Anaya J M, Correa P A, Mantilla R D, Jimenez F, Kuffner T, McNicholl J M
Rheumatology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia.
Semin Arthritis Rheum. 2001 Dec;31(3):191-8. doi: 10.1053/sarh.2001.27737.
Little data is available on the prevalence and incidence of rheumatoid arthritis (RA) or the genetic and environmental factors that influence RA risk and severity in non-Caucasian populations. The prevalence of RA in Caucasians and some Native American populations is 1% or more; in contrast, low prevalences of RA have been reported in some African populations. We determined the hospital incidence (HI) and period prevalence (PP) of RA in African Colombians in Quibdo, Colombia, by using data collected at the Hospital San Francisco de Asis, a primary-to-tertiary care center. Genetic and immunologic studies of factors that influence RA risk and severity, such as HLA genes, immunoglobulin-A (IgA) rheumatoid factor (RF), and antikeratin antibodies (AKA) were performed. African Colombians with RA also were compared with Mestizo RA patients from Medellín, Colombia.
To determine the HI, all the outpatient charts for 1995 were reviewed (n = 3,044). PP during 1996 (Jan-Dec) was assessed by stratified sampling of all African Colombians aged 18 or more having arthralgia. Participants completed a survey and a pretested standard questionnaire, had hands and feet X-rays, and provided a blood sample. Total and IgA RF were measured by turbidimetry and ELISA, respectively; AKA were assessed by indirect immunofluorescence on rat esophagus. HLA-DRB1 and DQB1 alleles were determined by polymerase chain reaction technique with primers of specific sequence and by reverse dot blot.
The HI was 0.65 cases per 1,000 person years. There were 321 individuals with arthralgia (0.3%; 95% CI, 0.28-0.3), 18 of whom fulfilled the American College of Rheumatology criteria for RA (PP in the general population, 0.01%; 95% CI, 0.008-0.02). Lower erosion scores were seen in African Colombian patients compared to Mestizos (n = 56), although duration of disease was similar in each group. No association between any HLA allele and RA risk or RA severity or between autoantibodies and RA severity was observed in African Colombians. Comparisons showed no significant differences between African Colombians and Mestizo patients in the presence of RF (total and IgA), AKA, age at onset, extra-articular manifestations, formal education level, and history of malaria.
These results suggest that RA in African Colombian patients from Quibdo is rare, may be less severe in terms of radiographic damage than in Colombian Mestizo patients, and lacks association to HLA-DRB1 and DQB1 alleles. Additionally, RF (total and IgA) and AKA are not markers of progression and activity of the disease in this population.
关于非白种人群中类风湿关节炎（RA）的患病率、发病率以及影响RA风险和严重程度的遗传和环境因素的数据很少。白种人和一些美洲原住民人群中RA的患病率为1%或更高；相比之下，一些非洲人群中RA的患病率较低。我们利用旧金山德阿西斯医院（一家从初级护理到三级护理的中心）收集的数据，确定了哥伦比亚基布多非洲裔哥伦比亚人中RA的医院发病率（HI）和期间患病率（PP）。对影响RA风险和严重程度的因素进行了遗传和免疫学研究，如HLA基因、免疫球蛋白A（IgA）类风湿因子（RF）和抗角蛋白抗体（AKA）。还将患有RA的非洲裔哥伦比亚人与来自哥伦比亚麦德林的混血RA患者进行了比较。
为确定HI，回顾了1995年所有门诊病历（n = 3,044）。通过对所有18岁及以上有关节痛的非洲裔哥伦比亚人进行分层抽样，评估了1996年（1月至12月）的PP。参与者完成了一项调查和一份经过预测试的标准问卷，进行了手部和足部X光检查，并提供了血样。分别通过比浊法和酶联免疫吸附测定法测量总RF和IgA RF；通过对大鼠食管进行间接免疫荧光评估AKA。通过使用特定序列引物的聚合酶链反应技术和反向点杂交确定HLA - DRB1和DQB1等位基因。
HI为每1000人年0.65例。有321人有关节痛（0.3%；95%可信区间，0.28 - 0.3），其中18人符合美国风湿病学会RA标准（一般人群中的PP，0.01%；95%可信区间，0.008 - 0.02）。与混血儿（n = 56）相比，非洲裔哥伦比亚患者的侵蚀评分较低，尽管每组的病程相似。在非洲裔哥伦比亚人中，未观察到任何HLA等位基因与RA风险或RA严重程度之间或自身抗体与RA严重程度之间存在关联。比较显示，在存在RF（总RF和IgA）、AKA、发病年龄、关节外表现、正规教育水平和疟疾史方面，非洲裔哥伦比亚患者与混血患者之间无显著差异。
这些结果表明，来自基布多的非洲裔哥伦比亚患者中的RA很罕见，在影像学损伤方面可能比哥伦比亚混血患者的病情轻，并且与HLA - DRB1和DQB1等位基因无关。此外，RF（总RF和IgA）和AKA不是该人群中疾病进展和活动的标志物。
