Type 1 Diabetes: Risk Factors

Risk Factors

Up to 1,000,000 people in the U.S. are estimated to have type 1 diabetes, with about 30,000 new cases diagnosed each year. It is much less common than type 2, however, consisting of only 7 - 10% of all cases of diabetes. Nevertheless, like type 2 diabetes, the incidence in type 1 has been rising over the past few decades.

Risk Factors in Children

Type 1 can occur at any age but usually appears between infancy and the late 30s, most typically in childhood or adolescence. Boys and girls are equally vulnerable. Studies report the following may be risk factors for developing type 1 diabetes:

• Being ill in early infancy.
• Early foods. Some studies have reported that early exposure to cow's milk in infancy and not being breast fed increased the risk for type 1 diabetes. Two studies in 2003 suggested that very early exposure to cereal -- not cow's milk -- plays a role in risk. Any risk from early dietary factors is still very low and likely to affect children who already have a genetically impaired immune response to dietary proteins. Breast milk contains factors that may help regulate the immune response and prevent diabetes in such children. National differences in risk also suggest that not all cow's milk is the same, and some proteins may confer higher risks than others.
• Having a parent with type 1 diabetes.
• Having an older mother.
• Having a mother who had preeclampsia during pregnancy.
• Obesity in children has long been linked to a higher risk for type 2 diabetes. Two 2001 studies reported an association between high weight at birth and obesity during childhood as risk factors for type 1 diabetes as well. The common risk factor may be an increase in insulin secretion, which occurs with obesity. This theoretically could overstress the beta cells so that they become susceptible to damage by overactive immune factors (particularly cytokines), and eventually destruction in children genetically vulnerable to type 1 diabetes.

Until recently, diabetes in children was almost always type 1 diabetes. Of major concern, however, are estimates that between 8 - 45% of new diabetes cases in children are now type 2, most likely because of the increase in childhood obesity. [See In-Depth Report #60: Diabetes - type 2.]