Diabetes Mellitus and Entero-Virus Infection
What causes Juvenile Diabetes or Type I Diabetes Mellitus is not completely understood. It is believed that it develops due to a complex interplay between genetic predisposition, immune system and environmental factors. In recent years we have seen an increased prevalence of Juvenile Diabetes, especially in children below the age of 5-years. Europe alone has seen a 3.9% increase. Previous studies have suggested that maternal entero-virus infection during pregnancy increases the risk of offspring developing Type I -Diabetes during adolescence or young -adulthood. Entero-virus infections may initiate and accelerate the beta-cell damaging process leading to diabetes. Entero-virus are small viruses which are made of Ribo Nucleic Acid (RNA) and protein. Besides the 3-polio viruses, there are 60 types of cold related viruses that can cause infection and are more prevalent in summer and during the fall. Entero-virus cause an estimated 10-15 million or more symptomatic infections per year in the United States. RNA from entero-virus can be detected in stools, tissue and blood samples. Statistics reveal an increased incidence of diabetes following entero-virus epidemics. Observational studies have shown that entero-virus infection increases the risk of pancreatic islet autoimmunity or type 1 diabetes mellitus. But systematic review of serological studies had found no association between pancreatic islet autoimmunity and type 1 diabetes mellitus.
Therefore, scientists wanted to review the association between current entero-virus infection and development of autoimmunity or type 1 diabetes mellitus on the basis of molecular studies. For this purpose they went through several studies which were limited to humans (animal studies were not considered) and that measured entero-virus RNA or viral capsid protein in blood, stool or tissue of patients with pre-diabetes and diabetes; and used molecular methods for viral detection. Depending upon whether autoimmunity or type 1 diabetes was the outcome of the study the results were classified into two groups- pre-diabetes and diabetes. Using the Mantel-Haenszel method scientists calculated unadjusted odds ratio with 95% confidence intervals and P values for entero-virus identification in patients with pre-diabetes versus no diabetes and patients with diabetes versus no diabetes.
They found that there was an association between Type I Diabetes Mellitus and entero-virus infection, with a more than 9 times the risk of infection in cases of diabetes and thrice the risk in children with pancreatic islet autoimmunity. Persistent entero-virus infection is also common among patients with Type I Diabetes.
British Medical Journal