MYOCARDIAL INFARCTION: FACTORS INFLUENCING AGE OF ONSET AND COMPARISON WITH THE PAST DECADE

Background- Coronary artery disease is the most common cause of death worldwide. The objective of this study was to determine the average age of onset of myocardial infarction (MI) and compare it with that in the past decade. Also, the frequency of risk factors for MI in different age groups and in military personnel compared to the general population was evaluated.
Methods- In this two-stage case series study, patients admitted with acute MI in three hospitals, Baqiatallah General Hospital, Jamaran Heart Hospital and Shaheed Rajaie Cardiovascular Medical Center, were studied. Data including age, sex, occupation, risk factors, etc. were gathered. A total of 471 patients with AMI were studied, 349 of whom were admitted in 2001 with AMI and underwent interviews and medical record evaluation, and 122 had AMI in 199I and had their records evaluated and research forms completed.
Results- In 2001, the average age of the patients was 59.1±12.2 years old, and in 1991, this figure was 59.18±10.8 yrs (p=0.94). In 2001, 60 patients from the total of 349 studied (17.2%) were below 45 years old, and the remainder was older than 45 years of age. In the younger than 45 years old group, the most common risk factor was smoking (23.3%), followed by hyperlipidemia (20.9%). In the over 45 group, smoking was also the most common risk factor (21.9%, P=0.36). In 1991, 13 of the 122 patients studied (10.7%) were below 45 years old. The most common risk factor in this group was smoking (53.8%). In the over 45 years old group, smoking (22.2%), followed by hypertension (22.2%) were the most common risk factors (P=0.07). In the military personnel, the average age of the patients was 45.7±8.4, and in the general population, the average age was 61.8±11.0 (P<0.001).
Frequency of patients with no risk factors in the military personnel group was 11 patients (31.4%), and 38 patients (17.9%) in the general population (P=0.16).
Conclusion- The average age of patients with AMI in the past decade has not significantly changed. Although the average age of onset of AMI in our country is not very young, it is younger than that in some countries. The frequent risk factors involved are mainly smoking and hyperlipidemia, which are a reflection of lifestyle. Also, age of onset of acute MI in military personnel is significantly earlier than that in the general population, and risk factors are slightly more prevalent in this group.