Table 2.

Hazard ratios (HR) and 95% confidence intervals (CIs) for the association between migraine and invasive ovarian cancer risk, by cohort and histology

	NHSII			WHS
	Cases	Model 1 HR (95%CI)	Model 2 HR (95%CI)	Cases	Model 1 HR (95%CI)	Model 2 HR (95%CI)
All invasive	236	1.34 (1.00, 1.80)	1.29 (0.96, 1.74)	205	0.58 (0.34, 1.00)	0.60 (0.34, 1.06)
Serous and poorly differentiated	108	1.57 (1.03, 2.40)	1.52 (0.99, 2.33)	143	0.58 (0.31, 1.09)	0.60 (0.30, 1.16)
Non-serous (endometrial, clear cell, mucinous)	92	1.27 (0.79, 2.06)	1.24 (0.76, 2.02)	52	0.51 (0.16, 1.66)	0.56 (0.14, 2.14)

Model 1: Adjusted for age (continuous) and time period

Model 2: Further adjusted for BMI (continuous), family history of breast or ovarian cancer (yes, no), parity (0, 1,2, 3, 4+), oc use (NHSII: never, <1, 1–5, 5–9,10+ years; WHS: never, <0.5 year, 0.5–2 years, 3–4 years, 5+years), smoking (never, past, current), alcohol (none, 0–5, 5+ g/day), NSAID use (never, past, current), menopausal status (premenopausal, postmenopausal, unknown), postmenopausal hormone therapy (ever estrogen only HT use, ever estrogen plus progestin HT use, ever other HT use), tubal ligation (yes, no), unilateral oophorectomy (NHSII: yes, no, unknown; WHS: yes, no), hysterectomy (NHSII: yes, no, unknown; WHS: yes, no)

p-for-heterogeneity by histologic subtype in NHSII=0.54

p-for-heterogeneity by histologic subtype in WHS=0.90