Heart Disease and Stroke
Smoking causes fatty deposits to build up in the blood vessels, leaving them narrow or blocked. This leads to heart disease or stroke. About 40% of deaths due to heart disease before the age of 65 are related to smoking.
Cancer
Cigarette smoke contains more than 50 cancer-causing substances.
Smoking is the most common, preventable cause of lung cancer. Smokers are 22 times more likely to develop lung cancer. 90% of all lung cancer cases in Singaporean males occur among smokers
The longer one smokes, the greater the risk of developing cancers such as cervical and breast cancer, cancer of the mouth, throat, larynx, pharynx, oesophagus, stomach, pancreas, kidney and bladder.
Chronic Obstructive Pulmonary Disease (COPD)
Smoking narrows the airways and destroys the air sacs in the lungs. This makes breathing difficult. Smoking is the most common cause of COPD, which includes chronic bronchitis and emphysema. COPD is the 6th largest cause of death in Singapore.
Bone Loss and Osteoporosis
Osteoporosis is a disease that causes bones to lose density and become brittle, leading to hip, spine and wrist fractures.
Women who smoke are 50% more likely to suffer from osteoporosis than non-smokers.
Re-productive and Sexual Health
Smoking increases the risk of infertility in both men and women.
Men
•Smokers are 50% more likely to suffer from impotence or erectile dysfunction.
•Smoking reduces the volume of ejaculation, lowers sperm count, distorts sperm shape and impairs sperm mobility.
Women
•Women who smoke may experience early menopause and more menopausal symptoms.
•Smoking may lead to decreased egg counts due to destruction of eggs in the ovaries before the eggs reach maturity.
•Smoking during pregnancy increases the risk of miscarriage, stillbirth, preterm delivery, and low birth weight. The smoke inhaled (either directly from a cigarette or from second-hand smoke) by a pregnant woman goes directly to her baby's lungs. It prevents as much as 25 % of oxygen from reaching the placenta.
Second-hand Smoke
About 90% of the smoke from every cigarette ends up in the air as environmental tobacco smoke (ETS).
ETS
•causes lung cancer in people who have never smoked before.
•causes heart attack, especially among the spouses of smokers. ETS also increases the risk of repeated heart attacks if one has suffered from heart attack before.
•increases the risk of heart disease, lung disease, asthma, allergies, sinus problems, blood vessel disease or worsen the symptoms if one is already suffering from these.
A LONG TRAIL OF EVIDENCE LINKS CIGARETTE SMOKING TO LUNG CANCER
As someone who’s life has been touched by the tragic effects of cigarette smoking, I was saddened last week when the Supreme Court barred the FDA from regulating cigarettes. About 48 million adult Americans smoked cigarettes last year, according to the CDC. That’s one in four people, a fact that astonishes and alarms me. Why? Because this year an estimated 180,000 people will be diagnosed with lung cancer in the United States, and 90% of them will die within three years -- and 96% of these cancer victims are cigarette smokers.
Is there a cause-and-effect connection between smoking cigarettes and lung cancer? Two years ago, I wrote my first columns for the Post Dispatch, explaining the scientific evidence that cigarette smoking causes lung cancer, and that cigarette smoking is addictive. If these two points are indeed true, then cigarettes , so much a part of American life, are in fact an addictive deadly drug! In the hope of encouraging readers to urge congress to act, I am reprinting these columns. In today’s column we will follow the trail of evidence that proves clearly that smoking causes cancer. In next week’s column I will examine the evidence that smoking tobacco is addictive.
POINTING THE FINGER AT CIGARETTES
The long trail of evidence linking cigarettes to lung cancer has its beginnings right here in St. Louis, at Washington University’s School of Medicine. In 1948 a young first-year medical student, Ernst Wynder, witnessed an autopsy of a man who had died of lung cancer, and noted the lungs were blackened. Curious, he looked into the background of the patient. There was no obvious exposure to air pollution, but the man’s wife revealed he had smoked two packs of cigarettes a day for thirty years! Like a dog with a juicy bone, Wynder had found a puzzle that would occupy him much of his professional life, and despite much controversy, he never let go of it.
Over the next two years, Wynder doggedly reviewed records to see if there were other cases linking cigarettes and lung cancer. He found that many lung cancer patients were smokers. Interviewing lung cancer patients and "control" patients with other cancers, far more cancer occurred among the smokers. Early in 1950 he published his results in the Journal of the American Medical Association. Comparing 649 lung cancer patients with 600 controls, he found lung cancer an incredible 40 times higher among smokers, with the risk of cancer increasing with the number of cigarettes smoked.
