title: Enhanced Pain Sensitivity Among Individuals With Symptomatic Knee Osteoarthritis: Potential Sex Differences in Central Sensitization.
abstract: OBJECTIVE
  Symptomatic knee osteoarthritis (OA) is a condition commonly associated with increased pain, disability, and functional limitations. Given the poor correspondence between radiographic evidence and clinical pain, central sensitization has been implicated as a potential mechanism underlying pain facilitation in knee OA. Sex may be a moderator of centrally mediated changes in knee OA pain; however, few studies have systematically assessed this. Therefore, the aim of this study was to examine differences in peripheral and central sensitization in men and women with symptomatic knee OA, as well as to determine whether these differences vary across age (middle age versus older age).
  
  
  METHODS
  Participants (n = 288) between the ages of 45 and 85 years completed a battery of quantitative sensory pain procedures assessing sensitivity to contact heat, cold pressor, mechanical pressure, and punctate stimuli. Differences in temporal summation (TS) were examined, as well as measures of clinical pain and functional performance.
  
  
  RESULTS
  When compared to men, women exhibited greater sensitivity to multiple pain modalities (i.e., lower heat, cold, pressure thresholds/tolerances, greater TS of pain); however, there were no sex differences in clinical pain, with the exception of greater widespread pain observed in women. Although there were select age-related differences in pain sensitivity, sex differences in pain varied minimally across the age cohort.
  
  
  CONCLUSIONS
  Overall, these findings provide evidence for greater overall sensitivity to experimental pain in women with symptomatic knee OA compared to men, suggesting that enhanced central sensitivity may be an important contributor to pain in this group.
authors.affiliation: University of Florida, Gainesville.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Bartley
authors.affiliation: University of Florida, Gainesville.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: King
authors.affiliation: University of Florida, Gainesville.
authors.forename: Kimberly T
authors.initials: KT
authors.lastname: Sibille
authors.affiliation: University of Florida, Gainesville.
authors.forename: Yenisel
authors.initials: Y
authors.lastname: Cruz-Almeida
authors.affiliation: University of Florida, Gainesville.
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Riley
authors.affiliation: University of Florida, Gainesville.
authors.forename: Toni L
authors.initials: TL
authors.lastname: Glover
authors.affiliation: University of Alabama, Birmingham.
authors.forename: Burel R
authors.initials: BR
authors.lastname: Goodin
authors.affiliation: University of Alabama, Birmingham.
authors.forename: Adriana S
authors.initials: AS
authors.lastname: Sotolongo
authors.affiliation: University of Alabama, Birmingham.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Herbert
authors.affiliation: University of Alabama, Birmingham.
authors.forename: Hailey W
authors.initials: HW
authors.lastname: Bulls
authors.affiliation: University of Florida, Gainesville.
authors.forename: Roland
authors.initials: R
authors.lastname: Staud
authors.affiliation: University of Alabama, Birmingham.
authors.forename: Barri J
authors.initials: BJ
authors.lastname: Fessler
authors.affiliation: University of Alabama, Birmingham.
authors.forename: David T
authors.initials: DT
authors.lastname: Redden
authors.affiliation: University of Alabama, Birmingham.
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Bradley
authors.affiliation: University of Florida, Gainesville.
authors.forename: Roger B
authors.initials: RB
authors.lastname: Fillingim
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D059333:Central Nervous System Sensitization; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D007719:Knee Joint / Q000294:innervation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D010147:Pain Measurement; D058748:Pain Perception; D017288:Pain Threshold; D012307:Risk Factors; D012737:Sex Factors