Fig. 1From: Placental mitochondrial DNA and CYP1A1 gene methylation as molecular signatures for tobacco smoke exposure in pregnant women and the relevance for birth weightEstimated mean levels of mtDNA content and mtDNA methylation in placental tissue of non-smokers (n = 255), past smokers (n = 65), and current smokers (n = 62). The bars represent the estimated means with 95% confidence intervals for the non-smoking (filled circle), past-smoking (filled square), and smoking group (filled triangle). a Relative mtDNA content levels (unitless) are log10-transformed; b Methylation of the MT-RNR1 gene are absolute methylation levels. Both the generalized linear model for mtDNA content and the mixed-effects model for mtDNA methylation were adjusted for maternal age, gestational age, newborn’s sex, maternal education, ethnicity, parity, pre-pregnancy BMI, and alcohol consumption. (*)p = 0.06; *p < 0.05; **p < 0.005: difference compared to the non-smoking groupBack to article page