Table 4.

Relationship between FREE2 methylation in FM females and age (predictor) by fitting segmented linear regression model of each CpG on age for the MOR of each CpG unit (plotted in Fig. 3)

Outcome variable	n	Break point		Break point Age (years)	Segmented linear regression
		Estimate	95% CI		Coef (β)	SE	P-value	R2a	R2b	AICa	AICb
CpG 1	103	11.1	5.13–17.0	<11.1	−1.68	0.74	0.025	0.144	0.041	−163.9	−156.2
				≥11.1	0.02	0.08	0.792
CpG 2	103	11.2	4.30–18.0	<11.2	−1.21	0.63	0.057	0.094	0.007	−198.7	−193.3
				≥11.2	0.07	0.06	0.310
CpG 6/7	104	10.0	4.27–15.8	<10.0	−1.56	0.70	0.030	0.160	0.082	−191.4	−186.2
				≥10.0	−0.06	0.07	0.427
CpG 8/9	104	12.2	1.86–22.5	<12.2	−1.05	0.70	0.138	0.091	0.033	−176.5	−174.1
				≥12.2	0.002	0.08	0.976
CpG 10–12	104	10.1	2.53–17.7	<10.1	−1.26	0.75	0.096	0.096	0.046	−179.2	−177.6
				≥10.1	−0.04	0.08	0.632

P values less than 0.05 are highlighted in bold.

Coefficient (Coef) and standard error (SE) were multiplied by 100. Coefficient of determination (R²) and Akaike information criteria (AIC) were determined for ^asegmented linear regression models and ^bLinear regression models.