Epidemiology of rheumatoid arthritis.

Rheumatoid arthritis remains the most important form of arthritis seen in rheumatological practice in the developed world. It presents some tantalizing epidemiological features. It is a relatively rare disease particularly in young life.

Population study of tender point counts and pain as evidence of fibromyalgia.

Objective: To determine the relation between tender points, complaints of pain, and symptoms of depression, fatigue, and sleep quality in the general population.

Design: Two stage cross sectional study with an initial questionnaire about pain to classify those eligible for an examination of tender points.

Setting: Two general practices in north west England.

An investigation of gene-environment interaction in the etiology of rheumatoid arthritis.

The etiology of rheumatoid arthritis is explained by both genetic and hormonal environment factors. Using a survey of twins conducted in the British Isles in 1989, the authors have investigated the extent of a possible genetic-hormonal environment interaction in conferring susceptibility for rheumatoid arthritis. This was done by comparing the hormonal history of three groups of cases and controls: 1) disease-discordant monozygotic twins, thus matching cases and controls for genetic susceptibility; 2) disease-discordant dizygotic twins; and 3) a group of twins with rheumatoid arthritis who were age matched to population controls.

The incidence of rheumatoid arthritis in the United Kingdom: results from the Norfolk Arthritis Register.

This paper provides the first data on the incidence of RA based on a prospective population-based register. All new cases of inflammatory polyarthritis in the Norwich Health Authority are notified by general practitioners to the Norfolk Arthritis Register. The patients are then clinically evaluated by metrologists and blood taken for RF estimation.

A comparison of the performance of different methods of disease classification for rheumatoid arthritis. Results of an analysis from a nationwide twin study.

Objective: We have assessed the importance of the distinction between classification criteria for rheumatoid arthritis (RA) that recognize the presence of currently active disease from those that, in addition, incorporate evidence of past disease activity in ascertaining disease occurrence. We applied 7 classification schemes to a population of twins with inflammatory arthritis to determine (a) the number of individuals classified as RA positive by each scheme and hence the effect on the estimate of disease concordance in the twins and (b) their performance in correctly assigning a diagnosis compared with a physician's opinion.

Methods: The schemes assessed were the 1958 ARA (Rome) criteria which detect active disease, the 1966 New York (using both the 2/4 and 3/4 published cutoffs) which detect "ever" disease and 4 variants of the 1987 ARA criteria.

Measurement of shoulder related disability: results of a validation study.

Objective: To develop and validate a questionnaire to quantify disability associated with shoulder symptoms.

Methods: A set of questions relevant to shoulder symptoms from a general disability interview was developed and the questionnaire applied to a cross-sectional population survey and a prospective study of general practice attenders. Subjects included adults who reported current shoulder pain in a population survey and patients from three general practices who attended with shoulder symptoms during a six month period.

Consistency of morning stiffness: an analysis of diary data.

This study aimed to determine the within-individual daily variation in morning stiffness (MS) of RA patients, and to validate the routine clinically derived duration of MS against that recorded prospectively by patients. Forty-nine RA patients, who during a detailed clinical interview reported experiencing MS that week were studied. They were asked to prospectively record, using a diary, daily information on the duration of their MS.

Breast-feeding and the onset of rheumatoid arthritis.

Objective: In a recent study we demonstrated that the postpartum period, particularly after the first pregnancy, is a time of increased risk for the development of rheumatoid arthritis (RA). The present study was undertaken to investigate whether this risk might be explained by breast-feeding.

Methods: Through a nationwide media campaign, we identified 187 women who had developed RA within 12 months of a pregnancy, and we compared their breast-feeding histories with those of 149 similarly aged women chosen from the patient registers of a nationwide group of general practitioners.

Psoriatic arthritis. Historical background and epidemiology.

Psoriatic arthritis was first described in the early part of the nineteenth century. Over the past 50 years, concepts of the disease have evolved as a result of clinical, epidemiological, radiological and immunogenetic study. Epidemiological and clinical investigations suggest that the disease is a unique arthropathy rather than the coincident occurrence of two common diseases.

Increased levels of sCD23 in rheumatoid arthritis are related to disease status.

The low affinity receptor for IgE (Fc epsilon RII, CD23) is involved in many aspects of T and B cell regulation. In the current study, serum levels of sCD23 were measured in monozygotic (MZ) twins discordant for rheumatoid arthritis (RA) to examine whether an increased level of sCD23 in RA is, at least in part, genetically determined. Paired analysis showed significantly elevated sCD23 levels in affected twins when compared with their unaffected co-twins (p < 0.

Low prevalence of rheumatoid arthritis in black-Caribbeans compared with whites in inner city Manchester.

Objective: To compare the prevalence of rheumatoid arthritis (RA) in Black-Caribbeans and Whites living in the same urban area.

Methods: Cases of inflammatory joint disease were ascertained initially from a postal screening survey of 1851 Black and 1829 age and sex-matched non-Blacks identified from general practice age-sex registers of seven general practices in the Moss Side and Hulme districts of Manchester. The ethnicity of respondents was confirmed using data from a postal screening questionnaire.

"Homozygosity" for the HLA-DR shared epitope contributes the highest risk for rheumatoid arthritis concordance in identical twins.

Objective: To assess the contribution of HLA-DRB1 alleles in determining rheumatoid arthritis (RA) concordance in monozygotic twins.

Methods: Ninety-one monozygotic twins pairs in which at least 1 twin was affected were typed for HLA-DRB1 using both serologic methods and polymerase chain reaction amplification with sequence-specific oligonucleotide hybridization. The role of DR4 and of the shared epitope in disease concordance was investigated.

