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A J Silman

Publications and source records attributed to A J Silman.

At least 19 recordsLinked to original sources
PubMed1995

Estimating the prevalence of low back pain in the general population. Evidence from the South Manchester Back Pain Survey.

STUDY DESIGN: This report gives the results of a population-based cross-sectional mailed questionnaire, with prospective follow-up of survey responders and nonresponders. OBJECTIVE: To determine the 1-month period prevalence of low back pain in an adult population in the United Kingdom and to estimate the effect of nonresponse bias. SUMMARY OF BACKGROUND DATA: Previous United Kingdom population studies have reported a 1-year period prevalence of low back pain of 37%. However, the definitions of low back pain have varied, and the influence of nonresponse rarely has been reported. METHODS: The study population was made up of all 7669 adults (18 to 75 years old) registered with two family practices in a sociodemographically mixed suburban area. The questionnaire, including a pain drawing to identify the site of any pain, was mailed to the entire study population. Two repeat mailings were sent to nonresponders. Family practice consultations about low back pain by individuals from the study population were monitored over the following 12 months using computerized records of all surgery contacts. RESULTS: Of the study population, 4501 (59%) responded. The 1-month period prevalence of low back pain was 39% (35% in males, 42% in females). The age distribution was unimodal, with peak prevalence in those aged 45 to 59 years old. Responders to the first mailing had a small but nonsignificant increase in prevalence compared with those who responded to the second or third mailing. Nonresponders had a subsequent consultation rate for low back pain that was 22% lower than that for the survey responders. CONCLUSIONS: After considering potential differences in nonresponders, the estimated 1-month prevalence of low back pain was between 35% and 37%. Prevalence figures in survey responders may overestimate the true population prevalence by a modest amount.

Adolescent↗
PubMed1995

The patient with fracture: the risk of subsequent fractures.

This article reviews the available data considering the question of whether patients who have suffered one fragility fracture are at an increased risk of a subsequent fracture. A number of methodologic concerns are highlighted. There are also a relatively limited number of datasets available for consideration. There is, however, a consistent observation that patients who have had one fracture are at an increased risk of having subsequent fractures. The earlier the age at fracture and the greater the number of previous fractures, the greater the subsequent risk. Many recent population surveys on osteoporotic fracture have focused on screening populations for vertebral deformity as a useful population guide to osteoporotic fracture occurrence. The same conclusions apply to the risk of subsequent fractures. It is difficult to distinguish three possible hypotheses to explain this increased risk. First, and intuitively most likely, risk factors for the development of one fracture are still operative to increase susceptibility to a second and subsequent event. Second, the occurrence of a fracture, particularly in the limbs, is followed by bone loss, not completely reversible, which could lead to an increased risk of subsequent fracture. Finally, there may be mechanical influences caused by having had one fracture, and it may be these mechanical effects that increase this subsequent risk.

Fractures, Bone↗
PubMed1995

Osteoporosis in rheumatoid arthritis. A monozygotic co-twin control study.

OBJECTIVE: To quantify the magnitude and distribution of osteoporosis in rheumatoid arthritis (RA). METHODS: Bone mineral density (BMD) was measured by dual x-ray absorptiometry, in a monozygotic co-twin control study. RESULTS: BMD was reduced at most skeletal sites in the twin with RA compared with the co-twin (lumbar spine 4.6%, femoral neck 9.7%, total body 5.7%). Differences in lean soft tissue (5.6% for total body) correlated with differences in BMD between twins at multiple sites. CONCLUSION: Osteoporosis in RA is generalized and may be related to loss of mobility or muscle mass associated with the disease.

Arthritis, Rheumatoid↗
PubMed1995

Number of children as a risk factor for low back pain in men and women.

OBJECTIVE: To estimate the influence of the number of liveborn children on the risk of low back pain. METHODS: The study design was a cross-sectional population-based survey. The 4,501 respondents to a postal survey were asked to provide data on the occurrence of low back pain and on any children they had. Data on some potential confounding variables were also obtained. RESULTS: There was an increased risk of low back pain in those who were married compared with those who were unmarried, among both men (odds ratio 1.7) and women (odds ratio 1.6). Among married individuals, there was a linear trend of increasing risk with increasing numbers of children. CONCLUSION: The risk of low back pain is related more to childrearing than to childbearing, although this effect might be partially mediated by unknown confounders associated with increasing family size.

Adolescent↗
PubMed1995

Scleroderma.

In practice, the classification of scleroderma is less problematic than that of most other connective tissue diseases given the distinctive pattern of skin involvement. Classification of early and limited disease is more problematic and is difficult to separate from severe forms of Raynaud's phenomenon. Division of scleroderma into two groups depending on the presence or absence, early in the disease, of truncal skin involvement makes biological and clinical sense. Measurement using a clinical skin score remains the best approach to monitoring disease progress.

