High prevalence of rheumatoid arthritis in Yakima Indians

Urinary Metals Concentrations and Biomarkers of Autoimmunity among Navajo and Nicaraguan Men

Metals are suspected contributors of autoimmune disease among indigenous Americans. However, the association between metals exposure and biomarkers of autoimmunity is under-studied. In Nicaragua, environmental exposure to metals is also largely unexamined with regard to autoimmunity. We analyzed pooled and stratified exposure and outcome data from Navajo (n = 68) and Nicaraguan (n = 47) men of similar age and health status in order to characterize urinary concentrations of metals, compare concentrations with the US National Health and Nutrition Examination Survey (NHANES) male population, and examine the associations with biomarkers of autoimmunity. Urine samples were analyzed for metals via inductively coupled plasma mass spectrometry (ICP-MS) at the US Centers for Disease Control and Prevention. Serum samples were examined for antinuclear antibodies (ANA) at 1:160 and 1:40 dilutions, using an indirect immunofluorescence assay and for specific autoantibodies using enzyme-linked immunosorbent assay (ELISA). Logistic regression analyses evaluated associations of urinary metals with autoimmune biomarkers, adjusted for group (Navajo or Nicaraguan), age, and seafood consumption. The Nicaraguan men had higher urinary metal concentrations compared with both NHANES and the Navajo for most metals; however, tin was highest among the Navajo, and uranium was much higher in both populations compared with NHANES. Upper tertile associations with ANA positivity at the 1:160 dilution were observed for barium, cesium, lead, strontium and tungsten.

Characterization of indigenous community engagement in arthritis studies conducted in Canada, United States of America, Australia and New Zealand

BACKGROUND

Research adhering to community engagement processes leads to improved outcomes. The level of Indigenous communities' engagement in rheumatology research is unknown.

OBJECTIVE

To characterize the frequency and level of community engagement reporting in arthritis studies conducted in Australia (AUS), Canada (CAN), New Zealand (NZ) and the United States of America (USA).

METHODS

Studies identified through systematic reviews on topics of arthritis epidemiology, disease phenotypes and outcomes, health service utilization and mortality in Indigenous populations of AUS, CAN, NZ and USA, were evaluated for their descriptions of community engagement. The level of community engagement during inception, data collection and results interpretation/dissemination stages of research was evaluated using a custom-made instrument, which ranked studies along the community engagement spectrum (i.e. inform-consult-involve-collaborate-empower). Meaningful community engagement was defined as involving, collaborating or empowering communities. Descriptive analyses for community engagement were performed and secondary non-parametric inferential analyses were conducted to evaluate the possible associations between year of publication, origin of the research idea, publication type and region of study; and meaningful community engagement.

RESULTS

Only 34% (n = 69) of the 205 studies identified reported community engagement at ≥ 1 stage of research. Nearly all studies that engaged communities (99% (n = 68)) did so during data collection, while only 10% (n = 7) did so at the inception of research and 16% (n = 11) described community engagement at the results' interpretation/dissemination stage. Most studies provided community engagement descriptions that were assessed to be at the lower end of the spectrum. At the inception of research stage, 3 studies reported consulting communities, while 42 studies reported community consultation at data collection stage and 4 studies reported informing or consulting communities at the interpretation/dissemination of results stage. Only 4 studies described meaningful community engagement through all stages of the research. Inferential statistics identified that studies with research ideas that originated from the Indigenous communities involved were significantly more associated with achieving meaningful community engagement.

CONCLUSIONS

The reporting of Indigenous community engagement in published arthritis studies is limited in frequency and is most frequently described at the lower end of the community engagement spectrum. Processes that support meaningful community engagement are to be promoted.

