Table 4.

Multivariate model for independent associations with incident oral HPV infection in young men, University of Washington Oral Human Papillomavirus (HPV) Cohort.

Characteristic	# infections/person-years	Unadjusted HR*	95% CI	Adjusted HR*,#	95% CI
Frequency of performing oral sex on a woman in the last 4 months$
<1 per time per week	15/4853	1		1
≥1 per time per week	11/835	4.85	(1.7, 13.83)	3.66	(1.38, 9.75)
Frequency of open mouth kissing a woman in the last 4 months
0 to 30 times per month	11/4107	1		1
≥31 times per month	15/1552	3.32	(1.24, 8.87)	1.91	(0.68, 5.38)
Anal sex with a man in the last 4 months$
No	24/5610	1		1
Yes	2/67	10.67	(3.02, 37.65)	42.9	(8.95, 205.54)
Current genital HPV infection$
No	15/5542	1		1
Yes	11/146	10.38	(3.72, 28.97)	6.24	(2.37, 16.44)
Current hyponychial HPV infection$
No	17/5645	1		1
Yes	9/42	24.68	(5.31, 114.65)	11.8	(4.07, 34.21)

^*Based on models containing data on all HPV types with stratification by type and correlation accounted for using GEE with robust standard errors

^#All characteristics presented in table are included in the multivariate model

^$p-value≤0.05 for characteristic in the multivariate model