Zoetermeer Survey. Comparison of Radiological Osteoarthritis in a Dutch Population with That in 10 Other Populations

Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

Annals of the Rheumatic Diseases, 1989; 48, 271-280

Scientific papers Epidemiology of osteoarthritis: Zoetermeer survey. Comparison of radiological osteoarthritis in a Dutch population with that in 10 other populations

JAN L C M VAN SAASE,13 LEO K J VAN ROMUNDE,1 ARNOLD CATS ,2 JAN P VANDENBROUCKE,3 AND HANS A VALKENBURG1 From the 'Department of Epidemiology, Erasmus University Medical School, Rotterdam, The Netherlands; and the Departments of 2Rheumatology and 3Clinical Epidemiology, Leiden State University, Leiden, The Netherlands

SUMMARY The prevalence of mild and severe radiological osteoarthritis was investigated in a random sample of 6585 inhabitants of a Dutch village. Radiographs were graded 0-4 according to the criteria described by Kellgren and Lawrence. The prevalence of radiological osteoarthritis increased strongly with age and was highest for cervical spine (peak: men 84.8%, women 84-3%), lumbar spine (peak: 71-9%, women 67.3%), and distal interphalangeal joints of the hands (peak: men 64-4%, women 76%). Prevalence did not exceed 10% in sacroiliac joints, lateral carpometacarpal joints, and tarsometatarsal joints. Severe radiological osteoarthritis (grade 3 or grade 4) was uncommon under age 45; in elderly persons the prevalence of severe radiological osteoarthritis did not exceed 20% except for the cervical and lumbar spine, distal interphalangeal

joints of the hands and, in women only, metacarpophalangeal joints, first carpometacarpal joints, http://ard.bmj.com/ first metatarsophalangeal joints, and knees. Overall, differences between men and women were small except for hips and knees; however, severe radiological osteoarthritis was found in a higher proportion in most of the joints in women. Our data were compared with data from similar population surveys. The slope between joint involvement and age was strikingly constant for most of the joints. Differences between populations were mainly differences in level. These differences of prevalence of radiological osteoarthritis may be attributed to interobserver differences-that is, different criteria used to establish radiological osteoarthritis, in addition to on October 1, 2021 by guest. Protected copyright. genetic or environmental factors, or both. Key words: prevalence, human.

Osteoarthritis causes morbidity that will be of age 25. osteoarthritis mainly affects older age increasing importance in populations with greater groups.2 3 Several investigations compared the pre- proportions of elderly people. Epidemiology can valence of osteoarthritis in different races, different help establish the causes of chronic diseases like populations, and different geographic areas. osteoarthritis.1 One of the major tools used by Although a number of carefully conducted large epidemiologists to accomplish this is a comparison population surveys are available, only a limited of populations. Epidemiological studies have shown number of these were adequately compared.7 In that radiological osteoarthritis is a ubiquitous dis- this paper we describe the prevalence of radiological order. Although present in some individuals around osteoarthritis of 22 joints and groups of joints in a random population sample of 6585 inhabitants of Accepted for publication 4 August 1988. Zoetermeer in the Netherlands. The results are Correspondence to Dr Jan L C M van Saase, Department of Clinical Epidemiology, Leiden State University, PO Box 9600, compared with results from 10 similar population 2300 RC Leiden, The Netherlands. surveys. 271 Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

