Global burden and epidemiology

Tobacco use (smoked and smokeless) contributes substantially to cardiovascular disease, chronic respiratory disease, cancer, reproductive harm and increased susceptibility to infections. The burden is highest in low- and middle-income countries where exposure and limited cessation resources compound harms.

Major organ-system impacts

• Cardiovascular: increased risk of myocardial infarction, stroke, peripheral arterial disease and atherosclerosis; smoking accelerates endothelial dysfunction and thrombosis.
• Respiratory: chronic obstructive pulmonary disease (COPD), chronic bronchitis, emphysema, increased respiratory infections and decreased lung function.
• Oncological: lung cancer, head & neck cancers, oesophageal, bladder, pancreatic and several other malignancies linked to tobacco carcinogens.
• Oral health: periodontal disease, oral cancers, tooth loss and mucosal changes; smokeless tobacco causes oral lesions and leukoplakia.
• Reproductive & perinatal: reduced fertility, ectopic pregnancy, placental problems, low birth weight, preterm birth and sudden infant death risk.
• Metabolic & endocrine: increased diabetes risk and poorer glycaemic control in smokers; altered lipid profiles.
• Immune & infectious: impaired immune response, higher TB risk and worse outcomes with respiratory infections.

Less-recognised or “other” tobacco-induced disorders

• Hypertensive crises and vascular inflammation: acute nicotine effects can precipitate hypertensive episodes and vascular events.
• Gastrointestinal disorders: peptic ulcers, GERD exacerbation and impaired healing post-surgery related to tobacco use.
• Dermatological: premature skin ageing, delayed wound healing, increased psoriasis severity.
• Ocular: increased risk of age-related macular degeneration and cataracts.
• Medication interactions: smoking induces CYP1A2 leading to altered levels of drugs (e.g., clozapine, olanzapine, theophylline), requiring dose adjustments.
• Second-hand and third-hand exposure: significant health risks to non-smokers; third-hand exposure (residual chemicals on surfaces) particularly affects children.

Pathophysiology — how tobacco harms the body

• Tobacco smoke contains thousands of chemicals including nicotine, carbon monoxide and multiple carcinogens (PAHs, nitrosamines) that cause oxidative stress, inflammation and DNA damage.
• Nicotine is highly addictive, acting on mesolimbic pathways to reinforce use and complicate cessation.
• Smokeless tobacco delivers high nicotine doses and local carcinogens affecting oral mucosa and systemic absorption contributing to cardiovascular risk.

Clinical assessment — what to screen for

• Tobacco use history: product(s), duration, quantity, age of initiation, attempts to quit and readiness to change.
• Medical assessment: respiratory symptoms, cardiovascular risk, oral exam, pregnancy status, comorbid substance use and mental health.
• Investigations as indicated: spirometry for COPD, chest imaging, screening for cardiovascular risk (lipids, BP), cancer screening where applicable.
• Medication review for interactions and dose adjustment needs (e.g., smokers on clozapine require higher doses).

Prevention & population strategies

• Tobacco taxation, smoke-free policies, advertising bans and plain packaging reduce initiation and prevalence at population level.
• School-based prevention, community education and targeted interventions for high-risk groups (pregnant women, adolescents) are effective.
• Mass media campaigns and cessation support services increase quit attempts and successful cessation.

Clinical interventions — cessation & harm reduction

• Brief interventions using the 5 A’s (Ask, Advise, Assess, Assist, Arrange) at every clinical encounter.
• Pharmacotherapy: NRT (patches, gum, lozenges), bupropion, varenicline — combination NRT often more effective for heavy smokers.
• Behavioural support: counselling, CBT, quitlines, mobile health interventions and group programs.
• Harm reduction: switching to less harmful nicotine delivery (e.g., NRT) while working toward cessation; e-cigarettes as a last-resort harm reduction tool under supervision where legal and appropriate.

Key takeaways

• Tobacco use causes multi-system disease and is the single biggest preventable cause of death—addressing tobacco use should be a priority in all clinical settings.
• Recognise both common and less-recognised tobacco-induced disorders and consider product-specific harms in assessment.
• Combine population-level policies with individual-level interventions (pharmacotherapy + behavioural support) for best outcomes.
• Monitor for medication interactions and offer tailored cessation support, especially in high-risk groups and perioperative patients.