Table 5.

Age- and multivariable-adjusted^a HRs (95% CI) for breast cancer classified according to age at diagnosis and menopausal status at diagnosis (n=39,696)

	No migraine (n=32,378)		Any migraine (n=7,318)
				Age-adjusted	Multivariable-adjusted
	No of cases	HR (95% CI)	No of cases	HR (95% CI)	HR (95% CI)
Age at diagnosis
≥ 50 yrs (n=66)	46	1.00	20	1.63 (0.96, 2.75)c	1.69 (1.00, 2.87)e
> 50 yrs (n=2,212)	1,795	1.00	417	1.06 (0.96, 1.18)c	1.08 (0.97, 1.20)e
Postmenopausal status at diagnosisb
Premenopausal (n=133)	101	1.00	32	1.22 (0.82, 1.82)d	1.38 (0.92, 2.06)f
Postmenopausal (n=1,963)	1,595	1.00	368	1.08 (0.96, 1.21)d	1.10 (0.98, 1.23)f

^aModels were adjusted for age, BMI, alcohol consumption, smoking status, postmenopausal status, age at menarche, age at menopause, postmenopausal hormone use, hormone replacement therapy use, number of pregnancies, age at first pregnancy, family history of breast cancer, history of benign breast disease

^b182 women had dubious/unknown postmenopausal status and only contributed person-time

All p-value for heterogeneity were calculated using the Cochran's Q-Test.

^cp for heterogeneity: 0.12

^dp for heterogeneity: 0.54

^ep for heterogeneity: 0.10

^fp for heterogeneity: 0.29