Because several cofactors may influence the development of cervical intraepithelial
neoplasia (CIN) in young women, we compared differences in behaviors (sexual activity,
contraception, and cigarette use), sexually transmitted disease (STD) infection rates
(Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and herpes simplex
virus), and cervical maturation (age of menarche and percentage of cervical ectopy)
in groups of sexually active female adolescents with and without CIN. Those with CIN
were compared with three non-CIN groups: (1) teenagers who were referred to a teen
colposcopy clinic but had no evidence of CIN (high-risk group), (2) teenagers seen
at a gynecology clinic without STD symptoms (asymptomatic group), and (3) teenagers
seen at the gynecology clinic with STD symptoms (symptomatic group). The percentage
of cervical ectopy was measured by colpophotography. Subjects with CIN had more lifetime
sexual partners than the asymptomatic group (p less than 0.001) and were more likely
to smoke cigarettes than either gynecology clinic group (p less than 0.01). No differences
in behaviors existed between the CIN and high-risk groups. The mean age of menarche
in those with CIN was 1 year older than all three non-CIN groups (p less than 0.05),
and those with CIN had a greater area of ectopy than those without CIN (p less than
0.02). Those with CIN were more likely to have a past or present history of C. trachomatis
infection than the two gynecology clinic groups; no difference was found between the
CIN and high-risk groups. We conclude that cofactors such as smoking, sexual promiscuity,
and C. trachomatis infection may influence cervical vulnerability. However, cervical
biologic immaturity is an important risk factor for development of CIN in adolescent
girls.