title: Prevalence and associated factors of knee osteoarthritis in a rural Chinese adult population: an epidemiological survey.
abstract: BACKGROUND
  The exact pathogenic mechanism of knee osteoarthritis (OA) is still unknown. With the exception of clinical treatment to alleviate symptoms, or total knee replacement, there is currently no effective treatment method. Consequently, an in-depth etiological and epidemiological study of knee OA can provide clues for diagnosis, treatment and scientific research, and will ultimately have a beneficial effect on public health.
  
  
  METHODS
  A cross-sectional community study in the rural village of Gaoyou was conducted in 3428 Chinese adults (aged ≥ 40 years). Subjects completed an interviewer-administered questionnaire, evaluating knee pain and associated disability, analgesia, use of health services, past medical history, walking, income, smoking, and use of oral contraceptives, and standardized weight-bearing knee radiographs were obtained. Patient demographic characteristics and biochemical parameters were recorded.
  
  
  RESULTS
  Single-factor regression analysis indicated that age, overweight, central adiposity, high low-density lipoprotein cholesterol (LDLC), high total cholesterol (TC), high triglycerides (TG), dyslipidemia, hypertension and low income were the associated factors for knee OA in females; age, high LDLC, hypertension, low income and frequent walking were the associated factors for knee OA in males. Interestingly, male heavy smokers were less likely to develop severe knee OA compared with non-smokers. Stepwise logistic regression analysis indicated that age and overweight were the associated factors for knee OA for all individuals. Although central adiposity, high LDLC, high TC, high TG, dyslipidemia, hypertension and low income appeared to be related to knee OA in females according to univariate analysis, these factors were not identified in stepwise logistic regression analysis. In addition although age, high LDLC, hypertension and frequent walking were also the associated factors for knee OA in males by stepwise logistic regression analysis, smoking as a protective factor was not identified in this analysis.
  
  
  CONCLUSIONS
  In this study, aging, obesity, frequent walking, low income and relevant multiple metabolic disorders were the associated factors for knee OA. Smoking might be associated with a lower prevalence of OA in male smokers according to univariate analysis. A retrospective association of smoking with OA may constitute an important etiologic clue, but further well-designed, large-scale prospective controlled trials are required to confirm these findings.
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
authors.forename: Ningxia
authors.initials: N
authors.lastname: Liang
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Guang Zhou Road 300, Nanjing, 210029, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Fan
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
authors.forename: Zuhu
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Centre Clinics of Baqiao, Gaoyou, 225642, China.
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Centre Clinics of Baqiao, Gaoyou, 225642, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Guang Zhou Road 300, Nanjing, 210029, China. junhu89@vip.sina.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D015897:Comorbidity; D003430:Cross-Sectional Studies; D050171:Dyslipidemias / Q000453:epidemiology; D005260:Female; D006304:Health Status; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D020370:Osteoarthritis, Knee / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data*; D012907:Smoking / Q000453:epidemiology; D016474:Weight-Bearing
references.citation: Hypertens Res. 2012 Jul;35(7):739-44
references.pmid: 22357521
references.citation: Rheumatology (Oxford). 2005 Mar;44(3):349-51
references.pmid: 15546963
references.citation: Br J Rheumatol. 1993 May;32(5):366-70
references.pmid: 8495255
references.citation: J Rheumatol. 1992 Oct;19(10):1595-9
references.pmid: 1464874
references.citation: J Rheumatol. 1989 Sep;16(9):1241-5
references.pmid: 2810282
references.citation: Arthritis Rheum. 1987 Aug;30(8):914-8
references.pmid: 3632732
references.citation: Am J Manag Care. 2002 Oct;8(15 Suppl):S383-91
references.pmid: 12416788
references.citation: Arthritis Rheum. 2001 Sep;44(9):2065-71
references.pmid: 11592368
references.citation: Ann Rheum Dis. 2001 Aug;60(8):756-64
references.pmid: 11454639
references.citation: BMC Public Health. 2015;15:855
references.pmid: 26334523
references.citation: Mod Rheumatol. 2015 Mar;25(2):292-7
references.pmid: 25065916
references.citation: Arthritis Res Ther. 2014;16(2):R61
references.pmid: 24594022
references.citation: J Am Acad Orthop Surg. 2014 Jul;22(7):467-8
references.pmid: 24966254
references.citation: PLoS One. 2013;8(8):e70893
references.pmid: 23951031
references.citation: J Hum Hypertens. 2013 Apr;27(4):265-70
references.pmid: 22648266
references.citation: J Am Acad Orthop Surg. 2013 Mar;21(3):161-9
references.pmid: 23457066
references.citation: Nat Rev Rheumatol. 2012 Dec;8(12):729-37
references.pmid: 22907293
references.citation: Curr Opin Rheumatol. 2013 Jan;25(1):114-8
references.pmid: 23090672
references.citation: Eur J Epidemiol. 2005;20(6):537-42
references.pmid: 16121763
references.citation: Joint Bone Spine. 2012 May;79(3):291-7
references.pmid: 21803633
references.citation: Osteoarthritis Cartilage. 2012 Jan;20(1):6-12
references.pmid: 22044842
references.citation: Ann Rheum Dis. 2011 Jul;70(7):1231-7
references.pmid: 21474488
references.citation: Arthritis Res Ther. 2010;12(6):R225
references.pmid: 21190567
references.citation: Curr Opin Rheumatol. 2010 Sep;22(5):512-9
references.pmid: 20592604
references.citation: J Arthroplasty. 2010 Apr;25(3):416-9
references.pmid: 19278817
references.citation: Ann Rheum Dis. 2010 Jan;69(1):70-81
references.pmid: 19174392
references.citation: Arthritis Rheum. 2009 May 15;61(5):641-7
references.pmid: 19405001
references.citation: Ann Rheum Dis. 2009 Apr;68(4):490-6
references.pmid: 18467514
references.citation: Arthritis Rheum. 2009 Jan;60(1):114-22
references.pmid: 19116908
references.citation: Redox Rep. 2008;13(5):194-8
references.pmid: 18796237
references.citation: Osteoarthritis Cartilage. 2007 Sep;15(9):1097-8
references.pmid: 17434763
references.citation: Diabetes Care. 2006 Dec;29(12):2682-7
references.pmid: 17130205
references.citation: Diabetes Care. 2005 Nov;28(11):2745-9
references.pmid: 16249550
references.citation: Diabetes Care. 2016 Feb;39(2):179-86
references.pmid: 26798148
references.citation: Ann Rheum Dis. 1999 Mar;58(3):151-5
references.pmid: 10364912