Later that year, Richard Doll, a well known British scientist, reported an even more convincing finding linking smoking to lung cancer. Over a period of years, Doll had interviewed quite a large number of physicians, inquiring of each about their smoking habits -- then waited to see which ones developed lung cancer. Overwhelmingly, they were the smokers. Because it was not "after the fact", Doll’s test of the smoking causes cancer hypothesis was particularly rigorous and powerful. From that day forward, the scientific case linking smoking to lung cancer has been clear-cut.
CIGARETTE MANUFACTURERS ARE NOT CONVINCED
As evidence linking cigarettes and lung cancer mounted in the 1950s, the cigarette manufacturers funded the Tobacco Industry Research Commission (later to become the Tobacco Research Council) to look into the matter. This industry-funded group found no compelling evidence of a cause-and-effect relationship between cigarettes and smoking, suggesting that many other factors may contribute, such as air pollution.
However, over the 1950s and 1960s, the mounting evidence became increasingly difficult to ignore. Two lines of evidence were particularly telling. The first consisted of detailed information about cancer rates among smokers. The annual incidence of lung cancer among nonsmokers is only a few per hundred thousand, but increases with the number of cigarettes smoked per day to a staggering 300 per hundred thousand for those smoking 30 cigarettes a day. The world’s longest-running survey of smoking, begun in 1951 in Britain, revealed that by 1994 the death rate for smokers was three times that for nonsmokers among men over 35.
The second line of evidence consisted of changes in the incidence of lung cancer that mirror changes in smoking habits. Look carefully at the data presented in the graph. The upper curves are compiled from data on American men and show the incidence of smoking and of lung cancer since 1900. As late as 1920, lung cancer was a rare disease. About 20 years after the incidence of smoking began to increase among men, lung cancer also started to become more common. Now look at the lower curves, which present data on American women. Because of social mores, significant numbers of American women did not smoke until after World War II, when many social conventions changed. As late as 1963, when lung cancer among males was near current levels, this disease was still rare among women. In the United States that year, only 6588 women died of lung cancer. But as women’s frequency of smoking has increased, so has their incidence of lung cancer, again with a lag of about 20 years. American women today have achieved equality with men in the number of cigarettes they smoke, and their lung cancer death rates are now rapidly approaching those for men. This year, an estimated 66,000 women will die of lung cancer in the United States.
Cigarette manufacturers were not convinced by these relationships, however compelling they might seem, and continued to argue that the causal connection between lung cancer and smoking had not been proved. In a long series of court cases -- all of which they won -- the cigarette manufacturers never backed away from their claim that these relationships were coincidental.
UNRAVELING THE RIDDLE: HOW CANCER HAPPENS
With the "War on Cancer," scientists began in the 1970s a frontal assault on the problem of what causes cancer. Some data pointed to viruses as a potential cause, while other data implicated chemicals of various kinds. Over the next twenty five years, hundreds of laboratories bore down on the problem, and gradually a clear picture emerged. Cancer, it turns out, is a defect in the system cells use to control how frequently they divide. A battery of critical regulatory genes control this process in much the same way you control the speed of a car -- some genes act as accelerators, others as breaks. Cancer results when a gene mutation occurs that stomps on the accelerator or removes the breaks. The first cancer to be studies in molecular detail, a form of bladder cancer, proved to be a point mutation in a gene specifying a protein that was part of a cell division accelerator.
Cancer, then, is the direct result of damage to genes that restrain cell division. Without controls, the mutated cell divides continuously, now a cancer cell. Because healthy cells possess many controls that act as breaks on cell division (called tumor suppressors), it usually takes several mutations to induce cancer. That is why cancer is more common among older people than children.
Chemicals that cause mutations in genes are called mutagens. Cigarette smoke contains many powerful mutagens. Introducing cigarette smoke to the lungs of mice and other laboratory animals creates mutations in the epithelial cells that line their lungs (and thus are exposed to the chemicals). Cancer biologists propose that the lungs of cigarette smokers are similarly sensitive, and that lung cancer is caused by mutation of growth-regulating genes by mutagenic chemicals within cigarette smoke.
THE SMOKING GUN
Cigarette manufacturers claimed to be unimpressed by this work, largely carried out in mice. Humans, they claimed, never encounter conditions such as those imposed on research mice, and there is, as yet, no clear case for cause-and-effect in humans.
The tide turned in 1998. Scientists studying a tumor suppressor gene called p53 demonstrated a direct link between cigarettes and lung cancer. p53 is the cell’s error-detecting system, proofreading the DNA before cell division to make sure there is no damage. When it detects DNA damage, p53 halts cell division and stimulates DNA repair enzymes that fix the trouble. Mutations that inactivate p53 remove a key barrier to unrestricted cell division. p53 is inactivated in 70% of all lung cancers. A puzzling discovery was that the p53 mutations in cancer cells almost all occur at one of three "hot spots" within the p53 gene.
