Epidemiology of juvenile idiopathic arthritis in a multiethnic cohort: Ethnicity as a risk factor

Abstract

Objective. To study the influence of ethnicity on the risk of developing juvenile idiopathic arthritis (JIA) in a multiethnic community of patients with unrestricted access to health care.Methods. A questionnaire on ethnicity was distributed to all patients with JIA being followed up at the Conclusion. In this multiethnic cohort, European descent was associated with a significantly increased risk of developing JIA, and the distribution of JIA subtypes differed significantly across ethnic groups.

Unraveling the Phenotypic Variability of Juvenile Idiopathic Arthritis across Races or Geographic Areas — Key to Understanding Etiology and Genetic Factors?

“…It has been argued that the differences observed between geographic areas may reflect underrepresentation of milder forms of JIA, particularly oligoarthritis, because of referral bias, which could be attributed to restrictions in access to healthcare facilities. An indirect confirmation of this phenomenon was provided by an analysis of a multiethnic cohort in a large Western tertiary care hospital, which in contrast with some studies from India, did not find any difference in the percentage of patients with persistent oligoarthritis between patients of Indian subcontinent descent and either the total JIA cohort or the patients of European ancestry 7 . This limitation does not apply to the study by Fitzpatrick, et al, as nearly all their patients had access to health insurance.…”

“…Over the past 3 decades, several epidemiologic surveys have documented a remarkable, yet unexplained, disparity in the prevalence of JIA subtypes among different geographic areas or racial/ethnic groups 5,6,7,8,9,10,11,12,13 . In Western countries, the most common category is oligoarthritis, but this form is rare in India, New Zealand, The Middle East, and South Africa, where polyarthritis predominates.…”

“…African American (AA) and black South African patients have a higher rate of rheumatoid factor (RF)-positive polyarthritis, whereas juvenile psoriatic arthritis (PsA) is rare in Turkey, Egypt, and Thailand. There is evidence that European ancestry may be an important predisposing factor for antinuclear antibody (ANA)-positive JIA associated with uveitis 7,14 . Conversely, both ANA positivity and ocular involvement are rarely encountered in JIA patients living in the Middle East, East Asia, India, New Zealand, and Central America.…”

Association of HLA-A*02:06 and HLA-DRB1*04:05 with clinical subtypes of juvenile idiopathic arthritis

“…Mean age at onset of JIA in the patients with uveitis was 3.2 years (range 0-14) ( Table 2). The mean age for developing uveitis was 5.2 years (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14], and the mean time interval between the onset of JIA and development of uveitis was 21.9 months (range À4 to 48), with one case developing uveitis 4 months before the onset of JIA. Oligoarticular onset, rheumatoid factor negativity (o14 IU ml À1 ) and low anti-cyclic citrullinated peptide (o4.5 U ml À1 ), as well as younger age at onset of JIA were all significantly associated with JIA accompanied by uveitis (Table 2).…”

“…3,5 However, the contribution of each risk factor may also vary among ethnic groups, presumably because of variations in genetic background. 6 Human leukocyte antigen (HLA) typing is considered useful for assisting in the diagnosis of autoimmune disease-associated uveitis such as HLA-B27-associated uveitis. 7 It has also been reported that HLA-DRB1*13 is associated with susceptibility to JIA-associated uveitis in a Caucasoid population.…”