Table III.

Predictors of global methylation assessed by univariate general linear model (cases = 176 and controls = 173)

Variables	Among controls			Among all participants (cases + controls)
	Mean ± SE of 5-mdC	β	P value	Mean ± SE of 5-mdCa	βb	P valueb
Total	4.38 ± 0.03			4.28 ± 0.02
Age (continuous)		0.001	0.730		<0.001	0.996
<Median (55)	4.41 ± 0.04			4.30 ± 0.03
+Median (55)	4.34 ± 0.04	−0.068	0.208	4.26 ± 0.03	−0.043	0.263
Race
Caucasian	4.38 ± 0.03			4.27 ± 0.02
African-American	4.41 ± 0.08	−0.032	0.781	4.31 ± 0.06	−0.036	0.646
Batch (category on date)		−0.001	0.776		0.004	0.248
Family history of BRCA
Yes	4.36 ± 0.03			4.27 ± 0.02
No	4.43 ± 0.06	0.069	0.300	4.29 ± 0.05	0.030	0.532
Education
≤high school	4.35 ± 0.07			4.25 ± 0.04
>high school	4.38 ± 0.03	0.033	0.624	4.28 ± 0.02	0.036	0.429
BMI (continuous)		0.001	0.790		0.002	0.496
<25	4.37 ± 0.04			4.26 ± 0.03
25–29.9	4.34 ± 0.04			4.26 ± 0.03
30+	4.39 ± 0.06	0.012	0.730	4.28 ± 0.04	0.009	0.717
Smoking habit
Never	4.38 ± 0.04			4.25 ± 0.03
Ever	4.37 ± 0.04	−0.007	0.904	4.30 ± 0.03	0.043	0.272
Pack-year (continuous)		0.001	0.534		<0.001	0.766
Never smoker	4.38 ± 0.04			4.25 ± 0.03
Below median	4.37 ± 0.06			4.30 ± 0.05
At or above median	4.37 ± 0.06	−0.005	0.891	4.27 ± 0.04	0.009	0.716
Alcohol consumption habit
Never	4.45 ± 0.07			4.33 ± 0.05
Ever	4.36 ± 0.03	−0.087	0.209	4.26 ± 0.02	−0.076	0.109
Alcohol drinking frequency (continuous)		−0.004	0.334		Less than –0.001	0.929
Never	4.45 ± 0.07			4.33 ± 0.05
<median	4.42 ± 0.04			4.29 ± 0.03
+median	4.30 ± 0.04	−0.078	0.031	4.23 ± 0.03	−0.053	0.036
Age at menarche
<13	4.41 ± 0.04			4.30 ± 0.03
+13	4.35 ± 0.04	−0.055	0.334	4.26 ± 0.03	−0.036	0.375
Age at first birth
<25	4.34 ± 0.04			4.28 ± 0.03
+25	4.36 ± 0.05			4.25 ± 0.03
Nulliparous	4.47 ± 0.06	0.062	0.080	4.31 ± 0.04	0.013	0.596
Parity (continuous)		−0.004	0.884		−0.002	0.916
Nulliparous	4.47 ± 0.06			4.27 ± 0.04
1–2	4.36 ± 0.04			4.26 ± 0.03
3+	4.34 ± 0.04	−0.062	0.086	4.31 ± 0.03	−0.021	0.424
Menopausal status
Premenopausal	4.38 ± 0.04			4.28 ± 0.03
Postmenopausal	4.37 ± 0.04	−0.001	0.982	4.27 ± 0.03	−0.013	0.736
Age at menopause
Premenopausal	4.38 ± 0.04			4.28 ± 0.03
<50	4.46 ± 0.05			4.31 ± 0.04
+50	4.27 ± 0.06	−0.042	0.220	4.22 ± 0.04	−0.026	0.271
HRTc
Never	4.37 ± 0.03			4.28 ± 0.02
Ever	4.38 ± 0.05	0.015	0.824	4.27 ± 0.04	−0.012	0.793
Multivitamin use
Never or occasionally	4.39 ± 0.05			4.31 ± 0.03
Regularly	4.37 ± 0.03	−0.004	0.892	4.25 ± 0.03	−0.023	0.303

BMI, body mass index; BRCA, breast cancer; HRT, hormone replacement therapy.

^aLeast square means adjusted for group (case and control) status.

^bAdjusting for group (case and control) status.

^cAdjusting for menopausal status.