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Knee joint replacement and individual susceptibility for progression of knee osteoarthritis and tibial cartilage volume loss: not only genes run in the family
Osteoarthritis and Cartilage 23 (2015) 1817e1818
Letter to the Editor
Knee joint replacement and individual susceptibility for progression of knee osteoarthritis and tibial cartilage volume loss: not only genes run in the family Dear Editor The study of interactions between genetic and non-genetic factors can be quite complex. Also the identification of risk factors for the worsening of knee osteoarthritis (OA) is difficult but knowing these risk factors is essential for the selection of effective individual, community level and workplace interventions for this rapidly growing disabling disease1. Khan et al. used in their longitudinal study with an impressive follow-up period of 10 years an innovative proxy for the genetic factor namely adults (offspring) of parents of whom at least one was operated for knee replacement due to severe primary knee OA2. All participating adults were of working age at baseline: mean 45 years, standard deviation 7. The radiographic changes and cartilage loss in the knee in the offspring group (n ¼ 115) were compared with 105 sex and age matched healthy population controls. In the analysis, Body Mass Index (BMI), knee pain, cartilage defects, tibial bone area and leg strength were taken into account. Khan et al. concluded that this is the first study to confirm that offspring of those with a knee replacement for OA have a higher risk of worsening knee OA. This suggests that the genes responsible may express themselves later in life, possibly through interaction with factors such as BMI and muscle strength, as pointed out by reduction in estimates after adjustment for baseline differences2. We think that an important non-genetic factor should have been discussed in their interesting study, namely knee-demanding work. First of all, it has been established that persons with lower socio-economic position (SEP) have a substantial increased risk for knee joint replacement: in 2010 an estimated rate per 1,000 male person years of 8.32 (95% CI 7.97e8.68) vs 6.28 (95% CI 6.00e6.58)3. Moreover, the percentage patients in working age operated for knee replacement surgery perform more often physically demanding work compared to the distribution of physically demanding work among the general working population: an estimated ratio of about 5:3 in the Netherlands4. There is ample evidence that SEP is partly determined by intergenerational transmission and, thus, this also implies that their offspring has a lower SEP and are more exposed to established occupational risk factors for knee OA like lifting5,6. Adjusting for BMI as is done by Khan et al. seems not sufficient given for instance the finding of an multiplicative interaction between BMI and lifting6,7. Therefore, discussing possible confounding due to knee-demanding work and SEP might have shed more light on the complex interaction between genetic and non-genetic factors in their paper2. DOI of original article: http://dx.doi.org/10.1016/j.joca.2015.05.031.
We like to share our thoughts on this topic in order to overcome that future health impact assessments on prevention for knee OA underestimate the true contribution of non-genetic factors like occupational risk factors for prevention8. Author contribution Paul Kuijer came up with the idea for the manuscript and was the primary writer. Arthur Kievit, Jos Verbeek, Lex Burdorf and Monique Frings-Dresen revised the paper critically for important intellectual content and gave final approval of the version to be published. Funding None. Conflict of interest No conflict of interest. Acknowledgments For the preparation of the manuscript no funding was received. References 1. Culliford D, Maskell J, Judge A, Cooper C, Prieto-Alhambra D, Arden NK, COASt Study Group. Future projections of total hip and knee arthroplasty in the UK: results from the UK clinical practice research datalink. Osteoarthr Cartil 2015 Apr;23(4): 594e600, http://dx.doi.org/10.1016/j.joca.2014.12.022. 2. Khan HI, Aitken D, Chou L, McBride A, Ding C, Blizzard L, et al. A family history of knee joint replacement increases the progression of knee radiographic osteoarthritis and medial tibial cartilage volume loss over 10 years. Osteoarthr Cartil 2015;23(2): 203e9. 3. Brennan SL, Lane SE, Lorimer M, Buchbinder R, Wluka AE, Page RS, et al. Associations between socioeconomic status and primary total knee joint replacements performed for osteoarthritis across Australia 2003-10: data from the Australian Orthopaedic Association National Joint Replacement Registry. BMC Musculoskelet Disord 2014;15:356. 4. Kievit AJ, van Geenen RC, Kuijer PP, Pahlplatz TM, Blankevoort L, Schafroth MU. Total knee arthroplasty and the unforeseen impact on return to work: a cross-sectional multicenter survey. J Arthroplasty 2014;29(6):1163e8.
