The harm of smoking

Smoking is extremely harmful to health, affecting nearly every organ in the body, and is one of the leading causes of preventable diseases and deaths worldwide. Here are the main health risks of smoking:
Cancer
Smoking is a major cause of various cancers, including:
Lung cancer (the most common; smokers are 15-30 times more likely to develop it than non-smokers)
Oral, laryngeal, and esophageal cancer
Pancreatic cancer
Bladder and kidney cancer
Liver and stomach cancer
Cervical cancer (in women)
Respiratory diseases
Chronic obstructive pulmonary disease (COPD) — including chronic bronchitis and emphysema, causing severe breathing difficulties.
Increased infection risk — smokers are more prone to pneumonia, tuberculosis, and severe influenza.
Aggravated asthma — smoking worsens asthma symptoms and triggers attacks.
Cardiovascular diseases (heart and blood vessel diseases)
Heart disease — smoking damages blood vessels, leading to coronary heart disease, heart attacks, and strokes.
Atherosclerosis — plaque buildup in arteries, restricting blood flow.
Peripheral arterial disease (PAD) — reduced blood flow to limbs, increasing the risk of amputation.
Increased risk of high blood pressure and blood clots — raising the risk of stroke and heart failure.
Impaired immune system
Slows wound healing and increases infection risk.
Higher susceptibility to autoimmune diseases like rheumatoid arthritis.
Reproductive and sexual health issues
Infertility — smoking reduces fertility in both men and women.
Erectile dysfunction — smoking damages blood vessels, reducing blood flow to the penis.
Pregnancy complications — increases the risk of miscarriage, premature birth, low birth weight, and birth defects (e.g., cleft lip/palate).
Other health risks
Type 2 diabetes — smokers have a 30%-40% higher risk than non-smokers.
Vision problems — increases the risk of cataracts and macular degeneration.
Accelerated aging — causes wrinkles, yellowed teeth, and bad breath.
Bone fragility — higher risk of osteoporosis and fractures.
Harm of secondhand smoke
Non-smokers exposed to secondhand smoke are also at risk of lung cancer, heart disease, and respiratory infections.
Children exposed to secondhand smoke are more likely to experience sudden infant death syndrome (SIDS), asthma, and ear infections.
Summary
Quitting smoking at any time can significantly reduce health risks and improve quality of life. After quitting:
Within 20 minutes, heart rate begins to drop;
Within 1 year, the risk of heart disease is halved;
Within 10 years, the risk of lung cancer is halved compared to continuing smokers.
If you want to quit smoking or help someone else quit, consider nicotine replacement therapy (NRT), medication, or counseling support.