Measuring the consequences of osteoarthritis and joint pain in population-based studiesCan existing health measurement instruments capture levels of participation.код для вставкиСкачать
Arthritis & Rheumatism (Arthritis Care & Research) Vol. 51, No. 5, October 15, 2004, pp 755–762 DOI 10.1002/art.20703 © 2004, American College of Rheumatology ORIGINAL ARTICLE Measuring the Consequences of Osteoarthritis and Joint Pain in Population-Based Studies: Can Existing Health Measurement Instruments Capture Levels of Participation? R. WILKIE, G. PEAT, E. THOMAS, AND P. R. CROFT Objective. To identify health measurement instruments to investigate levels of participation associated with joint pain in a population survey questionnaire. Method. A comprehensive electronic search of the published literature was performed to identify potential instruments that could measure participation. All items from identiﬁed instruments were assessed for the ability to measure participation by 2 experienced and 2 inexperienced assessors. Agreement was determined in terms of actual agreement (%) and agreement beyond chance (). Results. Twenty-seven instruments (912 items) were identiﬁed. Agreement between the experienced assessors occurred in 86% of items ( ⴝ 0.70, 95% conﬁdence interval [95% CI] 0.65– 0.75) and between the inexperienced assessors in 72% ( ⴝ 0.40, 95% CI 0.34 – 0.46). The greatest proportion of participation items in one instrument was 82%. Conclusion. None of the identiﬁed instruments consisted entirely of participation items. The concept of participation and its translation into measurement for use in the general population is likely to need further development. KEY WORDS. Participation; Population survey; Joint pain; Health measurement instruments; International Classiﬁcation of Functioning, Disability and Health. INTRODUCTION Osteoarthritis (OA) affects an estimated 25% of the general population aged 55 years and older (1). It is one of the most common chronic health conditions in this age group and, in light of projected demographic trends, the total number of people with the disease is likely to increase (2). An important question is how to measure the impact of OA on individuals and society. Population-based epidemiologic studies of OA have consistently highlighted discrepancies between radiographic evidence of joint pathology on the one hand and This research is part of a study investigating the natural history of joint pain that is supported by a Programme Grant from the Medical Research Council. R. Wilkie, BSc, G. Peat, BSc, MSc, PhD, E. Thomas, BSc, MSc, PhD, P. R. Croft, BA, MBChB, MRCGP, MSc, MD: Primary Care Sciences Research Centre, Keele University, United Kingdom. Address correspondence to R. Wilkie, Primary Care Sciences Research Centre, Keele University, Keele, Staffordshire, United Kingdom ST5 5BG. E-mail: r.wilkie@ keele.ac.uk. Submitted for publication March 3, 2003; accepted in revised form March 1, 2004. patient reports of pain severity and levels of disability on the other (3–5). Such discordance has been reported in other conditions as well (6 – 8). It suggests that the level of suffering and the impact on everyday life among individuals with joint pain and OA may be highly variable, even when the severity of the underlying disease pathology is comparable. The recently revised International Classiﬁcation of Impairment, Disability, and Handicap (ICIDH)—now referred to as the International Classiﬁcation of Functioning, Disability and Health (ICF) (9)— offers a useful framework with which to describe the various consequences of OA. The ICF classiﬁes functioning at 3 distinct levels: anatomic/physiologic (body function), individual person (activities), and societal (participation). Abnormal functioning at the 3 levels is described, respectively, as impairment (e.g., pain, stiffness), activity limitation (e.g., difﬁculty walking 100 yards), and participation restriction (e.g., difﬁculty looking after others). They broadly correspond to the older typology of impairment, disability, and handicap. A range of contextual factors in an individual’s life, both personal and environmental, may act upon function at each level and modify relationships between these different levels (please refer to Appendix for deﬁnitions of terms). 