Why is the risk of blood vessel diseases increased so much in diabetes?

There  are several reasons why the  risk of vascular diseases, such as heart attack, stroke, and diseases of the vessels in the limbs (peripheral vascular disease), is increased in both  types  of diabetes. The  weight gain  and  lack of exercise common  in  people with type  2  diabetes  lead  to  other  conditions  such  as abnormal cholesterol levels and high blood pressure, which are potent causes of vascular disease. If all of these   risk  factors  are  not  treated  effectively, the probability of  vascular disease remains high.  High blood sugar over months and years leads to a chemi- cal reaction of the sugar in the blood vessels, damag- ing them structurally. Perhaps most  importantly, we now know that diabetes and obesity can be described as  irritants  to  the  body tissues, meaning  that  the body becomes generally inflamed. We know that this is so  because we can measure high  levels of com- pounds that  indicate inflammation in the blood of many  people with  diabetes. It  turns  out  that  this inflammation, when  maintained over time, extends to  the  lining  of  the  blood  vessels, which  attracts inflammatory cells out of the  bloodstream. Choles- terol  also takes  on  an  inflamed  form,  enters  the lining of the  blood vessels, and  attracts  still  more inflammatory cells from the bloodstream, setting the stage for serious damage.

Other  contributors to vascular disease include the fact that  high  blood  pressure  results  from  nephropathy, which  further  damages  blood  vessels. This  further damages the kidney and blood pressure rises still fur- ther, setting up a vicious cycle. Even short periods of high glucose, such as may occur after meals in people with diabetes and even prediabetes, can cause  prob- lems with the function of blood vessels, making them more sticky, inflamed, and less able to relax. Whether these  repeated  briefer  periods  of  high  blood  sugar combine over time to cause permanent vascular dam- age is not known. However, it is known that the risk of vascular disease is  already high  in  people with prediabetes.