http://dx.doi.org/10.1016/j.joca.2015.02.1000 1063-4584/© 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
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Letter to the Editor / Osteoarthritis and Cartilage 23 (2015) 1817e1818
5. McWilliams DF, Leeb BF, Muthuri SG, Doherty M, Zhang W. Occupational risk factors for osteoarthritis of the knee: a meta-analysis. Osteoarthritis and Cartilage 2011;19(7):829e39. 6. Apold H, Meyer HE, Nordsletten L, Furnes O, Baste V, Flugsrud GB. Risk factors for knee replacement due to primary osteoarthritis, a population based, prospective cohort study of 315,495 individuals. BMC Musculoskelet Disord 2014;23:217. 7. Martin KR, Kuh D, Harris TB, Guralnik JM, Coggon D, Wills AK. Body mass index, occupational activity, and leisure-time physical activity: an exploration of risk factors and modifiers for knee osteoarthritis in the 1946 British birth cohort. BMC Musculoskelet Disord 2013 Jul 24;14:219. €n JH, 8. Coenen P, Gouttebarge V, van der Burght AS, van Diee Frings-Dresen MH, van der Beek AJ, et al. The effect of lifting during work on low back pain: a health impact assessment based on a meta-analysis. Occup Environ Med 2014;71(12): 871e7. P.P.F.M. Kuijer* Netherlands Center for Occupational Diseases, Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
A.J. Kievit Orthopaedic Research Center Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands J.H. Verbeek Finnish Institute of Occupational Health, Kuopio, Finland A. Burdorf Department of Public Health, Erasmus MC, University Medical Center, Rotterdam, The Netherlands M.H.W. Frings-Dresen Netherlands Center for Occupational Diseases, Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands *
Address correspondence and reprint requests to: P.P.F.M. Kuijer, Netherlands Center for Occupational Disease, Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands. Tel.: 31-20-566-5339; fax: 31-20-697-7161. E-mail address: [email protected] (P.P.F.M. Kuijer). 13 February 2015
Letter to the Editor
Knee joint replacement and individual susceptibility for progression of knee osteoarthritis and tibial cartilage volume loss: not only genes run in the family Dear Editor The study of interactions between genetic and non-genetic factors can be quite complex. Also the identification of risk factors for the worsening of knee osteoarthritis (OA) is difficult but knowing these risk factors is essential for the selection of effective individual, community level and workplace interventions for this rapidly growing disabling disease1. Khan et al. used in their longitudinal study with an impressive follow-up period of 10 years an innovative proxy for the genetic factor namely adults (offspring) of parents of whom at least one was operated for knee replacement due to severe primary knee OA2. All participating adults were of working age at baseline: mean 45 years, standard deviation 7. The radiographic changes and cartilage loss in the knee in the offspring group (n ¼ 115) were compared with 105 sex and age matched healthy population controls. In the analysis, Body Mass Index (BMI), knee pain, cartilage defects, tibial bone area and leg strength were taken into account. Khan et al. concluded that this is the first study to confirm that offspring of those with a knee replacement for OA have a higher risk of worsening knee OA. This suggests that the genes responsible may express themselves later in life, possibly through interaction with factors such as BMI and muscle strength, as pointed out by reduction in estimates after adjustment for baseline differences2. We think that an important non-genetic factor should have been discussed in their interesting study, namely knee-demanding work. First of all, it has been established that persons with lower socio-economic position (SEP) have a substantial increased risk for knee joint replacement: in 2010 an estimated rate per 1,000 male person years of 8.32 (95% CI 7.97e8.68) vs 6.28 (95% CI 6.00e6.58)3. Moreover, the percentage patients in working age operated for knee replacement surgery perform more often physically demanding work compared to the distribution of physically demanding work among the general working population: an estimated ratio of about 5:3 in the Netherlands4. There is ample evidence that SEP is partly determined by intergenerational transmission and, thus, this also implies that their offspring has a lower SEP and are more exposed to established occupational risk factors for knee OA like lifting5,6. Adjusting for BMI as is done by Khan et al. seems not sufficient given for instance the finding of an multiplicative interaction between BMI and lifting6,7. Therefore, discussing possible confounding due to knee-demanding work and SEP might have shed more light on the complex interaction between genetic and non-genetic factors in their paper2. DOI of original article: http://dx.doi.org/10.1016/j.joca.2015.05.031.
