[VAGASP]   SECONDHAND  SMOKE - HAZARD TO LIFE

This page contains facts, links to fact sheets, excerpts from articles.  Updated as of January 28, 2006.

There may be many things that people will accept secondhand -- but smoke is NOT one of them. Tobacco Smoke is so dangerous, it can even kill secondhand.

Tobacco companies do not allow smoking around tobacco seedlings -- because it kills them -- tobacco mosaic virus.  Tomato plants are also susceptible to this.  People are also hurt and killed by secondhand smoke.

For this reason, more and more workplaces are going smoke-free around the world.

FACT SHEETS on secondhand smoke:
ETS
Repace

Pets and ETS:
    Articles may be searched at the web site of the American Journal of Epidemiology,  for example,
    Cats -- increased risk of lymphoma from breathing secondhand smoke.



Environmental tobacco smoke linked to reading, math, logic, and reasoning declines in children
Press release from Cincinnati Children's Hospital Medical Center

January 4, 2005

CINCINNATI – A new Cincinnati Children's Hospital Medical Center study shows that exposure to environmental tobacco smoke, even at extremely low levels, is associated with decreases in certain cognitive skills, including reading, math, and logic and reasoning, in children and adolescents.

The study is the largest ever to look at the effects of environmental tobacco smoke on children's health. It is published in the January issue of Environmental Health Perspectives.

"This study provides further incentive for states to set public health standards to protect children from exposure to environmental tobacco smoke," says Kimberly Yolton, PhD, a researcher at the Children's Environmental Health Center at Cincinnati Children's and the study's main author. "We estimate that more than 33 million children in the United States are exposed to levels consistent with the adverse effects seen in this study."

The study's findings translate into nearly a three-point decline in a standardized reading test and nearly a two-point decline in a standardized math test, given an average score of 100 and a modest increase in exposure to environmental tobacco smoke.

Logic and reasoning skills were tested in a task that involved the assembly of blocks. This task evaluated a child's ability to visually organize and reason in constructing a design quickly and accurately. The study found a .55 decline in block-design scores, given an average score of 10 and a modest increase in exposure.

"These declines may not be clinically meaningful for an individual child, but they have huge implications for our society because millions of children are exposed to environmental tobacco smoke in the United States," says Dr. Yolton.

The study is based on data gathered from 1988-94 for the third National Health and Nutrition Examination Survey (NHANES-III), conducted by the National Center for Health Statistics at the Centers for Disease Control and Prevention. NHANES is designed to collect information about the health and diet of people in the United States.

To measure exposure to environmental tobacco smoke, researchers measured levels of cotinine, a substance produced when nicotine is broken down by the body. Cotinine can be measured in blood, urine, saliva and hair. It is considered the best marker of environmental tobacco smoke exposure.

For this study, cotinine was measured in the blood of 4,399 children between 6 and 16 years old. Children were only included in the analysis if their serum (blood) cotinine levels were at or below 15 ng/ml, a level consistent with environmental tobacco smoke exposure, and if they denied using any tobacco products in the previous five days.

Cognitive and academic abilities were assessed using portions of standardized intelligence and achievement tests. Reading, math and reasoning scores were highly related to environmental tobacco smoke exposure: The greater the levels of exposure as measured by cotinine levels, the greater the decline in reading and reasoning ability, even at extremely low levels of exposure, according to Dr. Yolton.

Surprisingly, Dr. Yolton and colleagues at Cincinnati Children's also found greater decreases in cognitive skills at lower levels of exposure. While there was, on average, a one-point decline in reading scores for each unit increase in cotinine at levels above 1 ng/ml, there was a five-point decline for each unit increase in cotinine at levels below 1 ng/ml. In the United States, 43 percent of children are exposed to environmental tobacco smoke in their own homes, and 85 percent of children have detectable levels of cotinine in their blood.

