Why is smoking bad for you?

Smoke in shape of EKG
Smoking causes damage to nearly every organ in the body and is directly responsible for a number of diseases.

Every year, more than 480,000 people die in the United States (U.S.) due to tobacco-related diseases. That is around 1 in 5 of all deaths in the U.S. annually. It is estimated that 1 in 2 smokers will die from a smoking-related disease.

Smoking causes more deaths in the U.S. each year than the following combined:

alcohol use
firearm-related incidents
HIV
illegal drug use
motor vehicle incidents

Smoking shortens the life of a male by about 12 years and the life of a female by around 11 years.

Two poisons in tobacco that affect peoples' health are:

Carbon monoxide is found in car exhaust fumes and is fatal in large doses. It replaces oxygen in the blood and starves organs of oxygen and stops them being able to function properly.
Tar is a sticky, brown substance that coats the lungs and affects breathing.

The impact of smoking:

Brain
Bones
Heart and circulation
Immune system
Lungs
Mouth
Reproduction and fertility
Skin
Cancer

Health risks associated with smoking

Smoking affects many different areas of the body. Below, we cover each part of the body in turn:
Brain

Smoking can increase the likelihood of having a stroke by 2 to 4 times. Strokes can cause brain damage and death.

One way that stroke can cause brain injury is through a brain aneurysm, which occurs when the wall of the blood vessel weakens and creates a bulge. This bulge can then burst and lead to a serious condition called a subarachnoid hemorrhage.
Bones

Smoking can make bones weak and brittle, which is particularly dangerous for women, who are more prone to osteoporosis and broken bones.
Heart and circulation

Smoking causes plaque to build up in the blood. Plaque sticks to the walls of arteries (atherosclerosis), making them narrower; this reduces blood flow and increases the risk of clotting.

Smoking also narrows the arteries, making it harder for blood to flow, as well as increasing blood pressure and heart rate.

Also, chemicals in tobacco smoke increase the chance of heart problems and cardiovascular diseases.

Some of the most common are:

Coronary heart disease - narrow or blocked arteries around the heart. It is among the leading causes of death in the U.S.
Heart attack - smokers are twice as likely to have a heart attack.
Heart-related chest pain.

Carbon monoxide and nicotine in cigarettes make the heart work harder and faster; this means that smokers will find it more difficult to exercise.

Even smokers who smoke 5 or fewer cigarettes a day can have early signs of cardiovascular disease.
Immune system

The immune system protects the body against infection and disease. Smoking compromises this and can lead to autoimmune diseases, such as Crohn's disease and rheumatoid arthritis.

Smoking has also been linked to type 2 diabetes.
Lungs
Lungs as ash tray
Smoking can cause a variety of lung problems.

Perhaps the most obvious part of the body affected by smoking is the lungs. In fact, smoking can impact the lungs in a number of different ways.

Primarily, smoking damages the airways and air sacs (known as alveoli) in the lungs.

Often, lung disease caused by smoking can take years to become noticeable, this means it is often not diagnosed until it is quite advanced.

There are many lung and respiratory problems caused by smoking; below are three of the most common in the American population:

Chronic obstructive pulmonary disease (COPD): This is a long-term disease that worsens over time. It causes wheezing, shortness of breath, and chest tightness. It is the third leading cause of death in the U.S. There is no cure.

Chronic bronchitis: This occurs when the airways produce too much mucus, leading to a cough. The airways then become inflamed, and the cough is long-lasting. In time, scar tissue and mucus can completely block the airways and cause infection. There is no cure, but quitting smoking can reduce symptoms.

Emphysema: This is a type of COPD that reduces the number of sacs in the lungs and breaks down the walls in between. This destroys the person's ability to breathe, even when resting. In the latter stages, patients often can only breathe using an oxygen mask. There is no cure, and it cannot be reversed.

Other diseases caused by smoking include pneumonia, asthma, and tuberculosis.
Mouth

Smoking can cause bad breath and stained teeth, as well as gum disease, tooth loss, and damage to the sense of taste.
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Reproduction and fertility

Women who smoke can find it more difficult to become pregnant. Women who smoke when pregnant increase a number of risks for the baby, including:

premature birth
miscarriage
stillbirth
low birth weight
sudden infant death syndrome
infant illnesses

Smoking can cause impotence in men because it damages blood vessels in the penis. It can also damage sperm and affect sperm count. Men who smoke have a lower sperm count than men who are non-smokers.
Skin

Smoking reduces the amount of oxygen that can reach the skin, which speeds up the aging process of the skin and can make it dull and gray.

Smoking prematurely ages the skin by 10-20 years and makes facial wrinkling, particularly around the eyes and mouth, three times more likely.
Cancer

Smoking causes around 30 percent of all cancer deaths in the U.S. In the case of lung cancer, around 80 percent of all deaths are caused by smoking.

Lung cancer is the leading cause of cancer death in both men and women; it is extremely difficult to treat.

Tobacco smoke has around 7,000 chemicals in it, and around 70 of those are directly linked to causing cancer.

As well as the lungs, smoking is also a risk factor for these types of cancer, among others:

mouth
larynx (voice box)
pharynx (throat)
esophagus (swallowing tube)
kidney
cervix
liver
bladder
pancreas
stomach
colon/rectum
myeloid leukemia

Cigars, pipe-smoking, menthol cigarettes, chewing tobacco, and other forms of tobacco all cause cancer and other health problems. There is no safe way to use tobacco.
The benefits of quitting

Quitting smoking reduces health risks.

The chances of having a stroke reduces to half of that of a non-smoker in 2 years, and the same as a non-smoker in 5 years.

Risks for cancers of the mouth, throat, esophagus, and bladder drop by half within 5 years. The risk for lung cancer drops by half after 10 years.

A year after quitting smoking, the risk of a heart attack is reduced by half. After 15 years, it is the same as someone who has never smoked.

Overall, once someone stops smoking, their health will improve and their body will begin to recover.