Lung cancer is a disease where abnormal cells in the lungs grow uncontrollably, forming tumors that can interfere with breathing and may spread (metastasize) to other parts of the body. It is one of the leading causes of cancer-related deaths worldwide.
When these chemicals enter the lungs, they damage the DNA in lung cells. Over time, repeated exposure causes mutations that can lead to uncontrolled cancer cell growth.
Types of Lung Cancer Linked to Smoking
Non-Small Cell Lung Cancer (NSCLC)
The most common type, slowly developing but still deadly.
Small Cell Lung Cancer (SCLC)
Very aggressive and fast-spreading; strongly associated with long-term smoking.
Combining smoking with alcohol, pollution, or occupational chemicals
Common Signs and Symptoms
Lung cancer may not cause symptoms early, but later symptoms include:
Persistent cough or “smoker’s cough”
Chest pain or discomfort
Shortness of breath or wheezing
Coughing up blood
Unexplained weight loss and fatigue
Frequent lung infections (pneumonia, bronchitis)
Hoarseness of voice
Complications
Difficulty breathing
Spread (metastasis) to bones, brain, liver, or lymph nodes
Severe infections
Respiratory failure
Death
Can Quitting Smoking Reduce Risk?
Yes. Quitting smoking:
Lowers lung cancer risk significantly, even after years of smoking
Reduces further DNA damage
Helps lung cells repair to some degree
Improves response to treatment if cancer occurs
However, the risk never returns completely to that of someone who never smoked — which is why early quitting matters most.
Prevention Tips
Stop smoking as early as possible
Avoid secondhand smoke
Get regular medical check-ups
Maintain a healthy diet and active lifestyle
Conclusion
Smoking is the main cause of lung cancer, and the disease is often fatal. The chemicals in tobacco smoke damage lung cells, leading to DNA mutations and tumor growth. Quitting at any age reduces the risk and greatly improves long-term health.
When individuals consider cancers linked to smoking, lung cancer is invariably the first that comes to mind. The majority of lung cancer fatalities, nearly 90% in men and 80% in women, are attributed to cigarette smoking. Additionally, there are numerous other types of cancer associated with smoking, including cancers of the oral cavity, pharynx, larynx, esophagus, bladder, stomach, cervix, kidney, pancreas, and acute myeloid leukemia. The list of permitted additives in cigarette production comprises 599 potential ingredients. Upon combustion, cigarette smoke releases over 4000 chemicals, with more than 40 recognized as carcinogens.
* Cancer ranks as the second leading cause of death and was one of the initial diseases directly linked to smoking.
* Lung cancer stands as the primary cause of cancer-related deaths, with cigarette smoking responsible for the majority of cases.
* In comparison to nonsmokers, male smokers are approximately 23 times more likely to develop lung cancer, while female smokers are about 13 times more likely. Smoking accounts for roughly 90% of lung cancer deaths in men and nearly 80% in women.
* In 2003, it was estimated that 171,900 new lung cancer cases were diagnosed, resulting in approximately 157,200 deaths from the disease.
* The 2004 Surgeon General's report provides further evidence supporting earlier findings that smoking is a cause of cancers affecting the oral cavity, pharynx, larynx, esophagus, lung, and bladder.
* Carcinogenic substances present in tobacco smoke harm crucial genes that regulate cell growth, leading to abnormal growth or excessive reproduction of cells.
* Cigarette smoking is a significant contributor to esophageal cancer in the United States. Decreasing smoking and smokeless tobacco usage could avert many of the estimated 12,300 new cases and 12,100 deaths from esophageal cancer that occur each year.
* The interplay of smoking and alcohol consumption is responsible for the majority of laryngeal cancer cases. In 2003, an estimated 3800 deaths were attributed to laryngeal cancer.
* In 2003, approximately 57,400 new bladder cancer cases were identified, with an estimated 12,500 fatalities resulting from the disease.
* The risk of cancers attributable to smoking typically escalates with the quantity of cigarettes consumed and the duration of smoking, and it generally diminishes after complete cessation.
* Smoking cigarettes with a lower tar yield does not significantly lessen the risk of lung cancer.
