There is a close to six-fold gradient in the incidence of type 1 diabetes between Russian Karelia and Finland, although the predisposing HLA DQ genotypes are equally frequent in the two populations. This suggests that environmental factors contribute to this steep difference in the incidence rate between these adjacent regions.

Aims/hypothesis: We have previously observed an inverse correlation between the incidence of type 1 diabetes and enterovirus infections in the background population. The aim of this study was to analyse whether maternal enterovirus antibody status, which reflects both the frequency of enterovirus infections and the protection conferred by the mother on the offspring, also correlates with the incidence of type 1 diabetes. Methods: Maternal enterovirus antibodies were analysed from serum samples taken from pregnant women between 1983 and 2001 in Finland and Sweden using enzyme immunoassay and neutralisation assays. Comparable samples were also taken between 1999 and 2001 in countries with a lower incidence of diabetes (Estonia, Germany, Hungary, Israel, Lithuania, Russia). Results: A clear decrease was observed in maternal enterovirus antibody levels over the past 20 years (p<0.0001). The frequency of enterovirus antibodies was higher in countries with a low or intermediate incidence of type 1 diabetes compared with high-incidence countries (p<0.0001). Conclusions/interpretation: These findings are in line with our previous observations supporting the hypothesis that a low frequency of enterovirus infection in the background population increases the susceptibility of young children to the diabetogenic effect of enteroviruses.

The incidence of type 1 diabetes varies markedly between countries. As enterovirus infections have been linked to type 1 diabetes, we determined whether this variation correlates with the frequency of enterovirus infections in different Caucasian populations in Europe. Enterovirus antibodies were examined in the background population (1-year-old and 10-14-year-old children) in seven countries with either exceptionally high (Finland and Sweden) or low/intermediate incidence of diabetes (Estonia, Germany, Hungary, Lithuania, Russia) using EIA and neutralisation assays. Enterovirus antibodies were less frequent in countries with high diabetes incidence compared to countries with low diabetes incidence (P<0.001). This suggests that enterovirus infections are not particularly common in countries with high diabetes incidence. In contrast, there seems to be an inverse correlation between the incidence of type 1 diabetes and enterovirus infections in the background population, which is in line with the previously proposed polio hypothesis according to which the complications of enterovirus infections become more common in an environment with a decreased rate of infections.

OBJECTIVE -We sought to study the prevalence of autoantibodies to various islet cell antigens in the background population of two neighboring countries with a sixfold difference in the incidence of type 1 diabetes.RESEARCH DESIGN AND METHODS -Serum samples were obtained from 3,652 nondiabetic schoolchildren in Finland and from 1,988 schoolchildren in the adjacent Karelian Republic of Russia. The Karelian children were divided into three groups (Finns/Karelians, Russians, and others) based on the ethnic background of their mother. The samples were analyzed for islet cell antibodies (ICAs), insulin autoantibodies (IAAs), GAD antibodies (GADAs), and the tyrosine phosphatase-like insulinoma antigen 2 (IA-2A) protein and HLA class II genotypes.RESULTS -The frequency of ICAs, IAAs, and GADAs did not differ significantly between the Karelian (3.5, 0.6, and 0.9%, respectively) and Finnish children (2.8, 0.9, and 0.5%, respectively). Similarly, the frequency of multiple (Ն2) autoantibodies was similar in both countries (0.5 vs. 0.6%). The frequency of IA-2A was, however, four times higher in Finland (0.6 vs. 0.15% in Russian Karelia; P ϭ 0.03). There were no significant differences in autoantibody prevalence among the three ethnic groups in Russian Karelia. There was a falling frequency of GADAs and of positivity for multiple autoantibodies along with decreasing HLA-conferred disease susceptibility among the Finnish schoolchildren.CONCLUSIONS -These data indicate that ␤-cell autoimmunity among schoolchildren is as frequent in Russian Karelia as in Finland, although the incidence of clinical type 1 diabetes is six times higher in Finland. However, in contrast to this general trend, IA-2As were more common in Finland. Since IA-2As usually appear late in the preclinical process, this suggests that progressive ␤-cell autoimmunity is more rare in Russian Karelia. Diabetes Care 30:95-100, 2007

Die Reaktion von MgO mit technischem Al2O3, Al‐Pulver und deren Gemischen wird im Zusammenhang mit Problemen der Herstellung von Periklas‐Keramiken untersucht.