Objective: To assess whether the detection of enterovirus RNA in blood predicts the development of clinical type 1 diabetes in a prospective birth cohort study. Further, to study the role of enteroviruses in both the initiation of the process and the progression to type 1 diabetes.
Research design and methods: This was a nested case-control study where all case children (N = 38) have progressed to clinical type 1 diabetes. Nondiabetic control children (N = 140) were pairwise matched for sex, date of birth, hospital district, and HLA-DQ-conferred genetic susceptibility to type 1 diabetes. Serum samples, drawn at 3- to 12-month intervals, were screened for enterovirus RNA using RT-PCR.
Results: Enterovirus RNA-positive samples were more frequent among the case subjects than among the control subjects. A total of 5.1% of the samples (17 of 333) in the case group were enterovirus RNA-positive compared with 1.9% of the samples (19 of 993) in the control group (P < 0.01). The strongest risk for type 1 diabetes was related to enterovirus RNA positivity during the 6-month period preceding the first autoantibody-positive sample (odds ratio 7.7 [95% CI 1.9-31.5]). This risk effect was stronger in boys than in girls.
Conclusions: The present study supports the hypothesis that enteroviruses play a role in the pathogenesis of type 1 diabetes, especially in the initiation of the β-cell damaging process. The enterovirus-associated risk for type 1 diabetes may be stronger in boys than in girls.