Pronounced increase in risk of acute ST-segment elevation myocardial infarction in younger smokers
- Amelia Lloyd1,
- Lloyd Steele1,
- James Fotheringham2,
- Javaid Iqbal1,3,
- Ayyaz Sultan3,
- M Dawn Teare2,
- Ever D Grech3
- 1The University of Sheffield, Sheffield, UK
- 2The School of Health and Related Research (ScHARR), The University of Sheffield, Sheffield, UK
- 3The South Yorkshire Cardiothoracic Centre, Northern General Hospital, Sheffield, UK
- Correspondence to Dr Ever D Grech, The South Yorkshire Cardiothoracic Centre, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK;
- Received 5 March 2016
- Revised 14 September 2016
- Accepted 26 September 2016
- Published Online First 29 November 2016
Objectives Previous studies have shown that smokers presented with ST-segment elevation myocardial infarction (STEMI) a decade earlier than non-smokers. However, no account has been made for population smoking trends, an important deficit addressed by this study.
Methods The combination of admission data on patients with acute STEMI undergoing percutaneous coronary intervention and demographic data supplied by the Office for National Statistics for the South Yorkshire population between 2009–2012 were analysed to generate incidence rates and rate ratios (RR) to quantify the relative risk of STEMI from smoking, overall and by age group.
Results There were 1795 STEMI patients included of which 72.9% were male. 68 patients were excluded as they had no smoking status recorded, leaving 48.5% of the remaining population as current smokers, 27.2% ex-smokers and 24.3% never smokers. Smokers were over-represented with overall smoking prevalence in South Yorkshire calculated at 22.4%. The incidence of STEMI in smokers aged under 50, 50–65 and over 65 years was 59.7, 316.9 and 331.0 per 100 000 patient years at risk compared to 7.0, 60.9 and 106.8 for the combined group of ex- and never smokers. This gave smokers under the age of 50 years an 8.47 (95% CI 6.80 to 10.54) increase in rate compared to non-smokers of the same age, with the 50–65 and over 65 age groups having RRs of 5.20 (95% CI 4.76 to 5.69) and 3.10 (95% CI 2.67 to 3.60), respectively.
Conclusions Smoking was associated with an eightfold increased risk of acute STEMI in younger smokers, when compared to ex- and never smokers. Further efforts to reduce smoking in the youngest are needed.
Contributors Study concept and design: AL, LS, JF, AS, JI, MDT and EDG. Acquisition of data: AL, LS, JF, AS and JI. Analysis and interpretation of data: AL, LS, JF, JI, MDT and EDG. Drafting of the manuscript: AL, LS, JF, AS, JI and EDG. Critical revision of the manuscript for important intellectual content: AL, LS, JF, AS, JI and EDG. Statistical analysis: AL and JF. Administrative, technical, or material support: AS, JI and EDG. Study supervision: EDG.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement We are unable to release any data obtained from the Office for National Statistics or Myocardial Ischaemia National Audit Project and this was released to us solely for internal validation and data calculations.