Background: Although cigarette smoking is a major risk factor for acute myocardial infarction (MI), cigarette tar yield has not been clearly demonstrated to affect MI risk.
Methods: A case-control study of first MI in smokers aged 30 through 65 years was conducted among 68 hospitals in an 8-county area during a 28-month period. Case subjects were smokers hospitalized at any of the area hospitals with a first MI. Approximately 4 community control smokers per case subject were randomly selected from the same geographic area using random digit dialing. Detailed data on smoking history and cigarette brand were collected.
Results: We identified 587 case subjects and 2685 controls who smoked cigarettes with known tar yields. After adjustment using multivariable logistic regression, the odds ratios (ORs) for subjects smoking medium- and high compared with low-tar-yield cigarettes were 1.86 (95% confidence interval [CI], 1.21-2.87) and 2.21 (95% CI, 1.47-3.34), respectively. The adjusted OR increased as tar per day intake increased (P<.001 for the trend); compared with the lowest category of tar per day, the ORs (95% CIs) for increasing tar per day were 1.16 (0.83-1.62), 1.85 (1.35-2.52), 2.42 (1.54-3.78), and 2.50 (1.78-3.52). There was a similar trend of increasing ORs as tar per day increased in smokers of lower-yield cigarettes (P<.001 for the trend) and when low-yield cigarette smokers were excluded (P<.001 for the trend).
Conclusions: Smoking higher-yield cigarettes is associated with an increased risk of MI, and there is a dose-response relationship between total tar consumption per day and MI.