###

Cincinnati Children's Hospital Medical Center is a 423-bed institution devoted to bringing the world the joy of healthier kids. Cincinnati Children's is dedicated to transforming the way health care is delivered by providing care that is timely, efficient, effective, family-centered, equitable and safe. It ranks third nationally among all pediatric centers in research grants from the National Institutes of Health. The Cincinnati Children's vision is to be the leader in improving child health. Additional information can be found at www.cincinnatichildrens.org.

Source:

Exposure to Environmental Tobacco Smoke and Cognitive Abilities among U.S. Children and Adolescents
Environmental Health Perspectives Volume 113, Number 1 January 2005
Kimberly Yolton,1,2 Kim Dietrich,1,3 Peggy Auinger,4 Bruce P. Lanphear,1,2 and Richard Hornung1,3,4

1Cincinnati Children's Environmental Health Center, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; 2Department of Pediatrics and 3Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA; 4Department of Pediatrics, University of Rochester School of Medicine and the American Academy of Pediatrics Center for Child Health Research, Rochester, New York, USA; 5Institute for Health Policy and Health Services Research, University of Cincinnati, Cincinnati, Ohio, USA

Abstract:

We used the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 to 1994, to investigate the relationship between environmental tobacco smoke (ETS) exposure and cognitive abilities among U.S. children and adolescents 6-16 years of age. Serum cotinine was used as a biomarker of ETS exposure. Children were included in the sample if their serum cotinine levels were 15 ng/mL, a level consistent with ETS exposure, and if they denied using any tobacco products in the previous 5 days. Cognitive and academic abilities were assessed using the reading and math subtests of the Wide Range Achievement Test-Revised and the block design and digit span subtests of the Wechsler Intelligence Scale for Children-III. Analyses were conducted using SUDAAN software. Of the 5,365 6- to 16-year-olds included in NHANES III, 4,399 (82%) were included in this analysis. The geometric mean serum cotinine level was 0.23 ng/mL (range, 0.035-15 ng/mL); 80% of subjects had levels < 1 ng/mL. After adjustment for sex, race, region, poverty, parent education and marital status, ferritin, and blood lead concentration, there was a significant inverse relationship between serum cotinine and scores on reading (ß = -2.69, p = 0.001), math (ß = -1.93, p = 0.01), and block design (ß = -0.55, p < 0.001) but not digit span (ß = -0.08, p = 0.52). The estimated ETS-associated decrement in cognitive test scores was greater at lower cotinine levels. A log-linear analysis was selected as the best fit to characterize the increased slope in cognitive deficits at lower levels of exposure. These data, which indicate an inverse association between ETS exposure and cognitive deficits among children even at extremely low levels of exposure, support policy to further restrict children's exposure. Key words: children, cognition, environment, environmental tobacco smoke, epidemiology. Environ Health Perspect 113:98-103 (2005). doi:10.1289/ehp.7210 available via http://dx.doi.org/ [Online 7 October 2004]

This paper was presented in part at the annual meeting of the Pediatric Academic Society, May 2002.

The authors declare they have no competing financial interests.

Received 27 April 2004; accepted 7 October 2004 .

http://ehp.niehs.nih.gov/docs/2004/7210/abstract.html

Editor's note: The full article is available at: http://ehp.niehs.nih.gov/members/2004/7210/7210.html

The PDF is available at: http://ehp.niehs.nih.gov/members/2004/7210/7210.pdf


British Medical Association condemns tobacco industry ventilation claims
EXCERPTS from: BMA condemns tobacco industry ventilation claims - News-Medical.Net January 13, 2005

Following a conference held this morning by the Scottish Licensed Trade Association, the BMA stressed that ventilation does not protect employees or customers from the deadly effects of passive smoke and condemned arguments otherwise as untrue and based on flawed science.

Research in America found that there was 50 times more air pollution in a smoky bar than in New York's Holland tunnel at rush hour, and studies have found that ventilation in bars does not reduce the risk to the health of customers or staff.

