Radiographic hand osteoarthritis in two ethnic groups living in the same geographic area.

The aim of the study was to compare the prevalence of radiographic hand osteoarthritis (OA) and its association with age, sex, body mass index in two ethnic groups, Russian and Buryats who reside in the same geographic area. It was a cross-sectional observational study. The study population comprised ethnic Russians (N = 572) and Buryats (N = 327) from the Barguzinsky District of the Buryat Republic, Russian Federation. OA was evaluated in 14 joints of the left hand according to Kellgren and Lawrence's grading system. A diagnosis of OA was determined by the number of affected joints and by the presence of at least one affected joint. Statistical analyses included prevalence estimation, linear and logistic regressions, and chi(2) tests. Our major finding was that individuals of different ethnic groups, residing in the same location, have similar prevalence and severity of radiographic hand OA. Considering the results of our previous study, where we found significant differences in the prevalence and severity of hand OA between the Russian samples (same ethnicity) with diverse places of residence, we conclude that environmental factors play an important role in the development of hand OA.