Table 1.

Incidence (per 100 000 person-years) and risk of histologically confirmed cervical carcinoma in situ (CIS) and/or invasive cancer (ICC) in relation to human papillomavirus (HPV) status at baseline and second examinations among 10 123 women who were cytologically normal at study entry

HPV infection	No. of women (%)	No. of cancers (ICC/CIS)	Incidence (10−5)*	HR (95% CI)	P†
Baseline examination	10123 (100.0)	68 (34/34)	46.4
HPV negative	8780 (86.7)	20 (9/11)	15.7	1.0 (referent)
HPV positive (any type)	1343 (13.3)	48 (25/23)	252.0	16.2 (9.6 to 27.3)	<.001
Carcinogenic types‡	784 (7.7)	41 (24/17)	370.8	23.8 (14.0 to 40.7)	<.001
Probably or possibly carcinogenic types§	161 (1.6)	3 (0/3)	136.2	8.9 (2.6 to 29.9)	<.001
Other HPV types alone‖	398 (3.9)	4 (1/3)	69.1	4.4 (1.5 to 12.9)	.007
Second examination¶ (subgroup)	6666 (100.0)	37 (18/19)	42.5
HPV negative	5769 (86.5)	9 (3/6)	13.2	1.0 (referent)
HPV positive (any type)	897 (13.5)	28 (15/13)	243.4	20.6 (9.7 to 43.6)	<.001
Carcinogenic types‡	479 (7.2)	24 (13/11)	395.7	33.5 (15.6 to 72.0)	<.001
Probably or possibly carcinogenic types§	115 (1.7)	1 (0/1)	67.2	5.7 (0.7 to 43.1)	.098
Other HPV types alone‖	303 (4.5)	3 (2/1)	75.9	6.4 (1.7 to 23.7)	.005

^*Incidence rate: per 100 000 person-years.

^†Hazard ratios (HRs) and their 95% confidence intervals (CIs) were estimated using Cox proportional hazard models. All statistical tests were two-sided.

^‡Carcinogenic types include HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59.

^§Probably or possibly carcinogenic types include: HPV68 and HPV26, 53, 66, 67, 70, 73, and 82 (without any carcinogenic type[s], as listed previously).

^‖Other HPV types, including HPV6, 11, 32, 37, 42, 43, 44, 54, 55, 61, 62, 69, 71, 72, 74, 81, 83, 84, and 85 (without any carcinogenic or any probably or possibly carcinogenic type[s], as listed previously).

^¶HPV infection status at the second examination 2 years later (regardless of HPV status at baseline).