Osteoarthritis Epidemiologicosteoarthritis and Genetic Aspects Epidemiologic and Genetic Aspects
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From the Department of Orthopedics, Clinical Sciences From the DepartmentLund University, of Orthopedics, Lund, Sweden Clinical Sciences Lund University, Lund, Sweden Osteoarthritis EpidemiologicOsteoarthritis and genetic aspects Epidemiologic and genetic aspects Jonas Franklin Jonas Franklin Thesis 2010 Thesis 2010 Contact address Jonas Franklin Department of Orthopedics Akureyri University Hospital IS-600 Akureyri Iceland E-mail: [email protected] ISSN 1652-8220 ISBN 978-91-86443-87-0 Lund University, Faculty of Medicine Doctoral Dissertation Series 2010:71 Printed in Sweden Mediatryck, Lund 2010 To Hlíf Atli Egill and Jóhann Jonas Franklin 1 Contents List of papers, 2 Radiographic techniques, 17 Radiographic classification, 17 Definitions and abbreviations, 3 Statistical methods, 17 Thesis at a glance, 4 Ethics, 18 Description of contributions, 6 Data encryption and protection of the individual, 18 Introduction, 7 Symptoms and signs of osteoarthritis, 7 Summary of results of papers I-V, 19 Natural history of osteoarthritis, 8 Discussion, 24 Radiographic features of osteoarthritis, 8 Research methodology, 24 Definition of osteoarthritis, 9 Abnormal mechanical loading is a risk factor for Definition of hip fractures, 9 OA, 25 Study methodology, 9 Natural history of OA, 27 Epidemiology of osteoarthritis, 11 OA and hip fracture, 28 Epidemiology of hip fractures, 11 Conclusions, 30 Risk factors for osteoarthritis ,12 Summary, 31 Risk factors for hip fracture, 13 Populärvetenskaplig sammanfattning på Aims, 14 svenska, 33 Patients and methods, 15 Ágrip á íslensku, 35 Overview of patient/subject allocation, 15 Acknowledgements, 37 Patient identification, 15 References, 38 Populations examined, 16 2 Osteoarthritis - Epidemiologic and genetic aspects List of papers This thesis is based on the following papers: I. Franklin J, Ingvarsson T, Englund M, IV. Franklin J, Englund M, Ingvarsson T, Lohmander LS. Sex differences in the Lohmander LS. The association between association between body mass index hip fracture and hip osteoarthritis. A and total hip or knee joint replacement case-control study. Submitted. resulting from osteoarthritis. Ann Rheum Dis 2009;68:536–540. V. Franklin J, Ingimarsson O, Styrkarsdottir U, Jonsson GF, Ingvarsson T, Englund II. Franklin J, Ingvarsson T, Englund M, M, Lohmander LS. Relatives of patients Lohmander LS. Association between with total hip replacement due to occupation and knee and hip replacement osteoarthritis do not have reduced risk of due to osteoarthritis: A case-control hip fracture: A study of the inheritance study. Submitted. of hip osteoarthritis and hip fracture in Iceland. Manuscript. III. Franklin J, Ingvarsson T, Englund M, Ingimarsson O, Robertsson O, Lohmander LS. The natural history of radiographic hip osteoarthritis. A retrospective cohort study with 11-28 years follow-up. Submitted. Jonas Franklin 3 Definitions and abbreviations ACR American College of Rheumatology MRI Magnetic resonance imaging AGES study Age, Gene, Environment, OA Osteoarthritis Susceptibility Study OR Odds ratio AP Anteroposterior PIN Personal Identification Number BMI Body mass index Qualitative measurement Measurement with an CI Confidence interval ordinal, subjective scale such as K&L grading of radiological OA Dichotome A binary variable Quantitative measurement Measurement with a Extracapsular fracture Hip fracture that is quantitative scale such as millimetres outside the joint capsule (basocervical, pertrochanteric, and subtrochanteric fractures) ROC Receiver Operator Characteristic HR Hazard ratio RR Relative Risk IBD Identical by descent SD Standard Deviation ILO International Labour Organization THR Total hip replacement Intracapsular fracture Hip fracture that is TJR Total joint replacement inside the joint capsule (fractures of the femoral neck) TKR Total knee replacement K & L Kellgren and Lawrence WHO World Health Organization MJS Minimal joint space WOMAC Index Western Ontario and McMaster Universities Osteoarthritis Index 4 Osteoarthritis - Epidemiologic and genetic aspects Thesis at a glance Paper I: Sex differences in the association inheritance of occupation a possible confounder between body mass index and total hip in this question? or knee joint replacement resulting from Patients: 1408 patients (832 women) with THR osteoarthritis and/or TKR and 1082 (592) controls that Is body mass index associated with total joint participated in the Icelandic OA Genealogy replacement in the hip or knee? study. Patients: 1473 patients (872 women) with THR Methods: Questionnaire data as outlined for and/or TKR and 1103 controls (599 women) that Paper I above. Inheritance was calculated by participated in the Icelandic OA Genealogy comparing the cohort with the Icelandic study. A randomly selected population