We like to share our thoughts on this topic in order to overcome that future health impact assessments on prevention for knee OA underestimate the true contribution of non-genetic factors like occupational risk factors for prevention8. Author contribution Paul Kuijer came up with the idea for the manuscript and was the primary writer. Arthur Kievit, Jos Verbeek, Lex Burdorf and Monique Frings-Dresen revised the paper critically for important intellectual content and gave final approval of the version to be published. Funding None. Conflict of interest No conflict of interest. Acknowledgments For the preparation of the manuscript no funding was received. References 1. Culliford D, Maskell J, Judge A, Cooper C, Prieto-Alhambra D, Arden NK, COASt Study Group. Future projections of total hip and knee arthroplasty in the UK: results from the UK clinical practice research datalink. Osteoarthr Cartil 2015 Apr;23(4): 594e600, http://dx.doi.org/10.1016/j.joca.2014.12.022. 2. Khan HI, Aitken D, Chou L, McBride A, Ding C, Blizzard L, et al. A family history of knee joint replacement increases the progression of knee radiographic osteoarthritis and medial tibial cartilage volume loss over 10 years. Osteoarthr Cartil 2015;23(2): 203e9. 3. Brennan SL, Lane SE, Lorimer M, Buchbinder R, Wluka AE, Page RS, et al. Associations between socioeconomic status and primary total knee joint replacements performed for osteoarthritis across Australia 2003-10: data from the Australian Orthopaedic Association National Joint Replacement Registry. BMC Musculoskelet Disord 2014;15:356. 4. Kievit AJ, van Geenen RC, Kuijer PP, Pahlplatz TM, Blankevoort L, Schafroth MU. Total knee arthroplasty and the unforeseen impact on return to work: a cross-sectional multicenter survey. J Arthroplasty 2014;29(6):1163e8.
http://dx.doi.org/10.1016/j.joca.2015.02.1000 1063-4584/© 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
1818
Letter to the Editor / Osteoarthritis and Cartilage 23 (2015) 1817e1818
5. McWilliams DF, Leeb BF, Muthuri SG, Doherty M, Zhang W. Occupational risk factors for osteoarthritis of the knee: a meta-analysis. Osteoarthritis and Cartilage 2011;19(7):829e39. 6. Apold H, Meyer HE, Nordsletten L, Furnes O, Baste V, Flugsrud GB. Risk factors for knee replacement due to primary osteoarthritis, a population based, prospective cohort study of 315,495 individuals. BMC Musculoskelet Disord 2014;23:217. 7. Martin KR, Kuh D, Harris TB, Guralnik JM, Coggon D, Wills AK. Body mass index, occupational activity, and leisure-time physical activity: an exploration of risk factors and modifiers for knee osteoarthritis in the 1946 British birth cohort. BMC Musculoskelet Disord 2013 Jul 24;14:219. €n JH, 8. Coenen P, Gouttebarge V, van der Burght AS, van Diee Frings-Dresen MH, van der Beek AJ, et al. The effect of lifting during work on low back pain: a health impact assessment based on a meta-analysis. Occup Environ Med 2014;71(12): 871e7. P.P.F.M. Kuijer* Netherlands Center for Occupational Diseases, Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
A.J. Kievit Orthopaedic Research Center Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands J.H. Verbeek Finnish Institute of Occupational Health, Kuopio, Finland A. Burdorf Department of Public Health, Erasmus MC, University Medical Center, Rotterdam, The Netherlands M.H.W. Frings-Dresen Netherlands Center for Occupational Diseases, Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands *
Address correspondence and reprint requests to: P.P.F.M. Kuijer, Netherlands Center for Occupational Disease, Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands. Tel.: 31-20-566-5339; fax: 31-20-697-7161. E-mail address: [email protected] (P.P.F.M. Kuijer). 13 February 2015