Table 2.

Age at initial treatment or at index cytology test for CIN and comparison cohorts^*

Age, y	No. in CIN cohort (%)	No. in comparison cohort (%)
21–30	18 155 (48.9)	24 322 (34.2)
30–39	12 533 (33.7)	20 822 (29.2)
40–49	4550 (12.3)	12 499 (17.6)
≥50	1904 (5.1)	13 570 (19.1)
Total	37 142 (100.0)	71 213 (100.0)

^*The CIN cohort included women 21 years or older with a cytology test in the previous year, a first histological diagnosis of CIN 1, 2, or 3 between 1986–2000, and documented treatment. The comparison cohort was selected from a 10% random sample of women in the British Columbia Cancer Agency cytology database from 1985–2000, aged 21 years or older, who had three consecutive negative cytology tests and no history of CIN. The age range presented is for initial treatment for the CIN cohort, and for the index cytology test for the comparison cohort. CIN = cervical intraepithelial neoplasia.