The tobacco industry has proposed that ventilation is the solution to the problem of passive smoke, however, scientific evidence proves that conventional ventilation and air-cleaning systems do not provide effective protection against the health hazards of second hand smoke.

Ventilation systems use a filtration method to re-circulate air. However, while this method can clear the smoky atmosphere, the toxins present in the gas of second hand smoke remains.

Dr Peter Terry, Chairman of BMA Scotland said: "Passive smoke kills.  Businesses installing expensive ventilation systems will do so in the belief that they are protecting staff and the public from the ill-effects of second hand smoke. The sad truth is that they are mistaken.

"Although good ventilation can help reduce the irritability of smoke, it does not eliminate its poisonous components. Tobacco smoke contains 4,000 toxins and more than 50  cancer-causing substances. Many of these are odourless, invisible gasses, which are not removed by ventilation systems.

"Partial bans on smoking in enclosed public places would not protect people from the harmful health effects of exposure to passive smoke, and voluntary measures have failed.

"Smoke free enclosed public places are what Scotland wants and needs. Our only hope now is that our MSPs are not wavered by misleading claims fuelled by the tobacco industry. The only way to protect the significant majority of the population who do not smoke is to legislate for smoke free enclosed public places."

http://www.bma.org.uk

http://www.news-medical.net/?idr90




NATIONS
that require smoke-free workplaces, please see the web page on this.



ENVIRONMENTAL TOBACCO SMOKE KILLS.

Secondhand Smoke, or Environmental Tobacco Smoke [ETS], has been labeled
a Class A carcinogen by the U.S. Environmental Protection Agency.  Carcinogens are cancer producing substances.

ETS is a known human carcinogen, according to the Report on Carcinogens, 2000, of the National  Toxicology Program of the U.S. Department of Health and Human Services, Public Health Service.

Environmental Tobacco Smoke [ETS], or secondhand smoke, is the third leading cause of preventable disease, disability and death in the U.S.A.; the first is active smoking, the second is alcohol use.

ETS is the single most important source of harmful indoor air pollution.

ETS kills through:
     Several types of cancers
     Cardiovascular disease (atherosclerosis, heart disease, stroke)
     Respiratory diseases
     Perinatal death, miscarriage, low birth weight
     Sudden Infant Death Syndrome (SIDS)

ETS increases the risk of illness including:
     Atherosclerosis (hardening of the arteries)
     Respiratory infections -- pneumonia, bronchitis, bronchiolitis, colds, sore throats
     Asthma
     Middle ear infections
     Dental caries


The British Medical Association (BMA) has called for smoke-free workplaces and enclosed public places.  Noting on their web site, http://www.bma.org.uk,
The politicians in Ireland, Norway, and New York have decided to put the health of their citizens first by banning smoking in enclosed public places. Surely we have a right to ask the same from our Governments?

EXCERPTS from the press release from the British Medical Association (BMA), November 9, 2004, calling on the English Health Secretary, John Reid, to set a date to ban workplace smoking in the United Kingdom.


In a stark BMA report, The Human Cost of Tobacco, published today (9 November 2004), doctors chronicle individual stories behind the statistics to show how second-hand smoke destroys lives and health.

Every year at least 1000 people die from the effects of passive smoking. The BMA believes the biggest single step governments can take to improve the health of the public is to take action at national level to stop smoking in enclosed workplaces.

In his foreword to the report, BMA Chairman, Mr. James Johnson, offers the Health Secretary, John Reid, the same advice as smokers get:
There is no doubt that giving up smoking can be extremely difficult – like any addiction kicking the habit is no easy task. When smokers decide to quit they are often advised to set a date, bin the fags and then just do it. Support from a doctor or health professional during this time can be invaluable. I am going to give the same advice to John Reid.

