Table 4.

Association between environmental and genetic factors and ovarian cancer risk in a multiplicative joint effects model

	Invasive		Serous		Mucinous		Endometrioid		Clear cell
	OR^a (95% CI)	P	OR^a 95% CI	P	OR^a 95% CI	P	OR^a 95% CI	P	OR^a 95% CI	P	P_het across histology
Endometriosis
Yes vs. no	1.53 (1.30–1.81)	<0.001	1.17 (0.95–1.44)	0.143	1.54 (0.86–2.74)	0.145	2.40 (1.78–3.23)	<0.001	3.59 (2.50–5.15)	<0.001	<0.001
First-degree family history
Yes vs. no	2.09 (1.70–2.57)	<0.001	2.29 (1.81–2.89)	<0.001	2.40 (1.25–4.61)	0.009	1.96 (1.28–3.00)	0.002	2.15 (0.94–4.92)	0.071	0.929
Oral contraceptive use
1–1.99 years vs. never	0.70 (0.59–0.83)	<0.001	0.80 (0.65–0.98)	0.031	0.75 (0.36–1.57)	0.451	0.64 (0.45–0.92)	0.016	0.76 (0.46–1.24)	0.272	0.798
2–4.99 years vs. never	0.57 (0.50–0.65)	<0.001	0.65 (0.56–0.77)	<0.001	0.56 (0.35–0.90)	0.016	0.45 (0.34–0.60)	<0.001	0.55 (0.37–0.83)	0.004	0.167
5–9.99 years vs. never	0.48 (0.42–0.55)	<0.001	0.53 (0.45–0.62)	<0.001	0.68 (0.46–1.01)	0.054	0.41 (0.31–0.54)	<0.001	0.40 (0.27–0.58)	<0.001	0.097
10+ years vs. never	0.34 (0.30–0.39)	<0.001	0.39 (0.33–0.46)	<0.001	0.48 (0.32–0.72)	<0.001	0.28 (0.21–0.38)	<0.001	0.28 (0.18–0.44)	<0.001	0.083
Tubal ligation
Yes vs. no	0.74 (0.67–0.83)	<0.001	0.84 (0.74–0.95)	0.007	0.65 (0.42–0.99)	0.043	0.57 (0.44–0.73)	<0.001	0.68 (0.47–0.99)	0.046	0.041
Parity
1 birth vs. no births	0.76 (0.66–0.88)	<0.001	0.89 (0.75–1.06)	0.175	0.76 (0.49–1.17)	0.214	0.69 (0.53–0.91)	0.009	0.39 (0.26–0.58)	<0.001	0.002
2 or more births vs. no births	0.58 (0.51–0.65)	<0.001	0.66 (0.58–0.76)	<0.001	0.52 (0.37–0.73)	<0.001	0.42 (0.34–0.53)	<0.001	0.25 (0.18–0.33)	<0.001	<0.001
Risk score quartile
Second vs. first quartile	1.25 (1.12–1.40)	<0.001	1.33 (1.15–1.53)	<0.001	1.72 (1.20–2.48)	0.004	1.25 (0.98–1.59)	0.068	1.19 (0.84–1.69)	0.329	0.463
Third vs. first quartile	1.29 (1.16–1.44)	<0.001	1.36 (1.19–1.56)	<0.001	1.31 (0.91–1.90)	0.151	1.13 (0.89–1.43)	0.321	1.20 (0.86–1.69)	0.289	0.577
Fourth vs. first quartile	1.65 (1.48–1.84)	<0.001	1.85 (1.62–2.11)	<0.001	1.76 (1.24–2.48)	0.001	1.64 (1.31–2.05)	<0.001	1.59 (1.15–2.21)	0.006	0.728

↵^aOR conditioned on age and race/ethnicity, individual models by site; estimate derived from meta-analysis of individual site models.