Systematic review of rheumatic disease phenotypes and outcomes in the Indigenous populations of Canada, the USA, Australia and New Zealand

We performed a systematic review designed to characterize clinical phenotypes and outcomes in Indigenous populations with rheumatic disease to enhance the understanding of how rheumatic disease presents in Indigenous populations and allow for better projection of the healthcare needs of the communities affected. A systematic search was performed in medical (Medline, EMBASE, CINAHL), Indigenous and conference abstract databases (to June 2015). Search terms for Indigenous populations were combined with terms for inflammatory arthritis conditions, connective tissue disorders, crystal arthritis and osteoarthritis. Studies were included if they reported on disease features, disease activity measures, or patient-reported outcomes in Canadian, American, Australian or New Zealand Indigenous populations. Data were extracted in duplicate, and a narrative summary was prepared. A total of 5269 titles and abstracts were reviewed, of which 504 underwent full-text review and 85 met inclusion criteria. Nearly all the studies described outcomes in the North American populations (n = 77), with only four studies from Australia and four studies from New Zealand. The majority of studies were in rheumatoid arthritis (n = 31) and systemic lupus erythematosus (n = 19). Indigenous patients with rheumatoid arthritis had higher disease activity and reported more significant impact on patient-reported outcomes and quality of life than non-Indigenous patients. Spondyloarthropathy features were described in North American populations, with most patients having advanced manifestations. In systemic lupus erythematosus, nephritis was more frequent in Indigenous populations. Gout and osteoarthritis were more severe in New Zealand Maori populations. The existing literature supports differences in disease phenotype and severity in Indigenous populations of Canada, America, Australia and New Zealand. We encourage investigators in this area of research to undertake contemporary studies that disentangle differences between phenotype and severity that are biologic in etiology or merely reflecting differences in access to care and that provide a longitudinal assessment of outcomes in more diverse populations.

Rheumatoid arthritis in a north american native population: longitudinal followup and comparison with a white population

OBJECTIVE

To describe differences in phenotype and outcomes in North American Native (NAN) patients with rheumatoid arthritis (RA) followed prospectively and compared to white patients with RA.

METHODS

Patients from a single academic center were followed over 20 years using a custom database. Data included diagnoses, year of disease onset, ethnicity, modified Health Assessment Questionnaire (mHAQ) score, patient and physician global scores, tender and swollen joint counts, treatment, serology, and erythrocyte sedimentation rate (ESR). Records of all white (n = 1315) and NAN (n = 481) patients with RA were abstracted. Cumulative treatment data and clinical measures were compared.

RESULTS

Disease duration was longer in white patients compared to NAN patients (16 +/- 11 vs 14 +/- 10 years, respectively; p = 0.03). Onset age was 34 years for NAN patients and 43 years for white patients (p < 0.001). NAN patients were more frequently positive for rheumatoid factor (89% vs 74%; p < 0.001) and antinuclear antibody (57% vs 21%; p < 0.001). Although mean tender joint counts and swollen joint counts were similar, NAN patients had higher Lansbury scores (weighted joint count; 66.5 vs 49.7; p < 0.001), mHAQ scores (1.1 vs 0.9; p = 0.001), and ESR (31 vs 25 mm/h; p < 0.012). NAN patients had more frequent knee (53% vs 34%; p < 0.001) and elbow (62% vs 48%; p = 0.007) involvement. Compared to white patients, NAN patients took a higher lifetime number of disease-modifying antirheumatic drugs (3.2 +/- 1.9 vs 2.2 +/- 1.7; p < 0.001), had more combination therapy (38% vs 29%; p = 0.002), and had more frequent prednisone use (55% vs 39%; p < 0.001).

CONCLUSION

Compared to white patients, NAN patients with RA develop disease earlier, are more frequently seropositive, have greater large joint involvement, and greater disease burden, although treatment is more aggressive. These differences are present early and persist throughout the disease course.

Genetics of rheumatoid arthritis

Rheumatoid arthritis (RA) is a heterogeneous autoimmune disorder of unknown cause with variable clinical expression. About 70% of patients are women. Genetic factors play an important role and likely account for about 60% of disease susceptibility and expression. The association with the HLA-DRB1 gene is the best understood, although several non-HLA loci have been linked to RA, including the 18q21 region of the TNFRSR11A gene, which encodes the receptor activator of nuclear factor kappaB, important in bone resorption in RA. Genetic factors are also important in the treatment of RA because the activity of enzymes relevant in the metabolism of drugs such as methotrexate and azathioprine, including methylenetetrahydrofolate reductase and thiopurine methyltransferase, are in part genetically determined.

