Thursday 18th January 2007
Glycated LDL, a component of blood and a type of low-density lipoprotein is known to be higher in diabetics. Normally known as ??bad? cholesterol, LDL increases the risk of a heart attack in diabetics. A new study in Italy has found that glycated LDL levels increase heart attack risk not just in diabetics but also in persons without diabetes.
The researchers followed a cohort of elderly people in southern Italy for the study. More than 4,450 participants who had not had a heart attack were covered under the study, which was an arm of the Onconut Study. The latter is an ongoing investigation of lifestyle and dietary predictors of cancer being conducted in persons over 50 years of age in Italy.
103 people from the total study population suffered a heart attack within five years. Of these 34 were diabetics at the beginning of the study while the remaining 69 were not. Blood samples were taken from all participants at the start of the study. Levels of fasting glucose, insulin, cholesterol, triglycerides, HDL, LDL and glycated LDL were measured for all the participants.
When the researchers checked the levels of all the above blood components in the heart attack patients and compared them with those who had not suffered heart attacks (controls), they found only one common component that was significantly higher in both. This component in both diabetic and non-diabetic cases was glycated LDL.
Analysis revealed diabetics with the highest levels of LDL at the start of the study were at nearly three times higher the risk of suffering a heart attack within five years as compared to those who had low LDL levels. Even amongst the diabetics, high glycated LDL levels meant double the risk of having a heart attack.
The results of the study have been published in the December 2006 online edition of Nutrition, Metabolism and Cardiovascular Diseases and will appear in the January print edition.
??The association of glycated LDL with myocardial infarction could explain why diabetes is a risk factor for MI (heart attack),? said Maurizio Trevisan, Dean of the School of Public Health and Health Professions and senior author on the study.
??In fact, glycated LDL is more easily oxidized than normal LDL and more easily metabolized by macrophages, the precursors of foam cells of the atherosclerotic plaque,? said Trevisan, a Professor of Social and Preventive Medicine. ??This is probably because the sugar molecule attached to the apoprotein B of LDL interferes with the link of the apoprotein with its membrane receptor.?
??Glycated apoprotein B, like glycated hemoglobin (HbA1c), is present also in non-diabetics and its increase could be due to temporary hyperglycemia caused by a high-glycemic-load meal, by stress and by other conditions,? he added.
While the findings do provide interesting information, Trevisan noted that they can??t be applied to the population at large because their study population was selected from people who had sought the services of clinical laboratories affiliated with Italy??s National Health Service. This meant the study population was not the general population.
??These findings need to be confirmed,? noted Trevisan, ??and if the relationship is confirmed, interventions aimed at lowering the glycation of lipoproteins should be organized to test whether such interventions can lower the risk of coronary heart disease." The 20-year follow-up of participants in the study, which began in 1992, should provide more concrete data, he said.