755 756 Previous epidemiologic studies of OA have investigated the prevalence of impairment (e.g., radiographic joint space narrowing and osteophytes). However, there is increasing interest in the societal and personal consequences of OA (10), accompanied by a recognition that these cannot be inferred from levels of impairment or activity limitation alone (11). For example, Heberdens nodes may not affect functional abilities of the hand, but may result in social isolation due to feelings of inadequacy resulting from observable deformity. Hence, directly measuring levels of participation and participation restriction is an important step for epidemiologic research. However, the extent to which this has been satisﬁed in previous studies is unclear. The ICF framework is relatively new and postdates many of the epidemiologic studies in this ﬁeld. Measurement of disability has been a feature of some studies (12–16) but coverage of participation restriction by the instruments used is uncertain. As a preliminary step to investigating the prevalence, patterns, and determinants of participation restriction in population-based studies of joint pain and OA, we undertook a review of current self-report health instruments potentially relevant to the measurement of participation restriction. However, we wanted to identify instruments that could be completed by all older adults, not only those with joint pain. Our aims therefore were to 1) identify health measurement instruments that might include some measurement of participation (or participation restriction) and could be applied in a population survey; 2) reliably determine the proportion of items within these health measurement instruments that captured some aspect of participation (or participation restriction) to indicate the ability of instruments and their scores to exclusively represent participation; and 3) ascertain whether different observers with varying levels of survey experience and knowledge of the ICF framework could consistently identify participation items in these instruments. METHODS The study was conducted in 4 phases and a standardized deﬁnition of participation was presented to the assessors at the start. The ﬁrst phase was a comprehensive search of the published literature to identify instruments that might contain items measuring participation. In the second phase, criteria were applied to the instruments identiﬁed in phase 1 to exclude those that could not be applied in a self-completion population questionnaire survey and did not contain any items that measured participation. In the third phase, all items in the remaining instruments were independently assessed for their ability to measure participation by 2 assessors who were used to working with the ICF concepts (experienced) and 2 assessors who were new to the ideas (inexperienced). The assessors used a standardized deﬁnition of participation based on World Health Organization (WHO) literature. Agreement within the experienced assessor group, within the inexperienced assessor group, and between the groups was analyzed in phase 4. Wilkie et al Standardization of participation deﬁnition. Before the study was undertaken, assessors read speciﬁc WHO literature (Appendix A; Taxonomic and terminological issues from the ICIDH-2 pre-ﬁnal draft: deﬁnitions of activities and participation. Available at URL: www.who.int/classiﬁcation/ icf/intros/ICF-Eng-Intro.pdf) to establish a consistent approach to and knowledge of the participation concept. They were presented with the WHO deﬁnition of participation, which is “an individual’s involvement in life situations in relation to health conditions, body functions and structure, activities and contextual factors” (9). An item was considered as having the ability to measure participation if it met 2 criteria: It must obtain information relating to an action, task, or life situation and the action, task, or life situation must occur in relation to contextual factors. The assessors were also provided with examples of participation items from the ICF domains for the measurement of activities and participation. Of the 9 domains described in the ICF, 3 (learning and applying knowledge, general tasks and demands, and communication) were deemed to capture activities and not participation. In 2 domains (mobility and self care), some subdomains were speciﬁed as capturing activities and some as capturing participation. There were 4 domains (domestic life; interpersonal interactions and relationships; major life areas, e.g., work; and community, social, and civic life) deemed to measure participation (Table 1). This structuring matched 1 of 4 methods, proposed by the WHO, for applying the domains to capture