To compare the prevalence of rheumatoid arthritis (RA) in related, but geographically separate, indigenous circumpolar populations.
Cases were identified by community survey in Russia and by examination of cases located through arthritis registries, a computerized patient information database, and query of local health care providers in Alaska. All possible cases were verified by examination and application of the American College of Rheumatology 1987 criteria.
The prevalence rates of RA (age standardized to US population of 1980) varied from 0.62% in the Alaskan Yupik to 1.78% in the Alaskan Inupiat. The Russian Chukchi rate was 0.73% and that of the Siberian Eskimo was 1.42%.
The Alaskan Yupik Eskimo and Chukchi natives had prevalence rates of RA within the usual range of North American Caucasian groups, in contrast to the Russian Siberian Eskimo and the Alaskan Inupiat Eskimo of the Barrow region, whose high rates approached those of unrelated North American native groups living in very different environments. The Alaskan Inupiat rate was significantly higher than that of the Alaskan Yupik (OR = 2.51, 95% CI 1.25-5.07; p = 0.013), but statistical inferences are limited in the Russian study populations by the small case numbers. The high prevalence rates probably have a genetic basis, although an environmental influence cannot be excluded.