Table 2.

Age, BMI, grip strength and lower limb muscle strength and muscle mass in subjects with and without knee pain

	Right knee					Left knee
	Pain -	Pain +	Adjusted OR	95 % CI	P values	Pain -	Pain +	Adjusted OR	95 % CI	P values
Overall
N	1708	444				1721	431
Age, years	70.8 ± 12.5	74.8 ± 10.4*	1.04	1.03–1.035	<0.0001	70.8 ± 12.5	74.7 ± 10.4*	1.04	1.03–1.05	<0.0001
BMI, kg/m2	22.5 ± 3.3	23.7 ± 3.7*	1.13	1.10–1.17	<0.0001	22.4 ± 3.3	23.8 ± 3.5*	1.14	1.11–1.18	<0.0001
Grip strength, kgf	28.7 ± 9.7	25.5 ± 8.5*	0.98	0.96–0.9996	0.0448	26.9 ± 9.5	23.8 ± 8.5*	0.99	0.97–1.01	0.3464
Quadriceps muscle strength,kgf (5kgf increase)	29.1 ± 11.2	23.9 ± 10.3*	0.83	0.78–0.88	<0.0001	27.9 ± 11.2	22.8 ± 10.2*	0.84	0.79–0.89	<0.0001
Weight bearing index, kgf/kg (0.1 kgf/kg increase)	0.54 ± 0.20	0.44 ± 0.18*	0.81	0.76–0.86	<0.0001	0.52 ± 0.19	0.42 ± 0.19*	0.83	0.77–0.88	<0.0001
Lower limb muscle mass/height2,kg/m2 (0.1kg/m2 increase)	2.59 ± 0.43	2.58 ± 0.43	0.97	0.92–1.02	0.2421	2.56 ± 0.43	2.56 ± 0.42	0.98	0.94–1.03	0.4326
Men
N	586	104				594	96
Age, years	71.9 ± 12.5	76.1 ± 11.0*	1.04	1.02–1.07	<0.0001	72.0 ± 12.3	76.1 ± 11.7*	1.04	1.02–1.07	<0.0001
BMI, kg/m2	22.9 ± 3.2	23.9 ± 3.8*	1.13	1.06–1.21	0.0002	22.9 ± 3.2	23.9 ± 4.0*	1.13	1.06–1.21	0.0003
Grip strength, kgf	37.5 ± 9.5	35.1 ± 9.0*	0.98	0.95–1.01	0.3070	35.5 ± 9.0	33.3 ± 9.7*	0.99	0.96–1.02	0.5031
Quadriceps muscle strength,kgf (5kgf increase)	32.9 ± 12.5	26.4 ± 12.0*	0.80	0.72–0.89	<0.0001	31.4 ± 12.6	25.4 ± 11.4*	0.82	0.91–1.23	0.0001
Weight bearing index, kgf/kg (0.1 kgf/kg increase)	0.54 ± 0.20	0.42 ± 0.19*	0.75	0.65–0.85	<0.0001	0.52 ± 0.20	0.41 ± 0.18*	0.78	0.68–0.89	0.0002
Lower limb muscle mass/height2, kg/m2 (0.1kg/m2 increase)	2.95 ± 0.44	3.03 ± 0.47	1.01	0.92–1.10	0.8897	2.90 ± 0.44	2.97 ± 0.50	0.98	0.89–1.08	0.7281
Women
N	1122	340				1127	335
Age, years	70.2 ± 12.5	74.4 ± 10.2*	1.03	1.02–1.05	<0.0001	70.2 ± 12.6	74.3 ± 10.0*	1.03	1.02–1.05	<0.0001
BMI, kg/m2	22.2 ± 3.3	23.7 ± 3.6*	1.13	1.09–1.18	<0.0001	22.2 ± 3.4	23.8 ± 3.4*	1.15	1.11–1.19	<0.0001
Grip strength, kgf	24.1 ± 5.8	22.5 ± 5.8*	0.98	0.95–1.004	0.1014	22.3 ± 6.0	21.1 ± 5.7*	0.99	0.97–1.02	0.6256
Quadriceps muscle strength, kgf (5kgf increase)	27.2 ± 9.9	23.2 ± 9.5*	0.84	0.78–0.91	<0.0001	26.1 ± 9.8	22.1 ± 9.7*	0.85	0.79–0.91	<0.0001
Weight bearing index, kgf/kg (0.1 kgf/kg increase)	0.55 ± 0.20	0.45 ± 0.18*	0.83	0.77–0.90	<0.0001	0.52 ± 0.19	0.43 ± 0.19*	0.84	0.78–0.91	<0.0001
Lower limb muscle mass/height2,kg/m2 (0.1kg/m2 increase)	2.41 ± 0.27	2.45 ± 0.32*	0.95	0.89–1.02	0.1421	2.38 ± 0.29	2.44 ± 0.31*	0.99	0.93–1.04	0.6166

*p < 0.05 by non-paired student t test

Adjusted ORs were calculated by multiple logistic regression analysis after adjustment for age, sex, and BMI overall and after adjustment for age and BMI in men and women

BMI Body mass index, mJSW, Minimum joint space width