participation (9). Phase 1: Search strategy and identiﬁcation of instruments. A comprehensive search strategy was conducted by a single observer (RW). Search criteria were devised to obtain instruments containing items that might measure levels of participation in people with joint pain. The ﬁrst search was restricted to reviews of health measurement instruments. The review articles obtained did not contain instruments developed after the year 2000. Therefore, a second search was undertaken of individual peer-reviewed articles to ﬁnd instruments developed after 1997, together with a hand search of references in all the obtained literature for additional instruments. Both searches were performed with the following key words (MeSH headings and text words): joint pain, outcome measures, disability, handicap, participation, quality of life, musculoskeletal, arthritis, work related pain, and epidemiology (plus review in the ﬁrst search) applied individually and in combination. Publications were sought in the English language, and retrieved by an online electronic search of 12 databases (BIDS, Zetoc, Index to thesis, CHID Online, Cochrane database, WebMedlit, CINAHL, Medline, Embase, Bandolier, Institute for Scientiﬁc Information Proceedings, and PsycINFO). Instruments were identiﬁed from the searches if their reported design was 1) a generic health or quality of life measure; or 2) to measure the societal consequences of health conditions (whether generic or condition speciﬁc), such as handicap instruments; or 3) to measure the consequences of musculoskeletal conditions, excluding those relating to speciﬁc anatomic sites (e.g., low back, knee). Capturing Levels of Participation 757 Table 1. Deﬁned activities and participation domains, with partial overlap* Domains and subdomains designated by a single observer to capture activities or participation ICF domains for the measurement of activities and participation Activity domains—all items capture activities Overlapping domains—Items within domains are speciﬁed as measuring activities or participation Activity domains 1. 2. 3. 4. Learning and applying knowledge General tasks and demands Communication Mobility 4.10–4.19 Changing and maintaining body position 4.30–4.49 Carrying, moving, and handling objects 4.50 Walking 5. Self-care 5.50 Eating 5.60 Drinking Participation—all items capture participation Participation domains 4. Mobility 4.2 Transferring oneself 4.55–4.69 Moving around 4.70–4.89 Moving around using equipment 5. Self-care 5.10 Washing oneself 5.20 Caring for body parts 5.30 Toileting 5.40 Dressing 5.70 Looking after one’s health 6. Domestic life 7. Interpersonal interactions 8. Major life areas 9. Community, social, and civic life * Please note these domains have been constructed and presented by the World Health Organization (9). This interpretation and structure of domains has been determined by a single observer and not the World Health Organization. ICF ⫽ International Classiﬁcation of Functioning, Disability and Health. Phase 2: Selection of instruments. A single observer (RW) reviewed all identiﬁed instruments and excluded from further evaluation, those that 1) were not designed to be self completed by the study participants; or 2) consisted entirely of items that could not capture participation (e.g., “How many relatives do you have?” “Have you had knee pain in the last month?”). Phase 3: Rating of all items by experienced and inexperienced assessors. To determine the proportion of items within the selected health measurement instruments that might measure participation, 2 assessors (A and B) independently rated, separately and blind to the title of the instrument, each item from the selected instruments for its ability to capture participation. These assessors were deemed to be experienced in that they had been working on the development of a population survey based on the ICF framework and had gained an in-depth knowledge of the participation concept. To ascertain whether different observers with varying levels of knowledge of the ICF framework and the participation concept could consistently identify measures of participation, an additional 2 assessors (C and D) rated each of the items in the selected questionnaires for their ability to measure participation. They again worked separately and blind to the title of the instrument. Assessor C was a health survey researcher with a nominal amount of knowledge of the ICF who had never applied the concept in studies. Assessor D was a