title: Influence of parity-related factors adjusted for abortion on knee osteoarthritis in Korean women aged 50 or older: A cross-sectional study.
abstract: OBJECTIVE
  Knee osteoarthritis (OA) is pervasive in aged populations, and induces considerable socioeconomic expense. The objective of this study was to investigate the association between OA prevalence and pregnancy and parity in Koreans, considering for the potential effect of abortion.
  
  
  METHODS
  A total 5449 women aged ≥50 years with radiological knee examination results of 24,173 participants of the 5th Korean National Health and Nutrition Examination Survey (2010-2012) were analyzed in a cross-sectional study.
  
  
  METHODS
  Association between OA prevalence (Kellgren/Lawrence grade) and pregnancy and parity as odds ratios (ORs) by logistic regression.
  
  
  RESULTS
  Knee OA results were normal in 1996 participants (36.1%), suspected in 1012 (18.6%), mild in 781 (14.3%), moderate in 1073 (19.7%), and severe in 617 (11.3%). Increase in number of pregnancies adjusted for abortion was significantly associated with increased OA prevalence (OR 1.081; 95% CI 1.015, 1.152). OA prevalence increased with parity (continuous variable) in ever-abortion (OR 1.092; 95% CI 1.009, 1.181) and with parity (categorical variable) with reference value set at 1-2 (P for trend; p=0.0195). In analyses adjusted for abortion, ever-abortion negatively influenced OA prevalence. Parity was not associated with OA in number of pregnancies unadjusted for abortion or in never-abortion women.
  
  
  CONCLUSIONS
  This study shows that maternity-related factors such as pregnancy and parity were related with knee OA prevalence in this population-based sample of older women, and that relationships with abortion were stronger.
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea.
authors.forename: You Hwa
authors.initials: YH
authors.lastname: Jung
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea.
authors.forename: Joon-Shik
authors.initials: JS
authors.lastname: Shin
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea.
authors.forename: Jinho
authors.initials: J
authors.lastname: Lee
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea.
authors.forename: Me-riong
authors.initials: MR
authors.lastname: Kim
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea.
authors.forename: Ki Byung
authors.initials: KB
authors.lastname: Park
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea.
authors.forename: Areum
authors.initials: A
authors.lastname: Choi
authors.affiliation: Department of Natural Science, Michigan State University, East Lansing, MI, USA.
authors.forename: Dongjin
authors.initials: D
authors.lastname: Shin
authors.affiliation: Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul, Republic of Korea. Electronic address: hanihata@gmail.com.
authors.forename: In-Hyuk
authors.initials: IH
authors.lastname: Ha
mesh_terms: D000028:Abortion, Induced / Q000009:adverse effects*; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D009749:Nutrition Surveys; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D010298:Parity; D011247:Pregnancy; D015995:Prevalence; D011859:Radiography; D056910:Republic of Korea / Q000453:epidemiology; D012720:Severity of Illness Index
keywords: Abortion; Cross-sectional studies; Health surveys; Osteoarthritis; Parity; Pregnancy