Type 1 diabetes incidence rising in Colorado youth

NEW YORK (Reuters Health) - The incidence of type 1 or "insulin-dependent" diabetes is increasing in Colorado among non-Hispanic and Hispanic youth between infancy and 17 years old, data suggest.

Dr. Dana Dabelea, of the University of Colorado School of Medicine, Denver, and colleagues used two databases to examine the long-term trends in the incidence of type 1 diabetes in Colorado.

The overall incidence of type 1 diabetes in Colorado was 14.8 cases per 100,000 per year between 1978 and 1988, which rose to 23.9 cases per 100,000 per year between 2002 and 2004. The incidence increased by 2.3 percent per year from 1978 to 2004.

The annual increase of type 1 diabetes was 2.7 percent for non-Hispanic white youth and 1.6 percent for Hispanic youth. A greater but nonsignificant increased incidence was also observed in the 0- to 4-year age group between the first and second time periods.

"We may be seeing an onset of type 1 diabetes in children at younger ages, which gives this age group a larger increase comparatively," Dabelea said in an interview with Reuters Health. "These findings are particularly noteworthy given the current limited data on the incidence of diabetes of any type among youth nationwide," she said.

"We are facing important changes in the environment in which these youth are growing up that in turn may be changing the face of diabetes in this country," she continued.

"Although the reasons for this increase are unclear, several hypotheses have been proposed," Dabelea said. "The 'hygiene hypothesis' proposes that the decreasing early life exposure to infectious agents in westernized societies has led to an impairment in the maturation of the immune system, thus permitting an increased occurrence of immune-mediated disorders, such as asthma and type 1 diabetes," she explained.

"The 'accelerator' and the 'overload hypotheses' both postulate that an increase in body size in genetically susceptible youth accelerates the onset of type 1 diabetes." All of these hypotheses require further study, Dabelea said.