Table 1.

Subject characteristics and modifiable factors at baseline (n= 1801)

Age [years (sd)]	62.7 (8.0)
Gender [n (%) female]	1135 (63)
Education [ n (%) some college]	1279 (71)
ROA* [n (%)]	1045 (58.5)
Patelofemoral ROA [n (%)]	80 (4.5)
Tibiofemoral ROA [n (%)]	604 (33.8)
Patelofemoral and Tibiofemoral ROA [n (%)]	361 (20.2)
Comorbidities [ n (%) none]	991 (55)
BMI† [kg/m2(sd)]	30.9 (6.0)
Knee Pain [VAS‡ 0–10 (sd)]	3.0 (2.2)
Walking Speed [m/s (sd)]§	1.18 (0.2)
Knee Strength [Newton Meters (sd)]**	68 (36)
Depressive Symptoms [CES-D†† 0–60 (sd)]	8 (7.7)
Physical Activity [PASE‡‡ 0–360 (sd)]	171 (87)
Arthritis medications or steroid injection§§ [n (%)]	698 (39)
Baseline WOMAC*** Physical Function Score [4–68 (sd)]	18.7 (11.2)

^*ROA = Radiographic knee osteoarthritis

^†BMI = Body Mass Index

^‡VAS = Visual Analogue Scale

^§Walking Speed measured in meters per second (m/s) over a 20 meter walk at a usual pace

^**Isokinetic knee extensor strength. Weaker value of two knees used for analysis.

^††CES-D = Center for Epidemiologic Studies Depression Scale

^‡‡PASE = Physical Activity Scale for the Elderly

^§§Arthritis medication taken every day or almost everyday including Aspirin, Ibuprofen, Acetominophen, Cox2 inhibitors, or other non-steroidal or anti-inflammatory medications, or a steroid injection, such as Cortisone, in either knee in the past 12 months.

^***WOMAC = Western Ontario McMaster Universities Osteoarthritis Index