Home › DIVISIONS › Rheumatology › Multidisciplinary Clinical Research Center (MCRC) › Ongoing Projects › Project 3 - PI Dunlop ›

MCRC Project 3, Some of Our Advances...

in

Advances in Northwestern University Physical Activity Research  
Work in Physical Activity in Persons with or at High Risk of Developing Knee OA.Program has established: :

  • The benefits of physical activity are related to better economic measures assessed by health-related utility. This relationship is important because health utility is used to evaluate the standard cost-effectiveness metric. The largest difference in health utility was between the bottom (worst) and middle physical activity tertile groups, suggesting that interventions which target people with the least activity lifestyles could have the greatest return per dollar invested.  (Manheim et al. AC&R 2012; Epub ahead of print)

  • Despite known benefits from physical activity almost half (48.9%) of adults with knee osteoarthritis are inactive.  Inactivity was objectively assessed via accelerometer monitoring using government standards, i.e., no physical activity sessions of moderate/vigorous activity that lasted 10 minutes over the course of a week. (Lee et al. AC&R 2012;  Epub ahead of print)

  • Objective accelerometer measurement of physical activity in adults with knee osteoarthritis showed that fewer than one in seven men and one in twelve women met federally recommended physical activity guidelines. (Dunlop et al. A&R 2011; 63: 127-36. PMC: PMCID: 3010474).  


 

  • Only 2% of African Americans with and at risk for knee osteoarthritis met physical activity guidelines, based on objective accelerometer monitoring.  The substantially lower rate of guideline attainment among African Americans compared to Whites (2% versus 13%)  was only partially attenuated by differences related to knee pain and weight status (Song et al. AC&R 2012; Epub ahead of print) .
  • Among adults with rheumatoid arthritis, 42% were inactive, based on objective accelerometer measurement.   Lack of motivation and lack of belief in benefit from physical activity were stronger factors than pain for explaining physical inactivity.  Together, the lack of motivation and lack of belief explained almost 65% excess physical activity in the sample. (Lee et al. AC&R 2012; 64: 488-93. PMC: PMCID: 3315605.)
  • A “dose-response” relationship was demonstrated between physical activity and function (Dunlop et al.  A&R 2011, 63: 127-134. PMC:PMCID: 3010474)
  • Increased physical activity was the only identified risk factor that predicted improved function over time based on national data from the Health and Retirement Study (Feinglass et al. AJPH 2009; 99:533-539 PCM: PMCID: 2661455). 
  • An important methodological advance in physical activity measurement is our work on the translation of raw accelerometer measures into objective physical activity measures.   Our translation algorithms produce more reliable measures in rheumatic disease samples, than the application of manufacturer- provided accelerometer software based on healthy adults. (Song et al. Arthritis Care 2010;62(12):1724-32. PMCID: PMC2995807; Semanik et al.  Med Sci Sports Exerc. 2010;42:1493-501. PMCID: PMC2891385).
Additionally, our work established:

  • Adults with arthritis use 45%-60% more medical services and incur 30-200% medical expenses than similar adults without arthritis. ((Dunlop et al. A&R. 2001;44:212-221;Dunlop et al.  JGSS 2002; 57: S221-S233;. Dunlop et al. A&R 2003; 49:101-113).

  • Out of pocket expenses for adults with arthritis show increases above inflation (Luire et al. A&R 2008: 2236-2240, PMCID:  2704568)

  • Greater use of medical care is largely due to higher levels of disability in rheumatic populations.(Dunlop et al.  JGSS 2002; 57: S221-S233, Dunlop et al. A&R 2003; 49:101-113)  

  • Almost 1 in every 4 new cases of disability is due to arthritis ( Song et al. A&R 2006;  55: 248-255)

  • Higher levels of disability explain as much as 35% excess functional decline for persons with arthritis. (Dunlop et al. A&R 2005; 52:1274-128)

  • Low levels of disability are identified as a modifiable risk factor for the development of disability in persons with arthritis, based on a national representative population sample. Low levels of physical activity could account for as much as 32% of excess disability in adults with arthritis (Dunlop et al. A&R 2005; 52:1274-1282).  

This work points to the importance of the promotion of physical activity to reduce disability and its contribution to health care costs.