272 van Saase, van Romunde, Cats, Vandenbroucke, Valkenburg Subjects and methods history, rheumatic complaints, profession, daily activities, drug use, schooling history, and lifestyle ZOETERMEER POPULATION habits by a questionnaire. In a specially equipped To study the prevalence and determinants of centre joints were investigated, blood pressure, rheumatic and cardiovascular diseases a population weight, and height were measured, and radiographs survey was conducted between 1975 and 1978 in two were taken of all 6585 participants. Blood was districts of Zoetermeer, a suburban metropolitan obtained for determination of rheumatoid factor, area near The Hague in The Netherlands.8 Respon- total serum cholesterol, and uric acid. dents were inhabitants of the original agricultural village and the recently built parts, which were RADIOGRAPHS principally inhabited by white collar workers. All Radiographs were obtained of hands, forefeet, and inhabitants of the old village centre and one part of lateral cervical spine. Several additional radiographs the new area were invited to participate in this were taken of all respondents of 45 years and older: survey. Of 4134 eligible men and 4523 eligible lumbar spine in anteflexion and dorsiflexion and women of 19 years and older, 6585 (76-1%) partici- pelvis and knees in anteroposterior and standing pated in the study (3109 men, 3476 women). Survey position. During the last year of the survey radio- completion was greatest between 20 and 64 years of graphs of both shoulders were taken of all respon- age (78.2%) and was only 61% in those over 65. dents of 45 years and older. Examination of radio- Information was gathered on previous medical graphs was performed by two investigators indepen-

ZOETERMEER POPULATION (EPOZ) ZOETERMEEIR POPULATION (EPOZ) (B) Men: handjointts radiological oslteoarthritis grade > 2

DIP http://ard.bmj.com/ MCP CMC-I Fig. 1 Age specificprevalences of WRIST PIP osteoarthritis ofhands andfeetfor CARPUS inhabitants ofZoetermeer. DIP=distal interphalangealjoints; CMC-L ... I w C CMC-I=first carpometacarpal 20 30 40 S0 00 70 s0 20 30 40 70

INY0 joint; MCP=metacarpophalangeal on October 1, 2021 by guest. Protected copyright. AGE IN YEARS AGE IIN YEARS joints; PIP=proximal ZOETERMEER POPULATION (EPOZ) ZOETERMEEIR POPULATION (EPOZ) interphalangealjoints; (D) CMC-L=second to fifth Men: feetlointi .e radiologIcal osite8arthntisiteoarthritis grade >>22 carpometacarpaljoints; a MTP-I=first metatarsophalangeal coI joint; MTP-L=second tofifth 2 metatarsophalangeal joints; TMT=tarsometatarsaljoints.

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AGE IN YEARS Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

Epidemiology of osteoarthritis 273 dently, based on the grading system for radiological CRITERIA FOR CHOICE OF COMPARISON osteoarthritis according to the Atlas of Standard POPULATIONS Radiographs of arthritis.9 This atlas contains radio- Population surveys suited for comparison were cross graphic examples of osteoarthritis of several joints sectional and contained random or stratified popula- in several stages of the disease. A five point scale tion samples. Not all surveys could be used: radio- has been used for staging (O=absent, 1=dubious, graphs had to be available of nearly all respondents 2=mild, 3=moderate, 4=severe). Small joints of without regard to complaints; an acceptable sample hands and feet were graded as groups (Figs 1 and 2) size of above 500 participants was necessary; sex and according to the most affected joint of the whole age specific information about radiological osteo- group. Right and left side were not separated, arthritis had to be available; and the radiological except for hips, knees, shoulders, and sacroiliac osteoarthritis data had to be presented for individual joints. When a one point difference in grading joints or groups of joints. Furthermore, information occurred between both investigators the higher about the origin of the population, the sample size, score was accepted, but where there was greater the sampling technique, and the range of age and of disagreement about the grading or when one obser- joints for which radiographs had been taken had to ver scored grade 1 and the other grade 2 the films be available. Table 1 presents the basic data of 10 were reassessed at a joint reading session until a populations with a total of 22 629 participants. Two final score was agreed. Interobserver and intraob- large surveys, the Alaskan Eskimo1 and the server agreement has been discussed elsewhere.10 Jamaican survey,12 were not included because no

ZOETERMEER POPULATION (EPOZ) ZOETERMEER POPULATION (EPOZ) (A) 100' (B) Women: hips, knees, shoulders and SI-joints Men: hips, knees, shoulders and Si-joints .Lo radiological osteoarthritis grade > 2 radiological osteoarthritis grade > 2 c t 80 0to ao 0 z 0 .3 0 0.o 0CO 70- http://ard.bmj.com/

