Background
The association between increased concentrations of low-density lipoprotein cholesterol(LDL-C) and increased rate of premature coronary heart disease has been clearly demonstrated. However, significant risk for cardiovascular disease often remains after elevated low-density lipoprotein cholesterol levels have been treated to goal. Apolipoprotein B(apo B) is a better measure of circulating LDL particle number concentration and is a more reliable indicator of risk than LDL-C. Now, apo B can be measured by commercial immunoassay. But this is time-consuming and increase cost. Although there were formulas estimating apo B, that was derived from western people. So, we tried to make a formula estimating apo B from Asian people.
Aim and methods
The aims of this study was to develop a formula calculating apo B by using routinely checked lipid battery results. Total 73,047 apparently healthy subjects were recruited in this study. All subjects (mean age of 41.73짹8.4 years, 44,118 males were 41.9짹8.1-years old, 28,929 females were 41.4짹8.7-years old) participated in a routine health check-up program that was held at the Health Promotion Center of Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea in 2008.
Results
We divided subjects with training set and validation set by random.In bivariate correlation analyses, LDL, TC , ln(TG), ln(BMI) and ln(AGE) showed positive correlation with apo B.In multiple regression analysis,ln(BMI) was less effective to estimate apo B. We derived an equation for calculating apo B from measurements of LDL-C and triglyceride(TG). ApoB=-33.12+0.675��LDL+11.95��ln(tg) This equation predicts apo B result with CCC 0.936(95%CI(0.935,0.937)). We compared this formula with previously reported one that estimate apo B. By comparison, we got a better perfomance result from our formula than other one.
Conclusion
Our equation provides a convenient means of estimating apo B from easily available measurements of LDL-C and triglycerides without more time and cost. This can be a useful clinical tool for estimating apo B, regardless of the apo B assay used. This equation was derived from Asian people. This could be a limitation of our study. But, The number of subjects participated in this study was larger than other previous study. and this also could be more useful for assessing Asian people.