Differential Risk of ST-Segment Elevation Myocardial Infarction in Male and Female Smokers

Smoking is a well-documented risk for acute ST-segment elevation myocardial infarction (STEMI). The differential effect between sexes has yet to be quantified.

The purpose of this study was to differentiate the effect of smoking on increased risk of STEMI between sexes.

For this retrospective ecological cohort study, all patients at a U.K. tertiary cardiothoracic center who presented between 2009 and 2014 with acute STEMI were combined with population data to generate incidence rates of STEMI. Age-standardized incidence rate ratios (IRRs) using the Poisson distribution were calculated comparing STEMI rates between smokers and nonsmokers stratified by sex and 3 age groups (18 to 49, 50 to 64, and >65 years).

A total of 3,343 patients presented over 5,639,328 person-years. Peak STEMI rate for current smokers was in the 70 to 79 years age range for women (235 per 100,000 patient-years) and 50 to 59 years (425 per 100,000 patient-years) in men. Smoking was associated with a significantly greater increase in STEMI rate for women than men (IRR: 6.62; 95% confidence interval [CI]: 5.98 to 7.31, vs. 4.40; 95% CI: 4.15 to 4.67). The greatest increased risk was in women age 18 to 49 (IRR: 13.22; 95% CI: 10.33 to 16.66, vs. 8.60; 95% CI: 7.70 to 9.59 in men). The greatest risk difference was in the age 50 to 64 years group, with IRR of 9.66 (95% CI: 8.30 to 11.18) in women and 4.47 (95% CI: 4.10 to 4.86) in men.

This study quantifies the differential effect of smoking between sexes, with women having a significantly increased risk of STEMI than men. This information encourages continued efforts to prevent smoking uptake and promote cessation.