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. Author manuscript; available in PMC: 2015 Mar 27.
Published in final edited form as: Sex Transm Dis. 2012 Nov;39(11):860–867. doi: 10.1097/OLQ.0b013e318269d098

Table 3.

Hazard ratios (HRs) for univariate 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
Age at baseline (years)
 18 to 20 17/4032
 21 to 24 9/1656 1.91 (0.7, 5.24)
Race/Ethnicity
 White 19/4672 1
 Non-White 7/1015 1.39 (0.41, 4.73)
Smoked cigarettes
 Never 19/4891 1
 Former 5/450 2.60 (0.66, 10.14)
 Currently 2/346 0.70 (0.17, 2.89)
Smoked cigars#
 Never 20/4803 1
 Former 1/473 0.35 (0.04, 2.78)
 Currently 5/411 2.51 (0.57, 11.10)
Smoked a pipe#
 Never 20/5103 1
 Former 4/294 1.61 (0.26, 10.11)
 Currently 2/290 2.12 (0.59, 7.60)
Smoked marijuana#
 Never 11/3038 1
 Former 2/431 0.90 (0.11, 7.42)
 Currently 13/2219 1.49 (0.53, 4.20)
Teeth-brushing per week
 ≤7 9/1373 1
 7 to 13 5/1420 0.50 (0.13, 1.94)
 ≥14 12/2866 0.68 (0.23, 2.01)
Number of females on whom performed oral sex in the last 4 months
 0 9/2522 1
 1 17/3166 1.55$ (0.59, 4.10)
 ≥2 0/210
New female partner on whom performed oral sex in the last 4 months
 No new partner 24/4594 1
 New partner 2/1094 0.42 (0.05, 3.31)
Frequency of performing oral sex on female in the last 4 months&
 No oral sex 9/2522 1
 <Once per month 1/1034 0.32 (0.04, 2.74)
 ~1–2 times per month 5/1297 0.97 (0.26, 3.61)
 ≥1 time per week 11/835 4.16 (1.36, 12.72)
Number of females open mouth kissed in the last 4 months
 0 3/604 1
 1 19/3252 1.38 (0.30, 6.37)
 ≥2 4/1803 0.62 (0.11, 3.57)
Open mouth kissing frequency in the last 4 months £
 0 to 1 per month 3/1439 1
 2 to 9 per month 5/1619 1.72 (0.28, 10.39)
 10 to 30 per month 3/1049 1.50 (0.20, 11.44)
 ≥31 per month 15/1552 4.54 (0.93, 22.17)
Number of vaginal sex partners in the last 4 months
 0 4/1502 1
 1 18/2901 2.32 (0.75, 7.15)
 ≥2 3/819 1.89 (0.32, 11.14)
New vaginal sex partner in the last 4 months
 No 19/4149 1
 Yes 7/1538 0.96 (0.31, 2.96)
Number of vaginal sex acts in the last 4 months
 0 5/1740 1
 1 to 4 4/1011 1.82 (0.33, 9.95)
 5 to 16 7/1343 2.12 (0.54, 8.28)
 ≥17 10/1426 2.40 (0.72, 8.06)
Number of female digital sex partners in the last 4 months
 0 3/1120 1
 1 19/3459 2.10 (0.42, 10.37)
 ≥2 4/1097 1.53 (0.24, 9.62)
Frequency of digital sex with a female in last 4 months
 No digital sex 3/1120 1
 <Once per month 2/1002 1.15 (0.10, 13.25)
 1–2 times per month 3/1170 0.83 (0.14, 4.82)
 ≥1 time per week 18/2384 2.83 (0.58, 13.95)
Anal sex with a male in the last 4 months&
 No 24/5610 1
 Yes 2/67 10.67 (3.02, 37.65)
Current genital HPV infection with same HPV type&
 No 15/5542 1
 Yes 11/146 10.38 (3.72, 28.97)
Genital HPV infection with same HPV type 1 visit prior&
 No 23/5565 1
 Yes 3/123 3.28 (1.00, 10.76)
Current hyponychial HPV infection with same HPV type&
 No 17/5645 1
 Yes 9/42 24.68 (5.31, 114.65)
Hyponychial HPV infection with same HPV type 1 visit prior&
 No 23/5656 1
 Yes 3/31 18.64 (3.64, 95.53)
*

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

#

To be considered a smoker of cigars, pipes or marijuana a participant must have smoked at least once a month for >1 year

$

With no incident oral HPV infections in the ≥ 2 category, the 1 and ≥ 2 categories were combined

&

p-value ≤ 0.05 for characteristic

£

p-value ≤ 0.05 for trend by categories given (quartiles)