Low education level most important socioeconomic risk factor for AMI
MedWire News: Low education level is the socioeconomic status (SES) marker most consistently associated with increased risk for acute myocardial infarction (AMI) globally, show results from the INTERHEART study.
Overall, the study found that people in the lowest third category of education had a 1.3-fold greater risk for AMI than those with the highest level of education.
About half of this risk increase was due to modifiable risk factors, and the effect of education was more marked in high-income than low- or middle-income countries, report Annika Rosengren (Sahlgrenska University Hospital, Gothenburg, Sweden) and co-authors.
As described previously in MedWire News, INTERHEART is an international case–control study which was carried out in 52 countries, and revealed that nine major, modifiable risk factors collectively explained over 90% of the population attributable risk for AMI.
Rosengren and team used INTERHEART data to study which of these modifiable risk factors may explain the relationship between SES and AMI, and to evaluate the relative impacts of different aspects of SES, which the researchers explain is a complex construct representing multiple dimensions.
Out of the whole INTERHEART population, this study included 12,242 (98.2%) patients with incident first AMI and 14,622 (99.9%) controls who had complete education data.
A low level of education (≤8 years) was significantly more common in cases than controls (45.0% vs 38.1%, p<0.0001), the researchers report in the journal Heart.
After adjustment for age, gender, and region, 8 years or fewer of education was associated with a significant 1.56-fold increased odds for AMI compared with more than 12 years of education (including, trade school, college, or university education).
Adjustment for psychosocial factors, apolipoprotein (apo)B/apoA1 ratio, hypertension, and diabetes did not change the odds ratio estimates appreciably.
After adjusting for lifestyle variables (smoking, exercise, daily consumption of vegetables and fruits, alcohol, abdominal obesity) the odds for AMI associated with low education was still significant, but fell to 1.31. However, this did not change further after adjustment for the nine main modifiable risk factors identified in the original INTERHEART study analysis, nor after additional mutual adjustment for all SES factors.
Family income, numbers of possessions, and non-professional occupation were associated with smaller estimates, and none remained significant after adjustment for other socioeconomic factors, "implying that almost all important information on SES in the present study was contained in education," Rosengren and colleagues note.
In high-income countries, the adjusted odds for AMI associated with low education was higher, at 1.61, whereas it was substantially lower in low-/middle-income countries, at 1.25. This probably reflects their different stages in the “epidemiological transition,” notes the team.
“These findings suggest that improving education levels has the potential to partially prevent the rising epidemic of cardiovascular disease in developing countries, as it could lead to healthier lifestyles,” the authors conclude.
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By Caroline Price