The key link that explains the "hot spots" and links lung cancer to cigarettes is a chemical called benzo (a) pyrene (BP), a potent mutagen released into cigarette smoke from tars in the tobacco. The epithelial cells of the lung absorb BP from cigarette smoke and chemically alter it to a derivative form, benzo (a) pyrene diol epoxide (BPDE). BPDE binds directly to the tumor suppressor gene p53 and mutates it to an inactive form. The key evidence linking cigarette smoking and cancer, the "smoking gun," is that when the mutations of p53 caused by BPDE from cigarettes were examined, they were found to cluster at precisely the same three specific "hot spots" seen in lung cancers! The conclusion is inescapable: the mutations inducing lung cancer are caused by chemicals in cigarette smoke.
Faced with this new incontrovertible evidence, the tobaccco companies have abandoned their claim that cigarettes have not been shown to cause cancer.
DODGING THE BULLET: HOW TO AVOID CANCER
Clearly, the best way to avoid cancer is not to smoke. While one cigarette is not likely to induce cancer, the accumulated risk of many cigarettes progressively increases the odds of disaster. Imagine locking yourself in a dark closet with a companion armed with a pistol. You spin the companion to mask your location, then say "Shoot!" What are the odds you will be hit by the bullet? Not great. How many times would you let your companion shoot? Every cigarette is one more shot at p53.
Using studies of how life expectancy is reduced by smoking cigarettes, life insurance companies have calculated that smoking a single cigarette lowers one’s life expectancy by 10.7 minutes (that is longer than it takes to smoke the cigarette!). Every pack of 20 cigarettes bears an unwritten label"
"The price of smoking this pack of cigarettes
is 3 1/2 hours of your life."
I started smoking a pack of cigarettes a day when I was 13, and quit when I was 30. That’s some 120,000 chances I took. How could I have been so stupid? I wasn’t unaware of how dangerous my habit was. I just couldn’t quit. In next week’s column I will explore why
Home > Why Quit? > Harmful Effects of Smoking
Harmful Effects of Smoking
Do you know that smoking causes 25 diseases and 11 Cancers?
There are over 4000 types of chemicals in each cigarette. 400 of them are poisonous and at least 50 of them cause cancer. Some of these chemicals include:
•Nicotinecauses addiction
• Carbon monoxidea dangerous gas found in car exhaust smoke
• Tarused to cover surface of roads
•Acetonepaint stripper
•DDTa pesticide which kills mosquitoes and ants
•Arsenicwhite ant poison
• Formaldehydeused to embalm dead bodies
• Ammoniaactive ingredient in floor cleaners
•Hydrogen cyanidepoison used in gas chambers
Not many people know that nicotine in cigarettes is as addictive as heroin and cocaine. Smoking can kill you in many ways:
Heart disease and stroke - Smoking causes fatty deposits to build up in the blood vessels, leaving them narrow or blocked. This leads to heart disease or stroke. About 40% of deaths due to heart disease before the age of 65 are related to smoking.Cancer - Cigarette smoke contains more than 50 cancer-causing substances. Smoking is the most common, preventable cause of lung cancer. Smokers are 22 times more likely to develop lung cancer. 90% of all lung cancer cases in Singaporean males occur among smokers.Chronic Obstructive Pulmonary Disease (COPD) - Smoking narrows the airways and destroys the air sacs in the lungs. This makes breathing difficult. Smoking is the most common cause of COPD, which includes chronic bronchitis and emphysema. COPD is the 6th largest cause of death in Singapore.Do you smoke at home in the presence of your spouse and children?Think twice before you light up in front of the TV or even in the open-air hawker centres. Passive smokers (other people who inhale your smoke) suffer serious negative health effects, especially young children.
Exposure to cigarette smoke, even for brief periods, can cause eye, nose and throat irritation. It can also cause headaches, dizziness, nausea, coughing and wheezing.
Cigarette smoke smoke can make it worse for people already suffering from allergies or asthma.
Cigarette smoke can cause you to develop heart disease and cancer.
• Your spouse will be affected by your cigarette smoke. A wife is put at greater risk of death from heart disease if she breathes in the smoke from her husband.
• Chemicals in cigarette smoke can stimulate the formation of various cancers and/or speed up its development.
Children are especially vulnerable to the effects of passive smoking. This is because they breathe faster than adults and inhale more air and pollutants relative to their body weight.
Children of smokers are twice more likely to develop respiratory infections, middle ear infections, asthma and chronic bronchitis than children of non-smokers.
Children of smokers are also twice as likely to start smoking themselves compared to children of non-smokers.
Protect the health of your family, quit smoking today!