Estimation of VLDL, IDL, LDL, HDL2, apoA-I, and apoB from the Friedewald inputs--apoB and IDL, but not LDL, are associated with mortality in type 1 diabetes.
BACKGROUND
There is an unmet need for a straightforward and cost-effective assessment of multiple lipoprotein risk factors for vascular diseases.


OBJECTIVE
1) To study the relation of various lipoprotein lipid and apolipoprotein (apo) measures on the Friedewald inputs, i.e. plasma triglycerides (TG), cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C). 2) To build up regression models for the appropriate measures based solely on the Friedewald inputs.


METHODS
Data were available for 1,775 plasma samples, from which very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and HDL were also isolated by ultracentrifugation. For HDL(2)-C and apolipoproteins, 343 and 247 samples were available, respectively.


RESULTS
Accurate models were obtained for VLDL-TG (cross-validation r=0.98), LDL-C (r=0.91), HDL(2)-C (r=0.92), apoA-I (r=0.92), and apoB (r=0.95). A semi-quantitative model was obtained for IDL-C (r=0.78). Due to the anticipated role of IDL-C in atherosclerosis, it was still kept within the accepted models and pursued further. The associations of the estimates with premature deaths were studied in 4,084 patients with type 1 diabetes. The associations of IDL-C and LDL-C were markedly different, the best predictors of mortality being apoB, apoB to apoA-I ratio, and IDL-C.


CONCLUSIONS
The new models allow identification of clinically relevant lipoprotein profiles with no added cost to the conventional Friedewald formula.
Computational Medicine Research Group, Department of Biomedical Engineering and Computational Science, Helsinki University of Technology, Finland.
Jaakko
J
Niemi
Ville-Petteri
VP
Mäkinen
Jukka
J
Heikkonen
Leena
L
Tenkanen
Yrjö
Y
Hiltunen
Minna L
ML
Hannuksela
Matti
M
Jauhiainen
Carol
C
Forsblom
Marja-Riitta
MR
Taskinen
Y Antero
YA
Kesäniemi
Markku J
MJ
Savolainen
Kimmo
K
Kaski
Per-Henrik
PH
Groop
Petri T
PT
Kovanen
Mika
M
Ala-Korpela
D000465:Algorithms; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications / Q000401:mortality*; D050171:Dyslipidemias / Q000150:complications; D006801:Humans; D008074:Lipoproteins / Q000097:blood* / Q000378:metabolism; D015233:Models, Statistical; D012044:Regression Analysis; D018570:Risk Assessment; D014280:Triglycerides / Q000097:blood / Q000378:metabolism
D008074:Lipoproteins; D014280:Triglycerides; D002784:Cholesterol