AGE-RELATED CHANGES IN BLOOD CONCENTRATIONS OF GLUCOSE, PROINSULIN AND INSULIN AMONG RESIDENTS OF THE RUSSIAN ARCTIC

Abstract

Introduction: Extreme natural and climatic conditions of the Arctic have led to development of a special type of glucose metabolism and its regulating links, although the evidence on age-related changes in these mechanisms among Arctic residents is still scarce. Aim: To study age-related changes in blood concentrations of glucose, proinsulin and insulin in residents of Russian circumpolar territories. Methods: In total 1 058 healthy individuals of both genders aged 16-74 years took part in a multicenter cross-sectional study. Of them, 629 permanently lived in the Arctic region while 429 were residents of the Subarctic areas. By age the participants were classified as 16-21, 22-35, 36-45, 46-60 and 61-74 years old. Concentrations of proinsulin and insulin were determined by the enzyme immunoassay methods while glucose level was assessed by spectrophotometric analysis. Between group differences in numeric characteristics were analyzed using Mann-Whitney tests with Bonferroni correction. Associations between variables were studied by non-parametric correlation analysis. Results. Blood glucose concentration increased with age. Among the 16-21-year-olds, higher concentrations of glucose was observed among Subarctic residents. Regional differences reduced in parallel with age. In the Arctic region, an increase in blood glucose in comparison with the youngest group began from 22-35 years while in the Subarctic region. The proportion of people with high glucose levels in age-groups 46-60 and 61-74 years was greater among the Arctic residents compared with their Subarctic counterparts (22.5% and 33.3 % vs. 14.7% and 27.9 %). This was combined with greater proportions of people in the AR with increased proinsulin levels (37.5% and 33.3 % vs. 24.7% and 28.8%) and decreased levels of insulin (57.5% and 53.8 % vs. 74.0 and 36.8 %). Conclusion: A gradual decrease in glucose utilization with age seems to be associated with a decrease in the intensity of proinsulin processing into insulin suggesting early depletion of the functional and receptor activity of pancreatic p-cells. The changes were more pronounced among the residents of the Arctic areas compared to their Subarctic counterparts.