Table 3. Results of a pooled reanalysis of the association between oral contraceptives and cervical carcinoma—analyzed and presented in a similar manner to an individual study (24).

Duration of use	Time since last use	Cases/controls	Mean duration of use in years (cases)	RR	95% CI*	p-value*
Never		7356/21682	–	1.00	–	–
5+ years	Current user	880/1466	11.1	1.90	1.69–2.13	s.
	2–9 years	747/1510	9.3	1.28	N. A.	s.
	10+ years	412/1654	8.1	0.94	N. A.	n. s.

Trend test: χ² = 66.2; p < 0.0001

RR, relative risk, adjusted for age, study or study center, age at first sexual intercourse,

number of sex partners, number of full-term pregnancies, smoking and screening status;

^* Information taken from the publication; CI, confidence interval; N.A., not available;

s., significance at the level α = 5%; n.s., not significant at the level α = 5%

(Shortened and modified from: International Collaboration of Epidemiological Studies of Cervical Cancer: Cervical cancer and hormonal contraceptives: collaborative reanalysis of individual data for 16,573 women with cervical cancer and 35,509 women without cervical cancer from 24 epidemiological studies. Lancet 2007; 370: 1609–21. With the kind permission of Elsevier)