In the forthcoming White Paper for England, he should set a date for banning smoking in all enclosed public places, this will give the bars and restaurants time to bin their ash-trays and then these workplaces will just have to abide by the law. John Reid already has the support of the medical profession.

The report charts around 70 cases throughout the United Kingdom of doctors’ experiences of dealing with patients who have been exposed to second-hand smoke. For example:

LUNG CANCER
“I have had three confirmed cases of inoperable primary lung cancer in life-long non-smokers in the last two years. The biopsies showed the type of lung cancer only seen in smokers, and all three worked in public places where they were heavily exposed to secondary cigarette smoke. All three died within weeks of diagnosis.”

RESPIRATORY DISEASE
"I have recently seen a thirty-four year old landlady with severe bronchial irritation and a history of recurrent wheezy chest infections caused by her work environment in a smoky pub. She now needs regular inhaled drugs including steroids to control her symptoms. She herself has never smoked.”

CHILDREN
“I saw a young boy on a number of occasions suffering from severe asthma attacks. His mother said she could not think of anything that brought on the attack, but the young boy said 'I always get sick after seeing grandad'. Apparently his grandfather owns a small and usually smoke filled restaurant.”

PREGNANCY
“In my current post in obstetrics I see numerous cases of low-birthweight babies and difficult pregnancies exacerbated by passive smoking."

The BMA has been calling for legislation to ban smoking in enclosed public places since 1986.


EXCERPTS from The Toledo Blade, March 8, 2004, Letters to the Editor, headlined, Danger of secondhand smoke is real

William Delaney, owner of Delaney's Lounge, was quoted ... as saying "secondhand smoke will not kill anyone." I invite Mr. Delaney to tell that to the family of Dr. Abid M. Hanson.

A nonsmoker who suffered from asthma, Dr. Hanson was a passenger aboard an Olympic Airways international flight in 1998 and was seated near the smoking section. After he began suffering major breathing distress, Dr. Hanson and his wife made repeated requests of the flight crew to have him moved away from the smoke. The flight crew refused to move him. Dr. Hanson later died on that smoke-filled flight at the age of 52.

The family sued Olympic Airways for negligence; the court awarded damages in the amount of $1.4 million. That award was upheld by the Ninth Circuit Court of Appeals in December 2002.

On Feb. 24 the United States Supreme Court upheld the award for Dr. Hanson's family. I hope that Dr. Hanson's tragic and unnecessary death will help destroy the myth that secondhand smoke has never killed anyone.

EDWARD L. SWEDA, JR.
Boston, Mass.
Editor's note: Mr. Sweda is senior attorney for the Tobacco Control Resource Center at the Northeastern University School of Law.


Lung cancer victim, Alice K. Helm, spoke out in testimony shortly before her death in June, 2003.  Helm, a courageous fighter for the right to breathe smoke free air, gave testimony to Maryland's Montgomery County Council (USA), June 12, 2003:

This is Alice K. Helm.  Most of you know me. This testimony is in the form of an open letter to Mark Doherty, General Manager of the Anchor Inn restaurant, since it probably will be my last public comments about smoke filled restaurants.  There are several points I want to make before I die to Mr. Doherty, other owners of smoke-filled restaurants and bars, non-supportive Council members, and County Executive Duncan.

This is an issue of killing people, not whether the Anchor Inn may lose some business.

I never smoked.  However, for many of my 75 years I inhaled the carcinogens borne by second hand smoke in restaurants such as the Anchor Inn, in elevators, at meetings, on airplanes, in stores.  Health experts say that's probably why I now have fourth-stage lung cancer that also has spread elsewhere in my body.

Since Mr. Duncan vetoed the smoking ban in restaurants a few years ago, progressive states and local jurisdictions have enacted smoke free legislation such as the bill we passed then in Montgomery County.  Those jurisdictions did not see patron flight from their restaurants.  Instead, what they did see was a reduced number of health problems that were due to the inhalation of carcinogens that previously permeated their smoke-filled restaurants.