clinical trials coordinator who had no previous knowledge of the ICF. When rating each item, assessors used a 3-category scale: Yes, item captures participation information; unsure if it does; and no, it does not. Phase 4: Statistical analysis of agreement between assessors. Agreement in rating items was determined separately for experienced (A and B) and inexperienced (C and D) assessors. Agreement was assessed for each item individually and for each instrument as a whole, by actual agreement (%; proportion of all items assessed where there was agreement). Agreement for all items was assessed by actual agreement and by agreement beyond chance (). Levels of agreement were compared between experienced and inexperienced pairs using actual agreement (%) and by comparing their respective kappas using a chi-square test (17). RESULTS Potential instruments. The search for reviews produced a total of 3 books, 3 book chapters, and 16 peer-reviewed articles, highlighting 72 instruments. The search for instruments published after 1997 and a hand search of obtained literature highlighted an additional 3, resulting in a total of 75 instruments that might contain items measuring participation. Selection of instruments. Forty-eight instruments were removed because they had not been designed to be self administered or did not contain any items relating to actions, tasks, or life situations. Of the remaining 27 instru- 758 Wilkie et al Table 2. Agreement on individual items within the 2 pairs of observers (experienced and inexperienced)* Agreed Participation Nonparticipation Disagreed Health measurement instrument (reference) Inclusion criteria Total number of items 30-item screening scale (18) World Health Organization Quality of Life-100 (19) Functional Limitations Proﬁle (20) Self Care Assessment Schedule (21) Functional Status Questionnaire (22) Functional Assessment Screening Questionnaire (23) Self Evaluation of Life Function (24) The Lambeth Disability Screening Questionnaire (25) European Quality of Life Scale (26) Ofﬁce of Population Census and Surveys Postal Screening Questionnaire—1985 (27) Dartmouth COOP Charts (28) Duke Health Proﬁle (29) Nottingham Health Proﬁle (30) The McMaster Health Index (31) The Quality of Life Index (32) Life Satisfaction Rating Scales (33) Medical Outcomes Study ShortForm 36 (15) Disease Repercussions Proﬁle (34) Craig Handicap Assessment and Reporting Technique (35) New Handicap Scale (36) Reintegration to Normal Living (37) Impact on Participation and Autonomy (38) London Handicap Scale (39) Health Assessment Questionnaire (13) Arthritis Impact and Measurement Scale (40) McMaster-Toronto Arthritis and Rheumatism Questionnaire (41) Arthritis Helplessness Index (42) Totals a a 30 100 3 (10) 18 (18) 1 (3) 5 (5) 23 (72) 72 (72) 19 (63) 75 (75) 4 (13) 10 (10) 10 (33) 20 (20) a a a a 136 10 34 15 35 (26) 3 (30) 15 (44) 6 (40) 10 (7) 0 (0) 11 (32) 2 (13) 80 (59) 3 (30) 12 (35) 7 (47) 72 (53) 5 (50) 15 (44) 8 (53) 21 (15) 4 (40) 7 (21) 2 (13) 54 (40) 5 (50) 8 (24) 5 (33) a a 54 22 6 (11) 3 (14) 6 (11) 14 (64) 40 (74) 11 (50) 37 (69) 0 (0) 8 (15) 8 (36) 11 (20) 8 (36) a a 5 37 1 (20) 1 (3) 1 (20) 0 (0) 3 (60) 31 (84) 2 (40) 29 (78) 1 (20) 5 (14) 2 (40) 8 (22) a a a a a a a 9 17 45 74 5 32 36 2 (22) 2 (12) 7 (16) 9 (12) 2 (40) 0 (0) 10 (28) 0 (0) 2 (12) 8 (18) 4 (5) 1 (20) 0 (0) 2 (6) 7 (78) 12 (71) 37 (82) 52 (70) 2 (40) 30 (94) 24 (67) 6 (67) 14 (82) 33 (73) 50 (68) 2 (40) 31 (97) 24 (67) 0 (0) 3 (18) 1 (2) 13 (18) 1 (20) 2 (6) 2 (6) 3 (33) 1 (6) 4 (9) 20 (27) 2 (40) 1 (3) 10 (28) b b 6 27 1 (17) 14 (52) 0 (0) 6 (22) 2 (33) 4 (15) 2 (33) 3 (11) 3 (50) 9 (33) 4 (67) 18 (67) b b b 11 11 23 6 (55) 9 (82) 15 (65) 6 (55) 8 (73) 17 (74) 4 (36) 0 (0) 0 (0) 0 (0) 2 (18) 2 (9) 1 (9) 2 (18) 8 (35) 5 (45) 1 (9) 4 (17) b c 6 20 3 (50) 2 (10) 3 (50) 1 (5) 1 (17) 18 (90) 1 (17) 13 (65) 2 (33) 0 (0) 2 (33) 6 (30) c 100 25 (25) 22 (22) 69 (69) 56 (56) 6 (6) 22 (22) c 32 3 (9) 2 (6) 25 (78) 0 (0) 4 (13) 30 (94) c 15 912 0 (0) 201 (22) 0 (0) 132 (14) 0 (0) 127 (14) 0 (0) 264 (29) A vs B no. (%) C vs D no. (%) A vs B no. (%) C vs D no. (%) A vs B no. (%) C vs D no. (%) 15 (100) 15 (100) 584 (64) 516 (57) * vs ⫽ versus; a ⫽ the instrument was designed as generic health quality of life measure; COOP ⫽ Cooperative Information Project; b ⫽ the instrument was designed to capture the societal consequences of health conditions; c ⫽ the instrument was designed to capture the consequences of musculoskeletal conditions ments, 17 (15,17–32) were designed