* Cigarette smoking heightens the likelihood of developing cancers of the mouth. This risk is also elevated among individuals who smoke pipes and cigars.
* A decrease in the number of individuals who smoke cigarettes, pipes, cigars, and other tobacco products, or who use smokeless tobacco, could avert the majority of the estimated 30,200 new cases and 7,800 fatalities from oral cavity and pharynx cancers each year in the United States.
New cancers identified in this report:
* The 2004 Surgeon General's report has newly recognized additional cancers linked to smoking, including those of the stomach, cervix, kidney, pancreas, and acute myeloid leukemia.
* In 2003, approximately 22,400 new stomach cancer cases were diagnosed, with an estimated 12,100 deaths anticipated.
* Individuals who have quit smoking exhibit lower rates of stomach cancer compared to those who continue to smoke.
* For women, the risk of cervical cancer escalates with the length of time spent smoking.
* In 2003, around 31,900 new kidney cancer cases were diagnosed, resulting in an estimated 11,900 deaths from the disease.
* In 2003, it was estimated that 30,700 new cases of pancreatic cancer were diagnosed, leading to 30,000 deaths. The average duration from diagnosis to death for pancreatic cancer is approximately 3 months.
* In 2003, roughly 10,500 cases of acute myeloid leukemia were diagnosed in adults.
* Benzene is recognized as a causative agent of acute myeloid leukemia, and cigarette smoke is a primary source of benzene exposure. Among smokers in the U.S., 90% of benzene exposure is derived from cigarettes.
Smoking continues to be the foremost cause of preventable mortality and adversely affects health at every stage of life. It poses risks to unborn babies, infants, children, adolescents, adults, and the elderly.
Smoking affects almost every organ in the human body. The chemicals in tobacco smoke — including nicotine, carbon monoxide, and tar — cause damage that can be immediate, long-lasting, and often irreversible.
🫁 1. Respiratory System
Irritation of airways, persistent coughing, and mucus buildup
Destruction of cilia (airway cleaners), leading to infections
The impact of smoking on human health is severe and often fatal. Cigarettes contain around 4000 chemicals, many of which are harmful. These substances influence everything from the internal operations of organs to the effectiveness of the immune system. The consequences of cigarette smoking are both destructive and far-reaching.
* Nicotine reaches the brain within 10 seconds of inhalation. It has been detected in all body parts, including breast milk.
* Carbon monoxide attaches to hemoglobin in red blood cells, hindering these cells from transporting a full supply of oxygen.
* Carcinogenic substances in tobacco smoke damage crucial genes that regulate cell growth, leading to abnormal growth or excessive reproduction of cells.
* The carcinogen benzo(a)pyrene attaches to cells in the airways and major organs of smokers.
* Smoking impairs immune system function and may elevate the risk of respiratory and other infections.
* There are several probable mechanisms through which cigarette smoke inflicts damage. One such mechanism is oxidative stress, which mutates DNA, encourages atherosclerosis, and results in chronic lung injury. Oxidative stress is believed to be a fundamental process in aging, contributing to the onset of cancer, cardiovascular diseases, and COPD.
* The body generates antioxidants to assist in repairing damaged cells. Smokers exhibit lower levels of antioxidants in their bloodstream compared to nonsmokers.
* Smoking correlates with increased levels of chronic inflammation, another harmful process that may lead to oxidative stress.
Smoking is one of the leading preventable causes of early death worldwide. Smokers, on average, die years earlier than non-smokers due to long-term damage to major organs, especially the heart, lungs, and circulatory system.
2. Leading Cause of Several Fatal Diseases
Smoking greatly increases the likelihood of deadly illnesses, including:
Non-smokers exposed to cigarette smoke are also at risk of serious illness and premature death, especially infants and children. This includes increased chances of SIDS (Sudden Infant Death Syndrome), childhood asthma, and fatal respiratory complications.
5. Smoking Shortens Life Expectancy
Studies show that smoking can shorten a person’s lifespan by up to 10 years or more, depending on age, lifestyle, and duration of smoking. Heavy or long-term smokers face significantly higher mortality rates than occasional or former smokers.
