title: Endogenous parathyroid hormone and knee osteoarthritis: a cross-sectional study.
abstract: OBJECTIVE
  Although animal studies have shown that parathyroid hormone (PTH) analogs can have disease-modifying effect on experimental osteoarthritis, there is little human data. This study aimed to analyze the association between endogenous PTH and knee osteoarthritis in humans.
  
  
  METHODS
  This was a cross-sectional study including 5880 participants of The Fifth Korean National Health and Nutrition Examination Survey. Serum intact PTH was measured by chemiluminescence assay. Radiographic knee osteoarthritis was defined as a Kellgren-Lawrence grade of ≥ 2. The association between knee osteoarthritis and natural log-transformed PTH (lnPTH) was modeled using logistic regression analyses adjusting for age, body mass index categories, calcium intake and serum 25-hydroxyvitamin D in both sexes.
  
  
  RESULTS
  The prevalence of radiographic knee osteoarthritis tended to be higher in the highest quartile of PTH in women. In men, there was no clear trend across the quartiles of PTH. In multivariable analyses, there was no significant association between lnPTH and radiographic knee osteoarthritis in either sex (odds ratio [95% confidence interval]): 0.81 (0.64-1.02) in women and 0.88 (0.67-1.16) in men. Analyses on symptomatic radiographic knee osteoarthritis showed no significant association.
  
  
  CONCLUSIONS
  Although there was a trend for a negative association in women, no statistically significant association was found between endogenous PTH and knee osteoarthritis.
authors: Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea.
authors: Sunggun
authors: S
authors: Lee
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000000981:diagnostic imaging / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000097:blood*; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; C470125:PTH protein, human; D010281:Parathyroid Hormone
keywords: knee joint; osteoarthritis; parathyroid hormone