New Medical Evidence Is Here on Secondhand Smoke
By Yvan Silva, M.D. Maintaining Your Health on Mackinac

In the first historic report of 1964, Surgeon General Luther Terry concluded that "cigarette smoking is a health hazard of sufficient importance in the United States to warrant appropriate remedial action." And since 1964, the manufacturers and purveyors of tobacco products have resorted to masterful creativity and the artful dodge to convey conflicting messages to the public. The public, in return, has succumbed to the popularization and fanciful trends in a variety of forms of tobacco use. In the past 20 years, the issue of secondhand smoke has seen much debate.

In 1964, 53 percent of adult American men smoked cigarettes. Since then, 46 million Americans have kicked the habit and now 25 percent of the men in this country smoke, but the decline has been slow, and it has been even slower for women and minority groups. Smoking remains the leading cause of preventable death and disease in the United States. Smoking accounts for $50 to $73 billion in annual medicalcare expenditures, or six percent to 12 percent of all U.S. medical costs. A recent report from the Center for Disease

Control stated that 48 million U.S. adults currently smoke. The costs to the United States per year is at least $150 billion in health care and lost productivity, yet the projection of smoking as glamorous, social, and fun continues.

Smoking is bad, and on this everybody agrees. Over the years, several coalitions across the country, with a common anti-tobacco agenda, have spearheaded vigorous campaigns to increase the acceptance of non-smoking as the social norm by educating policy makers on the risks of tobacco and secondhand smoke, advocating regulatory changes to protect against tobacco-related problems, and promoting public health education. Increasingly the focus is on discouraging individuals from starting to smoke and encouraging those who smoke to quit as soon as possible. Nationally, the momentum continues to grow across a wide spectrum, ranging from the creation of smoke-free cities to smoke-free playgrounds to protect children from tobacco smoke.

Between 1964 and 2006 there have been 29 reports on Smoking and Health issued by the office of the Surgeon General. The subject of secondhand smoke has too often been ignored or pushed back from a perception of lack of good evidence; all this while more and more studies and reports have been published in journal articles. In 1986 the Surgeon General first published "The health consequences of involuntary exposure to tobacco smoke." This June 27, 2006, 20 years later, the U.S. Surgeon General issued a comprehensive scientific report with the same title, which concludes that there is no risk-free level of exposure to secondhand smoke.

Just what is secondhand smoke? The publication provided the following definitions. Secondhand smoke is composed of sidestream smoke (the smoke released from the burning end of a cigarette) and exhaled mainstream smoke (the smoke exhaled by the smoker). While secondhand smoke has been referred to as environmental tobacco smoke (ETS) in the past, the term "secondhand" smoke better captures the involuntary nature of the exposure. This Surgeon General's report uses the term "involuntary" in the title because most nonsmokers do not want to breathe tobacco smoke. The term "involuntary" was also used in the title of the 1986 Surgeon General's report on secondhand smoke.

Cigarette smoke contains more than 4,000 chemical compounds. Secondhand smoke contains many of the same chemicals that are present in the smoke inhaled by smokers. Because sidestream smoke is generated at lower temperatures and under different conditions than mainstream smoke, it contains higher concentrations of many of the toxins found in cigarette smoke. The National Toxicology Program estimates that at least 250 chemicals in secondhand smoke are known to be toxic or carcinogenic.

Secondhand smoke has been designated as a known "human carcinogen" (cancer-causing agent) by the U.S. Environmental Protection Agency, the National Toxicology Program, and the International Agency for Research on Cancer, and an occupational carcinogen by the National Institute for Occupational Safety and Health. Secondhand smoke contains more than 50 cancer-causing chemicals. When nonsmokers are exposed to secondhand smoke, they inhale many of the same cancer-causing chemicals that smokers inhale. The Surgeon General now states that evidence is "indisputable" that secondhand smoke is an "alarming" public health hazard and that it is responsible for tens of thousands of premature deaths among nonsmokers every year. Hundreds of studies have shown that the harm caused is far greater than believed earlier. The conclusions include:

There is no risk-free level of exposure to secondhand smoke; even small amounts of secondhand smoke exposure can be harmful to people's health. Many millions of Americans continue to be exposed to secondhand smoke. A smoke-free environment is the only way to fully protect nonsmokers from the dangers of secondhand smoke. Separating smokers from nonsmokers, cleaning the air, and ventilating buildings cannot eliminate exposure of nonsmokers to secondhand smoke.

Nonsmokers exposed to secondhand smoke at home or work increase their risk of developing heart disease by 25 to 30 percent and lung cancer by 20 to 30 percent.

The finding is of major public health concern owing to the fact that nearly half of all nonsmoking Americans are still regularly exposed to secondhand smoke. It accounted for 46,000 premature deaths from heart disease and 3,000 premature deaths from cancer last year.

The report finds that even brief secondhand smoke exposure can cause immediate harm. The report claims that the only way to protect nonsmokers from the dangerous chemicals in secondhand smoke is to eliminate smoking indoors.

Secondhand smoke is a cause of sudden infant death syndrome (SIDS), accounting for 430 deaths last year. The risk is increased for children of mothers who were exposed during pregnancy and children exposed in their homes at birth. The effects on children's health and development are more severe than previously believed.

While overall exposure to secondhand smoke has declined, 60 percent of nonsmokers show biological evidence of encountering it and 22 percent of children are exposed to it in their homes. Levels of cotinine (the form nicotine takes after it is metabolized) measured in nonsmokers have fallen by 75 percent among adults in blood samples taken from 1999 to 2002 compared with those taken 10 years earlier. This is owing to clearing the air of tobacco smoke in many environments. Yet, sustained efforts are required to protect the more than 126 million Americans who continue to be regularly exposed to secondhand smoke in the home, at work, and in enclosed public spaces.

Secondhand smoke is not a mere annoyance. It is a serious health hazard that has been shown to lead to disease and premature death in children and nonsmoking adults. Secondhand smoke contains more than 50 cancer-causing chemicals and is itself a known human carcinogen. Nonsmokers who are exposed to secondhand smoke inhale many of the same toxins as smokers. Even brief exposure to secondhand smoke has immediate adverse effects on the cardiovascular system and increases risk for heart disease and lung cancer, the report says. In addition, the report notes that because the bodies of infants and children are still developing, they are especially vulnerable to the poisons in secondhand smoke. Parents are now urged not only to quit, but to move their smoking outside when trying to quit, particularly to protect the children.

Unlike like some public health hazards, secondhand smoke exposure can be prevented. Smoke-free indoor environments are proven, simple approaches that prevent exposure and harm. The new evidence finds that even the most sophisticated ventilation systems cannot completely eliminate secondhand smoke exposure and that only smoke-free environments afford full protection.

Dr. Silva is a professor of surgery at Wayne State University and a resident of Woodbluff on Mackinac Island.