Table 3.

Association of smoking status, serum cotinine level and the prevalence of osteoporosis.

	OR (95% CI)
	Model 1	Model 2	Model 3
Log2-transformed cotinine, ng/mL	1.07 (1.05-1.08)	1.06 (1.04-1.07)	1.06 (1.04-1.07)
Cotinine categories
<0.05 ng/mL	1.00 [Reference]	1.00 [Reference]	1.00 [Reference]
0.05–2.99 ng/mL	0.99 (0.83-1.18)	0.91 (0.76-1.09)	0.91 (0.76-1.10)
≥3 ng/mL	2.27 (1.91-2.69)	2.03 (1.70-2.43)	2.04 (1.70-2.45)
P for trend	<0.001	<0.001	<0.001
Self-reported smoking status, %
Nonsmokers	1.00 [Reference]	1.00 [Reference]	1.00 [Reference]
Former smokers	0.96 (0.82-1.12)	1.01 (0.86-1.18)	1.02 (0.87-1.20)
Current smokers	2.30 (1.90-2.79)	2.16 (1.77-2.64)	2.16 (1.77-2.65)
P for trend	<0.001	<0.001	<0.001

Model 1 was adjusted as age, sex, and race;

Model 2 was adjusted as model 1 plus education level, drinking status, poverty, physical activity, and total energy intake.

Model 3 was adjusted as model 2 plus total cholesterol, high-density lipoprotein cholesterol, serum calcium, history of prednisone or cortisone, hypertension, diabetes, cardiovascular disease, and cancer.