C. co a KNEE-L KNEE-R Fig. 2 Age specific prevalences

HIP-R ofosteoarthritis oflarge joints and Y 10 0 _5RSHOUL-R/L disc degeneration for inhabitants 4 -QJ-~~~~SR/L ofZoetermeer. L = left; R = right; .0 on October 1, 2021 by guest. Protected copyright. 40 60 70 20 30 *0 S0 60 70 30 SHOUL=shoulder; SI=sacroiliac AGE INSI YEARSYA AGE IN YEARS CD joints; CS-DD=cervical spine disc ZOETERMEER POPULATION (EPOZ) ZOETERMEER POPULATION (EPOZ) degeneration; LS-DD=lumbar 0 (C) t*oo (D) Women: spine-radiological osteoarthritis Men: spine-radiological osteoarthritis spine disc degeneration; and disc degeneration grade > 2 ._ ,o ] and disc degeneration grade > 2 CS-OA=cervical spine osteoarthritis.

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AGE IN YEARS AGE IN YEARS Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

274 van Saase, van Romunde, Cats, Vandenbroucke, Valkenburg

Table 1 Radiological osteoarthritis datafrom JOpopulation surveys

Population Age Radiographs* Sample Method (reference) size Leigh 55-64 h,f,c,l,p(35+) 1343 Stratified (3, 13) 1954 England sample 200/decade Wensleydale 15+ h,f,c,1(35+), 891 Village (urban (3, 13) 1958 England p(35+) and rural) Blackfeet Indians 30+ h,f,c,p(45+) 1101 Tribe (14) 1961 USA Pima Indians 30+ h,f,c,p(45+) 969 Tribe (14) 1965 USA Tecumseh 35+ h,c 4415 Age and social class (15) 1962 USA strata Sofia 15+ h,f,c,l,p 4318 Age stratified (16) 1964 Bulgaria random sample Tswana 30+ h,f,p(55+), 801 Village (6) 1970 South Africa 1(55+) HANES I 25+ k,p 6913 Representative sample (17, 18) 1971-1974 USA Iwata Kamitonda 30+ h,f,p 1335 Village (personal communication) 1972 Japan Tsikundamalema 18+ h,f 543 Village (7) 1984 South Africa *h=hands; f=forefeet; c=cervical spine; l=lumbar spine; k=knee; p=pelvis; s=shoulders; (45+)=from the age of 45. age and sex specific prevalences were presented for Increased radiological osteoarthritis is strongly individual joints. related to aging. This holds both for small joints and Japanese population data from Kamitonda (K for large weight bearing joints and for both men and Shichikawa, personal communication) were in- women. Small joints of the hands, tarsometatarsal, cluded despite the lack of radiological information and lateral metatarsophalangeal joints of the feet in 45% because no other acceptable population and both knees were more often involved in women survey data were available about Asian people. The of all ages. The hips were more often involved in http://ard.bmj.com/ Sofia data are the only ones from Eastern Europe, middle aged men and the lumbar and cervical spine but they were presented while the survey was not were more often involved in all men. There was no fully completed and it is uncertain whether this was significant sex difference except for knees, hips in reason for bias. The Atlas of Standard Radiographs those aged 65 and over, and distal interphalangeal was used in all surveys except the Tecumseh study. 15 joints of the hands. Most radiographs were interpreted by investigators Considerable differences were found for the age originally trained by J S Lawrence or J H Kellgren. of onset and the prevalence of radiological osteoarthritis with age of different joints. Distal inter- on October 1, 2021 by guest. Protected copyright. phalangeal and metacarpophalangeal joints were Results already affected in 10% and first metatarsophalangeal joints even in 20% of the normal population Sex and age specific prevalences of radiological at the age of 40. Disc degeneration of lumbar and osteoarthritis of 22 joints and joint groups of the cervical spine was more often present than absent in Zoetermeer population are presented as graphs both men and women above the age of 50. (Figs 1 and 2). Age specific prevalences for both To compare differences and similarities of preva- mild and severe osteoarthritis, which we obtained in lences of radiological osteoarthritis between the this survey, are given in full in Tables 2 and 3. populations studied so far graphs were used in which Kellgren's grades 0 and 1 were considered as the percentages of involved, joints were plotted absence and grade 2, 3, and 4 as presence of against age. Not all joints about which data were radiological osteoarthritis. Shoulders were included available are presented here. Very different joints in the graphs, though radiographs were taken in are given as examples (Figs 3 and 4). Standard only one third of the total population sample and errors are not indicated on the graphs because they only few subjects in the higher age categories were were not always available and because of the density present. The standard errors of the prevalence of of the lines. During assessment of the graphs it must these joints will therefore be larger. be remembered that sample sizes were sometimes Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

