COMPARATIVE-STUDY OF THE EPIDEMIOLOGY OF SPONDYLARTHROPATHIES IN THE INDIGENOUS POPULATION OF THE CHUKOT PENINSULA AND ALASKA

The paper sums up the many-year cooperative Russian-American studies o f the epidemiology of spondylarthropathies in the arctic populations o f the Chukot Peninsula and Alaska. Aim. Comparison of the epidemiology of spondylarthropathies in the indigenous population of the Chukot Pe ninsula and Alaska. Materials and Methods. A universal design of inves tigation with the same diagnostic criteria was used in both countries. A total of 974 indigenous residents of the Chukot Peninsula were exam ined simultaneously, on the Alaska the sampling was formed as the resi dents 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, ankylosin g spondylarthritis and Reiter's syndrome and undifferentiated spondyla rthropathies and (rarely) psoriatic arthritis. Among HLA-B27 positive adults, the incidence of spondylarthropathies in all groups is 4.2% an d of ankylosing spondylarthritis 1.5%.. Conclusion. A high incidence o f spondylarthropathies, varying from 2 to 3.4%, was revealed in the Ar ctic populations of the Chukot Peninsula and Alaska with a high incide nce 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 non differentiated spondylarthropathies predominated, which can be explain ed by difference in the methods of examination.