Ethnic heterogeneity of juvenile arthritis in the Republic of Sakha (Yakutia) related to a high human leukocyte antigen B27 frequency

Table 2 Prevalence of juvenile idiopathic arthritis in the Republic of Sakha (Yakutia) in 2023, n (%)

The prevalence of JIA1	Total patients [n (%)/n]1	Sakha (n = 168) [n (%)/n]1	Russians (n = 49) [n (%)/n]1	P value
Population	266/293	596 (57.0)/152	622 (43.0)/70
Living area
Urban	123 (54.7)/73.6	87 (51.8)/139.3	30 (61.2)/45.4	0.258
Rural	102 (45.3)/102.8	81 (48.2)/89.8	19 (38.8)/406.2
Gender
Boys	118 (52.4)/86.8	83 (49.4)/106.6	19 (38.8)/52.7	0.198
Girls	107 (47.6)/81.9	85 (50.6)/113.6	30 (61.2)/86.6
JIA categories2
Systemic arthritis	8 (3.5)/3.0	3 (1.8)/2.0	4 (8.1)/5.7	0.00005
Oligoarthritis	76 (33.8)/28.5	47 (28.0)/30.8	26 (53.0)/36.8
Polyarthritis, RF (-)	33 (14.7)/12.4	25 (14.9)/16.4	8 (16.3)/11.3
Polyarthritis, RF (+)	2 (0.9)/0.8	2 (1.2)/1.3	0 (0.0)/0
Enthesitis-related arthritis	99 (44.0)/37.2	86 (51.1)/56.4	9 (18.4)/12.7
Psoriatic arthritis	7 (3.1)/2.6	5 (3.0)/3.3	2 (4.1)/2.8

¹Per 100000 children.

²According to the International League of Associations for Rheumatology classification[2].

JIA: Juvenile idiopathic arthritis; RF: Rheumatoid factor.