sample Genealogy Database. was used as a secondary control group. Results: The age adjusted odds ratio (OR) for Methods: All cases and controls answered a male farmers getting a TKR due to OA was 5.1 standardised questionnaire containing 79 (95% confidence interval (CI) 2.1-12.4) and for a questions on the subject’s height and weight, male farmer getting a THR due to OA the OR general health status, occupation, family history, was 3.6 (95% CI 2.1-6.2). The OR for a physical activities, previous injuries and a fisherman getting a TKR was 3.3 (95%CI 1.3- detailed description of all musculoskeletal 8.4). No other occupations showed increased risk symptoms. The hospital records of all cases were for men. For women there was no increased risk reviewed to confirm that the diagnosis of OA. for any occupation. Farming and fishing were Results: The OR, adjusted for age, occupation also the occupations that showed the greatest and presence of hand OA, for having a THR was degree of inheritance. 1.1 (95% CI 0.9 to 1.5) for overweight men and Conclusion: These results support an association 1.7 (95% CI 1.0 to 2.9) for obese men. The OR in males between physically demanding work for having a TKR was 1.7 (95% CI 1.1 to 2.6) for and both TKR and THR for OA, particularly overweight men and 5.3 (95% CI 2.8 to 10.1) for farming. Farming is however also the occupation obese men. The OR for having a THR was 1.0 that has the greatest degree of inheritance and (95% CI 0.8 to 1.3) for overweight women and this might interact with the results. 1.0 (95% CI 0.6 to 1.5) for obese women. The OR for having a TKR was 1.6 (95% CI 1.1 to 2.2) for overweight women and 4.0 (95% CI 2.6 Paper III: The natural history of to 6.1) for obese women. radiographic hip osteoarthritis. A Conclusion: The results of this study support a retrospective cohort study with 11-28 positive association between high BMI and TKR years follow-up in both sexes, but for THR the association with What is the future risk of THR and hip fracture in BMI seems to be weaker, and possibly negligible subjects with radiographic hip OA? for women. Patients: A cohort of subjects that had colon radiography in 1980-1997. Methods: MJS was measured in each hip it and graded according to Kellgren & Lawrence. Paper II: Association between occupation Subjects were followed until end of 2008. 1498 and knee and hip replacement due to subjects supplied 2953 hips for analysis. osteoarthritis: A case-control study Results: The cumulative incidence of THR was Is occupation associated with total joint 2.5% and the cumulative incidence of hip replacement in the hip or knee? Is the fracture was 2.6%. For hips with radiographic Jonas Franklin 5 hip OA (MJS 2.5 mm or less) the cumulative higher than for subjects with hip fracture without incidence of THR was 16.9%, and the hazard hip OA. ratio (HR) for THR was 13.2 (95% CI 8.1-21). Conclusions: The results of our study support Using Kellgren and Lawrence grading, the HR the inverse relationship between osteoporosis and for THR was 12.9 (95% CI 7.9-21) for hips with hip OA. radiographic OA, compared to those without. The HR for all types of hip fracture for hips with radiographic OA (MJS 2.5 mm or less) was 0.47 Paper V: Relatives of patients with total (95% CI 0.15-1.5), for intracapsular fractures hip replacement due to osteoarthritis do 0.29 (95% CI 0.04-2.1) and for extracapsular not have reduced risk of hip fracture: A fractures 0.67 (95% CI 0.16-2.8). study of the inheritance of hip Conclusions: The risk for THR due to OA is osteoarthritis and hip fracture in Iceland substantially increased in patients with Are patients with hip fracture and THR due to radiographic hip OA, regardless of symptoms OA less related to each other, than can be and increases with decreasing MJS. However, expected in the Icelandic population? 11-28 years after having had radiographic hip Patients: 4228 patients with THR due to OA OA, more than 4 out 5 of those having (THR-OA) and 8165 patients with hip fracture radiographic signs of hip OA had not had a THR compared with controls from the Icelandic for OA. Genealogy Database. Methods: The average pairwise kinship coefficient (KC) was calculated for patient lists Paper IV: The association between hip and control lists and the relative risk (RR) was fracture and hip osteoarthritis. A case- estimated for THR-OA and for hip fracture control study among relatives of patients with THR-OA. Ten What is the prevalence of hip OA in patients with thousand matched control lists, each the same hip fracture? size as the patient list, were created using the Patients: 562 patients with hip fracture at Genealogy Database. Akureyri University Hospital in 1990-2008 Results: The RR for THR-OA among relatives compared with 803 subjects from a colon of THR-OA patients was 2.80 for parents (95% radiography cohort. CI 2.45-3.18), and 2.27 (95% CI 2.08-2.37) for Methods: Radiographies of cases and controls siblings.