Table 2.

Association Between Sex Hormone Use and Breast Cancer Risk Among Chinese Women, Shanghai Breast Cancer Study, 1996–1998 and 2002–2005

Sex Hormone Use	No. ofCases	No. ofControls	Adjusted Odds Ratioa	95% Confidence Interval
Oral contraceptive use
Never	1,654	1,657	1.00
Ever	419	426	0.98	0.83, 1.15
Type of oral contraceptive used
None	1,654	1,657	1.00
Progesterone plus estrogen	328	324	1.05	0.88, 1.26
Progesterone only	42	52	0.85	0.56, 1.30
Estrogen only	24	30	0.82	0.47, 1.41
Other	25	20	1.33	0.73, 2.42
Duration of oral contraceptive use
Never	1,654	1,657	1.00
<18 months	208	225	0.96	0.78, 1.18
≥18 months	211	201	1.11	0.89, 1.37
P for trend			0.52
Period of oral contraceptive use
Never	1,654	1,657	1.00
Recent use (within 10 years)	53	56	0.98	0.66, 1.44
Previous use (>10 years ago)	366	369	0.97	0.82, 1.15
Hormone replacement therapy use (postmenopausal women only)
Never	753	822	1.00
Ever	48	41	1.16	0.75, 1.80

^aAdjusted for age, educational level, age at menarche, menopausal status, breast cancer in first-degree relatives, number of livebirths, and body mass index.