Table 2.

Relation of bilateral and unilateral knee pain among those with mild and moderate/severe pain at baseline to prevalence of low physical functioning.^§

	Baseline VAS* (0-100) [mean (sd)]	Baseline WOMAC† (0-68) [mean (sd)]	Low physical functioning‡ / total number of subjects	%	Prevalence Ratio [95% CI]
Mild Knee pain
Bilateral	23.4 (8.4)	16.3 (8.5)	63/666	10	1.0 Ref
Unilateral	18.7 (8.2)	11.9 (7.7)	15/588	3	0.3 [0.1-0.5]
Moderate/Severe Knee pain
Bilateral	59.9 (16.9)	30.5 (10.9)	386/643	60	1.0 Ref
Unilateral	56.6 (16.2)	26.8 (11.4)	81/172	47	0.9 [0.8-1.1]
Overall
Bilateral	41.3 (22.6)	23.3 (12.1)	449/1309	34	1.0 Ref
Unilateral	27.3 (19.0)	15.3 (10.7)	96/760	13	0.5 [0.3-0.7]

^*VAS=Visual Analogue Scale for knee pain severity

^†WOMAC= Western Ontario and McMasters Universities Osteoarthritis Index

^‡Defined as WOMAC physical function scores of 28 and greater.

^§Adjusted for age, sex, race, BMI, depressive symptoms, pain elsewhere, comorbidity, and pain severity.