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Background: After the Second World War, the population living in the Karelian region was strictly divided by the "iron curtain" between Finland and Russia. This resulted in different lifestyle, standard of living, and exposure to the environment. Allergic manifestations and sensitization to common allergens have been much more common on the Finnish compared to the Russian side. Objective: The remarkable allergy disparity in the Finnish and Russian Karelia calls for immunological explanations. Methods: Young people, aged 15‐20 years, in the Finnish (n = 69) and Russian (n = 75) Karelia were studied. The impact of genetic variation on the phenotype was studied by a genome‐wide association analysis. Differences in gene expression (transcriptome) were explored from the blood mononuclear cells (PBMC) and related to skin and nasal epithelium microbiota and sensitization. Results: The genotype differences between the Finnish and Russian populations did not explain the allergy gap. The network of gene expression and skin and nasal microbiota was richer and more diverse in the Russian subjects. When the function of 261 differentially expressed genes was explored, innate immunity pathways were suppressed among Russians compared to Finns. Differences in the gene expression paralleled the microbiota disparity. High Acinetobacter abundance in Russians correlated with suppression of innate immune response. High‐total IgE was associated with enhanced anti‐viral response in the Finnish but not in the Russian subjects. Conclusions and clinical relevance: Young populations living in the Finnish and Russian Karelia show marked differences in genome‐wide gene expression and host contrasting skin and nasal epithelium microbiota. The rich gene‐microbe network in Russians seems to result in a better‐balanced innate immunity and associates with low allergy prevalence. [ABSTRACT FROM AUTHOR]

Background: Increasing evidence links chronic infections, especially burden of several infections, with increased risk for cardiovascular diseases (CVD). We studied joint immune response against two major periodontal pathogens and herpes simplex virus (HSV) in relation to established risk factors of CVD., Methods: Serum antibody levels to HSV, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were determined by ELISA. The study included 1107 subjects, 734 from Finland and 373 from Russia., Results: Combined antibody response to periodontal pathogens was associated inversely (OR, 95% CI) with high-density lipoprotein (HDL) cholesterol concentration (beta = 0.35; 0.20, 0.60; P < 0.001) and directly with HSV antibody quartiles: compared with the first quartile, ORs (95% CI) for quartiles 2-4 were 1.43 (0.88-2.32), 1.74 (1.07-2.82), and 1.89 (1.18-3.02), respectively (P for trend <0.001), after adjusting for age, gender, area, education, smoking, BMI, alcohol, triglycerides, and number of teeth. In linear regression analysis, the 3-pathogen antibody score (comprising antibody levels against periodontal pathogens and HSV) was inversely associated with HDL cholesterol concentration (beta = -0.067/1 mmol/l; -0.235, -0.018; P < 0.05)., Conclusions: HSV infection may promote infection by periodontal pathogens. Furthermore, the infectious burden comprising HSV and periodontitis may increase the risk for CVD by clearly decreasing HDL cholesterol concentrations.

Background: Evidence of the influence of pathogen exposure on the development of atopy and atopic disease is not unequivocal. We investigated the association between markers of infections and occurrence of atopy among adults in eastern Finland and western Russia, two adjacent areas with profound differences in living conditions and lifestyles., Methods: Randomly selected adults aged 25-54 years from Finland (n = 790) and from Russia (n = 387) participated in the study. Skin prick tests were performed to 11 common airborne allergens, and at least one positive prick reaction was considered to indicate atopy. Antibodies to different pathogens including hepatitis A virus (HAV), Helicobacter pylori, Toxoplasma gondii, herpes simplex virus (HSV), Chlamydia pneumoniae and the periodontal pathogens Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans were measured., Results: In Finland 34.3% and in Russia 23.3% of the study population was atopic (p < 0.001). Seroprevalences to all these pathogens were significantly higher among the Russians. In multivariate logistic regression analysis, only H. pylori was inversely associated with atopy in Russia. A further stepwise analysis revealed that H. pylori alone can explain 32% of the difference in atopy between the countries, and T. gondii, A. actinomycetemcomitans, HSV and C. pneumoniae had a slightly additive effect, whereas, unexpectedly, seropositivity to HAV and, to a lesser extent, P. gingivalis had an opposite effect. The net result of the stepwise analysis showed that 44% of the difference in atopy between the countries could be explained by seropositivity to these seven pathogens., Conclusions: Seropositivity to select pathogens, particularly to H. pylori, could explain a substantial part of the difference in atopy prevalence between Finland and Russia. Exposure to HAV was not associated with protection against atopy in this adult population.