Epidemiology of osteoarthritis 275

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Epidemiology of osteoarthritis 277

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small (Table 1). The highest age category almost pal joint involvement. We are not certain whether always contained few participants and was certainly the carpometacarpal joints were separated into not always an adequate sample of the population. lateral and first carpometacarpal (base of thumb) The graphs show, firstly, that there are differ- joints. Data from Zoetermeer and Kamitonda con- ences in level between populations and, secondly, cern the first carpometacarpal joint. Furthermore, it that the slope of most lines is very much the same for is remarkable that participants from the village of individual joints and groups of joints in the various Tsikundamalema have a relatively high prevalence populations. Notable exceptions are Blackfeet and of radiological osteoarthritis of the distal interpha- Pima indians, who have a very high prevalence of langeal joints and a low prevalence of the car- radiological osteoarthritis of the distal interpha- pometacarpal joints. Other joints showed similar langeal joints, Bulgarians, who show a very low patterns: the same slope for the same joint, with prevalence of radiological osteoarthritis of the distal differences in level and occasional exceptions. None interphalangeal joints, and Tswana and Tsikunda- of the populations had a low or high prevalence for malema women, who have a very low carpometacar- all joints investigated. Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

278 van Saase, van Romunde, Cats, Vandenbroucke, Valkenburg

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Discussion The prevalence of radiological osteoarthritis decreased slightly in very old people for a number of The Zoetermeer population survey confirms the joints. This might be attributed to response bias. It high prevalence of radiological osteoarthritis. The was reported recently, however, that women with disorder increases progressively with age. Mild x ray changes of the knee were at increased risk for radiological osteoarthritis is more prevalent in subsequent mortality.20 Obesity 18 21 22 hyper- women and severe radiological osteoarthritis is tension,23 and diabetes mellitus, ' all associated much more prevalent in women. From postmortem with both osteoarthritis and a lower average life studies it is known that the pathological process expectancy, may be responsible for this observation. takes place several years before radiological detec- Excess radiological osteoarthritis of the right hip tion of the disorder is possible,'9 so the prevalence was found after the age of 75, though it must be of radiological osteoarthritis by age as presented remembered that sample sizes were small and this here is an underestimation of the actual prevalence difference in prevalence could be due to a single of cartilage degeneration. anomalous result. Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

