• 1
    World Health Organization.International Classification of Functioning, Disability and Health.Geneva:World Health Organization;2001.
  • 2
    Holmes WR, Joseph J. Social participation and healthy ageing: a neglected, significant protective factor for chronic non-communicable conditions. Global Health 2011;7:43.
  • 3
    Dale C, Prieto-Merino D, Kuper H, Adamson J, Bowling A, Ebrahim S, et al. Modelling the association of disability according to the WHO International Classification of Functioning, Disability and Health (ICF) with mortality in the British Women's Heart and Health Study. J Epidemiol Community Health 2012;66:1705.
  • 4
    Peat G, McCarney R, Croft P. Knee pain and osteoarthritis in older adults: a review of community burden and current use of primary health care. Ann Rheum Dis 2001;60:917.
  • 5
    Jordan K, Clarke AM, Symmons DP, Fleming D, Porcheret M, Kadam UT, et al. Measuring disease prevalence: a comparison of musculoskeletal disease using four general practice consultation databases. Br J Gen Pract 2007;57:714.
  • 6
    Wilkie R, Peat G, Thomas E, Croft PR. Factors associated with restricted mobility outside the home in community-dwelling adults ages fifty years and older with knee pain: an example of use of the International Classification of Functioning to investigate participation restriction. Arthritis Rheum 2007;57:13819.
  • 7
    World Health Organization.The burden of musculoskeletal conditions at the start of the new millennium: report of a WHO Scientific Group (WHO Technical Report Series: 919).Geneva:World Health Organization;2003.
  • 8
    Kadam UT, Croft PR. Clinical comorbidity in osteoarthritis: associations with physical function in older patients in family practice. J Rheumatol 2007;34:1899904.
  • 9
    Wilkie R, Peat G, Thomas E, Croft PR. Factors associated with participation restriction in community-dwelling adults aged 50 years and over. Qual Life Res 2007;16:114756.
  • 10
    Machado GP, Gignac MA, Badley EM. Participation restrictions among older adults with osteoarthritis: a mediated model of physical symptoms, activity limitations, and depression. Arthritis Rheum 2008;59:12935.
  • 11
    Kadam UT, Jordan K, Croft PR. Clinical comorbidity in patients with osteoarthritis: a case-control study of general practice consulters in England and Wales. Ann Rheum Dis 2004;63:40814.
  • 12
    Schram MT, Frijters D, van de Lisdonk EH, Ploemacher J, de Craen AJ, de Waal MW, et al. Setting and registry characteristics affect the prevalence and nature of multimorbidity in the elderly. J Clin Epidemiol 2008;61:110412.
  • 13
    Thomas E, Wilkie R, Peat G, Hill S, Dziedzic K, Croft P. The North Staffordshire Osteoarthritis Project-NorStOP: prospective, 3-year study of the epidemiology and management of clinical osteoarthritis in a general population of older adults. BMC Musculoskelet Disord 2004;5:2.
  • 14
    National Health Service Information.The clinical terms, version 3 (the READ codes).Birmingham (England):NHS Information Authority;2000.
  • 15
    Doherty M. Risk factors for progression of knee osteoarthritis. Lancet 2001;358:7756.
  • 16
    Ling SM, Xue QL, Simonsick EM, Tian J, Bandeen-Roche K, Fried LP, et al. Transitions to mobility difficulty associated with lower extremity osteoarthritis in high functioning older women: longitudinal data from the Women's Health and Aging Study II. Arthritis Rheum 2006;55:25663.
  • 17
    Jinks C, Jordan KP, Blagojevic M, Croft P. Predictors of onset and progression of knee pain in adults living in the community: a prospective study. Rheumatology (Oxford) 2008;47:36874.
  • 18
    Smith BH, Elliott AM, Hannaford PC, Chambers WA, Smith WC. Factors related to the onset and persistence of chronic back pain in the community: results from a general population follow-up study. Spine 2004;29:103240.
  • 19
    Aspden RM. Osteoarthritis: a problem of growth not decay?Rheumatology (Oxford) 2008;47:145260.
  • 20
    Sowers M, Karvonen-Gutierrez CA, Palmieri-Smith R, Jacobson JA, Jiang Y, Ashton-Miller JA. Knee osteoarthritis in obese women with cardiometabolic clustering. Arthritis Rheum 2009;61:132836.
  • 21
    Kenchaiah S, Evans JC, Levy D, Wilson PW, Benjamin EJ, Larson MG, et al. Obesity and the risk of heart failure. N Engl J Med 2002;347:30513.
  • 22
    Spangenberg L, Forkmann T, Brahler E, Glaesmer H. The association of depression and multimorbidity in the elderly: implications for the assessment of depression. Psychogeriatrics 2011;11:22734.
  • 23
    Jinks C, Jordan K, Ong BN, Croft P. A brief screening tool for knee pain in primary care (KNEST): results from a survey in the general population aged 50 and over. Rheumatology (Oxford) 2004;43:5561.
  • 24
    Vogelzangs N, Kritchevsky SB, Beekman AT, Brenes GA, Newman AB, Satterfield S, et al, for the Health ABC Study. Obesity and onset of significant depressive symptoms: results from a prospective community-based cohort study of older men and women. J Clin Psychiatry 2010;71:3919.
  • 25
    Knoop J, van der Leeden M, Thorstensson CA, Roorda LD, Lems WF, Knol DL, et al. Identification of phenotypes with different clinical outcomes in knee osteoarthritis: data from the Osteoarthritis Initiative. Arthritis Care Res (Hoboken) 2011;63:153542.
  • 26
    Schwartz CE, Rapkin BD. Reconsidering the psychometrics of quality of life assessment in light of response shift and appraisal. Health Qual Life Outcomes 2004;2:16.
