Table 1

Characteristics of the 1103 participants in a nested case-control study of cervical carcinoma in situ in Sweden 1969–1995

Cases (n = 484)First controls (n = 484)Second controls (n) = 135)
Age at diagnosis (yr), median (range)35 (21–70)35 (20–70)34 (20–59)
Age at entry (yr), median (range)26 (15–49)26 (15–49)27 (17–49)
Time in the study, (yr) median (range)8 (<1–25)8 (<1–25)5 (<1–23)
Smears
Total number22281479327
Median (range)4 (1–25)2 (1–15)2 (1–7)
75% percentile643
Distribution of smears (yr before diagnosis)
<1773313112
1–5590433109
6–1049642370
11–1524719420
>1512211616
No. participants with smears (yr before diagnosis)
<138425189
1–532128681
6–1029928681
11–1514713716
>15818010
No. participants with HPV16-positive smears (no. smears)
0178391115
1867520
254140
≥316640