Ventilation does not work.  Council members, Mr. Duncan and tobacco companies know this.  It is not a compromise.  It is a death sentence.  It is not Mr. Doherty's right to poison the air others must breath in order to make a dollar.  It is the government's mandate to protect the public's health.  That's why they inspect restaurants for rats, contaminated food and certainly the most important should be to prevent death from the carcinogens in second hand smoke.

I probably won't be here to enjoy Montgomery County's smoke free restaurants and bars.  But you will have the chance to see the lives of workers and patrons last longer.  And remember.  I'll be watching!



Employers and politicians, please note
    Smoky surroundings = lost productivity and lost $ from lost time at work.

Excerpts from Canadian Press, March 7, 2003, headlined, Second-hand-smoke fosters sore throats, colds, no writer noted.

WINNIPEG - The Manitoba Medical Association says second-hand smoke not only kills - it makes restaurant and bar workers more susceptible to colds and other annoying symptoms.

The association released a study Friday of short-term effects on 45 workers at both smoking and non-smoking bars and restaurants in Winnipeg and Brandon.

Dr. Mark Taylor said there are plenty of studies proving the long-term effects. But he said he hoped this one on the short-term impact would help spur city and provincial officials to implement an all-out ban on smoking in public places.

Kristina Hunter of the University of Manitoba's environmental health sciences faculty worked on the report.

She said hospitality workers are among the few exposed to such a hazardous work environment without any regulations regarding levels of exposure to a proven carcinogen.

"It tends to employ a lot of young people, a lot of females, people that are nearing their reproductive age, so they are at a very vulnerable time in their lives."

One Ottawa woman dying of cancer has already won workers' compensation benefits for her exposure to second-hand smoke. Heather Crowe, 57, has become an advocate for tougher smoking bans after 40 years as a waitress.

Non-smoking bar and restaurant workers also are many times more likely to have sore throats, coughs, teary eyes and colds if they work in places where smoking is allowed, the Manitoba study found.

Both the city of Winnipeg and the province are considering an all-out ban, and an all-party committee of the Manitoba legislature is going to review the issue later this year.

Coun. Mark Lubosch said he believes a bare majority of Winnipeg city councillors are ready to go for an all-out ban, but he wishes provincial politicians would have a little more courage.

"I don't know how much more evidence we need, whether it's the 250 people that are reportedly dying every year from second-hand smoke in this province or whether it's the $250 million that we're spending on additional health-care costs to treat people with preventable smoking-related illnesses," he said.

Brandon now has the toughest anti-smoking bylaw in the province, but the study was conducted both before and after its all-out ban was implemented.

The study was released at an Applebee's restaurant in Winnipeg. Janet Harder, who runs the chain's outlets in Alberta and Manitoba, said it's time for provinces to face facts and do the right thing.

A smoker herself, Harder said business at Applebee's fell off initially when they went smoke-free but they attracted new customers and their staff are happier and more productive.

Manitoba isn't the only province looking a breaking new ground with an all-out ban on smoking in public places.

Ontario Health Minister Tony Clement has also said his province will consider a provincewide ban as part of its review of Ontario's anti-smoking strategy.

The Ontario Medical Association is also applying pressure for an all-out ban, saying 2,600 people a year die in the province as a result of second-hand smoke.

Taylor admitted their sample in the Manitoba study was small and they hope to expand it in the future. They had trouble finding non-smoking employees working where smoking was allowed who would participate.

"We have no proof, but our suspicion is they're being discouraged from participating by their employers," he said.



Association of Pediatric Dental Caries With Passive Smoking
Conclusions:  There is an association between environmental tobacco smoke and risk of caries among children. Reduction of passive smoking is important not only for the prevention of many medical problems, but also for the promotion of children's dental health.