as generic health or quality-of-life measures (criterion 1), 6 (33–38) were designed to measure societal consequences of health conditions (criterion 2), and 4 (13,39 – 41) were designed to measure the consequences of musculoskeletal conditions (criterion 3; Table 2). These 27 instruments contained a varying number of items (range 5–136) providing a total of 912 items for rating. Agreement by 2 experienced assessors. Of the 912 items rated, the number of items considered by each assessor (A and B) to be measuring participation was 215 (24%) and 286 (31%), respectively (Table 3). Complete agreement between assessors occurred for 785 (86%) of the items rated (201 deemed to capture participation, 584 deemed not to, and none where both assessors were unsure). This level of agreement gave a of 0.70 (95% conﬁdence interval [95% CI] 0.65– 0.75). The proportion of items for which there was complete agreement between assessors ranged from 50% (Disease Repercussions Proﬁle) to 100% (Arthritis Helplessness Index, Health Assessment Questionnaire, Dartmouth Cooperative Information Project Charts; Table 2]. The highest proportions of agreed participation items were found in instruments designed to capture societal consequences of health conditions. In 5 of these instruments, 50% or more Capturing Levels of Participation 759 Table 3. Rating of all items into 3 categories by the 4 assessors Participation Unsure Nonparticipation No. of items No. of items No. of items Assessor (% of items) (% of items) (% of items) A B C D 286 (31) 215 (24) 272 (30) 187 (21) 1 (0) 75 (8) 72 (8) 42 (5) 625 (69) 622 (68) 568 (62) 683 (75) of the items were agreed to be measuring participation: the Reintegration to Normal Living Index (82%), the Impact on Participation and Autonomy Questionnaire (65%), the New Handicap Scale (55%), the Craig Handicap Assessment and Reporting Technique (52%) and the London Handicap Scale (50%). The Disease Repercussions Proﬁle, also designed to capture societal consequences, only contained 1 agreed item out of 6 rated that measured participation. Generic health instruments tended to contain a smaller proportion of agreed participation items (i.e., 10 items [28%] from the Medical Outcomes Study Short Form 36, and 35 items [26%] from the Functional Limitations Proﬁle). Of the instruments designed to capture the consequences of musculoskeletal conditions, the Arthritis Impact Measurement Scale (version 2) contained the greatest proportion (25%) of instrument items agreed as measuring participation. Agreement between 2 inexperienced assessors. The number of items considered by each assessor (C and D) to be measuring participation was 272 (30%) and 187 (21%), respectively (Table 3). Complete agreement between assessors occurred in 653 (72%) of all items (132 deemed to capture participation, 513 deemed not to, 8 items both assessors unsure). This gave a of 0.40 (95% CI 0.34 – 0.46). The agreement within instruments ranged from 6% (McMaster-Toronto Arthritis Patient Function Preference Questionnaire) to 100% (Arthritis Helplessness Index). The pattern of agreement was similar to the experienced assessors. Five of the 6 instruments designed to capture societal functioning contained 50% or more items agreed by the inexperienced assessors as measuring participation: the Impact on Participation and Autonomy questionnaire (74%), the Reintegration to Normal Living Index (73%), the New Handicap Scale (55%), and the London Handicap Scale (50%). The Disease Repercussions Proﬁle contained no items agreed to measure participation. In contrast to the experienced assessors, the inexperienced assessors agreed that ⬎50% of the Lambeth Disability Screening Questionnaire (64%) measured participation. Agreement between the experienced and inexperienced assessors. Complete agreement between the experienced and the inexperienced assessors occurred in 556 (61%) of the items. There was agreement that 97 items measured participation and that 459 did not (Table 4). Of the 201 items considered by both of the experienced assessors to measure participation, there were 104 items about which one or both of the inexperienced assessors disagreed. Of 584 items considered by both experienced assessors not to measure participation, there were 125 items about which one or both of the inexperienced assessors disagreed. Kappa scores for agreement beyond chance within experienced and inexperienced pairs were signiﬁcantly different from each other (P ⬍ 0.001). DISCUSSION We have reasoned