The last update and review: December 7, 2020.
A short summary.
This article is a “Test of Physiological Literacy” based on a discussion with one of our community members. The discussion is about the topics from a related test of physiological literacy and the answers that our community member proposed.
A Test of Physiological Literacy: Is high LDL particle number really an indication of insulin resistance and/or of heart disease?
The New Neander’s Educational on December 6, 2020:
In the paper by Garvey et al., 2003 (1), that you cited, there is a graph (see below) that shows that total LDL particle concentration is negatively correlated with the glucose disposal rate (=insulin resistance), but that large LDL particle concentration is positively correlated with the glucose disposal rate (=being insulin sensitive). These two trends are opposing and seem to cancel each other. Nevertheless, the authors write in the paragraph that you cited:
“…progressive insulin resistance was associated with … an overall increase in the number of LDL particles…”
The New Neander’s Educational on December 6, 2020, (continued):
There is a big debate about the possible role of LDL particle concentration (=”LDL particle number”) in cardiovascular disease independently of insulin resistance. That is, there would be an increased risk of cardiovascular disease in people with high LDL particle number even if they are insulin sensitive. Some recent guidances recommend that patients with elevated LDL particle number or with elevated ApoB, a marker related to LDL particle number, be treated with lipid-lowering drugs.
Here is, for example, one of the many papers that cite “the Party Line” on ApoB (the reference is in the screenshot below):
ApoB-containing lipoproteins are widely accepted as a causal factor for asCVD. This low density lipo-protein (LDL) hypothesis is supported by both epidemiological studies.
Thomas Dayspring, a researcher in blood lipids and a popular educator for medical doctors, also supports the importance of ApoB:
Personally I’d suggest (to routinely test) apoB & Lp(a) as first tests at age 20.
The New Neander’s Educational on December 6, 2020, (continued):
But do LDL particle number and ApoB, a marker related to LDL particle number, really correlate with insulin resistance and cardiovascular disease? This question is interesting also from the anthropological point of view. Indeed, a majority of medical doctors will never figure out the answer. A corollary “anthropological” question is: should you consult a medical practitioner who can never understand things that you yourself can?
An example of a fairly straight-forward question most of the medical doctors, including “professors”, struggle with.
A Test asked on social networks:
Which type of ApoB does the laboratory test provider, Labcorp, measure? Is it ApoB-100 or ApoB-48?
What does Quest Labs test measure? ApoB-100 or ApoB-48?
And here is the answer to the question above from a “Harvard professor” in cardiology Sek Kathiresan, MD:
apoB-100.
Does a “Harvard professor” ask himself important questions? Does a mastodont laboratory test provider Quest Diagnostics make important information available? Not sure.
Quest Diagnostics has an ApoB test. But what type of ApoB is not mentioned on the test report or test info. We have looked for it, and it is not there.
Conclusion: if you are interested in blood lipids, you may explore the question of risks associated with high LDL particle number.
The New Neander’s Educational on December 6, 2020, (continued):
There are a lot of discussions and debates also in the grassroots online health community about blood lipids. For a metabolically healthy individual, blood lipids are not the most urgent subject to study. But sometimes, experiments in diets can produce aberrant metabolic profiles. A reasonable understanding of blood lipids then becomes helpful for knowing when to worry and how to correct the values.
So, if you are interested in blood lipids, you may explore the question of whether high LDL particle number is really an indication of insulin resistance and/or of an increased risk of heart disease.
Related:
The Test of Physiological Literacy discussed in this article: Is there any athletes in the two groups who are insulin-resistant?
Another test that was also a part of the discussion with our community member.
Our courses in Physiological Literacy.
From the text of our introduction webpage:
Education. A community of Physiologically Literate people.
Maintaining good health is a part of personal responsibility. Physiological Literacy helps in achieving and maintaining good health. Physiological Literacy, as most of the other important knowledge, should be transmitted inside the family, from one generation to another.
Knowledge will help you to stay in control of your health and of the health of your loved ones. Start learning. Read, listen, use logical thinking. A good way to learn is to find answers to interesting questions. Try answering questions of our Tests of Physiological Literacy. Send us your answers, communicate with us. Become Physiologically Literate.
You may also be interested in taking our course in Physiological Literacy.
To contact us in the matters of educational and community activities, please write to us to the following address:contact-educational-en [at] nneandersphysiologicalliteracy.com
Selected references:
1. Garvey WT, Kwon S, Zheng D, Shaughnessy S, Wallace P, Hutto A, Pugh K, Jenkins AJ, Klein RL, Liao Y. Effects of insulin resistance and type 2 diabetes on lipoprotein subclass particle size and concentration determined by nuclear magnetic resonance. Diabetes. 2003 Feb;52(2):453-62. doi: 10.2337/diabetes.52.2.453. PMID: 12540621.
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