6. Quitting Reduces the Risk
Even if a person has smoked for many years, quitting at any age significantly lowers the risk of early death. The body gradually heals, reducing the chance of cancer, heart disease, and respiratory failure.
In Conclusion
Smoking dramatically increases the risk of early, preventable death through cancer, heart and lung diseases, toxic exposure, and chronic organ damage. However, stopping smoking — even later in life — can greatly improve survival and quality of life.
Cigarette smoking is the leading cause of preventable death in the United States.
Cigarette smoking causes more than 480,000 deaths each year in the United States. This is nearly one in five deaths.
Smoking causes more deaths each year than the following causes combined
Tobacco smoke irritates the lining of the respiratory tract. This triggers inflammation and swelling, causing coughing, wheezing, and shortness of breath. Over time, the airway walls become thicker and narrower, making breathing more difficult.
2. Damage to Cilia (Airway Cleaning System)
The lungs are protected by tiny hair-like structures called cilia, which remove mucus, dust, and germs. Smoking paralyzes and destroys these cilia, allowing harmful substances to stay in the lungs. This leads to mucus buildup, repeated infections, and persistent cough (“smoker’s cough”).
3. Emphysema (Destruction of Air Sacs)
Smoking gradually damages and destroys the alveoli — the tiny air sacs responsible for oxygen and carbon dioxide exchange. When alveoli break down, the lungs lose elasticity, causing emphysema, a condition where the lungs trap air and breathing feels constantly difficult and exhausting. This damage cannot be reversed.
4. Chronic Bronchitis
Smoking causes long-term irritation of the bronchial tubes, leading to excess mucus production and chronic inflammation. This results in chronic bronchitis, a persistent cough with thick phlegm lasting months or years. Together, emphysema and chronic bronchitis form Chronic Obstructive Pulmonary Disease (COPD).
5. Increased Risk of Lung Cancer
Cigarette smoke contains more than 7,000 chemicals, many of which are carcinogenic. These substances can damage lung cells, causing mutations that may lead to lung cancer, the leading smoking-related cause of death.
6. Reduced Lung Capacity and Function
Due to damaged airways and alveoli, smokers experience:
Reduced oxygen absorption
Difficulty during physical activity
Faster fatigue
Shortness of breath even during light tasks
7. Higher Risk of Respiratory Infections
With weakened cilia and inflamed airways, the lungs cannot effectively remove germs, increasing risks of:
Pneumonia
Bronchitis
Tuberculosis (higher susceptibility and more severe if infected)
8. Exacerbation of Asthma
Smoking irritates the airways and makes asthma symptoms worse, increasing the severity and frequency of asthma attacks.
Can Lung Damage Improve After Quitting?
Some improvements are possible:
Cilia begin to recover within weeks
Lung function improves within several months
Risk of lung cancer decreases over time (though never returns fully to that of a non-smoker)
However, damage like emphysema is permanent, making early cessation crucial.
Smoking is a habit that you may acquire at will but coming out of it can be virtually impossible for many. There has been a constant research going on to figure out the best to kick the butt, but only two out of three smokers try to quit it every year. And only half of those who try succeed. Addiction to tobacco, especially smoking, is a major health problem globally and is the cause for serious respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), as well as tuberculosis and lung cancer. Adolescents who smoke are more likely to suffer chronic respiratory disorders and risk permanent damage to their lungs. The lungs continue to grow well into adulthood, but inhaling the toxins found in tobacco smoke, especially nicotine, slows this process and causes potentially irreversible lung damage.
Anyone who starts using tobacco, especially during their teens, can become addicted to nicotine: The younger you are when you begin to smoke, the more likely you are to become addicted to nicotine much like cocaine, heroin or other drugs. The repeated, compulsive seeking or use of a substance despite its harmful effects and unwanted consequences is addiction which is also marked by a mental or emotional dependence on the substance.
Using tobacco products regularly leads to addiction as they are easily absorbed into the blood through the lungs and quickly spreads throughout the body. Nicotine causes pleasant feelings and distracts you from unpleasant feelings, when taken in small amounts. It reaches the brain within seconds after taking a puff and the chemistry of the brain and central nervous system affects the mood of the user and makes the user want to use more.