Epidemiology of osteoarthritis 279 All data were obtained from cross sectional Another explanation for differences in level is the population surveys and were therefore less suited distinction, as proposed by the American Rheuma- for evaluation of the process of joint involvement by tism Association, between idiopathic and secon- age. Conclusions about joint involvement and age dary types of osteoarthritis. This distinction was not can therefore only be drawn from these data if birth reported separately in any of the populations. cohort effects are negligible. This may be a source of Therefore it is even more surprising that even bias, for example, for populations where selective without information about the distribution of mortality occurred during periods of starvation or idiopathic and secondary osteoarthritis the graphs war. As no follow up surveys are available, how- show such strong parallelism. This may suggest that ever, we ignored possible birth cohort effects and secondary osteoarthritis has more or less the same compared the results of the Zoetermeer survey with prevalence in different populations or that the those of 10 other population surveys. Figures 2A prevalence of secondary osteoarthritis is low and and 2B demonstrate identical slopes (parallelism) does not influence the slope. Lack of information together with differences in level for most joints. about risk factors and about the prevalence of This means that when the process of osteoarthritis secondary osteoarthritis limits causal inferences first occurs in a certain joint or group of joints the based on these comparison data. Surveys in areas rate of increase of degeneration of that joint or where the prevalence of osteoarthritis is determined group of joints per unit of time is the same in all by the occurrence of special joint diseases like populations from that point on. A higher level Mseleni joint disease3o and Kashin-Beck disease3' 32 means that the radiological appearance of osteo- were not included in this study. arthritis occurs at younger ages. Differences in level Osteoarthritis is a slowly developing process, showed a tendency to increase while differences of which makes it very difficult to approach the slope remained minimal when several joints were problem by intervention studies. We had hoped that considered together, as shown for all the joints of comparison data of very different populations would the hand.4 give solutions for the many problems that surround Differences between populations can be ex- the causes and development of this disease or group plained in several ways. Firstly, different investiga- of diseases. The only data that could be compared tors may be more or less inclined to give a higher or from a reasonable number of surveys were the lower score, and interobserver variation is probable radiological data. Data on body mass index, pain, in the interpretation of radiographs. Furthermore, limitation of movement, bone mass, etc are not the freedom of interpretation of the standardising available from most of the populations. Further http://ard.bmj.com/ atlas is rather large. Interobserver variation as the epidemiological studies of osteoarthritis, especially sole cause for differences in level is less probable. when prevention is one of the ultimate goals, should Lawrence and Sebo read radiographs from 17 be directed towards differentiating the types of surveys with a total of 7919 participants.5 They osteoarthritis. Secondary types, like crystal arthro- found important differences between populations, pathy, osteoarthritis developing in the course of though it was not stated whether these were differ- endocrine disorders, and psoriasis, should be sepa- ences in level or differences of slope. Secondly, it is rated from so called idiopathic osteoarthritis. For a on October 1, 2021 by guest. Protected copyright. quite possible that differences between populations number of population surveys it is probably suffi- are not artificial. Evidence from genetic as well as cient to re-evaluate the existing data and reread the environmental studies indicates that differences are, radiographs. at least in part, true differences. An increased or We conclude that osteoarthritis is a worldwide decreased presence of risk factors or protective disease and that no population investigated so far factors may be responsible for these differences in has been spared. Differences exist between popula- level. Osteoporosis for instance seems to protect tions. These differences are differences in level and against osteoarthritis.25 Factors that influence whether they are real differences or due to interob- (subchondral) bone density, like vitamin D, alcohol server variation or to differences in the distribution consumption, and anthropometric status, differ of risk factors or genetic differences has yet to be between races and populations.26-- Furthermore, established. Joints with a low prevalence of osteoar- differences in level may in part be explained by a thritis in one population are relatively spared in all different distribution of these risk factors. Obesity is populations, while frequently affected joints show a strong risk factor for osteoarthritis for a number of signs of degeneration in all populations. It is joints.f 22 Between populations with a high and a therefore most likely that the aetiology of most low percentage of obese persons a level difference is osteoarthritis is the same in all populations. Cartil- likely. If this obesity-osteoarthritis relation were not age changes are the result of longstanding metabolic linear a difference of slope would exist. and mechanical processes. The relative importance Ann Rheum Dis: first published as 10.1136/ard.48.4.271 on 1 April 1989. Downloaded from

