Dyslipidemia is a significant morbidity associated with diabetes and cardiovascular disorders. The present study was undertaken to assess the lipid profile of type 2 diabetic and age-gender matched healthy subjects and its association, if any, with fasting plasma glucose. Clinically diagnosed diabetic subjects were recruited for the study. The fasting plasma glucose and lipid profiles were analyzed for 99 diabetic and 101 healthy volunteers. The blood samples were analyzed for fasting plasma glucose, total cholesterol, triglycerides, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol and very low density lipoprotein-cholesterol. Correlation analysis of lipid profile with fasting plasma glucose and calculation of risk ratio was done. The levels of high density lipoprotein-cholesterol and low density lipoprotein-cholesterol were found to be significantly low in diabetics and subjects with lower low density lipoprotein-cholesterol were on statins. Inspite of lower lipid values, the risk ratio for diabetics was significantly higher. The correlation analysis indicated significant difference in relationship between fasting plasma glucose, lipid parameters and risk ratios in the two groups. Diabetics with lower high density lipoprotein-cholesterol and higher total cholesterol present with a higher risk ratio pointing to need of non-statin high density lipoprotein-raising medications decreasing their predisposition to cardiovascular disorders. The study highlights the altered pattern of correlation of lipid profile with fasting plasma glucose in diabetics and their increased risk of cardiovascular disorders. The dyslipidemia in the form of triglyceridemia and significantly low high density lipoprotein-cholesterol in diabetics point towards the need of non-statin high density lipoprotein-raising medications

http://www.ncbi.nlm.nih.gov/pubmed/26798181

Meals have little effect on total cholesterol, HDLC and LDLC levels, and in fact, the levels are usually lower after a meal, probably because fluid shifts are more significant than cholesterol changes (Miida T, et al, .LDL-cholesterol and HDL-cholesterol concentrations decrease during the day.Ann Clin Biochem. 2002 May;39(Pt 3):241-9.).

The main reason for fasting is therefore to get a consistent triglyceride value, which does increase variably after meals. Although elevated triglycerides are very important (!), the strong reciprocal relationship between high triglycerides and low HDLC, and the low variability of HDLC, paradoxically means that low HDLC is a more reliable indicator of high triglycerides than high triglycerides! (See Tenenbaum A, Klempfner R, Fisman EZ. Hypertriglyceridemia: a too long unfairly neglected major cardiovascular risk factor. Cardiovasc Diabetol. 2014 Dec 4;13:159.)

The end result is that the reciprocal of HDLC is a reliable indicator of high triglycerides whether fasting or not, and the use of the Total Cholesterol / HDLC ratio can be applied on fasting or non fasting samples as the most powerful simple cardiovascular predictor (and the difference between TC-HDLC is a good marker for monitoring pharmacological treatment whether fasting or not). One word of warning though; HDLC is gender dependent and affected by steroid hormones with the differences appearing at puberty and altering also at menopause. Therefore the use of a single TC/HDLC cutoff (or single TC-HDLC cutoff), will introduce various gender dependent biases which are seldom appreciated in the literature even though metabolic syndrome definitions clearly have different HDLC cutoffs for men and women.

Thank you very much KA Sikaris.  Your write-up has been very useful.

There is now an extensive (!) discussion in Clin Chem 2016;62(3):428-435.