When the effects of nicotine start to wear off after a few minutes, the user may start to feel irritated and edgy and may experience irritability, nervousness, headaches, and trouble in sleeping, though it does not amount to serious withdrawal symptoms. As the body adapts to nicotine, smokers tend to increase the amount of tobacco they take in which raises the amount of the substance in their blood, eventually creating tolerance.
Smoking erodes vascular walls
Nicotine works much like other drugs and energises the reward circuits of the brain with a chemical called dopamine and also gives adrenaline rush that is enough to speed up the card and raise blood pressure. Each time an extra level of nicotine reaches our brain, it causes the body to activate its fight or flight stress defenses which immediately releases stored fats, intended to be used to provide the instant energy needed to the stress factors, into the bloodstream.
Nicotine affects the Blood Vessels and Heart
Nicotine also affects the blood vessels and causes erosion of the vessel wall, known as endothelium. The substance promotes functional and structural changes in vascular walls and stimulates catecholamine release, responsible for altering heart rate variability, increasing risk of ventricular and supraventricular arrhythmias, myocardial infarction, i.e. heart failure. In fact, smoking is the most complex cardiovascular risk factor and researchers have found that abstaining from smoking for as less as eight weeks can help reverse the endothelial damage caused by smoking but may still risk your heart.
People who have used tobacco regularly for a few weeks or longer will have withdrawal symptoms if they suddenly stop or greatly reduce the amount they use. There’s no danger in nicotine withdrawal, but the symptoms can be uncomfortable. Trying to quit smoking, tobacco or using any other form does not limit itself to the physical abstention, it also calls for tremendous mental and emotional stamina, and professional guidance to this end is an absolute must for better returns. Systematic approach through medication and Nicotine replacement therapy (NRT) can help reduce the severity of urges and cravings.
Smoking negatively affects almost every organ in the body. Its damage is both immediate and long-term, leading to chronic diseases, cancer, and reduced life expectancy.
1. Effects on the Respiratory System
Smoking damages the lungs early and progressively.
While nicotine may provide temporary relaxation, it worsens long-term mental well-being.
Addiction and withdrawal cycles
Increased stress and irritability
Higher risk of anxiety and depression
Stronger cravings that affect mood and focus
9. Secondhand Smoke Effects
Even non-smokers near cigarette smoke face health risks:
Asthma attacks
Lung cancer
Heart disease
Increased risks for pregnant women and infants
Benefits of Quitting Smoking
Quitting has immediate and lifelong benefits:
Heart rate improves within minutes
Lung function improves in weeks
Stroke and heart attack risks drop in months
Cancer risks decrease over years
Longer life expectancy and improved quality of life
Smokers have a harder time healing from surgeries, and have more overall health issues than do nonsmokers. This results in more time away from work, and more doctor and hospital visits. Smoking compromises a person's health in so many ways.
* Smokers are more likely to be absent from work than nonsmokers, and their illnesses last longer.
* Smokers tend to incur more medical costs, to see physicians more often in the outpatient setting, and to be admitted to the hospital more often and for longer periods than nonsmokers.
* Smokers have a lower survival rate after surgery compared to that of nonsmokers because of damage to the body's host defenses, delayed wound healing, and reduced immune response. Smokers are at greater risk for complications following surgery, including wound infections, postoperative pneumonia, and other respiratory complications.
* Periodontitis is a serious gum disease that can result in the loss of teeth and bone loss. Smoking is causally related to periodontitis. This may be because smoking affects the body's
ability to fight infection and repair tissue.
* Peptic ulcers, which are located in the digestive tract (stomach and duodenum), usually occur in people with an infection caused by the Helicobacter pylori bacterium. Among persons with this infection, smokers are more likely to develop peptic ulcers than nonsmokers. In severe cases, peptic ulcers can lead to death.
* Although only a small number of studies have looked at the relationship between smoking and erectile dysfunction, their findings suggest that smoking may be associated with an increased risk for this condition. More studies are needed, however, before researchers can conclude that the effect of smoking is causally related to erectile dysfunction.