that measuring participation in population-based studies is important for describing the personal and social consequences of joint pain in older adults. In this study, we sought to determine the extent to which existing health measurement instruments might be used in a population survey to measure levels of participation associated with joint pain. We identiﬁed a number of instruments that, by design, had the potential to be applied in this way. We rated individual items to determine the proportion within each instrument that captured participation and used this to indicate the extent to which instruments and their scale scores exclusively represent participation. Our ﬁndings demonstrate that participation coverage within these measures is variable, and there were no instruments that consisted entirely of participation items. Instruments with high proportions of relevant items may give reasonable estimates of participation frequency. However, these instruments were not designed to capture participation and contain items that do not measure participation. The removal of items that do not capture participation may affect the validity of these instruments, and further validation studies would be required prior to any application as participation measures in the population. Instruments designed to capture societal consequences, consistent with the handicap concept, contained the greatest proportion of participation items. This was expected, Table 4. Agreement between observers, experienced compared with inexperienced C versus D “inexperienced” A versus B “experienced” Agreed participation Agreed not participation Disagreed Totals Agreed participation Agreed not participation Disagreed Totals 97 7 28 132 14 459 43 516 90 118 56 264 201 584 127 912 760 as the conceptual models of handicap and participation are similar. The conceptual basis is important to consider when selecting an instrument because the underlying theory is shaping the measurement (43). Instruments designed to measure generic health status, quality of life, or the consequences of musculoskeletal conditions contained a smaller proportion of participation items. These instruments were not designed speciﬁcally to reﬂect the conceptual models of handicap or participation, and their ability to measure them has been questioned (44,45). The Reintegration to Normal Living Index contained the greatest proportion of participation items (9 of 11). It was designed as a clinical tool to measure levels of global function and has been applied in survey questionnaires (37,46). The second highest proportion was in the Impact on Participation and Autonomy (15 of 23), designed as a handicap questionnaire (38). Both questionnaires contained items that were not rated as participation items. This may reﬂect differences between the concepts of participation and handicap. Measurement of handicap has proven challenging, with the small number of instruments and lack of uniformity between them suggesting the concept is underdeveloped (34,45). It remains to be seen if similar problems occur with participation. Our ﬁndings were based on an analysis of instruments that might contain participation items. These were identiﬁed by a comprehensive and reproducible search of published literature and application of standard criteria to include only those that could be applied in population surveys to measure participation in relation to joint pain. We know of no other instruments for inclusion. Those such as the Western Ontario McMaster Universities Osteoarthritis Index (47), the Roland and Morris Low Back Questionnaire (48), and the Disabilities of the Arm, Shoulder and Hand outcome measure (49) were not included because they were designed to capture consequences of site-speciﬁc conditions. The WHO Disability Assessment Schedule (50) was published after our searches were performed. Other instruments with participation items (e.g., Assessment of Life Habits ) were not designed to be self completed. In the absence of a gold standard, we used agreement between the experienced assessors to determine the proportion of items within each instrument that captured participation. There are no other studies with which to compare this level of agreement. However, the level of agreement beyond chance for the experienced assessors was signiﬁcantly higher than for the inexperienced assessors. Intra-assessor variation was not assessed. We cannot therefore conclude whether the disagreement within the inexperienced pair or within