Impact of neighbourhood-level socioeconomic status, traditional coronary risk factors, and ancestry on age at myocardial infarction onset: A population-based register study

BACKGROUND: There is consensus that low socioeconomic status (SES) is associated with an increased risk of acute myocardial infarction (AMI), but the extent to which traditional coronary risk factors and other characteristics of low SES mediate this effect remains uncertain. This study examined AMI patients residing in neighbouring city districts with the same local hospital despite having among the most considerable differences in mean SES in Norway. Our purpose was to assess low SES as a coronary risk factor and examine whether traditional coronary risk factors or ancestry mediate this effect. METHODS: Six hundred six patients (215 and 391 with a low and high neighbourhood-level SES, respectively) admitted to Diakonhjemmet Hospital with non-ST-elevation myocardial infarction (NSTEMI) between 2014 and 2017, entered analysis. Data from the Norwegian Myocardial Infarction Register were used to identify patient characteristics, and the STATA/SE 15.1 software was used to perform the statistical analyses. RESULTS: Patients from socioeconomically disadvantaged city-districts had a 4.9 years earlier onset of AMI (68.99 vs. 73.89 years; p < 0.001) and a higher prevalence of previous AMI, known diabetes, and current smokers (36% vs. 27%, 25% vs. 12%, and 33% vs. 17%, respectively; all p ≤ 0.05). When only comparing patients with a first time AMI, an even greater difference in the age at AMI onset was found (6.1 yrs; p < 0.001). The difference in age at AMI onset remained statistically significant when adjusting for traditional coronary risk factors (3.28 yrs; 95% confidence interval (CI) 1.11−5.44; p = 0.003), but not when adjusting for presumed non-Northwest-European ancestry (1.81 yrs; 95% CI −0.55 to 4.17; p = 0.132). CONCLUSION: This study supports earlier research showing an increased risk of AMI in socioeconomically disadvantaged individuals. In our population, presumed non-Northwest-European ancestry could entirely explain the increased risk, whereas traditional coronary risk factors could only partly explain the increased risk.