Table 4.

Case-case comparisons of early life exposure and promoter methylation of at least one gene in breast tumors across menopausal status

			Any vs None			Any vs None
	Any one	None	OR (95% CI) 1	Any one	None	OR (95% CI) 1
	PREMENOPAUSAL			POSTMENOPAUSAL
Birth weight (kg)
≤2.5 (Below average)	20	8	1.47 (0.60–3.57)	39	59	0.87 (0.40–1.15)
2.6–3.9 (Average)	104	89	1.0	267	126	1.0
>3.9 (Above average)	28	7	2.31 (0.94–5.66)	37	22	0.82 (0.46–1.47)
Birth order
First born	51	12	1.0	124	87	1.0
Other than first born	106	63	0.38 (0.19–0.77)	250	101	1.77 (1.23–2.55)
Maternal age at delivery (yrs)
<25	60	25	1.0	135	86	1.0
25–30	45	26	0.67 (0.33–1.36)	116	45	1.59 (1.02–2.47)
>30	45	22	0.84 (0.42–1.69)	104	54	1.21 (0.79–1.87)
Having been breastfed
Yes	30	22	1.0	172	89	1.0
No	112	41	1.87 (0.91–3.83)	115	58	1.02 (0.67–1.57)
Age at menarche (yrs)
<12	40	19	1.15 (0.59–2.25)	85	43	0.95 (0.61–1.47)
12–13	78	44	1.0	213	100	1.0
>13	42	14	1.78 (0.86–3.67)	79	16	0.78 (0.50–1.21)
Age at first live birth (yrs)
<23	47	22	1.0	152	60	1.0
23–29	60	30	0.93 (0.46–1.88)	126	74	0.68 (0.44–1.05)
≥30	26	13	0.97 (0.40–2.35)	29	23	0.51 (0.27–0.97)
Adult height (m)
<1.60	27	23	1.02	136	60	1.02
1.60–1.64	51	27	1.69 (0.79–3.63)	119	65	0.84 (0.53–1.32)
≥1.65	82	27	2.88 (1.25–6.61)	122	64	0.83 (0.51–1.34)
Weight at 20 years (kg)
<54.4	65	34	1.0	179	93	1.0
≥54.4	95	43	1.17 (0.67–2.05)	198	96	1.08 (0.76–1.54)

¹Odds ratios and 95% confidence intervals adjusted for age, race, education, and ER status.

²Odds ratios and 95% confidence intervals adjusted for age, race, education, ER status, weight at 20s, weight 2 years ago, and maternal height.