Abstract
INTERHEART was a major global study into risk factors for myocardial infarction published in 2001. It showed that nine modifiable risk factors accounted for the majority of the population-attributable risk (PAR) of myocardial infarction. Of these, the apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) ratio accounted for approximately half of the PAR. In this latest paper from the study group, ApoB/ApoA1 ratios were compared with other cholesterol markers for assessing risk of myocardial infarction.
Blood samples from 9345 cases and 12,120 controls from 52 countries were processed for total cholesterol, high-density lipoprotein (HDL) cholesterol, ApoA1, ApoB and triglycerides. Odds ratios for increasing decile medians of apolipoproteins and lipids showed a stronger association with myocardial infarction for the ApoB/ApoA1 ratio than the total cholesterol/HDL cholesterol ratio. Changes in risk of myocardial infarction with a 1 standard deviation (SD) change in each lipid marker were more strongly associated with apolipoprotein than cholesterol measurements. ApoA1 was associated with a 33% risk reduction compared with a 15% reduction for a 1 SD difference in HDL cholesterol. A 1 SD change in ApoB/ApoA1 was again associated with a higher odds ratio than a 1 SD change in total cholesterol/HDL cholesterol (1.59 compared with 1.17, respectively). The association of ApoB/ApoA1 with myocardial infarction was shown to decrease with age (primarily due to the risk associated with ApoB beoming less pronounced) but it still remained a stronger association than any of the cholesterol ratios.
The authors concluded that the ApoB/ApoA1 ratio was superior to all the cholesterol ratios they examined with regard to risk of myocardial infarction. In addition, ApoB was superior to total cholesterol, LDL cholesterol and non-HDL cholesterol and ApoA1 better than HDL cholesterol in predicting myocardial infarction. They state that this is consistent with other large studies and suggest that ApoB and ApoA1 measurement should be introduced into routine clinical practice for assessing cardiovascular disease risk.