suggests to me that secondhand smoke increases the risk of those longer-term health problems as well.