Rheumatoid arthritis in American Indians and Alaska Natives: a review of the literature

BACKGROUND AND OBJECTIVES

An increased prevalence of rheumatoid arthritis (RA) has been reported in several American Indian and Alaska Native (AI/AN) populations. This article reviews the prevalence of RA in these populations, including clinical and serologic features.

METHODS

References were taken from Medline through November 2003, in addition to the Arctic Health Literature Database and the American Indian and Alaska Native Health Bibliography.

RESULTS

Published articles reveal an increased prevalence of RA in the Tlingit, Yakima, Pima, and Chippewa Indians. Clinically the disease in these groups is often severe, with early age of onset, high frequency of radiographic erosions, rheumatoid nodules, and positive rheumatoid factor. Studies of HLA alleles in cases and controls have found a high frequency of HLA DRB1*1402.

CONCLUSIONS

The increased prevalence of RA and more severe disease in specific AI/AN populations suggest an important genetic influence on the development of RA in AI/AN populations. A high frequency of specific high-risk HLA alleles in these populations may account for some of the increased risk, but other genetic factors are likely to contribute. Environmental factors have not been studied in detail, but may also play an important role.

RELEVANCE

Understanding the patterns and burden of disease in AI/AN populations may contribute to understanding the etiology of RA and to the development of preventive strategies.

Chronic arthritis in children and adolescents in two Indian health service user populations

Background

High prevalence rates for rheumatoid arthritis, spondyloarthopathies, and systemic lupus erythematosus have been described in American Indian and Alaskan Native adults. The impact of these diseases on American Indian children has not been investigated.

Methods

We used International Classification of Diseases-9 (ICD-9) codes to search two Indian Health Service (IHS) patient registration databases over the years 1998–2000, searching for individuals 19 years of age or younger with specific ICD-9-specified diagnoses. Crude estimates for disease prevalence were made based on the number of individuals identified with these diagnoses within the database.

Results

Rheumatoid arthritis (RA) / juvenile rheumatoid arthritis (JRA) was the most frequent diagnosis given. The prevalence rate for JRA in the Oklahoma City Area was estimated as 53 per 100,000 individuals at risk, while in the Billings Area, the estimated prevalence was nearly twice that, at 115 per 100,000. These rates are considerably higher than those reported in the most recent European studies.

Conclusion

Chronic arthritis in childhood represents an important, though unrecognized, chronic health challenge within the American Indian population living in the United States.

Rheumatic disease in native american children: Opportunities and challenge

Rheumatic diseases are prevalent in Native American adults at rates five to seven times higher than those seen in the Caucasian population. Little, however, has been published concerning rheumatic diseases in Native American children. The authors' work in Oklahoma and with tribes on the northern Great Plains demonstrates high rates of childhood-onset rheumatic disease in this population. Familial disease is common, and large, multiplex kindreds showing strong founder effects are likely found within specific Native American tribes. However, a deeper understanding of the genetic and environmental triggers of rheumatic disease in Native Americans will require a respect and appreciation for the specific and unique cultural and social issues that impinge on research with Native Americans and other indigenous people.

Arthritis beliefs and self-care in an urban American Indian population

OBJECTIVE

To describe beliefs and self-care strategies of American Indians with chronic arthritis joint pain.

METHOD

In-depth interviews were conducted with a convenience sample of urban-dwelling American Indians (n = 56) concerning self-care and beliefs about arthritis; objective measures of arthritis disease activity were obtained through standardized interview protocols.

RESULTS

Joint pain was not generally assumed to be arthritis nor directly related to aging. Belief that chronic pain affecting multiple joints was a serious and unexpected condition oriented American Indians' decisions to seek medical attention. However, verbal communications about pain may be subtle or under emphasized. Few coping strategies were used to control either chronic or episodic pain.

CONCLUSIONS

Chronic arthritis pain may not be optimally managed in this population. Cultural assessment should recognize that American Indian patients may understate serious symptoms. Community educational interventions should target this population to enhance self-care, pain management, and communication of arthritis symptoms to physicians.

Descriptions of joint pain by American Indians: comparison of inflammatory and noninflammatory arthritis

OBJECTIVE

To improve assessment of arthritis joint pain in American Indians by describing how symptoms are communicated.

