Prenatal parental tobacco smoking, gene specific DNA methylation, and newborns size: the Generation R study

Clinical Epigenetics

Table 3 Prenatal maternal tobacco smoking and DNA methylation, stratified by gender

	IGF2DMR methylation			H19 methylation
	bèta^a	95 % CI	P value	bèta^a	95 % CI	P value
Model 1: adjusted for correlations between CpG sites, bisulphite batch, gestational age at birth
Boys
No (n = 195)	Reference			Reference
First trimester only (n = 21)	0.12	−1.33; 1.57	0.870	0.18	−0.95; 1.31	0.754
Continued smoking, all (n = 81)	−0.89	−1.73; −0.06	0.037	−0.41	−1.07; 0.25	0.222
P for trend	0.044			0.249
Girls
No (n = 139)	Reference			Reference
First trimester only (n = 26)	−1.40	−2.79; −0.01	0.048	1.04	0.04; 2.03	0.041
Continued smoking, all (n = 44)	−1.46	−2.59; −0.33	0.011	−0.10	−0.90; 0.71	0.816
P for trend	0.005			0.817
Model 2: model 1 + maternal characteristics (age, educational level, parity, BMI, periconception folic acid supplement use)
Boys
No (n = 195)	Reference			Reference
First trimester only (n = 21)	0.15	−1.32; 1.61	0.845	0.14	−1.00; 1.28	0.810
Continued smoking, all (n = 81)	−0.72	−1.68; 0.24	0.142	−0.69	1.45; 0.08	0.078
P for trend	0.166			0.098
Girls
No (n = 139)	Reference			Reference
First trimester only (n = 26)	−1.25	−2.71; 0.21	0.093	1.00	−0.05; 2.03	0.063
Continued smoking, all (n = 44)	−1.38	−2.63; −0.14	0.029	−0.05	−0.93; 0.83	0.910
P for trend	0.018			0.813

Results from linear mixed model analyses with maternal and parental tobacco smoking as independent variable and DNA methylation as dependent variable, stratified by gender
^aAnalyses were performed with square root transformed methylation data and values are presented as regression coefficients (95 % confidence interval)

ISSN: 1868-7083