Wednesday, July 31, 2013

Is There A Simple Marker on Your Standard Labs That Can Tell You Whether You're at High Risk of Heart Disease & Insulin Resistance? If So, How High / Low Should It Be?

Apples are more likely to be insulin resistant than pears... no, we are not talking about the fruits and neither about their effects on insulin resistance, but rather about the areas where you carry most of your body fat. If it's on the buttocks and thighs, your risk of being insulin resistant is much lower than if the lion's share of your passive energy store resides right on your abs.
If you've read the headline of today's SuppVersity article you are already in the know what this is going to be all about. I am yet not sure, whether you actually understand why doing a study like this makes sense... don't worry if you don't I have to admit I had to thing about it for quite some time, until looking at the various measures until it dawned on me that the main advantage is - you guessed it - of monetary nature!

I mean, if you could tell simply by looking at the standard labtests, most of which do include both triglycerides and HDL levels, you could save a lot of money on HOMA-IR or QUICKI tests and still be certain you suffer or don't suffer from insulin resistance and concomitantly increased cardiovascular disease risk.

Now the $64,000 question is: "Were Miguel Murguía-Romero et al. able to save your insurance company a lot of money, or not?"

The truth about cholesterol and heart disease...

... turned out to be more complex than the "pioneers" believed and complex "truths" have the nasty tendency to be self-contradictory and difficult to understand -- too difficult, in fact, to make it to the mainstream media and as it turned out obviously even too difficult for the average general practitioner, who is still easily convinced by the pharma reps that it was "best practice" to prescribe a statin and send the patient, who would be "unwilling and unable to change his dietary habits and increase his amount of physical activity, anyway" home with a script and patient information full of known side-effects most of the patients like to ignore.
Table 1: Talking about "metabolic syndrome" (MetS) what are the criteria to diagnose MetS? (Grundy. 2004)
That being said, the most prominent of the currently heralded alternative indicators of increased risks of cardiovascular disease are...
  • a high level of low-density lipoprotein (LDL),
  • a low level of high density lipoprotein (HDL),
  • exuberant amounts of triglycerides (TRIGS),
... as well as all sorts of combination of the the two, respectively three bad guys (TC, TRIG, LDL)  and the one good guy (HDL). Research has also suggested that pre-existing co-morbidities like diabetes will increase the significance of the predictive effects of high triglycerides to high-density lipoprotein (TRIG/HDL) total cholesterol to high-density lipoprotein (TC/LDL), and LDL to high-density lipoprotein (LDL/HDL) ratios.

With their recently conducted experiment, the scientists from the Stanford University Medical School did now try to elucidate whether the triglyceride / HDL ratio, which has been emerging in trials with old(er) individuals as one of the best markers of cardiovascular disease, would predict the CVD risk in 2244 healthy college students  (17-24  years  old) of Mexican Mestizo ancestry  (1545 women and 699 men) and be able to identify younger individuals that are not merely at high risk of heart disease, but in whom this increased risk is direct consequence of being insulin resistant, as well.
Figure 1: Prevalence of insulin resistance ("objectively" confirmed by HOMA-IR data) as identified by the TG/HDL-C ratio or the criteria for "mebabolic syndrome" listed in table 1 (Murguía-Romero. 2013)
If you take a look at the data in figure 1 you can see that the "kill two birds with one stone"-, or rather "determine two medical problems with one parameter"-method the scientists wanted to establish is not exactly reliable. In fact the, chance of identifying people who had overtly high HOMA-IR values (=were effectively insulin resistant) just by the fact that their TRIG/HDL ratios were >3.5 for men and >2.5 for women is only 50/50.

A closer statistical analysis did still reveal a slightly higher sensitivity for the TRIG/HDL ratio (53% / 55% in women / men) than for the criteria catalog that's used to "diagnose" metabolic syndrome (see table 1), which ended up at a meager sensitivity of 36% for women and 46% for men. 

So where should your TRIG / HDL ratio be then?

In view of the results presented in the study at hand, the triglyceride-to-HDL ratio (TRIG / HDL) although it may not qualify as a diagnostic tool, is is a good indicator that there is something metabolically off. If that's your TRIG / HDL ratio that looks bad. Based on the figures in the study at hand this means:
  • Your ratio of triglycerides to HDL-C should be < 3.5 if you are a man, or 
  • Your ratio of triglycerides to HDL-C should be < 2.5 if you are a woman
If that'S not the case, this alone should be reason enough to investigate whether and how insulin resistant you actually are, what your real heart disease risk is like and what the underlying reasons of your potential health problems could be. You could start out by doing a glucose tolerance test and/or by tracking your glucose levels with a glucometer, for example, to gain some certainty with respect to your current insulin sensitivity. On the cholesterol side of things, however, a particle size analysis may be the next thing on your list (learn why particle size matters).

And don't forget that for most of the health-conscious victims of CVD, stress, not bad eating habits, or a lack of exercise, is the main problem - and that goes for both psychological and physiological stress (including overtraining; learn more).

Bottom line:
Suggested Read: "Eat Whole Eggs All Day and Throw Your Statins Away? 375x Increased Dietary Cholesterol Intake From Eggs Reduces Visceral Fat & Promotes Healthy Cholesterol Metabolism" - For most people eggs boost, not lower HDL and they are certainly not the reason for the ever increasing heart disease risk (learn more)
In view of the fact that the majority of general practictioners is not going to run HOMA-IR or QUICKI tests on their patients on a regular basis, this ratio is certainly one of the best indicators you will find on your standard labs - and what's most appealing: It's better than the set of criteria for "MetSyn" (see table 1), which would, for example, per se overlook all the skinny fats out there.

In fact, the main message associated with the low sensitivity of the "MetSyn" criteria as a benchmark for insulin resistance, may well be that the mere absence of "above normal" levels for abdominal circumference, blood pressure and even blood glucose are not reliable criteria to determine, whether you are insulin resistant, or not. I'd say this is a message with public importance, especially for the skinny fats, who may well be the 15% and 13% of young men and women in the "no metabolic syndrome, but still insulin resistant"-group in the study at hand (see figure 1).

References:
  • Grundy SM, Brewer HB Jr, Cleeman JI, Smith SC Jr, Lenfant C; American Heart Association; National Heart, Lung, and Blood Institute. Definition of metabolic syndrome: Report of the National Heart, Lung, and Blood Institute/American Heart Association conference on scientific issues related to definition. Circulation. 2004 Jan 27;109(3):433-8.
  • Murguía-Romero M, Jiménez-Flores JR, Sigrist-Flores SC, Espinoza-Camacho MA, Jiménez-Morales M, Piña E, Méndez-Cruz AR, Villalobos-Molina R, Reaven RM. Plasma triglyceride/high-density lipoprotein cholesterol ratio, insulin resistance, and cardio-metabolic risk in young men and women. Journal of Lipid Research. 2013 [epub ahead of print]