METHOD

In-depth interviews were conducted with American Indians who experience chronic joint pain (n = 56), to elicit descriptions and self-reported ratings of pain, disability, and beliefs associated with the pain for affected joints (n = 326).

RESULTS

Discrete sets of specific verbal descriptions distinguished inflammatory arthritis (n = 20 terms) from noninflammatory arthritis (n = 22 terms), and indicated levels of pain intensity. An additional set of 14 vague but commonly used verbal descriptors did not distinguish the type of joint disease or pain intensity.

CONCLUSIONS

Subtle pain complaints and vague verbal descriptions, such as "ache," "hurt," and "discomfort," may reflect severe pain symptoms, disability, and more serious joint disease in American Indian patients. In addition, certain specific sensory descriptions used by American Indians suggest inflammatory arthritis and may warrant further evaluation.

Risk for rheumatic disease in relation to ethnicity and admixture

Risk of systemic lupus erythematosus (SLE) is high in west Africans compared with Europeans, and risk of rheumatoid arthritis (RA) is high in Native Americans compared with Europeans. These differences are not accounted for by differences in allele or haplotype frequencies in the human leucocyte antigen (HLA) region or any other loci known to influence risk of rheumatic disease. Where there has been admixture between two or more ethnic groups that differ in risk of disease, studies of the relationship of disease risk to proportionate admixture can help to distinguish between genetic and environmental explanations for ethnic differences in disease risk and to map the genes underlying these differences.

Prevalence of rheumatoid arthritis in Dublin, Ireland: a population based survey

The prevalence of Rheumatoid Arthritis (RA) in Ireland has never been established. Studies from different countries show varying rates, being almost 100 per cent greater in the highlands of Scotland (10/1,000) than in rural Lesotho (6/1,000). A recent study also suggests a fall in the prevalence of RA among women in the London urban area. Given these variations the validity of extrapolating prevalence rates established for other countries to Ireland is questionable. This study aimed to establish a prevalence rate for RA in a defined Dublin population. A self-administered questionnaire was sent to 2,500 people chosen at random from the electoral register. The questionnaire was designed to select out both undiagnosed patients and those with definite arthritis. Respondents whose replies indicated an arthritic process, but in whom no diagnosis had been made, were asked to attend for further assessment and investigations as appropriate. Those who responded that they had been diagnosed with arthritis were asked for consent to inspect their hospital or general practitioner records. A diagnosis of RA was based on American Rheumatism Association (ARA) criteria. Valid responses were received from 1,227 people surveyed (response rate = 49 per cent). Six cases of RA were identified including 2 previously undiagnosed cases. A prevalence rate of 5/1,000 has been estimated based on these findings.

Rheumatic diseases in North America's indigenous peoples

OBJECTIVES

There are at least 3 million North American Indians and Eskimos in North America. The epidemiology of rheumatic diseases in Native North Americans differs from that described for the remainder of the North American population. An enhanced understanding of rheumatic diseases in these indigenous people may provide valuable clues to the cause of these disorders and improve rheumatologic care.

METHODS

The world literature was searched for all reports of rheumatic diseases in North American Indians and Eskimos. The reports were reviewed and the findings summarized by disease process.

RESULTS

Many Native American groups have high prevalence rates of rheumatoid arthritis (RA), systemic lupus erythematosus, connective tissue diseases, and spondyloarthropathies. There appears to be a correlation between the pattern of rheumatic diseases in Native North Americans and the patterns of migration and ancestry. In general, Amerind Indians have increased rates of RA and connective tissue disease, while Na-Dene Indians and Eskimos have high rates of spondyloarthropathies. The RA seen in Native Americans is generally severe, seropositive, with an early age of onset, and frequent extraarticular manifestations. Many Native American groups have very high frequencies of the RA shared epitope. The majority of Native American and Eskimo groups also have high frequencies of HLA-B27, and some of the world's highest prevalence rates of spondyloarthropathies are described in these groups. Although some groups show a marked tendency to develop either Reiter's syndrome or ankylosing spondylitis, psoriatic and enteropathic arthritis are rare.