Background and Objective: Western lifestyle has consistently been associated with the current asthma and atopy epidemics. We examined the occurrence and risk factors of atopy among schoolchildren and their mothers in 2 geographically adjacent areas with fundamental differences in living conditions and lifestyles., Methods: A population-based study of 2 generations was carried out in eastern Finland and in western Russia. Randomly selected schoolchildren aged 7 to 16 years (367 in Finland and 446 in Russia) and their mothers (365 and 437, respectively) were enrolled. Data were obtained by using a modified International Study of Asthma and Allergies in Childhood questionnaire and by performing skin prick tests against 14 common airborne and food allergens., Results: In children a 4-fold higher risk for atopy (> or =1 positive prick test result) was found in Finland compared with Russia. Sensitization rates in Finland were generally higher among children compared with those of their mothers, whereas in Russia the opposite trends emerged. Parental farming in early life (<1 year) in Finland (odds ratio [OR], 0.53; 95% CI, 0.28-0.99) and in Russia (OR, 0.47; 95% CI, 0.22-1.03) and currently in Finland (OR, 0.45; 95% CI, 0.22-0.91) conferred protection against atopy. Having pets, dogs in Finland (OR, 0.57; 95% CI, 0.35-0.95) and cats in Russia (OR, 0.43; 95% CI, 0.24-0.80), in early life was also inversely associated with atopy., Conclusion: Atopy was several-fold more common in Finland compared with in Russia, and disparities in sensitization rates between the countries have further increased during these generations. The similarity of explanatory variables of atopy in both countries suggests that determinants of atopy are shared, at least in similar geoclimatic conditions.

This study aimed to clarify how concentrations of vitamin C in plasma relate to the serology of periodontitis. The random sample used comprised 431 men, 194 from Finland and 237 from Russia. The plasma vitamin C concentration was determined by o-phtaldialdehyde-fluorometry, and serum immunoglobulin G antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were determined by a multiserotype enzyme-linked immunosorbent assay (ELISA). The mean plasma vitamin C concentration was higher (P < 0.001) in Finnish subjects (mean +/- standard deviation, 4.5 +/- 2.8 mg/liter) than in Russian subjects (1.4 +/- 1.8 mg/liter). Mean antibody levels to both A. actinomycetemcomitans (4.7 +/- 3.6 versus 5.2 +/- 3.1 ELISA units [P = 0.05]) and P. gingivalis (5.7 +/- 2.5 versus 7.6 +/- 2.9 ELISA units [P < 0.001]) were lower in Finnish men than in Russian men. In the combined Finnish and Russian population, the antibody levels to P. gingivalis were negatively correlated with vitamin C concentrations (r = -0.22; P < 0.001); this association remained statistically significant (P = 0.010) in a linear regression model after adjustment for confounding factors. The proportion of P. gingivalis-seropositive subjects decreased with increasing vitamin C concentrations (P for trend, <0.01), but no trend was seen among A. actinomycetemcomitans-seropositive subjects. In conclusion, P. gingivalis infection is associated with low concentrations of vitamin C in plasma, which may increase colonization of P. gingivalis or disturb the healing of the infected periodontium.

In the present study, alcohol consumption was estimated in a population survey in Pitkäranta in the Republic of Karelia, Russia (RUS) and in the neighbouring province of North Karelia in Finland (FIN) in the spring of 1997 in connection with the National FINRISK Study. Alcohol consumption was evaluated by self-report and by the biological markers carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT). In RUS, elevated CDT values were observed in 36.6% of the men and 17.6% of the women. In FIN, the respective rates were 9.6% and 9.4%, which are similar to average European rates. The prevalence of elevated CDT values seen in RUS is the highest prevalence ever reported in general population surveys. However, the self-reported alcohol consumption was similar in the two regions. These results suggest that alcohol consumption especially in Russia may not be reliably estimated by self-reporting, and that alcohol consumption is relatively high, especially among men, in RUS.

Background: There is growing evidence to show that atopic diseases are more common in Western Europe than in the former socialist countries of Eastern Europe., Objective: The aim of this study was to assess whether a similar difference exists between the most eastern province of Finland and a neighboring western district of Russia., Methods: A random sample of 25- to 54-year-old subjects was taken from the population registers in the North Karelia Province in eastern Finland and from the Pitkäranta district across the border in the western part of Russia. Participants filled out a questionnaire on atopic and allergic symptoms and participated in a clinical study, which included skin prick tests with 11 airborne allergens and IgE measurements., Results: Self-reported hay fever, allergic eye symptoms, atopic eczema, and asthma were much more common in Finland than in Russia. In Finland 34.2% and in Russia 21.8% had at least one positive skin prick test reaction. In Finland 21.5% but in Russia only 15.8% had at least one elevated allergen-specific IgE value of the 5 values measured. From 6% to 47% of the differences in self-reported symptoms between the countries were explained by atopy, as measured by means of skin prick testing or specific IgE values., Conclusions: A major difference in clinical allergic diseases and signs of symptoms was observed between the 2 geographically adjacent areas. This suggests that the difference in clinical allergy and atopic disposition is related to the differences in lifestyle and environmental factors.