Potential New Risk Factor for Type 1 Diabetes
Only a few risk factors for type 1 diabetes have been identified, but the authors of a new study have a potential new item to add to the list. According to investigators at the Institute of Diabetes Research, respiratory infections that occur in early childhood are suspect.
Why would a respiratory infection be a risk factor?
Among the possible (rather than known) risk factors for type 1 diabetes are two that involve infections: exposure to certain viruses, such as Epstein-Barr, mumps, cytomegalovirus, or coxsackievirus; and development of a respiratory infection shortly after birth. This second possibility was the subject of the latest study, the results of which appear in the new issue of JAMA Pediatrics.
In the study, investigators evaluated 148 children at high risk for type 1 diabetes; that is, they had a first-degree relative with the disease. These children experienced 1,245 infectious events during the first 36 months of their lives.
The investigative team, under guidance of Andreas Beyerlein, PhD, noted that respiratory infections that occurred during the first 12 months appeared to be a risk factor for development of type 1 diabetes. The greatest risk—double the chances of developing antibodies that often lead to development of type 1 diabetes—was seen among the children who had a respiratory disease during the first three months of life.
Among children who experienced a respiratory disease during months 6 through 12, the increased risk dropped to 32 percent. The higher risk of developing type 1 diabetes did not apply when respiratory conditions occurred during the second or third year of life.
In addition, the authors were not able to identify any one specific infectious agent that might be responsible for the increased risk of type 1 diabetes. However, they did point to “a potential role of infections in the upper respiratory tract and specifically of acute rhinopharyngitis (inflammation of the mucous membranes).”
The authors found evidence that such infectious events were associated with triggering the development of antibodies against islet cells in the pancreas. Different islet cells make different hormones, and beta cells, which are destroyed in people who have type 1 diabetes, make the hormone insulin.
This study is important because it suggests researchers may be able to eventually prevent type 1 diabetes by vaccinating against certain infectious agents once they are identified. Currently about 5 percent of the estimated 26 million people in the United States with diabetes have type 1.
Do you know the risk factors for type 1 diabetes?
Thus far, the known risk factors for type 1 diabetes are generally limited to three:
- Genetics—researchers have identified specific genes that may be responsible for some cases of type 1 diabetes
- Family history—having a parent or sibling with the disease slightly increases your risk
- Geography--the farther people live from the equator, the higher the risk of type 1 diabetes, with people in Finland having a 400 times greater risk than those living in Venezuela
Other possible risk factors for type 1 diabetes include the following:
- Vitamin D—although vitamin D may protect against developing type 1 diabetes, there is some evidence that drinking cow’s milk (which is a good source of vitamin D) at an early age increases one’s risk of type 1 diabetes
- Young mother—infants born to women younger than age 25 may be at greater risk
- Preeclampsia—occurrence of this pregnancy complication may increase the risk
- Jaundice—infants born with jaundice may be at higher risk
Results of the new study suggest that infants at risk for eventually developing type 1 diabetes because of family history may have a greater chance of getting the disease if they experience a respiratory infection during early life. However, according to Beyerlein, “we cannot explain yet why specifically respiratory infections might be relevant” in early life.
Beyerlein A et al. Respiratory infections in early life and the development of islet autoimmunity in children at increased type 1 diabetes risk: evidence from the BABYDIET study. JAMA Pediatrics 2013; published online doi: 10.1001/ajamapediatrics.2013.158