CONCLUSIONS

The excess rheumatic disease seen in this population is most likely genetic in origin. Because of the combination of high rates of rheumatic disease and relative genetic homogeneity, Native North Americans represent a singular opportunity to study genetic contributions to rheumatic disease. For clinicians, the index of suspicion for rheumatic diseases in North American Indians and Eskimos should be high, and the severe disease and sometimes atypical presentations kept in mind.

Epidemiology and estimated population burden of selected autoimmune diseases in the United States

Autoimmune diseases cause significant and chronic morbidity and disability. The actual number of persons in the United States that are affected by autoimmune diseases and the resultant magnitude of their impact on the public's health are limited to a few specific diseases. In order to understand the clinical, public health and economic importance of these diseases it is necessary to have estimates of incidence and prevalence rates in the population. In this analysis, we estimate the number of persons affected by 24 autoimmune diseases in the United States by applying mean weighted prevalence and incidence rates obtained from published articles to U. S. Census data. The study was restricted to 24 autoimmune predefined diseases for which there was direct or indirect evidence for autoimmune pathogenesis. Subsequently, we used computerized search software and ancestry searching (bibliographies) to conduct a comprehensive search of articles published from 1965 to the present. Eligible studies included those which adhered to standard disease definitions and which included population-based estimates of incidence or prevalence rates. Mean weighted incidence and prevalence rates were calculated from eligible published studies with greater weight proportionately given to larger studies. The mean rates were then applied to the U.S. Census population figures to estimate the number of persons currently afflicted with each disease and the number of new cases occurring each year in the United States. Only U.S. and European studies were used to estimate prevalence and incidence rates when there were at least six eligible studies available for a disease. When there were fewer than six studies, all available studies were included, regardless of country of origin. The number of eligible incidence and prevalence studies found in the literature varied considerably between the 24 autoimmune diseases selected. The largest number of eligible prevalence studies were conducted on multiple sclerosis (MS), rheumatoid arthritis, and systemic lupus erythematosus (SLE) (>/=23), followed by insulin-dependent diabetes (IDDM), myasthenia gravis, primary biliary cirrhosis, and scleroderma (>/=7). There were only one to four eligible studies done on 11 other diseases, and no prevalence studies on 6 diseases. Incidence studies were less frequent but the largest number of studies were conducted on IDDM (n = 37) and MS (n = 28), followed by Graves' disease/hyperthyroidism, glomerulonephritis, primary biliary cirrhosis, rheumatic fever, rheumatoid arthritis, scleroderma, and SLE (>/=9). On the other 11 diseases, there were one to six eligible studies, and no studies on 5 diseases. There were no eligible incidence or prevalence studies on Goodpasture's syndrome, idiopathic thrombocytopenia purpura, or relapsing polychondritis. Overall we estimate that 8,511,845 persons in the United States or approximately 1 in 31 Americans are currently afflicted with one of these autoimmune diseases. The diseases with the highest prevalence rates were Graves'/hyperthyroidism, IDDM, pernicious anemia, rheumatoid arthritis, thyroiditis, and vitiligo, comprising an estimated 7,939, 280 people or 93% of the total number estimated. Glomerulonephritis, MS, and SLE added an estimated 323,232 people. The prevalence of the other diseases reviewed were rare, less than 5.14/100,000. Most diseases were more common in women. From the incidence data we estimate that 237,203 Americans will develop an autoimmune disease in 1996 and that approximately 1,186,015 new cases of these autoimmune diseases occur in the United States every 5 years. Women were at 2.7 times greater risk than men to acquire an autoimmune disease. After reviewing the medical literature for incidence and prevalence rates of 24 autoimmune diseases, we conclude that many autoimmune diseases are infrequently studied by epidemiologists. As a result the total burden of disease may be an underestimate. (ABSTRACT TRUNCATED)

Increased prevalence of systemic sclerosis in a Native American tribe in Oklahoma. Association with an Amerindian HLA haplotype

OBJECTIVE

To investigate a high prevalence of systemic sclerosis (SSc; scleroderma) in a well-defined population of 21,255 Choctaw Indians residing in 8 southeastern Oklahoma counties who were "users" of Indian Health Services.