280 van Saase, van Romunde, Cats, Vandenbroucke, Valkenburg

of each of these processes can, unfortunately, not be 12 Bremner J M, Lawrence J S, Miall W E. Degenerative joint compared because they are rarely available and disease in a Jamaican rural population. Ann Rheum Dis 1968; 27: 326-32. even when available lack methodological standard- 13 Lawrence J S. Disc degeneration. Its frequency and relation to isation. Similarities of slopes argue in favour of the symptoms. Ann Rheum Dis 1969; 28: 121-38. possibility of extrapolating results from one popula- 14 Bennet P H, Burch T A. Osteoarthrosis in the Blackfeet and tion survey to others. Thus conclusions drawn about Pima Indians. In: Kellgren J H, Jeffrey M R, Ball J, eds. Atlas of standard rediographs. Vol II. The epidemiology of chronic this Dutch population can be applied to other rheumatism. Oxford: Blackwell Scientific, 1963: 407-12. populations. 15 Mikkelsen W M, Duff I F, Dodge H D. Age-specific prevalence of radiographic abnormalities of the joints of the hands, wrists The authors wish to thank Dr H C M Haanen who was the second and cervical spine of adult residents of the Tecumseh, Michigan, reader of most of the radiographs and Dr K Shichikawa who community health study area, 1962-1965. J Chronic Dis 1970; supplied the data from the Kamitonda study. This study was 23: 151-9. supported by grants from The Netherlands Prevention Fund and 16 Tzonchev V T, Pilossoff T, Kanev K. Prevalence of osteoarthri- The Netherlands Foundation against Rheumatism. tis in Bulgaria. In: Bennett P H, Wood P H N, eds. Population studies of the rheumatic diseases. 1st ed. New York: Excerpta Note Medica, 1966: 413-6. The following abbreviations areused in Tables 2 and 3: 17 National Centre for Health Statistics. Basic data on arthritis, CS-DD=cervical spine disc degeneration; CS-FJ=cercival spine knee, hip and sacroiliac joints in adults ages 25-74 years. United facet joints; LS-DD=lumbar spine disc degeneration; DIP=distal States 1971-1975. Public Health Service Publication No 1000. interphalangeal joints; PIP=proximal interphalangeal joints; 1979: series 11, No 213: 1-8. MCP=metacarpophalangeal joints; CMC-I=first carpometacarpal 18 Hartz A J, Fisher M E, Bril G, et al. The association of obesity joints; CMC-L=lateral carpometacarpal joints; TMT= with joint pain and osteoarthritis in the HANES data. J Chronic tarsometatarsal joints; MTP-I=first metatarsophalangeal joints; Dis 1986; 39: 311-9. MTP-L=lateral metatarsophalangeal joints; SI=sacroiliac joints. 19 Byers P D, Contepomi C A, Farkas T A. A post mortem study of the hip joint. Ann Rheum Dis 1970; 29: 15-31. 20 Lawrence R C, Everett D F, Cornoni-Huntley J, Hochberg References M C. Excess mortality and decreased survival in females with 1 Acheson R. Heberden oration 1981. Epidemiology and the osteoarthritis of the knee [Abstract]. Arthritis Rheum 1987; 30: arthritides. Ann Rheum Dis 1982; 41: 325-34. S130. 2 Kelsey J L. Prevalence studies of the epidemiology of osteoar- 21 Felson D T, Anderson J J, Naimark A, Walker A M, Meenan thritis. In: Lawrence R C, Shulman L E, eds. Epidemiology of R F. Obesity and knee osteoarthritis. The Framingham study. the rheumatic diseases. 1st ed. New York: Gower Medical, 1984: Ann Intern Med 1988; 109: 18-24. 282-8. 22 Saase J L C M van, Vandenbroucke J P, Romunde L K J van, 3 Lawrence J S, Bremner J M, Bier F. Osteoarthrosis. Preva- Valkenburg H A. Osteoarthritis and obesity in the general lence in the population and relationship between symptoms and population. A relationship calling for an explanation. J

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