What does this research mean for the field?

Early age at smoking initiation is associated with a 2.43 times higher risk of myocardial infarction and a 1.82 times higher risk of death compared to nonsmokers over nine years. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

What question did this study set out to answer?

Examine the impact of smoking initiation age on cardiovascular disease and mortality risks.

January 25, 2026

Early age at smoking initiation is associated with elevated cardiovascular disease and mortality risk in a nationwide population-based cohort.

Key Result

Smokers initiating before age 20 with ≥20 pack-years had the highest risks of myocardial infarction (HR 2.43), stroke (HR 1.78), and death (HR 1.82) compared to nonsmokers.

Key Points

Examine the impact of smoking initiation age on cardiovascular disease and mortality risks.
Analyzed data from 9,295,979 Korean adults without preexisting cardiovascular diseases.
Assessed risk of myocardial infarction, stroke, and mortality using Cox proportional hazard models.
Categorized smokers based on age of initiation and total pack-years.
Smokers who started before age 20 had significantly higher risks of MI (HR 2.43) and stroke (HR 1.78).
Those with initiation age under 15 experienced elevated risks of MI, stroke, and mortality.
Risk increases correlated strongly with earlier age at smoking initiation (p < 0.001).

Structured PICO

Does early age at smoking initiation increase the risk of incident MI, stroke, and all-cause mortality in adults without preexisting cardiovascular diseases?

Population

9,295,979 Korean adults without preexisting cardiovascular diseases who underwent health screening in 2009

Intervention

Early age at smoking initiation (e.g., < 20 years)

Comparator

Nonsmokers and smokers with initiation age ≥ 20

Outcome

Incident MI, stroke, MI or stroke, and all-cause mortality over a nine-year follow-uphard clinical

Early age at smoking initiation is associated with accentuated, pack-year-dependent increases in the risk of MI, stroke, and mortality.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Smoking is a major cause of cardiovascular diseases, including myocardial infarction (MI) and stroke. However, the role of age at smoking initiation in cardiovascular risk has not been fully established. We selected 9,295,979 Korean adults without preexisting cardiovascular diseases who underwent health screening in 2009. The association of age at initiation with incident MI, stroke, MI or stroke, and all-cause mortality was analyzed using Cox proportional hazard models stratified or adjusted for total pack-years (PY). Among the 3,724,368 smokers, 876,740 smokers (23.5%) started before age 20, and 75,299 smokers (2.0%) had age at initiation < 15. Over a nine-year follow-up, ≥ 20 PY smokers with age at initiation < 20 had the highest risks of MI (adjusted hazard ratio (HR), 2.43; 95% confidence interval (95% CI), 2.35-2.51), stroke (HR 1.78, 95% CI 1.73-1.83), MI or stroke (HR 2.00, 95% CI 1.96-2.04), and death (HR 1.82, 95% CI 1.79-1.85) relative to nonsmokers, significantly higher than in ≥ 20 PY smokers with initiation age ≥ 20. Earlier age at initiation was associated with increasing PY-adjusted risks of each outcome (p for trend < 0.001 each). Age at initiation also had significant interactions with total PY for each outcome (p < 0.001 each), with PY-dependent risk increases accentuated by earlier initiation. Early age at smoking initiation is associated with increased risks of MI and stroke. Focused smoking prevention measures may be warranted for both adolescents and young adults.

Bookmark

View Full Paper