[Comparative study of epidemiology of spondylarthropathies in indigenous population of the Chukot peninsula and Alaska].

Unlabelled: The paper sums up the many-year cooperative Russian-American studies of the epidemiology of spondylarthropathies in the arctic populations of the Chukot Peninsula and Alaska.
Aim: Comparison of the epidemiology of spondylarthropathies in the indigenous population of the Chukot Peninsula and Alaska.
Materials and Methods: A universal design of investigation with the same diagnostic criteria was used in both countries. A total of 974 indigenous residents of the Chukot Peninsula were examined simultaneously, on the Alaska the sampling was formed as the residents applied for care.
Results: In both regions the study revealed 1) a high incidence of HLA-B27, reaching 40% in the Chukot Eskimos; 2) a similarly high incidence of spondylarthropathies varying from 2 to 3.4%; 3) a similar spectrum of diseases, including, primarily, ankylosing spondylarthritis and Reiter's syndrome and undifferentiated spondylarthropathies and (rarely) psoriatic arthritis. Among HLA-B27 positive adults, the incidence of spondylarthropathies in all groups is 4.2% and of ankylosing spondylarthritis 1.5%.
Conclusion: A high incidence of spondylarthropathies, varying from 2 to 3.4%, was revealed in the Arctic populations of the Chukot Peninsula and Alaska with a high incidence of HLA-B27 antigen. Although the spectrum of detected diseases was similar in the two groups, ankylosing sponditis was more incident on the Chukot Peninsula, whereas on the Alaska reactive arthritis and nondifferentiated spondylarthropathies predominated, which can be explained by difference in the methods of examination.