JAMA, Journal of the American Medical Association.  2003;289:1258-1264
Vol. 289 No. 10, March 12, 2003 http://jama.ama-assn.org/cgi/content/short/289/10/1258

C. Andrew Aligne, MD, MPH; Mark E. Moss, DDS, PhD; Peggy Auinger, MS; Michael Weitzman, MD

Context:  Dental decay is the most common chronic disease of children, and it disproportionately affects those living in poverty, but the reasons for this are not clear. Passive smoking may be a modifiable risk factor for dental caries.

Objective:  To examine the relationship between dental caries and serum cotinine levels.

Design, Setting, and Participants:  Cross-sectional data from the Third National Health and Nutrition Examination Survey (1988-1994) of 3531 children aged 4 to 11 years, who had had both dental examinations and a serum cotinine level measurement.

Main Outcome Measures:  Passive smoking defined as serum cotinine levels of
0.2 to 10 ng/mL and caries defined as decayed (unfilled) or filled tooth
surfaces.

Results:  Twenty-five percent of the children had at least 1 unfilled decayed tooth surface and 33% had at least 1 filled surface.  Fifty-three percent had cotinine levels consistent with passive smoking. Elevated cotinine level was significantly associated with both decayed (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.5-2.9) and filled (OR, 1.4; 95% CI, 1.1-1.8) tooth surfaces in deciduous but not in permanent teeth.  This relationship persisted after adjusting for age, sex, race, family income, geographic region, frequency of dental visits, and blood lead level. For dental caries in deciduous teeth, the adjusted OR was 1.8 (95% CI, 1.2-2.7) for the risk of decayed surfaces and 1.4 (95% CI, 1.1-2.0) for filled surfaces.  We estimated the population attributable risk from passive smoking to be 27% for decayed and 14% for filled tooth surfaces.

Author/Article Information:
Author Affiliations: Pediathink, Rochester, NY (Dr Aligne); Eastman School of Dentistry, Rochester, NY (Dr Moss); and Center for Child Health Research of the American Academy of Pediatrics (Ms Auinger and Dr Weitzman) and Departments of Community and Preventive Medicine (Dr Moss) and Pediatrics (Ms Auinger and Dr Weitzman), University of Rochester School of Medicine, Rochester, NY.

Corresponding Author and Reprints: C. Andrew Aligne, MD, MPH, 620 Park Ave,
Box 135, Rochester, NY 14607 (e-mail: andy@pediathink.com ).

Author Contributions: Study concept and design: Aligne, Weitzman.

Funding/Support: This research was partially supported by a Special Projects grant from the Agency for Healthcare Research and Quality and the Ambulatory Pediatric Association, and by the Monroe County Smoking and Health Action Coalition of the New York State Department of Health.



EXCERPTS from Minnesota's newspaper, The Duluth News-Tribune, May 3, 2000, writer Melanie Evans; headlined:  The power of second-hand smoke,  Research suggests inhaling smoke has similar health effects as smoking, More on Duluth's proposed smoking ban

                      It is a truism that emerged unscathed after more than a half-century of legal
                      challenges and medical scrutiny: Smoking kills.

                      But what about that lazy trail of smoke that lilts from a lit cigarette into the
                      open air?

                      Scientists agree it contains the same cocktail of harmful compounds that
                      smokers inhale, more than 55 cancer-causing chemicals including
                      formaldehyde, arsenic and the powerful toxin benzoapyrene.

                      They also agree that nonsmokers inhale and digest the toxic smoke just as
                      their smoking counterparts do, albeit in smaller quantities. Traces of
                      chemicals found only in tobacco turn up in biological studies of nonsmokers
                      frequently exposed to cigarette smoke.

                      Tobacco causes increasingly stiff and narrow arteries that precipitate a heart
                      attack. Its chemicals create long-lasting genetic mutations that blossom into
                      lung cancer.

                      But how much damage does so-called passive smoking cause? Can
                      involuntary exposure, over time, wreak similar damage on the heart and
                      lungs of someone who has never lit up?

