U.S. IOM - like former Surgeon General Carmona stated there is no safe level of secondhand smoke..

October 15, 2009 - WASHINGTON – A major report from the Institute of Medicine (IOM) confirms what health officials long have believed: Bans on smoking in restaurants, bars and other gathering spots reduce the risk of heart attacks among nonsmokers.

"If you have heart disease, you really need to stay away from secondhand smoke (SHS, second hand, sidestream smoke, environmental tobacco smoke, ETS, passive smoke, involuntary smoking). It's an immediate threat to your life," declared Dr. Neal Benowitz of the University of California, San Francisco, who co-wrote Thursday's report from the prestigious Institute of Medicine.

More than 126 million nonsmoking people in the U.S. are regularly exposed to someone else's tobacco smoke. The surgeon general in 2006 cited "overwhelming scientific evidence" that tens of thousands die each year as a result, from heart disease, lung cancer and a list of other illnesses.

Yet smoking bans have remained a hard sell, as lawmakers and business owners debate whether such prohibitions are worth the anger of smoking customers or employees.

From the American Nonsmokers' Rights Foundation
U.S. 100% Smokefree Laws in Workplaces and Restaurants and Bars as of October 2, 2009.

Click on image to enlarge..

"The evidence is clear," said Dr. Thomas Frieden, Head of the federal Centers for Disease Control (CDC) and Prevention, which requested the study. "Smoke-free laws don't hurt business ... but they prevent heart attacks in nonsmokers."

Among the report's conclusions: While heavier exposure to secondhand smoke is worse, there's no safe level. It also cited "compelling" if circumstantial evidence that even less than an hour's exposure might be enough to push someone already at risk of a heart attack over the edge.

That's because within minutes, the smoke's pollution-like small particles and other substances can start constricting blood vessels and increasing blood's propensity to clot — key heart attack factors. Yet many people don't know they have heart disease until their first heart attack, making it important for everyone to avoid secondhand smoke, Benowitz said. "Even if you think you're perfectly healthy, secondhand smoke could be a potential threat to you," he said.

Many of the IOM committee members initially were skeptical they'd find much benefit from the bans, said statistician Stephen Feinberg of Carnegie Mellon University. He proclaimed himself "the resident skeptic" who changed his mind. "There was a clear and consistent effect of smoking bans," he said.

Since New York led the way in 2003, 21 states plus the District of Columbia now have what the CDC calls comprehensive laws banning smoking in both public and private workplaces, restaurants and bars — with no exception for ventilated smoking areas. Some other states have less restrictive laws.

That means 41 percent of people in the country are as protected in public from secondhand smoke as possible, Frieden said. The report found just 5 percent of the world's population was covered by comprehensive smoke-free laws.

While the public mostly connects smoking with lung cancer, heart disease is a more immediate consequence. About a third of all heart attacks in the U.S. are related to smoking, Frieden said.

How much do bans help? That depends on how existing bans were studied and how much secondhand smoke exposure different populations have. Some heavily exposed nonsmokers have the same risk of heart damage as people who smoke up to nine cigarettes a day, said Dr. Lynn Goldman, an environmental health specialist at Johns Hopkins University who led the Institute of Medicine committee.

Her team reviewed 11 key studies of smoking bans in parts of the U.S., Canada, Italy and Scotland. Those studies found drops in the number of heart attacks that ranged from 6 percent to 47 percent.

Some of the benefit may be to smokers who at least cut back because of public or workplace smoking bans, and may even quit at home, too. But two studies — one in Monroe, Ind., and another in Scotland — as well as a 52-country study of secondhand smoke's heart effects focused particularly on nonsmokers, to reassure that the bans do help them, Goldman said.

The impact can be quick.

Helena, Mont., for example, recorded 16 percent fewer heart attack hospitalizations in the six months after its ban went into effect than in the same months during previous years, while nearby areas that had no smoking ban saw heart attacks rise. More dramatically, heart attack hospitalizations dropped 41 percent in the three years after Pueblo, Colo., banned workplace smoking.

The institute is part of the National Academies, an independent organization chartered by Congress to advise the government on scientific matters.

To view report: Secondhand Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence...

Some related news briefs:
U.S. Institute of Medicine: Report - Secondhand-Smoke Exposure and Cardiovascular Effects: Making Sense of the Evidence..;
Secondhand smoke exposure and liver disease..;
England - ban on public smoking results in a fall in heart attack by 10%..;
Pregnant women exposed to passive smoke greater chance of child will have respiratory distress..;
More evidence - Casino workers face greater chance of disease..;
Tobacco smoke exposure on college campuses..;
New York City - nonsmokers exposed to cigarette smoke..;
Exposure to smoke changed cardiovascular function, particularly in men..;
Don't patronize places where people are smoking..;
Smoking bans lower heart attacks..;
U.S. - Children Remain Especially Vulnerable to Secondhand Smoke;
Massachusettes - Smoking ban drop in fatal heart attacks..;
Nicotine Dependence in Kids Exposed to Second-Hand Smoke...

Reference: IOM Report: Smoking bans protect nonsmokers' hearts, Associated Press, 10/15/2009.