Insulin Resistance Predicts A Diverseness Of Age-Related Diseases

In the concluding post, I reviewed a written report past times Gerald Reaven's grouping showing that insulin resistance strongly predicts the conduct chances of cardiovascular affliction over a 5-year period.  In 2001, Reaven's grouping published an fifty-fifty to a greater extent than smasher follow-up lawsuit from the same cohort (1).  This written report shows that non exclusively does insulin resistance predict cardiovascular affliction risk, it likewise predicts a diversity of age-related diseases, including hypertension, coronary ticker disease, stroke, cancer, type 2 diabetes, in addition to fifty-fifty overall mortality risk.


The study

The written report was real similar to the previous one: first, they recruited 147 thin in addition to overweight middle-aged volunteers without diabetes or diagnosed cardiovascular disease.  Then, they measured the volunteers' insulin sensitivity.  While most studies of this nature indirectly gauge insulin sensitivity only past times using a formula based on fasting insulin in addition to glucose measurements (HOMA-IR), which tin hold upward inaccurate, Reaven's grouping straight measured insulin sensitivity using a gilt measure method*.

Next, they waited six years in addition to watched who developed a diversity of diseases over that period.

The results

As inwards the previous study, they divided the volunteers into iii equal-sized groups based on their score of insulin resistance. Group I had the lowest bird of insulin resistance, grouping II had an intermediate level, in addition to grouping III had the highest level.  The next graph illustrates the issue of people who were diagnosed amongst affliction (and/or died) inwards each grouping over the course of didactics of the study:

As you lot tin see, over the 6-year period, none of the people inwards the to the lowest degree insulin-resistant grouping developed affliction or died.  In contrast, 36 percent of the people inwards the most insulin-resistant grouping developed affliction and/or died, from a diversity of causes including hypertension, coronary ticker disease, stroke, type 2 diabetes, in addition to cancer.  People inwards the middle grouping had an intermediate charge per unit of measurement of disease.

This is an incredibly smasher result.

Again, people who were most insulin-sensitive likewise had a diversity of other well for you lot signs, including less torso fatness, higher physical activity, lower blood pressure, lower levels of LDL ("bad") cholesterol, in addition to the higher levels of HDL ("good") cholesterol.  And again, afterwards mathematically adjusting for all of these other factors, "only insulin resistance was an independent predictor of the twoscore age-related clinical events."

Discussion

Many researchers, including myself, believe that insulin resistance is a key characteristic of a metabolic dysfunction syndrome that drives much of the chronic affliction of the modern affluent world.  Reaven's results strongly back upward this contention, since they present that insulin resistance clusters non exclusively amongst a diversity of other metabolic disturbances, but likewise amongst the conduct chances of a diversity of mutual chronic diseases.

These results don't let us to know whether insulin resistance caused the other metabolic disturbances and/or diseases, rather than only beingness associated amongst them, but other inquiry gives us practiced argue to suspect that it does play at to the lowest degree somewhat of a causal role.  Insulin resistance is intimately involved inwards the evolution of type 2 diabetes, which is itself damaging to the cardiovascular system.  Insulin resistance likewise contributes to disturbed blood lipid levels, including elevated LDL particle issue in addition to reduced HDL-cholesterol, which farther harm cardiovascular health.  The human relationship of insulin resistance amongst cancer is less straightforward, but the elevated insulin levels that accompany insulin resistance are idea to drive the progression of surely cancers.  Also, insulin resistance is typically associated amongst chronic, low-grade inflammation, some other constituent that tin promote the evolution of cancer.

Even though insulin resistance in addition to elevated insulin levels don't reliably predict weight attain over fourth dimension (2, 3), insulin resistance does predict chronic affliction risk.  This suggests that fifty-fifty though insulin resistance in all likelihood doesn't play a major role inwards torso fatness, it's nevertheless a metabolic characteristic nosotros should tending quite a fleck about.


* Insulin suppression test, which is a direct mensurate of insulin sensitivity that is highly correlated amongst euglycemic-hyperinsulinemic clamp (4).  The output is "SSPG" or Steady-State Plasma Glucose, which is the bird of blood glucose that results from "clamping" circulating insulin at a standardized level.  The higher your blood glucose (SSPG) is at a given bird of circulating insulin, the to a greater extent than insulin-resistant you lot are.