Smoking increases the risk of giving birth before the baby is fully developed, which can result in breathing issues, feeding problems, infections, and long-term developmental delays.
3. Low Birth Weight
Babies exposed to smoking in the womb are often born smaller and underweight. Low birth weight is linked to difficulty regulating body temperature, weak immune function, and long-term health challenges.
Smoking during pregnancy is dangerous for both mother and baby due to restricted oxygen, toxic exposure, and developmental harm. Quitting — even partway through pregnancy — greatly improves outcomes. Support from doctors, counselors, and nicotine cessation programs can help.
Getting pregnant
If you smoke and want to get pregnant, quitting the habit should be a priority. Smoking can prevent you from getting pregnant in the first place. Even in the first trimester smoking affects the health of your unborn baby. Both male and female smokers are about twice as likely to have issues with fertility compared to nonsmokers, according to the American Society for Reproductive Medicine.
The unexpected loss of a pregnancy is a tragic event at any stage. Miscarriages typically occur in the first three months of pregnancy. On rare occasions, they can occur after 20 weeks of gestation. This is called a stillbirth.
According to the U. S. Centers for Disease Control and Prevention (CDC)Trusted Source, smoking raises the likelihood of both early miscarriage and stillbirth. The dangerous chemicals in cigarettes are often to blame.
Other complications from smoking can lead to problems with the placenta or slow fetal development. These issues can also cause a miscarriage or stillbirth.
Ectopic pregnancy
Nicotine can cause contractions in the fallopian tubes. These contractions can prevent an embryo from passing through. One possible result of this is an ectopic pregnancy. This happens when a fertilized egg implants outside of the uterus, either in the fallopian tube, or in the abdomen. In this situation, the embryo must be removed to avoid life-threatening complications to the mother.
Placental abruption
The placenta is the “lifeline” structure that forms during pregnancy to provide the fetus with nutrients and oxygen. Smoking is a major risk factor for several complications linked to the placenta. One such problem is placenta abruption. This is a condition in which the placenta separates from the uterus before childbirth. Placenta abruption can cause severe bleeding and threaten the life of both the mother and the baby. There’s no surgery or treatment to reattach it. Immediate medical attention may help increase the chance of a healthy birth despite placenta abruption.
Placenta previa
Smoking is also a risk factor for placenta previa. During pregnancy, the placenta normally grows in the uterus towards the top of the womb. This leaves the cervix open for delivery. Placenta previa is when the placenta stays in the lower part of the uterus, partially or fully covering the cervix. The placenta often tears, causing excessive bleeding and depriving the fetus of vital nutrients and oxygen.
Smoking during pregnancy can cause preterm birth. That’s when a baby is born too early. There are numerous health risks associated with a preterm birth. These can include:
Smoking can also cause babies to be born with a low birth weight. This doesn’t just mean delivering a small baby. Low birth rate can also lead to other health problems and disabilities. Advances in medical care have reduced the number of deaths as a result of low birth weight. But it’s still a serious condition that can result in:
In extreme cases, low birth weight can cause the death of the newborn.
According to the American Cancer Society, women who quit smoking before getting pregnant lower their risk of having a baby with a low birth weight. Even women who stop smoking during their pregnancy are less likely to have babies with low birth weight than women who keep smoking.
Smoking during pregnancy raises the risk of your baby being born with birth defects. The most common types of problems are congenital heart defects and problems with the structure of the heart. Other health issues that have been linked to smoking while pregnant include cleft lip and cleft palate.
The unfortunate truth
Many pregnant women still smoke despite the known risks the habit will create for themselves and their babies.10 percent of women report that they smoked during the last three months of pregnancy. The only real way to avoid pregnancy complications associated with smoking is to quit.
