Cigarette smoking → Insulin resistance (HOMA-IR)
Higher Cigarette smoking increases Insulin resistance (HOMA-IR).
In Cho 2022, 4,043 Korean adults without diabetes who met both urine NNAL and cotinine smoker cutoffs had higher triglyceride-glucose odds than people who met neither (men 1.74, women 2.01 after age, BMI, drink, walk, income, and pack-years); Eliasson 1997's 17 quitters, against 23 who kept smoking, improved clamp insulin sensitivity in eight weeks despite modest weight gain.
Observational · Low · N=4043
The association disappears when you account for other factors, like socioeconomic status or healthy-user bias.
Mechanism
Cho treats smoking as a recent chemical exposure, read from urine. Cotinine marks the last day. NNAL marks the last month or so. People over both cutoffs had smoked through that window. People over NNAL only had smoked in the last weeks but not the last hours. The outcome is a triglyceride-glucose index, a fasting blood proxy for insulin resistance, not a HOMA-IR number and not a clamp. The authors think nicotine and smoke push belly fat, raise cortisol, catecholamines, and growth hormone, free fatty acids, and lower adiponectin. Those are the pathways they name. They do not isolate one of them. Eliasson asked healthy middle-aged men who already smoked to quit. Seventeen did. Twenty-three did not. Eight weeks later a euglycaemic clamp, the lab drip that measures how well insulin moves glucose, read better in the quitters even though they gained a little weight. That is less smoking and less resistance. It is the same directed pair as Cho, not a drug trial run backwards. Cho, Jeong, Shin, Park and Jang (2022) used KNHANES 2016 to 2018. They kept 4,043 adults after dropping people under 19, people with diabetes, people menstruating or pregnant, and people missing NNAL or cotinine. High TyG sat at 8.3878 in men and 8.60248 in women. Continuous smokers versus non-smokers: odds 1.74 (1.27 to 2.38) in men and 2.01 (1.33 to 3.03) in women after age, marriage, school, income, region, job, BMI, drink, walk, energy, chronic disease, secondhand smoke, pack-years, and survey year. Past smokers (NNAL high, cotinine low): 1.47 (1.03 to 2.09) and 1.37 (1.00 to 1.87). The cotinine-only cell was 12 men and 22 women and did not show an association. Eliasson, Attvall, Taskinen and Smith (1997) ran an open parallel follow-up, not a random assignment. Forty non-obese healthy men. Seventeen quit. Twenty-three kept smoking. The abstract reports better sensitivity and a better lipoprotein profile after eight weeks. It does not report the clamp M-value.
Caveats
Nobody assigned smoking in Cho. The seventeen who quit in Eliasson chose to quit. Observation alone cannot close the backdoor, so the stamp stays smoke. More papers of the same design do not settle the claim. Cho is one survey wave. A high TyG and a high NNAL can share a backdoor: body fat, drink, school, income, walking. The models adjust those. They cannot close reverse flow or leftover confounding. The outcome is TyG, not HOMA-IR. People with diabetes were dropped, which the authors say may have shrunk the association. The cotinine-only group is too small to read as proof that a day of smoke is harmless. Eliasson is forty men, eight weeks, and is available here only as an abstract. Weight rose a little and sensitivity still improved. That is a useful sign, not a trial. This page is smoking to insulin resistance. It does not cover smoking to death, smoking to cognition, or an education-mediated smoking Mendelian randomization. Those are other pages. This is a journal entry, not medical advice.
Effect
odds_ratio = 1.74. Cho 2022 men continuous vs non-smoker high TyG: OR 1.74 (1.27-2.38). Women 2.01 (1.33-3.03). Eliasson 1997 clamp improved after quit; no M-value in abstract. Archive n null.
Nodes
Named confounders
Cite this page
What Causes What. “Cigarette smoking → Insulin resistance (HOMA-IR).” https://whatcauseswhat.org/edges/e-smoking-insulin (atlas updated 2026-09-02).
Papers
- Short-term smoking increases the risk of insulin resistance.
SH Cho, SH Jeong, J Shin, S Park, SI Jang · 2022 · Scientific reports
- Smoking cessation improves insulin sensitivity in healthy middle-aged men.
B Eliasson, S Attvall, MR Taskinen, U Smith · 1997 · European journal of clinical investigation