It’s not even just the illnesses it directly causes it’s also the decreases in health it causes indirectly and conditions it can make worse such as pneumonia.
And heart disease. If we can't fix stupid maybe evidence with the least hallucinating llm can provide guidance.
Here is evidence based open evidence response on all the risks with links to peer reviewed journals.
Smoking is the leading preventable cause of morbidity and mortality worldwide, causing more than 8 million deaths annually and shortening life expectancy by roughly 10 years compared with never-smokers.[1][2][3] One-third to one-half of regular smokers die of a tobacco-related disease.[1] Most smoking-attributed deaths fall into three categories: cancer (~34%), cardiovascular disease (~32%), and respiratory disease (~21%).[1]
Cancer
- Lung cancer — nearly 90% of cases are attributable to smoking; current smokers carry roughly a 9-fold increased risk (RR ~8.96).[1][4]
- Highest-risk sites overall are laryngeal, aortic/pharyngeal, and lung outcomes. Strong evidence also links smoking to cancers of the oropharynx, larynx, esophagus, stomach, liver, pancreas, kidney/renal pelvis, bladder, uterine cervix, and colon/rectum, plus acute myeloid leukemia.[5][1][6]
- Mechanistically, >4,000 compounds in cigarette smoke generate reactive oxygen species and oxidative DNA damage driving carcinogenesis.[7]
Cardiovascular disease
- Smoking increases risk of coronary heart disease (MI, sudden death), stroke, peripheral artery disease, abdominal aortic aneurysm, heart failure, and arrhythmias.[8][6]
- Current smoking roughly doubles to triples CVD mortality (HR ~2.75) and raises any-CVD risk ~63%.[4]
- Risk is not confined to heavy use: even one cigarette per day raises CAD risk ~48% and stroke risk ~25% in men, with similar or higher increases in women.[4]
- Mechanisms include endothelial dysfunction, accelerated atherosclerosis, plaque destabilization, and a prothrombotic state.[8][9]
Respiratory disease
- Smoking causes approximately 80% of COPD deaths and increases risk of lower respiratory infections, tuberculosis, and asthma.[1][5]
Other organ systems
- Endocrine/metabolic: type 2 diabetes.[10][5]
- Neurologic: Alzheimer's disease and related dementias, Parkinson's disease, multiple sclerosis.[5]
- Ophthalmologic: nuclear cataract, age-related macular degeneration, glaucoma, thyroid eye disease.[7]
- GI/musculoskeletal: peptic ulcer disease, gallbladder disease, osteoporosis/fracture, rheumatoid arthritis.[5][6]
- Reproductive: reduced fertility and increased risk of spontaneous abortion.[6]
- Infectious: increased severity of COVID-19 and other infections.[3]
The following forest plot illustrates the graded, dose-response relationship between smoking status and mortality, infectious disease, and cancer outcomes, showing current smokers at highest risk and ex-smokers at intermediate risk relative to never-smokers.
Benefit of cessation — Quitting reverses much of the risk. Stopping before age 35 prevents almost all excess early mortality; quitting by age 60 adds about 3 years of life expectancy; and even cessation after 60 reduces mortality, cardiovascular disease, and cancer risk.[2] Notably, the health harm comes primarily from combustion products rather than nicotine itself.[1]
Would you like to review the most effective evidence-based strategies for helping patients quit smoking?
References
Treatment of Tobacco Smoking: A Review. Rigotti NA, Kruse GR, Livingstone-Banks J, Hartmann-Boyce J. JAMA. 2022;327(6):566-577. doi:10.1001/jama.2022.0395.
Behavioural interventions for smoking cessation: an overview and network meta‐analysis. Jamie Hartmann-Boyce, Jonathan Livingstone-Banks, José M Ordóñez-Mena, et al. Cochrane Database of Systematic Reviews. 2021. doi:10.1002/14651858.cd013229.pub2.
The Tobacco Endgame: Eradicating a Worsening Epidemic a Joint Opinion From the American Heart Association, World Heart Federation, American College of Cardiology, and the European Society of Cardiology. Willett J, Achenbach S, Pinto FJ, Poppas A, Elkind MSV. Journal of the American College of Cardiology. 2021;78(1):77-81. doi:10.1016/j.jacc.2021.04.005.
Cardiovascular disease and cancer: shared risk factors and mechanisms. Wilcox NS, Amit U, Reibel JB, et al. Nature Reviews. Cardiology. 2024;21(9):617-631. doi:10.1038/s41569-024-01017-x.
Health effects associated with smoking: a Burden of Proof study. Dai X, Gil GF, Reitsma MB, et al. Nature Medicine. 2022;28(10):2045-2055. doi:10.1038/s41591-022-01978-x.
Tobacco use, cancer causation and public health impact. Kuper H, Adami HO, Boffetta P. Journal of Internal Medicine. 2002;251(6):455-66. doi:10.1046/j.1365-2796.2002.00993.x.
Aqueous humor perturbations in chronic smokers: a proteomic study. Amer R, Koriat A. Scientific Reports. 2024;14(1):11279. doi:10.1038/s41598-024-62039-6.
2018 ACC Expert Consensus Decision Pathway on Tobacco Cessation Treatment: A Report of the American College of Cardiology Task Force on Clinical Expert Consensus Documents. Barua RS, Rigotti NA, Benowitz NL, et al. Journal of the American College of Cardiology. 2018;72(25):3332-3365. doi:10.1016/j.jacc.2018.10.027.
The effects of heavy smoking on oxidative stress, inflammatory biomarkers, vascular dysfunction, and hematological indices. Khudhur ZO, Smail SW, Awla HK, et al. Scientific Reports. 2025;15(1):18251. doi:10.1038/s41598-025-03075-8.
Epigenetic and Long-Term Effects of Nicotine on Biology, Behavior, and Health. Gould TJ. Pharmacological Research. 2023;192:106741. doi:10.1016/j.phrs.2023.106741.