Table 4

Relative risk (ORs with 95% CI) of cervical atypia (cytological SIL and/or CIN grade 1 or worse, CIN1+) stratified by the interval between menarche and age at FSI or between menarche and the age at start of OC use in young adult women followed up for 4 years

Frequency and relative risk of cytological atypia: SIL or CIN1 in the different categories by interval from menarche
VariableCategory 1Category 2
Menarche to FSI <3 years
SIL/CIN1+
Menarche to start of OCs ≥3 years
SIL/CIN1+
n/NOR (95% CI)n/NOR (95% CI)
Lag between FSI and menarche
 <3 years.53/301NA23/1100.9 (0.5 to 1.4)0.9 (0.8 to 1.0)
 ≥3 yearsNANA132/5651*Interval (cont.)
Lag between start of OCs and menarche
 <3 years.30/1910.7 (0.4 to 1.3)0.9 (0.9 to 1.0)NANA
 ≥3 years23/1101*Interval (cont.)155/675NA
  • CIN, cervical intraepithelial neoplasia; FSI, first sexual intercourse; OC, oral contraceptive; SIL, squamous intraepithelial lesion.