The relationship between the frequency (chronic, episodic, and sporadic) of arthritic pain in the hip and/or knee, other illness-related variables, physical disability, and a physically active lifestyle was analyzed in community-living subjects aged 55 to 74 years (N = 306). We tested the hypothesis that a physically active lifestyle is a mediating variable in the relationship between pain frequency and physical disability. Physical activity was measured with a structured interview method, and physical disability was measured with the Sickness Impact Profile. A stepwise regression model with demographic data, pain frequency, illness-related variables (such as radiological osteoarthritis and pain severity), and lifestyle variables explained 45% of the variance in physical disability; lifestyle variables explained 7% of the variance in physical disability. Our results support the hypothesis that a physically active lifestyle (in particular, sport activity) is a mediator in the relation between the frequency of pain and physical disability.
Marijke Hopman-Rock is with TNO Prevention and Health, Division of Public Health and Prevention, PO Box 2215, 2301 CE Leiden, The Netherlands. Floris W. Kraaimaat is with the Department of Medical Psychology, University of Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Johannes W.J. Bijlsma is with the Department of Rheumatology and Clinical Immunology, Utrecht University, PO Box 85500,3508 GA Utrecht, The Netherlands.