Adverse health effects from tobacco usage are well documented. According to the U.S. Surgeon General, over ten times as many Americans have died prematurely from cigarette smoking than have died in all the wars fought in U.S. history. Smoking can harm every organ in the human body, and it can directly result in death from heart disease, cancers or strokes. Cancer is far and away the most common of these diagnoses; 90% of lung cancer deaths in the U.S. can be attributed to smoking.
Chronic illness in the form of obstructive pulmonary disease, cardiac disease, diabetes, and autoimmune disorders has also been conclusively tied to smoking. Women are at particular risk and may experience difficulties with conception or pregnancy.
One third of all cancer deaths in the U.S. are related to smoking. Though the habit is most often associated with lung cancer, tobacco use can cause cancer anywhere in the human body. The U.S. Surgeon General's 2014 report, The Health Consequences of Smoking―50 Years of Progress, identified smoking as a direct cause of liver and colorectal cancers. Evidence suggests a causal link between breast and prostate cancers, but that has yet to be definitively proven. However, it is established that smokers bear an increased risk of dying from any cancer compared to their non-smoking neighbors. Quitting smoking immediately improves the survival odds of any cancer patient. According to research from the National Cancer Institute, quitting smoking by age 30 reduces the overall chance of smoking-related death by 90%. The rate is 50% for those who quit at around 50 years old.
Stroke and coronary heart disease, both of which may result from smoking, are the leading causes of death in the United States. Cigarette smokers are highly likely to develop cardiovascular disease at some point in life. Smoking damages blood vessels by thinning their walls, which in turn can result in narrowed passageways that obstruct blood flow to the heart. Over time, this can cause increased blood pressure, clot formation and damage to the heart muscle. Peripheral arteries may also be affected, and there is an increased likelihood of aortic aneurysms in smokers. Ultimately, smokers experience heart attacks and strokes at much higher rates than non-smokers.
Because cigarette smoke is inhaled directly into the lungs, tobacco has an immediate negative effect on the respiratory system. There are about 600 ingredients in cigarettes besides nicotine, many of which are known to be poisonous. These toxins not only displace oxygen but impair the lungs' ability to remove harmful particles. Chronic obstructive pulmonary disease (COPD), which manifests in shortness of breath, restricted airflow and sputum production, affects 20% of all smokers and 50% of lifelong smokers. Sufferers of COPD almost always are afflicted with emphysema and bronchitis, described below:
- Emphysema causes tiny air sacs tasked with oxygen exchange to deteriorate. Once these sacs lose their elasticity, the expansion and contraction necessary for optimum lung function is compromised.
- Chronic bronchitis occurs when the narrow tubes in the lining of the lungs, called bronchia, swell from irritation and damage. Over time, breathing becomes restricted as the bronchia lose their ability to transport oxygen.
The American Lung Association reports that COPD and other chronic lung diseases make up 73% of all smoking-related illnesses in the U.S. Some of these other illnesses causally linked to smoking include pneumonia, asthma and tuberculosis.
While it wasn't studied as early as other known outcomes of smoking, it is now understood that smoking poses a particular danger for pregnant women and fetuses. The entire reproductive cycle, from conception through delivery, is at risk when a woman smokes. Cigarette smokers are known to have more difficulty conceiving a child, and are more likely to experience life-threatening ectopic pregnancy or uterine rupture. Pregnant women who smoke must also consider the effects on their babies, because whatever circulates in the bloodstream of a pregnant mother is also delivered to a fetus, including nicotine. Fetuses exposed to the toxins in cigarettes suffer compromised oxygen supply and are at risk of complications including:
- Increased heart rate
- Miscarriage or fetal death
- Birth defects
- Respiratory illness
- Prematurity and/or low birth weight
- Sudden Infant Death Syndrome (SIDS)
Autoimmune Disorders and Other Chronic Illness
More recently, smoking has been linked to disorders of the autoimmune system. When this system malfunctions, the body mistakenly attacks healthy tissue as if it were a foreign invader. Severe and chronic illness can result, such as Crohn's disease, lupus and rheumatoid arthritis. Smoking increases the likelihood of these diagnoses and also reduces treatment efficacy. Many other serious health conditions have been linked to smoking, either as a contributing cause or a factor that makes treatment more difficult. Other smoking related health issues include diabetes, cataracts and other vision problems, osteoporosis, and dental problems.