Table 2. Unadjusted and adjusted odds ratios of knee osteoarthritis.

	Unadjusted OR* (95% CI)	P value	Adjusted OR† (95% CI)	P value	Adjusted OR‡ (95% CI)	P value
Age	1.083 (1.074–1.093)	<0.001	1.096 (1.084–1.108)	<0.001	1.095 (1.083–1.107)	<0.001
Sex (female)	3.383 (2.837–4.036)	<0.001	4.215 (3.367–5.278)	<0.001	3.235 (2.416–4.332)	<0.001
Obesity (BMI 27.5)	2.448 (2.021–2.966)	<0.001	2.451 (1.971–3.046)	<0.001	2.216 (1.763–2.787)	<0.001
BMD of total femur	0.034 (0.020–0.060)	<0.001	2.271 (1.037–4.977)	0.040	2.161 (0.984–4.745)	0.055
Serum vitamin D	1.003 (0.993–1.014)	0.570	1.015 (1.003–1.027)	0.010	1.017 (1.005–1.028)	0.005
Diabetes mellitus	1.564 (1.281–1.910)	<0.001	1.268 (1.018–1.578)	0.034	1.237 (0.993–1.542)	0.058
Physical activity (MET)	0.991 (0.972–1.009)	0.320	1.015 (0.996–1.035)	0.116	1.018 (0.999–1.038)	0.066
SMI	0.876 (0.860–0.894)	<0.001	0.976 (0.946–1.007)	0.127	-
Lower limbs SMI	0.815 (0.792–0.838)	<0.001	-		0.941 (0.900–0.983)	0.006

OR, odds ratio; CI, confidence interval; BMI, body mass index; BMD, bone mineral density; SMI, skeletal muscle mass index; MET, metabolic equivalent of task

*Unadjusted odds ratios by logistic regression analysis.

Adjusted odds ratios by multivariate logistic regression analysis; adjusted for all other variables in model with SMI† and both legs SMI‡.

- Not included in the final adjusted model.