Humans↗
PubMed1995

Heterogeneity of disease phenotype in monozygotic twins concordant for rheumatoid arthritis.

The objective of the study was to investigate the genetic contribution to the clinical expression of rheumatoid arthritis (RA) by comparison of disease features in RA-concordant monozygotic (MZ) twin pairs. Fourteen RA-concordant MZ twin pairs recruited from a nation-wide study were examined to determine the degree of similarity in: (a) age of disease onset; (b) pattern of joint involvement; (c) pattern of extra-articular disease; (d) toxic reactions to drugs; (e) disease course; and (f) serology for rheumatoid factor (RF) and antinuclear antibody. There was considerable within-pair diversity in the variables studied. Some similarity within twin pairs was observed for the ages at disease onset (R = 0.63), presence of erosive changes (kappa = 0.61) and the presence of IgM RF (R = 0.87). No important similarity was seen, however, in the pattern of joint involvement, the occurrence of extra-articular disease, adverse drugs reactions, clinical disease course and reported disability level. There is heterogeneity in the genetic contribution to the clinical expression of RA. The overall lack of similarity for the majority of clinical variables indicates the importance of non-genetic factors on the expression of disease.

Age Factors↗
PubMed1995

Lack of influence of non-inherited maternal HLA-DR alleles on susceptibility to rheumatoid arthritis.

OBJECTIVE: To reproduce findings from previous reports that non-inherited maternal HLA class II antigens might contribute to rheumatoid arthritis (RA) susceptibility in the offspring. METHODS: Families were recruited from the Arthritis and Rheumatism Council's National Repository of RA families and HLA-DRB1 alleles were examined in these individuals and their first degree relatives using DNA typing methods. RESULTS: There was no evidence of an increase in either non-inherited maternal HLA-DR4 or the HLA-DRB1 shared epitope as a whole compared with the frequency expected using the non-inherited paternal antigens as controls. CONCLUSIONS: The numbers of probands who were shared epitope negative were small, but we are unable to confirm in these families the findings that non-inherited maternal HLA contributes an additional susceptibility factor to rheumatoid arthritis.

Alleles↗
PubMed1995

Survey response rates: national and regional differences in a European multicentre study of vertebral osteoporosis.

STUDY OBJECTIVE: This analysis aimed to compare the response rates of those invited to attend for screening in a multicentre, multinational study within Europe. DESIGN: This was a population survey. SETTING: Thirty four centres in 16 European countries. SUBJECTS: Men and women aged 50 years and over were recruited from population based sampling frames to participate in a prevalence survey of osteoporosis. Subjects were invited by post to attend for radiological screening and interview, and non-responders were followed up by repeat mailing. RESULTS: There was a substantial variation between centres in response rates: the mean was 49% and the range 5-83%. Adjusting for those known to have died or moved house did not affect the overall ranking. The response rates to each mailing also varied between centres: first mailing 45% (range 5-83%) and second mailing mean 10% (range 0-23%). The response rates varied in relation to age and sex and were higher in women than men. Rates fell gradually with age in women but rose in men until the age of 65 years. Response rates varied regionally. These were highest in countries from northern Europe and lowest in southern European countries, but there was wide variation both within regions and within countries. CONCLUSIONS: Multicentre, multinational studies within Europe will probably become increasingly popular. In this study, despite a standardised approach, the range in response rates between centres both within and between countries was substantial. Attempts at cross national standardisation in survey design can have only a limited effect on yielding uniformity in response.

Aged↗
PubMed1994

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. When the medical histories of twins with rheumatoid arthritis were compared with those of population controls, both breast feeding and infertility problems appeared to be risk factors for the disease (odds ratios = 2.01 and 4.09, respectively). Also, oral contraceptive use appeared to have a protective effect (odds ratio = 0.43). However, when both monozygotic and dizygotic twins were compared, these effects were either less apparent or nonexistent. Our results therefore suggest that there does not exist any evidence of strong interaction between genetic and hormonal environment factors. More notably, in the absence of such an interaction, the comparison of both monozygotic and dizygotic discordant twins was overmatched and therefore of low power. The extent of any overmatching was measured using the kappa statistic.

Adult↗
PubMed1994

"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. Relative risks (RR) with 95% confidence intervals were determined. RESULTS: Increased concordance for RA was observed in both DR4 positive and shared epitope positive pairs (RR 3.4 and 3.7, respectively). A 5-fold risk for RA concordance was seen in twins who were "homozygous" for the shared epitope, compared with those negative for the shared epitope. CONCLUSION: In the absence of the shared epitope, RA concordance in monozygotic twins is rare. In contrast, "homozygosity" for the shared epitope is the most important factor in determining RA concordance.

