A clue as to why Type 1’s are more susceptible to heart disease than the general population. There are a whole lot of interesting articles about the science of diabetes on this site.
This article is vague. Mentions insulin “resistance” in Type 1 children, but any parent or caretaker knows that the resistance is usually temporary. Resistance occurs if on steroids, or under the influence of growth hormones in all children, magnified by the “raging”: hormones in adolescense. Our teen is extremely insulin resistant at times, but in general, very sensitive to insulin. I know long term health will be better if you get Type 1 after adulthood, yet there are studies that show children who are dx’d before age 4 have far less risk of kidney disease. Read a very recent article in Science Daily that found evidence of myopathy (cadiac) within five days of diagnosis. I find that hard to believe. But I do believe that the emphasis in keeping blood sugars as normal as possible is only part of the picture. Type 1 affects every system in your body, whether or not you achieve good blood sugar control. You can have poor control and live a long healthy life and vice versa. Genetic risks and protection for some. There is so much we don’t yet know. But with the risk of heart disease for Type 1s so great, be careful of saturated fat in your diet.
I could be wrong, but I don’t think they’re talking about the temporary, hormonal-based insulin resistance of adolescence. If that were true, non-diabetics would show it too, but be able to compensate for it with increased insulin production. But in this study, they did not show it.
I think there may be a persistent down-regulating of insulin receptors in response to hyperinsulinemia in the peripheral tissues because the insulin is injected under the skin instead of going directly to the portal vein as it does in non-diabetics. In the article, they are talking about the increased risk of heart disease in Type 1’s as they get older, and exploring the possible mechanisms for it. It’s NOT only Type 2’s that die early of heart disease. I think this is a very important topic, and should be discussed and researched more.
I have not read the article, but I have read doctors on the Children with Diabetes site say that Type 1s are indeed more insulin resistant than people without diabetes (though not as resistant as people with Type 2) due to exactly what you said, a down-regulation of the insulin receptors over the years. It is not something that causes Type 1, but rather that develops over years of treatment since Type 1s almost never have a truly “normal” level of insulin in their bloodstream, due to the differences between injected insulin and that which is naturally produced, and this is essentially the cause. I have also read that naturally-produced insulin is 25 times more powerful in its effect on blood sugar than the injected stuff, which I’m sure also has an impact.
My anecdotal experience: I was diagnosed with T1 at age 14. When I was a teenager I was taking upwards of 80 units of insulin a day. Today I take less than half of that.
Part of the reduction in dose, probably is that the insulin regimes of 30 years ago (R+N, once or twice a day) were primitive compared to modern practices. But I also feel that I really did need that much insulin back then.
It seems likely to me, that diabetes (be it T1 or T2) is more than just a disease of insulin and bg’s, and there are other processes happening at the cellular level that we see manifested as heart disease after many decades. Certainly the DCCT and UKPDS did not find a very strong correlation between average bg and cardiovascular disease.
Certainly the DCCT and UKPDS did not find a very strong correlation between average bg and cardiovascular disease.
For the DCCT (Type 1s), at least, this isn’t quite true: http://www.nih.gov/news/pr/dec2005/niddk-21.htm
I read the original journal publication. There were 12 T1D patients and 12 controls. The T1D kids were significantly less fit (by VO2max measurement). It would not be surprising that they are more insulin resistant. They were measured with a hyperinsulinemic-euglycemic clamp (the gold standard), and while it is possible that this was a simultaneous hormonal issue, it is more likely a statement on fitness.
It is already known that fitness is related causally to increased insulin sensitivity. As to whether T1D has anything to do with it is unclear, this study had nothing to say on that matter.
I think Tim actually mean to say that DCCT and UKPDS “did find” a strong correlation.
So all it really said is kids with T1 are less fit than kids without (at least in this very small sample)?
While there is some correlation between cardio health and bg in the T1 studies, it is not nearly as compelling as that between average bg and the microvascular complications and in the DCCT itself no cardio correlation was reached. As the follow-on studies (EDIC, others) progress some correlation is being found but it is not a profound correlation in the same way the microvascular ones were.
UKPDS and its followons are pretty direct in their summaries: “No significant effect of lowering blood glucose on cardiovascular complications was observed.” ( http://care.diabetesjournals.org/content/25/suppl_1/s28.full )
My personal conclusion is that normalizing bg in itself does not remove the cardiovascular risk.
The follow-on-to-the-DCCT studies (EDIC) did find some correlation but it was not nearly as compelling as the microvascular correlations.
Look at the DCCT graphs. The microvascular complications show an incredibly compelling link with average bg. The cardiovascular ones, not nearly so clear.
UKPDS similarly found only weak correlations.
My personal take on all this? That I have to do everything I can to lower my cardiovascular risks, and not just count on decent bg control.
Just what I wanted – a lively discussion!!
I am very interested in cardiovascular risks, because I have a triple whammy for CVD. First off, I had a coronary artery spasm when I was 44 – passed out, and am lucky I woke up, because the falling on the floor must have shocked the arteries out of their spasm. I’ve been on medication ever since. Second, my father had his first heart attack before the age of 53, which is when he had his second one. He was thin, and non-diabetic, but had high cholesterol. Third, let’s not even MENTION the big D!
So I am very interested in just what it is with diabetes that injures the blood vessels (and this includes microvascular problems as well), and of course, I am interested in your insights, too!