Validation of the International Study Group criteria for Behçet's disease.

The International Study Group (ISG) for Behçet's disease proposed new international criteria for Behçet's disease in 1990. The aim of this study was to assess the performance of these criteria in new patient groups. Sensitivity was determined in 300 patients with Behçet's disease from seven countries, and specificity in a group of 62 control patients from China.

Influence of previous exposure to human parvovirus B19 infection in explaining susceptibility to rheumatoid arthritis: an analysis of disease discordant twin pairs.

Objectives: To assess the association between exposure to parvovirus B19 and susceptibility to rheumatoid arthritis (RA).

Methods: One hundred and fifty five twin pairs (76 monozygotic (MZ) and 79 dizygotic (DZ)), discordant for RA, were tested for the presence of IgG antiparvovirus antibodies using ELISA. The data obtained were analysed using conditional logistic regression, from which odds ratios and 95% confidence intervals were calculated.

High prevalence of joint laxity in West Africans.

Previous surveys have suggested marked ethnic and geographical variation in the occurrence of joint hypermobility. We investigated the prevalence of joint hypermobility and the influences of age, sex, body mass and occupation in a rural Yoruba population in Nigeria. The study sample consisted of 204 individuals aged 6-66 yr from the townships of Igbo-ora and Eruwa in south western Nigeria.

Skin thickness score in systemic sclerosis: an assessment of interobserver variability in 3 independent studies.

Objective: Using data from 3 independent studies, to quantify the interobserver reliability of semi-quantitative skin scoring methods (the original and the modified Rodnan skin thickness scores) used to assess the degree and extent of cutaneous thickening in systemic sclerosis (SSc).

Method: Interobserver variability of the original Rodnan skin thickness score method (cutaneous thickness assessed in 26 body surface areas using a 0-4 scale) was evaluated in one study. The modified Rodnan method (cutaneous thickness assessed in 17 body surface areas using a 0-3 scale) was evaluated in 2 studies.

Features of systemic sclerosis (scleroderma) in an identical twin pair.

The aetiology of systemic sclerosis (scleroderma) is unknown but it is thought to have both genetic and environmental components. The familial incidence of the disease is very low and we have been able to find only one report of scleroderma in identical twins which was in the Russian literature. We report here on a set of identical twins and their mother who all had features of systemic sclerosis.

Twin concordance rates for rheumatoid arthritis: results from a nationwide study.

We report the concordance rate for RA in a nationwide study of 91 monozygotic (MZ) and 112 dizygotic (DZ) pairs. Twin pairs were recruited from both a national media campaign and a 2-month prospective inquiry of all UK rheumatologists. Disease status was established following a structured clinical and serological appraisal, together with radiological assessment where necessary.

Factors predicting death, survival and functional outcome in a prospective study of early rheumatoid disease over fifteen years.

Sixty-four survivors from a prospective study of early rheumatoid disease were assessed again at a mean of 15.2 years from presentation and their status compared with 29 patients who had died. Eleven of the dead and only two of the survivors had been treated with steroids.

An identical twin pair discordant for rheumatoid arthritis and ankylosing spondylitis.

Both rheumatoid arthritis (RA) and ankylosing spondylitis (AS) have an increased familial occurrence and each disease is associated with the inheritance of specific HLA antigens. We report a pair of identical twin brothers with discordant disease phenotypes: one developed AS at the age of 26, and the other developed RA at the age of 55. The twins possessed both of the disease susceptibility antigens HLA B27 and DR4.

A reevaluation of the symptom of morning stiffness.

Objective: To study, both qualitatively and quantitatively, morning stiffness in consecutive patients attending a rheumatology clinic.

Methods: A detailed interview from 93 patients with rheumatoid arthritis (RA) and 46 patients with noninflammatory joint disease.

Results: Occurrence, duration and severity of morning stiffness were similar in both groups, as was its detailed qualitative description.

Low prevalence of rheumatoid arthritis in the urbanized Chinese of Hong Kong.

Objective: To establish the prevalence of rheumatoid arthritis (RA) in the urbanized Chinese of Hong Kong.

Methods: 2000 adults in 2 housing blocks were screened using a structured interview. Those who screened positive had an examination, rheumatoid factor analysis and radiographs taken.

Lack of association of increased antibody levels to mycobacterial hsp65 with rheumatoid arthritis: results from a study of disease discordant twin pairs.

Objectives: To investigate the role of humoral immunity to mycobacterial hsp65 in the aetiology of rheumatoid arthritis.

Methods: Levels of IgG antibodies to recombinant mycobacterial hsp65 were measured by enzyme linked immunosorbent assay (ELISA) in serum samples of 152 twin pairs discordant for RA and in serum samples from 62 normal blood donors.

Results: No significant differences between antibody levels in the subjects with RA compared either with their unaffected twins or with a group of normal blood donors was observed.

Absence of an association between HLA-DRB1*04 and rheumatoid arthritis in newly diagnosed cases from the community.

Objectives: To determine HLA-DR4 and DR1 allele frequencies in a series of patients with newly diagnosed early inflammatory arthritis.

Methods: HLA-DR1 and DR4 frequencies were determined by oligonucleotide typing of 208 patients classified as having either rheumatoid arthritis (RA) or undifferentiated inflammatory polyarthritis.

Results: The frequency of occurrence of DR4 in these patients with RA did not differ significantly from that in controls in the United Kingdom (42 v 37%).