METHODS

A case-control study of 12 SSc cases and 48 matched non-SSc controls (4 per case) was conducted to investigate potential occupational, residential, and infectious exposures, as well as genetic factors which might predispose to SSc. HLA class II alleles were determined by DNA oligotyping, and class I and III alleles were defined serologically.

RESULTS

The prevalence of SSc in full-blooded Choctaws was at least 8/1,704, or 469/100,000 (95% confidence interval [95% CI] 203-930) over the 4-year interval 1990-1994 and was significantly higher than that among non-full-blooded Choctaws (6/19,551, or 31/100,000) (P = 0.00001, odds ratio [OR] = 15.4, 95% CI 4.9-49.8). The overall prevalence of SSc in Oklahoma Choctaws (66/100,000) also was significantly higher than that in other Native Americans in Oklahoma (9.5/100,000) (P = 10(-6), OR = 6.95, 95% CI 3.3-13.7), who showed a prevalence similar to that reported for whites (2.1-25.3/100,000). Among the SSc cases, there was striking homogeneity of disease expression with the majority exhibiting diffuse scleroderma, pulmonary fibrosis, and autoantibodies to topoisomerase I. No environmental exposures were found to be in excess among cases versus controls. The strongest risk factor for SSc in cases (100%) versus controls (54%) was an HLA haplotype bearing the alleles B35, Cw4, DRB1*1602 (DR2), DQA1*0501, and DQB1*0301 (DQ7) (P = 0.002, Pcorr = 0.036, OR = 21, 95% CI 2.9-437). Survey of another group of Choctaws residing in another state revealed no cases of SSc despite a high frequency of the same HLA haplotype.

CONCLUSION

Full-blooded Choctaw Native Americans living in southeastern Oklahoma have the highest prevalence of SSc yet found in any population. A major risk factor for disease is a uniquely Amerindian HLA haplotype; however, additional genes and/or an as-yet-unidentified environmental exposure seem likely.

Rheumatoid arthritis in a United States Public Health Service Hospital in Oklahoma: serologic manifestations in rheumatoid arthritis vary among tribal groups

OBJECTIVE

To study the serologic manifestations of rheumatoid arthritis (RA) at a United States Public Health Service Hospital that serves numerous tribes in Oklahoma.

METHODS

Forty-five patients with RA were identified, and serologic studies for antinuclear antibody (ANA), rheumatoid factor, and antibodies to extractable nuclear antigens were performed. Extraarticular manifestations of RA were also evaluated.

RESULTS

Twelve of the 45 patients with RA were Kiowa. These patients were significantly more likely to have a positive ANA (75%) than the other patients with RA (28%). In addition, anti-Ro was significantly more common among Kiowa (33%) than among members of other tribes (3%). There was no difference in the extraarticular manifestations of the Kiowa compared with the other Native American tribes.

CONCLUSION

RA can be distinctly characterized by serology among groups of American Indians living in the same geographic area.

The epidemiology of hip osteoarthritis and rheumatoid arthritis in the Orient

The prevalence of hip osteoarthritis and rheumatoid arthritis has been found to be lower in Chinese, Japanese, and other Asian populations than in whites. The low prevalence of osteoarthritis hip in the Chinese and Japanese populations cannot be explained by the rarity of hip dysplasia, which is as prevalent in those two populations as in whites. As in other populations, rheumatoid arthritis in the Chinese is associated with the shared epitope of the third hypervariable region of the DR gene. However, the low prevalence of rheumatoid arthritis in the Chinese cannot be accounted for entirely by genetic factors.

Decreasing incidence and prevalence of rheumatoid arthritis in Pima Indians over a twenty-five-year period

OBJECTIVE

To evaluate temporal trends in the incidence of rheumatoid arthritis (RA).

METHODS

Incident cases of RA were identified among a population-based cohort of Pima Indians in Arizona over the period 1965-1990.

RESULTS

Among 2,894 subjects, 78 incident cases of RA were identified. The age-adjusted incidence declined by 55% in men (Ptrend = 0.225), and by 57% in women (Ptrend = 0.017) after controlling for oral contraceptive or estrogen use and for pregnancy experience. During the same period, age-adjusted prevalence rates of active RA decreased by 29% in men (Ptrend = 0.63) and by 40% in women (Ptrend = 0.02). Fewer than 17% of subjects with known RA were taking slow-acting antirheumatic drugs (SAARDs) in 1990.

