Adult global DNA methylation in relation to pre-natal nutrition

Background Exposure to a pre-natal famine environment has been associated with a persistent decrease in DNA methylation of the IGF2 gene, although study findings on other loci have been highly variable. There have been no studies to date of the relation between pre-natal famine and overall global DNA methylation in adulthood. Methods Our study population includes 350 births with pre-natal exposure to the Dutch famine of 1944-45 selected from three birth clinics, 290 births from these clinics born before or after the famine as unexposed time controls and 307 same-sex siblings of either birth group as unexposed family controls. All study subjects were interviewed and underwent a medical examination at a mean age of 58 years when blood samples were also collected. As measures of genomic DNA methylation, we analysed two repetitive elements, LINE-1 (long interspersed nucleotide element 1) and Sat2 (Satellite 2 DNA sequence) by pyrosequencing and MethyLight, respectively, and overall genomic DNA methylation using the Luminometric methylation assay (LUMA). Results Mean DNA methylation by LUMA was 75.2% [ standard deviation (SD) 4.7], by LINE-1 was 77.1% (SD 2.5) and by Sat2 was 122.2 (SD 56.2). Pre-natal famine exposure was associated with negligible changes in all three assays {LUMA: -0.16% [ 95% confidence interval (95% CI) -0.49 to 0.81], P 0.63; LINE-1: -0.05 % (95% CI -0.33 to 0.22), P 0.70; and Sat2: -0.51% (95% CI -7.38 to 6.36), P 0.88} relative to unexposed controls, adjusting for age at examination and within family clustering. Conclusion Our results show no relation between overall global DNA methylation in adults and pre-natal famine exposure. Further work should focus on selected regions in the genome that may be differentially methylated in response to changes in early life exposures and predict adult health outcomes.