Type 2 diabetes (T2D) is increasingly common in younger patients1,2. Despite extensive literature documenting the 2-3 fold higher risk of myocardial infarction (MI) in type 2 diabetes patients, there is less data on the association between the age at T2D diagnosis and expected time course to sustaining a MI. The aim of this study was to determine the relationship between age at first MI, age at T2D diagnosis and duration of diabetes prior to MI.
Pre-specified clinical and demographic details for 500 consecutive T2D patients presenting to a metropolitan teaching hospital with a first MI were obtained from hospital and local doctor records. Logistic regression analysis was used to examine factors associated with age at first MI.
The mean age at diabetes diagnosis was 55±14 years and age at first MI 62±14 years. A histogram in figure 1 depicts the distribution for age at first MI. Both age at diabetes diagnosis (p<0.01) and duration of diabetes (p<0.01) were associated with age at first MI on uni-variable analysis. After adjustment for gender, hypertension, hypercholesterolaemia and smoking, age at diabetes diagnosis was independently associated with age at first MI (p<0.01) however duration of diabetes was not associated with age at first MI (p=0.95). Linear regression analysis revealed that every 1 year increase in age at diabetes diagnosis was associated with a 0.86 months increase in age at first MI (p<0.01) (Figure 2).
These observations suggest patients developing diabetes at a younger age also have an earlier time course to their first myocardial infarct and may require more aggressive cardiovascular risk factor management and screening for coronary artery disease.
Figure 1: Histogram of age at first myocardial infarction (MI). Line represents kernel density.
Figure 2: Age at first MI vs Age at DM diagnosis