A new study published in JAMA has shown that infants who have recurrent viral respiratory tract infections in the first 6 months of life may be at higher risk for developing type 1 diabetes by 8 years of age
Respiratory tract infections are defined as any infection of the nose, throat, throat, airways or lungs, and are usually caused by viruses. Types of respiratory tract infections include the common cold, flu, bronchitis, pneumonia, tonsillitis, laryngitis and tuberculosis. Respiratory tract infections are particularly common in children because children do not yet have immunity (resistance) built up to fight against the many viruses that can cause these infections.
Viral infections, or infections caused by viruses, have been suggested to cause type 1 diabetes. More recent studies have suggested a link between respiratory tract infections during the first 6 months of life and an increased risk of developing type 1 diabetes.
Type 1 diabetes is a chronic condition in which the pancreas produces little or no insulin, causing a rise in blood glucose (sugar) levels. Insulin is a hormone that helps control the level of glucose in the blood by allowing glucose to enter into cells. Without insulin, glucose builds up in the blood instead of going into the cells, thereby causing hyperglycemia (high blood sugar). When glucose does not enter the cells, the body is unable to use the glucose for energy, which can lead to symptoms such as increased thirst, frequent urination, extreme hunger, fatigue and weakness, and irritability. Type 1 diabetes commonly appears during childhood. Although there is no cure for type 1 diabetes, the condition can be managed. The exact cause of type 1 diabetes remains unknown. In most people with type 1 diabetes, the body’s immune system — which usually fights harmful viruses and bacteria — mistakenly destroys the insulin-producing cells in the pancreas. Genetics may play a role in this process, and exposure to certain environmental factors, such as viruses, may trigger the disease.
To examine the association between respiratory tract infections in the first 6 months of life and type 1 diabetes, researchers analyzed data of 295, 420 infants (45% female and 55% male) who were born in Bavaria, Germany between 2005 and 2007, and who were followed-up for an average period of 8.5 years.
The findings, published in Journal of the American Association (JAMA), showed that recurrent viral respiratory tract infections during the first 6 months of life were associated with an increased risk of developing type 1 diabetes by 8 years of age. Of the 295, 420 infants included in the study, 720 were found to be diagnosed with type 1 diabetes by the age of 8 years old; this represents a rate of 29 diagnoses per 100, 000 children per year. About 93% of all children had at least one infection during the first two years of life, whereas 97% of children with type 1 diabetes had at least one infection before this age. The researchers noticed that about 87% of these infections were respiratory infections and around 84% were viral infections.
The study also showed that children who had respiratory tract infections between birth and 2.9 months of age or between 3 and 5.9 months were more likely to develop type 1 diabetes by age 8, compared to children who did not have respiratory tract infections in these age intervals. The risk of type 1 diabetes was found to be further increased in children who had a respiratory tract infection during both age intervals, compared with children who had infections in only one age interval or who had no infections. Additionally, children who had viral infections between birth and 5.9 months of age were at an increased risk for type 1 diabetes by the age of 8 years, compared to those who did not have a viral infection.
The overall results of this study provide further evidence that early viral respiratory tract infections are associated with an increased risk of developing type 1 diabetes. However, it remains unknown whether the link with early infections suggests increased exposure to virus or an impairment of the immune system, possibly due to genetic susceptibility.
Written By: Nigar Celep, BASc