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)