title: The relationship between the presence of depressive symptoms and the severity of self-reported knee pain in the middle aged and elderly.
abstract: OBJECTIVE
  Knee pain is a very common symptom of knee osteoarthritis (OA), and identification of the major contributors to knee pain is important to establish management plans for patients with knee OA. Among the potential contributors, we hypothesized that coexisting depressive symptoms might increase the severity of knee pain because the increased cytokine levels and neurotransmitter changes related to depression are known to influence the threshold of physical pain perception. Therefore, a possible relationship between self-reported depressive symptoms and self-reported knee pain has been explored. Additionally, we sought to determine factors influencing the severity of knee pain in a middle-aged and elderly Korean population using data from the fifth Korean National Health and Nutrition Examination Survey.
  
  
  METHODS
  In total, 6599 persons aged ≥50 years were evaluated in terms of the radiographic severity of OA and pain severity using 10-point numerical rating scales. Depressive mood was assessed using a polar question: "Had the subject felt despair or depression every day for more than 2 weeks during the past year?"
  
  
  RESULTS
  The Kellgren-Lawrence knee OA grade, depression, gender, educational level, household income, smoking status, marital status, living place, comorbidity status, BMI, and age were identified by multiple linear regression as variables affecting knee pain severity. The presence of depressive symptoms was associated with an increased risk of severe knee pain (odds ratio 2.55 [95 % confidence interval 1.77-3.66]). After stratifying the group in terms of the radiographic severity of knee OA, the relationship with depression persisted in the minimal (2.89 [1.90-4.32]) and moderate OA subgroups (2.29 [1.33-3.94]), but not in the severe OA subgroup.
  
  
  CONCLUSIONS
  Severe knee pain was independently associated with the presence of depressive symptoms in middle-aged and elderly Korean subjects. This suggests that screening for and treatment of depression may help improve knee pain in elderly individuals.
  
  
  METHODS
  II.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Ho-Sung
authors.initials: HS
authors.lastname: Han
authors.affiliation: Department of Family Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jee-Yon
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, 20, Boramae-ro 5-gil, Dongjak-gu, Seoul, 156-707, South Korea.
authors.forename: Seung-Baik
authors.initials: SB
authors.lastname: Kang
authors.affiliation: Department of Orthopaedic Surgery, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, 20, Boramae-ro 5-gil, Dongjak-gu, Seoul, 156-707, South Korea. drchuc@chol.com.
authors.forename: Chong Bum
authors.initials: CB
authors.lastname: Chang
mesh_terms: D000368:Aged; D018771:Arthralgia / Q000150:complications / Q000523:psychology*; D003863:Depression / Q000150:complications*; D005260:Female; D006801:Humans; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology*; D010147:Pain Measurement; D057566:Self Report; D012720:Severity of Illness Index
keywords: Depression; KNHANES; Knee osteoarthritis; Knee pain