Journal Article

Maternal smoking DNA methylation risk score associated with health outcomes in offspring of European and South Asian ancestry

Cawte, Nathan, Moraes, Theo J, Azab, Sandi M, Anand, Sonia S, Subbarao, Padmaja, Turvey, Stuart E, Lamri, Amel, Mandhane, Piush J, de Souza, Russell J, Azad, Meghan B, Paré, Guillaume, Teo, Koon K, Campbell, Natalie, Simons, Elinor, Deng, Wei Q, Morrison, Katherine M, Atkinson, Stephanie A

2024

Overview

Maternal smoking has been linked to adverse health outcomes in newborns but the extent to which it impacts newborn health has not been quantified through an aggregated cord blood DNA methylation (DNAm) score. Here, we examine the feasibility of using cord blood DNAm scores leveraging large external studies as discovery samples to capture the epigenetic signature of maternal smoking and its influence on newborns in White European and South Asian populations. We first examined the association between individual CpGs and cigarette smoking during pregnancy, and smoking exposure in two White European birth cohorts (n=744). Leveraging established CpGs for maternal smoking, we constructed a cord blood epigenetic score of maternal smoking that was validated in one of the European-origin cohorts (n=347). This score was then tested for association with smoking status, secondary smoking exposure during pregnancy, and health outcomes in offspring measured after birth in an independent White European (n=397) and a South Asian birth cohort (n=504). Several previously reported genes for maternal smoking were supported, with the strongest and most consistent association signal from the gene (6 CpGs with p<5 × 10 ). The epigenetic maternal smoking score was strongly associated with smoking status during pregnancy (OR = 1.09 [1.07, 1.10], p=5.5 × 10 ) and more hours of self-reported smoking exposure per week (1.93 [1.27, 2.58], p=7.8 × 10 ) in White Europeans. However, it was not associated with self-reported exposure (p>0.05) among South Asians, likely due to a lack of smoking in this group. The same score was consistently associated with a smaller birth size (-0.37±0.12 cm, p=0.0023) in the South Asian cohort and a lower birth weight (-0.043±0.013 kg, p=0.0011) in the combined cohorts. This cord blood epigenetic score can help identify babies exposed to maternal smoking and assess its long-term impact on growth. Notably, these results indicate a consistent association between the DNAm signature of maternal smoking and a small body size and low birth weight in newborns, in both White European mothers who exhibited some amount of smoking and in South Asian mothers who themselves were not active smokers. This study was funded by the Canadian Institutes of Health Research Metabolomics Team Grant: MWG-146332.

• Publisher: eLife Sciences Publications Ltd,eLife Sciences Publications, Ltd
• Subject: Adult / Asian People - genetics / birth cohort / Birth weight / Body mass index / Body size / Cigarette smoking / Cohort Studies / Cord blood / CpG Islands / Data processing / Diabetes / DNA methylation / DNA Methylation - genetics / DOHaD / Epidemiology / Epidemiology and Global Health / Epigenesis, Genetic / Epigenetics / Ethnicity / Families & family life / Feasibility studies / Female / Fetal Blood / Genetics and Genomics / Humans / Infant, Newborn / Low birth weight / Male / Maternal smoking / Metabolomics / Mothers / Neonates / Nutrition research / Offspring / Population studies / Pregnancy / Prenatal Exposure Delayed Effects - genetics / Quality control / Smoking / Smoking - adverse effects / Smoking - genetics / Socioeconomic factors / South Asian / White People - genetics / Womens health