CONCLUSION

The decrease in incidence and prevalence of RA in this population over such a short period implicates the involvement of an environmental factor(s), other than exogenous estrogens, in the pathogenesis of the disease. However, the possibility that the observed decrease might be explained by an increased use of SAARDs in subjects with RA cannot be excluded.

T-cell receptor polymorphisms in Tlingit Indians with rheumatoid arthritis

Rheumatoid arthritis (RA) develops as a result of the interaction of both genetic and environmental factors. Among the genes in humans that have been suggested as candidate susceptibility genes in RA are those encoding the T cell receptor for antigen (TCR). A high prevalence and early age of onset of RA has previously been reported in Alaskan Tlingit Indians. In this study, the frequency of seven different restriction fragment length polymorphisms (RFLPs) in the TCR alpha and beta gene complexes were measured in a population of Alaskan Tlingit Indians. No statistically significant differences were noted when the frequencies of these RFLPs were compared between Tlingits with RA and healthy controls (p > 0.05). These results do not support the hypothesis of an RA-susceptibility allele in the vicinity of these TCR alpha or beta genes. Since TCR RFLPs have not been extensively studied in native American populations, TCR polymorphism frequencies in the Tlingits were also compared to the frequencies observed in a second control group of healthy Caucasians. Statistically significant differences were observed in these comparisons implying a different distribution of individuals in these populations with different TCR repertoires.

Rheumatoid arthritis in a population sample in the Gulf: clinical observations

In our practice we had constantly been under the impression that most Arab patients with RA tend to have a non-aggressive and rather nondisabling disease. Therefore, the spectrum of RA was studied in 42 hospital patients with classic or definite forms. Their mean age was 41.2 years and the mean duration of illness was 5.25 years. F:M ratio was 3.6:1. Seropositivity and radiological findings were observed in 59.5% and 45.2% of the patients respectively. They showed a marked lack of nonarticular manifestations with insignificant functional incapacity. The over-all assessment appeared to be in agreement with the initial clinical impression.

HLA antigens in Tlingit Indians with rheumatoid arthritis

HLA-DR4 has been described in association with rheumatoid arthritis (RA) in multiple populations. We have studied HLA antigens in Alaskan Tlingit Indians. HLA-DR4 was decreased in the RA group (n = 32) compared with controls (n = 62) (6% vs 21% p = 0.07). The predominant DR4 allele observed was DRB1*0403 (Dw13.1). The most striking observation in these studies was a marked predominance of the DRB1*1402 allele encoding Dw16 (DRw14). This allele was present in 91% of RA cases, but was also highly prevalent in controls (80%, OR = 2.4 p = 0.20). DRB1*1402 only was observed in 47% of cases and 31% of controls. The DRB3*0101 (DRw52), and the DQA*0501 and DQB*0301 alleles encoding a subset of DQw3 were associated with DRB1*1402 in cases and in controls. HLA-Bw62 was increased in RA cases (28%) compared with controls (8%) (OR = 4.5, p = 0.01, corrected p = ns).

Immunopathology of rheumatoid arthritis. Antikeratin antibodies precede the clinical disease

OBJECTIVE

We sought to determine whether circulating antikeratin antibodies (AKA) precede the onset of rheumatoid arthritis (RA).

METHODS

By matching the registers of 2 previous population studies with the registry of patients receiving antirheumatic drugs several years later, pre-illness serum specimens could be obtained from 39 individuals who subsequently developed RA. AKA were assayed with the standard indirect immunofluorescence technique.

RESULTS

Ten of 39 serum specimens from individuals who subsequently developed seropositive RA, and 1 of 15 sera from individuals who developed seronegative RA, were positive for IgG-class AKA by immunofluorescence assay. The AKA-positive sera were also positive for rheumatoid factors.

CONCLUSION

The findings focus attention on the role of pre-illness immunologic events in the pathogenesis of RA.

