Pathogeny
The etiology of diabetes has not yet been clarified. The etiology of different types of diabetes is different, even in the same type.
In general, genetic and environmental factors lead to the occurrence of diabetes. It is mainly due to the decrease of insulin secretion caused by islet cell dysfunction, or the body is not sensitive to insulin or both, which leads to the ineffective utilization and storage of glucose in the blood.
At present, the molecular etiology of most diabetes mellitus is not clear, except for some special types of diabetes. Diabetes has certain genetic susceptibility and family aggregation.
However, epidemiological and clinical studies have been very clear that the main cause of type 2 diabetes is bad lifestyle. If we want to reduce the number of diabetes in China, improving the social environment to promote the formation of unhealthy lifestyle is the fundamental way out.
Basic etiology
Genetic factors
Genetic factors play an important role in the pathogenesis of type 1 diabetes. More than 50 genetic variations have been found to be related to the genetic susceptibility of type 1 diabetes.
More than 400 genetic variants have been found to be associated with the risk of type 2 diabetes or hyperglycemia.
It should be noted that the genetic background only endows individuals with a certain degree of disease susceptibility, which is not enough to cause disease. Generally, the overall effect of multiple gene abnormalities under the action of environmental factors leads to the occurrence of diabetes.
Environmental (in vitro) factors
The environmental factors related to type 1 diabetes are unknown. Virus infection may be one of the environmental causes of type 1 diabetes, including rubella virus, mumps virus, Coxsackie virus, etc. these viruses can directly damage islet β cells and initiate autoimmune reaction, further damage islet β cells.
Some chemical poisons, such as rodenticide, such as methylnitrophenyl urea, can also lead to the destruction of islet beta cells and induce type 1 diabetes. In recent years, with the extensive use of programmed death receptor-1 (PD-1) inhibitors in cancer treatment, the number of patients with type 1 diabetes caused by these drugs has also increased significantly.
Environmental factors are particularly important in the occurrence of type 2 diabetes, including age growth, modern lifestyle, over nutrition, lack of physical activity and so on. The most important environmental factor leading to the increased risk of type 2 diabetes is the social environment leading to the formation of unhealthy lifestyle.
Autoimmune system defects
Under the combined action of environmental factors and genetic factors, the immune system attacks insulin producing islet cells, that is, autoimmunity, which leads to the damage and disappearance of islet β cells, and eventually leads to the reduction or lack of insulin secretion.