the experienced pair was reﬂecting general inconsistencies or systematic differences. However, agreement beyond chance between the inexperienced assessors was poor compared with that achieved by the experienced pair. This suggests that greater experience and familiarization with the WHO concepts lead to a greater common understanding and certainty in the application of these concepts. To guide the development of the conceptual and measurement models of participation, the main sources of disagreement were analyzed. Assessors found it difﬁcult to Wilkie et al determine if actions, tasks, or life situations occurred at the level of the individual (i.e., activities) or society (i.e., participation), an issue that also affected the application of the ICIDH (52). For example, with the item “Are you able to use the telephone?” (Self-Evaluation of Life Function question 3 ), one assessor from each pair assessed the item as measuring participation, whereas the other assessor did not. Disagreement concerned whether the telephone is a contextual factor that affects the fulﬁllment of the task. There were 97 items that the experienced and the inexperienced observers agreed captured participation, and these provide examples of participation items likely to be recognized more straightforwardly by any observer. Such items did not refer to speciﬁc actions, tasks, or life situations, but captured a collection of them, similar to the domain and subdomain headings presented in the ICF. For example, “I participate in social activities with family, friends, and/or business acquaintances as is necessary or desirable to me” (Reintegration to Normal Living Index question 7 ). The level of disagreement between the inexperienced assessors raises questions about the ability of the participation concept to be quickly understood and easily applied. It suggests that WHO literature does not lead to a consistent understanding of the concept, which may be why it is measured in a number of ways. The WHO, in introducing the ICF, does not present a gold standard for measurement or speciﬁc strategies of measurement, but instead present a base that requires tailoring to meet speciﬁc needs (53) as well as a description of the concept (54). To apply the concept for research purposes, further development and direction is required. In conclusion, there appear to be no existing health measurement instruments consisting entirely of participation items. It may be appropriate to develop both the concept and its translation into measurement to capture levels of participation in the general population. 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Negative aspect is impairment, which is deﬁned as a problem with body structure, e.g., radiographic joint space narrowing or osteophyte formation. Body functions. The physiologic functions of body systems (including physiologic functions). Negative aspect is All terms are deﬁned by the World Health Organization (9). Wilkie et al impairment, which is deﬁned as a problem with body function, e.g., limited joint range of movement, loss of muscle strength. Contextual factors. These represent the complete background to an individual’s life and living. They include 2 components: environmental factors and personal factors, which may have an impact on the individual with a health condition and that individual’s health and health-related status. Environmental factors. These make up the physical, social, and attitudinal environment in which people live and conduct their lives, e.g., poor access to public transport, health care professionals’ attitudes to osteoarthritis and aging. Functioning. An umbrella term encompassing all body functions, activities, and participation. Negative aspect is disability, which is referred to as impairment, activity limitation, and participation restriction. Major life areas. A domain of functioning that covers the tasks, actions, and life situations required to engage in education, work, and employment and to conduct economic transactions. Participation. Involvement in life situations. Negative aspect is participation restriction (formerly “handicap” in ICIDH), which is deﬁned as problems an individual may experience in involvement in life situations, e.g., difﬁculties obtaining/retaining paid employment. Personal factors. Refers to the particular background of an individual’s life and living, and comprise features of the individual that are not part of a health condition or health status, e.g., age, sex, coping style.