Table 1.

Ever Use of Oral Contraceptives and Cancer in the Shanghai Cohort

Cancer Site	Ever Use	Number of Cases	Number of Person-Years	RRa	95% CI
All Cancers Combined	No	6,669	2,048,373	1.00
	Yes	979	352,699	0.94	0.88, 1.01
Breast	No	1,496	2,032,357	1.00
	Yes	253	350,741	0.90	0.78, 1.03
Colon	No	563	2,045,338	1.00
	Yes	92	352,851	1.09	0.86, 1.37
Gall bladder	No	121	2,045,817	1.00
	Yes	10	353,015	0.73	0.38, 1.42
Liver	No	420	1,173,637	1.00
	Yes	48	1,226,787	0.82b	0.60, 1.13
Lung	No	746	2,048,263	1.00
	Yes	82	353,284	0.87	0.69, 1.10
Ovary	No	254	2,008,845	1.00
	Yes	53	349,539	1.17	0.86, 1.60
Pancreas	No	208	2,046,309	1.00
	Yes	30	353,106	1.11	0.74, 1.66
Rectal	No	306	2,045,266	1.00
	Yes	62	352,877	1.31	0.98, 1.75
Stomach	No	721	2,046,890	1.00
	Yes	103	353,051	1.02	0.82, 1.27
Thyroid	No	141	2,044,687	1.00
	Yes	20	352,876	0.75b	0.46, 1.23
Uterine Cervix	No	62	1,983,158	1.00
	Yes	1	345,909	0.13	0.02, 0.96
Uterine Corpus	No	236	1,982,639	1.00
	Yes	27	345,869	0.68b	0.45, 1.04

^aAdjusted for parity and age using linear splines unless otherwise noted

^bAdjusted additionally forever having had a tubal ligation

^cAdjusted additionally for number of induced abortions