TABLE 2.

Associations between family history and lifestyle factors and ovarian cancer risk by endometriosis status.

Without Endometriosis (7,670 cases, 12,678 controls) With Endometriosis (830 cases, 914 controls)
Risk Factor	Cases^a	Controls^a	OR^b	95% CI	Cases^a	Controls^a	OR^b	95% CI	P-interaction^c
BMI									.51
<18.5 kg/m²	178	290	1.12	0.92–1.36	16	21	0.82	0.42–1.62
18.5–<25 kg/m²	3,554	6,267	1.00	—	403	475	1.00	—
25–<30 kg/m²	2,142	3,588	0.97	0.91 −1.05	230	231	1.27	1.00–1.60
≥30 kg/m²	1,670	2,462	1.13	1.04–0.22	172	186	1.21	0.94–1.57
				P-trend = .04^d				P-trend = .06^d
Talc use^e									.65
Never	2,172	4,137	1.00	—	220	323	1.00	—
Nongenital use	1,391	1,909	0.76	0.49–1.19	162	140	0.83	0.39–1.77
Genital use	827	1,304	1.12	1.01–1.25	79	106	1.38	1.04–1.84
First-degree family history of ovarian cancer									.20
No	6,943	11,811	1.00	—	762	841	1.00	—
Yes	397	309	2.20	1.88–2.57	41	30	1.58	0.97–2.57
NSAID use									.50
Never	3,996	6,914	1.00	—	359	393	1.00	—
Ever	1,130	2,007	0.90	0.78–1.04	169	196	0.85	0.63–1.13

BMI = body mass index; CI = confidence interval; NSAID = nonsteroidal anti-inflammatory drug; OR = odds ratio.

Numbers may not sum to total because of missingness.

Models were fit in 50 imputed datasets, pooled using Rubin’s rule, and adjusted for age at reference date, race/ethnicity, education level, and Ovarian Cancer Association Consortium (OCAC) study.

P value for interaction using a likelihood ratio test.

P value for trend was calculated by fitting the categorical variable as an ordinal variable.

Models were fit among participants in studies conducted in Australia and the United States only.