Objective The decline in the incidence and mortality of acute myocardial infarction (AMI) has been less among younger compared with older individuals. The aim of this nationwide study was to assess the current incidence, risk factors and outcome of AMI in patients <45 years of age.
Methods All patients ≤80 years of age registered in the Norwegian Myocardial Infarction Register in 2013–2016 were included in this observational, nationwide cohort study. Follow-up was conducted through linkage with the Norwegian Patient Registry through 2017.
Results Among a total of 33 439 patients ≤80 years with AMI, 1468 (4.4%) were <45 years old. The incidence of AMI was 2.1 per 100 000 person-years in people aged 20–29 years, 16.9 in people aged 30–39 years and 97.6 in people aged 40–49 years. Compared with older patients, patients <45 years were more likely to be male (81%), current smokers (56%), obese (30%) and have a family history of premature AMI (44%), and their low-density lipoprotein-cholesterol levels were higher. Patients <45 years were more likely to have non-obstructive coronary artery disease (14% vs 10%, p<0.001) compared with older patients. During a median follow-up time of 2.4 years, 135 (9%) patients <45 years experienced a new AMI, stroke or death, and 58 (4%) patients died.
Conclusions The rate of AMI was low in people <45 years old in Norway, but almost one in ten patients with AMI <45 years old died or experienced a new cardiovascular event during follow-up. Increased efforts to improve risk factor control in these patients are warranted.
- acute myocardial infarction
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Contributors JJ and SH were responsible for the conception of the study and the analysis and interpretation of data. JJ drafted and SH critically revised the manuscript. AHP contributed to the interpretation of data and revision of the manuscript. JL critically revised the manuscript. All authors gave final approval and agreed to be accountable for all aspects of this work, ensuring its integrity and accuracy.
Funding This study was funded by Helse Sør-Øst RHF (http://dx.doi.org/10.13039/501100006095).
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval The Regional Committee for Medical and Health Research Ethics-North approved this study (REK 2016/170).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data may be obtained from a third party and are not publicly available. The data that support the findings of this study are available from the Norwegian Institute of Public Health. Restrictions apply to the availability of these data, which were used under licence for this study.
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