Table 3.

Dose-dependent methylation of individual OPRM1 promoter CpGs

CpG	Probe ID	< 25 MME vs. 25–90 MME1		< 25 MME vs. ≥ 90 MME1		Dosage anova2
		Coef	t val	Coef	t val	F2,29	p
CpG1	cg22370006	0.041	2.66	0.023	1.39	3.53	0.04
CpG2	cg14262937	0.051	2.77	0.014	0.69	4.20	0.02
CpG3	cg06649410	0.047	1.65	0.010	0.31	1.56	0.23
CpG4	cg23143142	0.018	1.56	0.000	-0.04	1.71	0.20
CpG5	cg23706388	0.010	0.76	0.006	0.38	0.29	0.75
CpG6	cg05215925	0.019	2.73	0.012	1.59	3.74	0.04
CpG7	cg14348757	0.042	2.78	0.019	1.16	3.92	0.03
CpG8	cg12838303	0.026	2.08	0.022	1.64	2.38	0.11
CpG9	cg22719623	0.006	0.52	0.004	0.33	0.14	0.87
CpG10	cg15085086	− 0.029	− 0.94	− 0.040	− 1.19	0.78	0.47

¹Regression estimates for higher dose groups (25–90 MME and ≥ 90 MME) relative to the lowest dose group (< 25 MME) based on linear mixed-effects model: lmer(CpG ~ dose + visit + (1|ID))

²Two-tailed p values for the main effect of dosage groups