  • 27
    Kadam UT, Croft PR, and the North Staffordshire GP Consortium Group. Clinical multimorbidity and physical function in older adults: a record and health status linkage study in general practice. Fam Pract 2007;24:4129.
  • 28
    Wilkie R, Peat G, Thomas E, Hooper H, Croft PR. The Keele Assessment of Participation: a new instrument to measure participation restriction in population studies. Combined qualitative and quantitative examination of its psychometric properties. Qual Life Res 2005;14:188999.
  • 29
    Department of Health.Health Survey for England.London:the Stationery Office;1999.
  • 30
    Bellamy N.WOMAC Osteoarthritis Index: a user's guide.Ontario (Canada):London Health Services Centre, McMaster University;1996.
  • 31
    Garrow AP, Papageorgiou AC, Silman AJ, Thomas E, Jayson MI, Macfarlane GJ. Development and validation of a questionnaire to assess disabling foot pain. Pain 2000;85:10713.
  • 32
    Jinks C, Jordan K, Croft P. Measuring the population impact of knee pain and disability with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pain 2002;100:5564.
  • 33
    Roddy E, Muller S, Thomas E. Defining disabling foot pain in older adults: further examination of the Manchester Foot Pain and Disability Index. Rheumatology (Oxford) 2009;48:9926.
  • 34
    Zigmond AS, Snaith RP. The Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 1983;67:36170.
  • 35
    Ware JE, Snow KK, Kosinski M, Gandek B.SF-36 health survey: manual and interpretation guide.Lincoln (RI):QualityMetric Incorporated;1993.
  • 36
    Muller S, Thomas E, Peat G. Derivation and testing of an interval-level score for measuring locomotor disability in epidemiological studies of middle and old age. Qual Life Res 2009;18:134155.
  • 37
    Office for National Statistics. Standard occupational classification. Vol.2. The coding index.London:Office for National Statistics;2000.
  • 38
    Office for National Statistics.The national statistics socio-economic classification user manual, version 1.London:Office for National Statistics;2001.
  • 39
    Thomas R. Question bank commentary: income.1999. URL:
  • 40
    Streiner DL. Finding our way: an introduction to path analysis. Can J Psychiatry 2005;50:11522.
  • 41
    Erikson R, Goldthorpe JH, Jackson M, Yaish M, Cox DR. On class differentials in educational attainment. Proc Natl Acad Sci U S A 2005;102:97303.
  • 42
    Buis ML. Direct and indirect effects in a logit model. Stata J 2010;10:1129.
  • 43
    Karlson KB, Holm A. Decomposing primary and secondary effects: using the Karlson-Holm-Breen decomposition method. Res Soc Strat Mobil 2011;29:22137.
  • 44
    Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJ.Global burden of disease and risk factors.New York:World Bank and Oxford University Press;2006.
  • 45
    Creed FH, Tomensen B, Davis I, Litlewood A, Chew-Graham C, Macfarlane GJ, et al. Multiple symptom reporting is associated with poor mental and physical health outcomes. J Psychosom Res. In press.
  • 46
    Miller GD, Nicklas BJ, Davis C, Loeser RF, Lenchik L, Messier SP. Intensive weight loss program improves physical function in older obese adults with knee osteoarthritis. Obesity (Silver Spring) 2006;14:121930.
  • 47
    Messier SP, Loeser RF, Miller GD, Morgan TM, Rejeski WJ, Sevick MA, et al. Exercise and dietary weight loss in overweight and obese older adults with knee osteoarthritis: the Arthritis, Diet, and Activity Promotion Trial. Arthritis Rheum 2004;50:150110.
  • 48
    Chew-Graham C, Kovandzic M, Gask L, Burroughs H, Clarke P, Sanderson H, et al. Why may older people with depression not present to primary care? Messages from secondary analysis of qualitative data. Health Soc Care Community 2012;20:5260.
  • 49
    Lin EH, Katon W, von Korff M, Tang L, Williams JW Jr, Kroenke K, et al, for the IMPACT Investigators. Effect of improving depression care on pain and functional outcomes among older adults with arthritis: a randomized controlled trial. JAMA 2003;290:24289.
  • 50
    Semanik PA, Chang RW, Dunlop DD. Aerobic activity in prevention and symptom control of osteoarthritis. PM R 2012;4 Suppl:S3744.
  • 51
    Blumenthal JA, Babyak MA, O'Connor C, Keteyian S, Landzberg J, Howlett J, et al. Effects of exercise training on depressive symptoms in patients with chronic heart failure: the HF-ACTION randomized trial. JAMA 2012;308:46574.
  • 52
    Preacher KJ, Hayes AF. Contemporary approaches to assessing mediation in communication research. In: Hayes AF, Slater MD, Snyder LB, editors.The Sage sourcebook of advanced data analysis methods for communication research.Thousand Oaks (CA):Sage Publications;2008. p.1354.
  • 53
    Karlson KB, Holm A. Decomposing primary and secondary effects: a new decomposition method. Res Soc Strat Mobil 2011;29:22137.
  • 54
    Merrill RM, Richardson JS. Validity of self-reported height, weight, and body mass index: findings from the National Health and Nutrition Examination Survey, 2001–2006. Prev Chronic Dis 2009;6:A121.
  • 55
    Stommel M, Schoenborn CA. Accuracy and usefulness of BMI measures based on self-reported weight and height: findings from the NHANES & NHIS 2001–2006. BMC Public Health 2009;9:421.
  • 56
    Persell SD, Wright JM, Thompson JA, Kmetik KS, Baker DW. Assessing the validity of national quality measures for coronary artery disease using an electronic health record. Arch Intern Med 2006;166:22727.