To identify the association between hours of being barefoot/wearing footwear, physical activity (PA) and knee osteoarthritis pain flares (KOAF).
Persons with a diagnosis of knee osteoarthritis, who reported previous KOAF, were followed up in a 3 months long telephone-based case-crossover study. Exposures to risk factors were assessed every 10 days and whenever the participants experienced a KOAF. Conditional logistic regression examined associations of KOAF with following: hours of being barefoot/using footwear and PA performed (P < .05).
There were 260 persons recruited, of whom 183 continued longitudinal follow up. Of them, 120 persons had at least one valid KOAF and control period. Participants were female (90%) with mean (SD) age and body mass index of 59.9 (7.0) years, 28.0 (5.0) kg/m
Increased duration of being barefoot 1 to 2 days before is associated with reduced risk of KOAF. Performing moderate PA 1 to 2 days before was associated with an increased risk of KOAF.