Increased stress cycle (temporary relief followed by craving)
Difficulty concentrating when craving
Possible link to anxiety and depression worsening over time
Benefits of Quitting
Heart and lung function begin improving within days to weeks
Lower risk of cancer, heart disease, and stroke
Longer life expectancy
Better breathing, smell, taste, and energy
Improved appearance and self-esteem
Money savings and better quality of life
Effects of tobacco smoke
Tar in cigarettes coats the lungs and can cause lung and throat cancer in smokers. It is also responsible for the yellow–brown staining on smokers' fingers and teeth. Carbon monoxide in cigarettes robs the muscles, brain and blood of oxygen, making the whole body — especially the heart — work harder.
Over time this causes airways to narrow and blood pressure to rise, and can lead to heart attack and stroke. High levels of CO, together with nicotine, increase the risk of heart disease, hardening of the arteries and other circulatory problems. A first-time smoker will often feel dizzy and sick.
‘Light’ or ‘low tar’ cigarettes
Research has shown that there is little difference between the amount of chemicals inhaled by people who smoke ‘light’ or ‘low tar’ cigarettes and those who smoke regular cigarettes. People who smoke ‘light’ cigarettes have the same risk of developing smoking-related diseases as people who smoke regular cigarettes.
Immediate effects
Soon after smoking tobacco, the following effects may be experienced:
* initial stimulation, then reduction in brain and nervous system activity;
* enhanced alertness and concentration;
* mild euphoria;
* feelings of relaxation;
* increased blood pressure and heart rate;
* decreased blood flow to body extremities like the fingers and toes;
* dizziness, nausea, watery eyes and acid in the stomach; and
* decreased appetite, taste and smell.
Overdose
Although rare, it is possible to overdose on the nicotine in tobacco. Very large doses of nicotine can result in an increase in the unpleasant effects, including feelings of faintness and confusion,
and a rapid decrease in blood pressure and breathing rate.
In some cases, it can lead to convulsions and death from respiratory failure. 60 milligrams of nicotine taken orally can be fatal for an adult.
Long-term effects
It is estimated that more than 140,000 hospital episodes and 19,000 deaths in Australia can be attributed to tobacco use every year. The principal diagnoses are cancer, heart disease and chronic obstructive pulmonary disease.
Passive smoking
Passive smoking can cause a number of health problems including heart disease, lung cancer and irritation of the eyes and nose. It involves breathing in tobacco smoke from other people's cigarettes:
smoke that has been exhaled or smoke from the end of a lit cigarette.
50 Australians die every day from smoking, compared to 10 who die from alcohol-related conditions and 4 who die as a result of road accidents. Tolerance and dependence
People who use tobacco tend to develop a tolerance to the effects of the nicotine in the tobacco very quickly. This means they need to smoke more and more in order to get the same effect.
With repeated use of tobacco, the risk of dependence on nicotine is high. Dependence on nicotine can be physiological, psychological or both.
People who are physically dependent on nicotine find their body has become used to functioning with the nicotine present and may experience withdrawal symptoms when they reduce their nicotine intake.
People who are psychologically dependent on nicotine may find they feel an urge to smoke when they are in specific surroundings, such as at the pub, or in particular situations such as during their lunch break or socialising with friends.
Research has shown that smoking is often associated with different roles and meanings for smokers, including the following.:
* Social roles, such as enjoyment of the company of friends, the drinking of coffee or alcohol, and promoting social confidence and feelings of independence (particularly for young women).
*Emotional roles — caring for the self, such as helping to deal with stress and anxiety, weight control and providing ‘companionship’.
* Temporal roles, such as connecting the flow of events or time in the smoker's day, providing a break from work or activities and relieving boredom.This may be why smoking is sometimes referred to as the most difficult drug to give up.
Withdrawal
If a person who is dependent on the nicotine in tobacco suddenly stops using it or reduces the amount they use, they will experience withdrawal symptoms because their body has to readjust to functioning without the drug.
Most of these symptoms will disappear within days or weeks of quitting smoking, but cravings may persist for years after stopping using tobacco.
Symptoms include:
* cravings;
* irritability, agitation, depression and anxiety;
* insomnia and disturbed sleeping patterns;
* increased appetite and weight gain;
* restlessness and loss of concentration;
* headaches;
* coughing and sore throat;
* body aches and pains; and
* stomach and bowel upsets.
