Table 2.

Association between serum 25-hydroxyvitamin D (25-OHD) deficiency^a and knee osteoarthritis (OA) after adjustment for gender by calculation of adjusted odds ratio (OR) and 95% confidence interval (95%CI) using logistic regression analysis

Patients	Independent variables	Adjusted OR (95% CI)	P values
All	Serum 25-OHD (< 20 vs. > 20 ng/ml)	1.62 (0.97–2.6)	0.06
	Gender (female vs. male)	3.06 (1.74–5,3)	0.001
	Age (years)	1.01 (0.99–1.03)	0.19
<60 years	Serum 25-OHD (< 20 vs. > 20 ng/ml)	2.26 (1.15–4.4	0.018
	Gender (female vs. male)	3.21 (1.28–8.04)	0.013
>60 years	Serum 25-OHD (< 20 vs. > 20 ng/ml)	1.01 (0.48–5.9)	0.96
	Gender (female vs. male)	2.9 (1.42–5.9)	0.003
<55 years	Serum 25-OHD (< 20 vs. > 20 ng/ml)	2.63 (1.16–5.95)	0.01
	Gender (female vs. male)	4.79 (1.55–14.8)	0.006

^a Serum 25-OHD < 20 ng/ml