Association of HLA-Dw16 with rheumatoid arthritis in Yakima Indians. Further evidence for the "shared epitope" hypothesis

Rheumatoid arthritis (RA) is prevalent in Yakima Indians, a Native American tribe. HLA-DR4, the HLA specificity commonly associated with RA in Caucasians, is rare among the Yakima. Using a specific oligonucleotide probe that recognizes DR4 nucleotide sequences associated with RA, a rare HLA-Dw16 gene was identified in 83% of Yakima patients with RA and in 60% of Yakima control subjects. This shared sequence encodes a discrete class II epitope that is highly correlated with RA in both DR4 positive and DR4 negative individuals.

Rheumatic diseases in an Inuit population

Prevalence and incidence rates for rheumatic diseases were found to be minimal among the Inuit people in the Keewatin District of the Northwest Territories, Canada. Patient identification was achieved by a review of medical records. All identified patients were interviewed and examined by a participating rheumatologist. Among women, the prevalence of rheumatoid arthritis, adjusted for age of the Manitoba population, was 1,822 per 100,000 and was comparable with that observed in other populations; no cases of rheumatoid arthritis in men were confirmed. The age-adjusted prevalence of osteoarthritis, 1,219 per 100,000 in men and 2,144 per 100,000 in women, was apparently low. A moderately high incidence of Reiter's syndrome, 24.9 per 100,000, was found. The findings in children suggested a high frequency of seronegative spondylarthropathies (yearly incidence 60.1 per 100,000), although the adjusted yearly incidence for juvenile rheumatoid arthritis also appeared to be high, 23.6 per 100,000. The frequencies of HLA antigens in patient groups were compared with those found in 19 patients with musculoskeletal complaints but no rheumatic disease. Both HLA-B27 and HLA-DR4 appeared to be common in these controls, 36.8% and 63.2%, respectively. Nevertheless, there was a higher frequency of HLA-B27 in patients with seronegative spondylarthropathies (87%) than in controls (P = 0.001). Because of the small numbers of patients who had rheumatoid arthritis, no associations with HLA were made for this condition. Although the findings suggest differences in the distribution of rheumatic diseases compared with those found in other populations, more complete studies are required to confirm these observations.

HLA antigens in Yakima Indians with rheumatoid arthritis. Lack of association with HLA-Dw4 and HLA-DR4

Women of the Yakima Indian Nation, a northwest Native American population, are known to have an increased prevalence of a rheumatoid arthritis-like disease characterized by erosive arthritis, frequent involvement of metacarpophalangeal and wrist joints, and positive rheumatoid factor. These patients are frequently positive for antinuclear antibodies and often demonstrate adverse reactions to gold therapy. HLA antigens were determined for 29 Yakima Indians with this disease, but there was no increased frequency of either HLA-Dw4 or HLA-DR4, in contrast to other populations with rheumatoid arthritis. There was, however, a trend toward an increase in HLA-B40 and a decrease in HLA-DR8. The relative risk for rheumatoid arthritis in Yakima Indians was 2.53 in the presence of B40 and 0.28 in the presence of DR8.

Rheumatoid arthritis in a Chippewa Band. I. Pilot screening study of disease prevalence

The Mille Lacs Band of Chippewa Indians in central Minnesota was screened for rheumatoid arthritis, with a 77% completion rate of the reservation census. Rheumatoid arthritis was found in marked excess, namely 6.8% of those evaluated or, minimally, 5.3% of the total band if all persons had been evaluated with no additional cases identified. This relatively closed population thus provides an opportunity to assess genetic and environmental factors of significance in this disease.

Rheumatoid arthritis in a Norwegian community (Jondal). A study based on the local doctor's file

This study of rheumatoid arthritis has been made in Jondal, Norway, on 803 persons between the ages of 16 and 75 years. Patients suspected of suffering from joint disease other than traumatic lesions were selected from the general practitioner's file, and further information on these patients was obtained from the local hospital and from personal interviews. It was found that 0.5% of the men and 1.2% of the women suffered from rheumatoid arthritis. Six persons (0.7%) fulfilled the ARA criteria for classical and definite rheumatoid arthritis, one fulfilled four criteria (probable RA). However, only 0.4% of the investigated population had more severe disease.