The ABO blood groups are associated with cardiovascular disease in individuals with hereditary hypercholesterolemia. This FinnDiane-study further explores the subject by investigating the relationship between the blood groups and cardiovascular disease in individuals with type 1 diabetes according to their diabetic kidney disease.
In previous studies, the ABO blood groups have been associated with cardiovascular disease (CVD) in individuals with hereditary hypercholesterolemia (high blood cholesterol). This FinnDiane-study (Finnish Diabetic Nephropathy Study) further explores the subject by investigating the relationship between the blood groups and CVD in individuals with type 1 diabetes according to their diabetic kidney disease.
Cardiovascular disease is a major cause of death among people with diabetes and kidney disease. In previous studies the ABO blood groups have been associated with cardiovascular disease. Here, the A and B blood groups where shown to increase the risk of ischemic heart disease (IHD), especially in individuals with hereditary hypercholesterolemia (high blood cholesterol). Contrary, the O blood group seem to have the lowest risk of thrombotic events overall.
In the present study, including 4531 adults with type 1 diabetes, it was shown that the A blood group entails an increased risk for ischemic heart disease (IHD) for individuals with increased levels of albumin in their urine, which is a marker of diabetic kidney disease.
The FinnDiane specializes in type 1 diabetes and the mechanisms of its complications. As diabetes can be seen as an epidemic of sorts, with over 250 million patients worldwide and as many as one in ten in Finland with some form of diabetes, finding ways to improve the care and prevention of diabetes by increasing the knowledge of the disease is essential.
Erika Parente, main author of the study at hand, is a physician specialized in endocrinology. Parente was living and working in Brazil until last year, when she was invited to Folkhälsan to do her post–doc.
– We are actually researching the risks factors for the complications of type 1 diabetes. We know that type 2 diabetes is not 100 percent avoidable, but it is possible to prevent it by doing exercise, eating healthy food and avoiding weight gain, even if the individual has the genetics for type 2. However, it is not possible to prevent type 1 diabetes if the individual has the genetics for it. So, this is something that we have to explore – what are the ways to avoid the complications of type 1 diabets? This is the main point of our research in FinnDiane, says Parente.
Parente explains that, even though genetic risk factors are unchangeable, such as blood groups, the knowledge of being in a risk group might increase the motivation to manage the modifiable risk factors by the individuals, such as blood glucose, triglycerides and lipids.
The ABO blood group system is based on the presence or absence of A and B antigens on the surface of our red blood cells. Furthermore, the ABO antigens are not found only on our red blood cells, but sometimes on several other tissues in our body as well as in our secretions.
– One of the hypotheses is that these antigens on the surface of the red blood cells can interact with other molecules in the body. The point is that if the individual has the A antigen on the top of the red blood cells and belong to FUT2 phenotype, these antigens may interact with the endothelium of the blood vessels and this might increase the risk of thrombosis, Parente explains.
In other words, these antigens, or the absence thereof, may affect how cells and tissues act or react with other molecules. While the exact mechanisms and pathways are still subject to further investigation the consequential associations are clear. Mainly, the blood group A has been associated with an increased risk of thrombotic events i.e. heart attacks and strokes, while the O group runs a lower risk.
This study showed that individuals with type 1 diabetes who belong to the A blood group and have early signs of diabetic kidney disease indicated by small traces of albumin in their urine, run a significantly higher risk of developing ischemic heart disease.
Parente explains that microalbuminuria indicates there is a damage in the kidney membranes and this is why albumin is being lost in urine. The microalbuminuria stage of diabetic kidney disease is associated with an inflammatory status. One hypothesis is the inflammatory status may change the adhesion of the A blood group antigens with the endothelium favoring to thrombotic events such as ischemic heart disease.
– It is possible the inflammation is somehow mediating the interaction between these molecules, but actually, the exact pathway of how this works is still unknown. We cannot say anything about cause and effect, but we can pinpoint the association and risk, which are important to motivate further studies to explore these mechanisms, Parente comments.
Parente argues that further studies should aim at identifying the precise mechanism involved in the relationship between the blood groups, kidney disease and heart disease. From a clinical perspective, her research raises the question whether the ABO blood groups should be considered as a risk factor when assessing cardiovascular disease risk in individuals with type 1 diabetes.
- My main message on this would be: If you have type 1 diabetes and the A blood group, take care of your blood glucose, lipids and blood pressure very well to avoid developing diabetic kidney disease. If microalbuminuria is already present, take even more care about the modifiable risk factors. Of course, this is a general message for everyone that has diabetes, but if you are from the A blood group, take more care, Parente summarizes.
Conclusively, the blood groups are a significant factor to several important health outcomes, and determining the blood group of a patient may enable a more individualized approach in healthcare and disease prevention.
The whole study can be read in full text here.
Simon Granroth, Science Communicator