                      During the past, biologists and courts have wrestled with the question,
                      occasionally arriving at different answers. Fueled by regulators' zeal to hold
                      the tobacco industry accountable for America's epidemic of
                      smoking-related illness, the legal and scientific debate has intensified during
                      the last five years.

                      And geneticists, epidemiologists and molecular and cellular biologists point
                      to a growing body of research on secondhand smoke.

                      Large research studies single out environmental tobacco smoke as the
                      culprit for a number of childhood ailments and chronic diseases: asthma, ear
                      infections, eye irritation and low birth weight babies.

                      A 1998 study, published in the Journal of the American Medical
                      Association, found secondhand smoke increased the rate at which
                      nonsmokers' arteries clog or harden by 20 percent.

                      Reports like these worry Bridgeman's waitress Carrie Newberg. Her father,
                      grandfather and grandmother all died of heart disease at early ages, 53, 56
                      and 38, respectively. Newberg turned 36 Tuesday.

                      Three of her four weekly shifts landed her in the Duluth restaurant's smoking
                      section, where the fumes aggravated her allergies. ``By the time I would get
                      home, I would have such a headache,'' she said.

                      Newberg and several Bridgeman's employees approached the restaurant's
                      operations manager, Warren Nelson, about eliminating the smoking section.
                      ``I just felt like it was a major factor for my health,'' she said.

                      He agreed.

                      The restaurant went smoke-free April 24.

                      Newberg is thrilled. The irritation, sneezing and sinus trouble that plagued
                      her at the end of each eight-hour shift have subsided. The air is clean, she
                      said.

                      The amount of secondhand smoke circulating in the air of restaurants and
                      bars can vary, according to recent medical studies. In some research,
                      investigators found the presence of smoke is no more than levels found in
                      the home of a smoker.

                      In other reports, the amount of smoke recorded in air samples was six times
                      that found in other workplaces and four times that found in the home of a
                      smoker, leading researchers to estimate that some hospitality industry
                      employees face as much as a 50 percent increased risk of developing lung
                      cancer.

                      The most clear-cut example of secondhand smoke's effects surface in
                      studies of lung cancer, where a unique trail of chemical footprints left by
                      harmful tobacco compounds has linked all cigarette smoke -- including
                      secondhand -- to the development of tumors.

                      Each time a person breathes in tobacco smoke, it triggers the body's
                      intricate genetic survival plan against cancer -- one that doesn't always
                      succeed.

                      Once inhaled, the smoke's cancerous chemicals come under attack as the
                      body tries to break down the toxic material into less harmful elements that it
                      can digest and reject.

                      This first line of defense can fail. More virulent chemicals can turn the tables.
                      Instead of falling prey to the body's foot soldiers -- proteins called enzymes
                      -- the cancer-causing agents take root and form a powerful, and potentially
                      unshakable, bond with DNA.

                      This tight link can mutate DNA, the genetic code found in each of the
                      body's 100 trillion cells. Genes carry instructions that guide cell growth.

                      Altering those instructions can produce fatal consequences: In cases of lung
                      cancer, scientists worry in particular about tampering with two genes.

                      One promotes the growth of tumors; the other suppresses them. Altering
                      either can make conditions ripe for cancerous tumors to flourish.

                      Desperate to shake loose from this destructive bond before it causes
                      damage to the genetic code, the body dispatches enzymes to repair cells'
                      DNA.

                      This second line of defense can fail too, triggering a last-ditch effort to rid
                      the body of the cell entirely, a sort of hari-kari of the cell, by which it
                      commits a programmed suicide.

                      Not all of the cells follow the body's survival code: Too many such rouges,
                      and a colony of mutated cells develops into a cancerous tumor.

                      Why do genetic defenses fail in some cases and succeed in others? What
                      makes some people more susceptible to developing lung cancer and others
                      seemingly immune?