Arthritis, Rheumatoid↗
PubMed1994

Variation in vertebral height ratios in population studies. European Vertebral Osteoporosis Study Group.

Vertebral height ratios are used to define vertebral deformity in clinical and epidemiologic studies of vertebral osteoporosis. However, few data have been obtained on the variation in these ratios in different populations using standard methods. We examined vertebral morphometric measurements obtained in a population survey from three centers: Malmö (Sweden), Montceau-les-Mines (France), and Graz (Austria), to study the influence of sex and the population center on vertebral height ratios. Radiographs were obtained according to a standardized protocol, and morphometric measurements, anterior height Ha, central height Hc, and posterior height Hp, made in Berlin. The height ratios anterior, Ha/Hp, central, Hc/Hp, posterior I, Hp/Hp', and posterior II, Hp/Hp" (Hp' = posterior height of vertebrae above, Hp" = posterior height of vertebrae below) were calculated for each vertebra from T4 to L4. The mean and standard deviation of these ratios for each sex and each center were derived using a statistical trimming procedure to normalize the distribution. Threshold values for defining grade 1 and grade 2 deformities, wedge, biconcavity, and compression, were calculated using these parameters. Anterior and central vertebral height ratios were smaller in males than females (p < 0.01). There were significant differences between the three centers (p < 0.01) both in the trimmed mean values for anterior and central vertebral height ratios and in the thresholds derived using standard criteria for defining wedge and biconcavity deformity. The data confirm the impression from single-center studies that vertebral height ratios vary between populations and suggest that reference values for vertebral height ratios should be derived separately for males and females within individual populations whenever possible.

Aged↗
PubMed1994

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. There are no validated criteria for classification; this is partly because of the heterogeneous clinical features associated with the disease, and the relapsing and remitting nature of both psoriasis and arthritis. Clinical subgroups have been proposed and have proved useful in study of the disease; however, there are inconsistencies and overlaps in the published data. The population prevalence of psoriatic arthritis is in the range of 2-10 per 10,000 although this is probably an underestimate as those with sacroiliac involvement only are not included. There are currently no incidence figures from population samples. The disease is slightly more common in females than males, although there is variation in the sex ratio by disease subgroup. There is evidence that hormonal and environmental factors play a role in the occurrence of disease.

Age Distribution↗
PubMed1994

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. Sixty-eight had reported joint pain as part of a population survey of arthritic disorders and each was age and sex matched with one household and one neighbour control. Joint hypermobility was assessed, at four peripheral sites bilaterally and forward flexion of the trunk, by a single observer using the Beighton score. Each subject had weight and height recorded, answered a brief questionnaire about occupation and joint symptoms and was examined for peripheral joint disease. Only 11 (5%) of the subjects were negative at all five sites whereas 111 (54%) were hypermobile at three or more sites including 23 (11%) positive at all five. Using a score of 4/9 or greater as a cutoff, 88 (43%) were positive, including 35% of males and 57% of females. There was a linear decline with age in females but a more rapid decline only to age 35 yr in males. There was no relation to body mass or occupation. We conclude that joint hypermobility amongst this population is substantially greater than that recorded for other groups but is not associated with joint pain.

Adolescent↗
PubMed1994

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. The ISG criteria performed well compared to the other criteria sets in current use.

Behcet Syndrome↗
PubMed1994

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. The times both of waking and of getting up were noted, as well as the times to first improvement, maximum improvement and complete disappearance of MS, providing six possible estimates of MS duration, three of which, using waking as starting points, could be compared with the interview. The daily variation of MS was assessed by the within-patient range. The median duration of the diary scores was then compared with the MS estimates recorded at the interview. There was a large intra-individual variation in duration of MS, whichever of the six definitions were used. Half of the patients recorded ranges of MS scores of 3 h or more within the same week. There was also marked variation between the median diary derived duration and that ascertained by interview. This variation was at its smallest when the duration of MS was calculated as time until maximum improvement. The routine recording of the 'typical' duration of MS seems to have little clinical value in the face of the large within-patient variation. Of the possible choices for estimating duration, the time from waking to maximum improvement appeared to be the best indicator of the average duration of MS in RA patients.

Aged↗
PubMed1994

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. Cases of RA were defined as all those notified with an onset of symptoms in 1990; who presented by 31 December 1991; and who satisfied the 1987 ARA criteria for RA at the time of presentation. Two hundred and ten patients were notified in the defined time-frame, of whom 104 were classified as having RA. The annual incidence rate was 36/100,000 for women and 14/100,000 for men. RA was rare in men aged under 45 yr. The incidence in men rose steeply with age. The incidence in women rose up to age 45 yr, plateaued to age 75 yr, and fell in the very elderly.

Adolescent↗