Harmful Effects of Tobacco and Smoking

Dr. Faheem Mahmood Butt
Consultant Pulmonologist
Shaukat Khanum Memorial Cancer Hospital & Research Centre

Tobacco & Smoking:
Smoking is a worldwide hazard. It is a single most important cause of preventable premature death. According to World Health Organization (WHO) figures there are about 1.3 billion smokers in the world.  Around 20 billion cigarettes are sold every day. One third of the world population smokes, 12 % of them are women and every day 100,000 kids are added to this number. Tobacco kills more than 8 million people globally every year. More than 7 million of these deaths are from direct tobacco use and around 1.2 million are due to non-smokers being exposed to second-hand smoke.

Smoking cigarette, pipe, cigar, Huqua, Shisha and other use of tobacco like chewing tobacco and tobacco sniffing all are dangerous and addictive. Nicotine present in tobacco smoke causes addiction by increasing the brain levels of chemicals like Dopamine and Endrophine. These chemicals give a sense of happiness hence there is craving for tobacco products. If a person tries to quit, withdrawal effects include irritability, anxiety, depression and lack of concentration.

Tobacco and tobacco smoke have about 4,000 chemicals, 200 of these are poisonous and 60 of these chemicals are known to cause cancer (carcinogens).  Some of these chemicals are, benzene (a petroleum product), ammonia (used in dry cleaning and toilet cleaning), formaldehyde (a chemical used to preserve dead bodies and) and Tar. Tobacco smoke causes atherosclerosis (hardening of the blood vessels) leading to heart attack and stroke. It also contains carbon mono oxide which decreases oxygen in the blood.

Tobacco use and COVID-19: (citation from WHO)

Tobacco smoking is a known risk factor for many respiratory infections and increases the severity of respiratory diseases. A review of studies by public health experts convened by WHO on 29 April 2020 found that smokers are more likely to develop severe disease with COVID-19, compared to non-smokers.

COVID-19 is an infectious disease that primarily attacks the lungs. Smoking impairs lung function making it harder for the body to fight off coronaviruses and other diseases. Tobacco is also a major risk factor for noncommunicable diseases like cardiovascular disease, cancer, respiratory disease and diabetes which put people with these conditions at higher risk for developing severe illness when affected by COVID-19. Available research suggests that smokers are at higher risk of developing severe disease and death.

WHO is constantly evaluating new research, including research that examines the link between tobacco use, nicotine use, and COVID-19. WHO urges researchers, scientists and the media to be cautious about amplifying unproven claims that tobacco or nicotine could reduce the risk of COVID-19.  There is currently insufficient information to confirm any link between tobacco or nicotine in the prevention or treatment of COVID-19.

Nicotine replacement therapies, such as gum and patches are designed to help smokers quit tobacco. WHO recommends that smokers take immediate steps to quit by using proven methods such as toll-free quit lines, mobile text-messaging programs, and nicotine replacement therapies.

Within 20 minutes of quitting, elevated heart rate and blood pressure drop. After 12 hours, the carbon monoxide level in the bloodstream drops to normal. Within 2-12 weeks, circulation improves and lung function increases. After 1-9 months, coughing and shortness of breath decrease.

WHO stresses the importance of ethically approved, high-quality, systematic research that will contribute to advancing individual and public health, emphasizing that promotion of unproven interventions could have a negative effect on health.

How smoking kills?
LUNG CANCER : 90% of people who develop lung cancer are current or former smokers. Risk for lung cancer increases with number of cigarette smoked (1 pack per day smoker is at higher risk  than half packs per day smoker) longer one has smoked more is the risk for lung cancer ( a person who has smoked for 20 years is at  a higher  risk than one who smoked for 10years). In USA, lung cancer causes more deaths than breast cancer, prostate cancer and colon cancer together

Smoking known cause of many other cancers like throat cancer, esophageal cancer, stomach cancer, cancer of pancreas, breast cancer, kidney cancer and prostate cancer.

Other Lung Diseases:
Smoking  causes medical conditions called emphysema and bronchitis (COPD).  In these conditions the lung tissue is permanently damaged, as a result patient develops cough, difficulty in breathing and may develop symptoms which mimic asthma. Patient gets lung infections (pneumonia) easily. In this case, lung cannot make enough oxygen which, ultimately, leads to breathing failure and death.

Heart Attack: Tobacco smoking is a leading cause of heart attack.  Smokers have twice risk of fatal heart disease. Tobacco smoke has chemicals which cause hardening of the blood vessel with plaque formation (atherosclerosis) which blocks the blood supply to the heart muscle resulting heart attack and death.

Stroke: Smoking increases the risk of stroke.  Smokers have three fold risk of stroke. 15% deaths due to stroke are smoking related.

Other Adverse Effects of Smoking: Risk for Hip, due to tinning of bones (osteoporosis), stomach ulcer, early wrinkling of skin and sleep disturbance.

Second Hand Smoking is a serious business. A person who smokes not only harms himself but people around him like coworkers and family members who are at a high risk to develop cancers, heart disease, stroke and lung infections. Children of smokers are at risk of developing asthma, bronchitis, sinus infections and mental retardation.

Smokeless tobacco like chewing and sniffing tobacco also has poisonous and cancerous chemicals which cause mouth, gum and throat cancers.

“I CANT QUIT,” is the most common response when a smoker is asked to quit.

“YES YOU CAN QUIT,” should be the answer.


By understanding the ill effects of smoking and also that you are not only poisoning yourself, but also your family and friends by giving them second hand smoke. There is help available in form of counseling by physicians, by nicotine products like nicotine patches, nicotine gum, and nicotine spray, and two drugs namely Bupropion and Varenicline. They help by preventing withdrawal symptoms by nicotine dependence. If a patient is motivated with the help of a physician, and one of these medications, he may able to quit.

Role of society and government:
Society in general is not fully aware of smoking/tobacco related hazards. There is a dire need of aggressive anti-smoking awareness campaign, involving civil society, media, business community, school, college and university students. Government needs to strictly implement already anti-smoking laws which prohibit smoking in public places.