Grant: CIHR Fellowship

Epigenetics holds promise in understanding how genes and environment together affect children's health. DNA methylation (DNAm) is a commonly studied epigenetic marker. Saliva, an easily accessible biological sample, is commonly used in studying DNAm in children. However, the diverse cell types present in saliva can complicate DNAm analysis, potentially leading to inaccurate results. Another layer to this challenge is that salivary cell composition is distinct between children and adults. Currently, the same tool is used to predict salivary cell composition in both children and adults but this may not be appropriate. Further, the source of these cellular differences is underexplored. Researchers need to gain a better understanding of these factors to analyze children's salivary epigenetic data appropriately. This study aims to address this challenge by comparing different tools used for predicting cell composition in children's saliva and investigating the factors influencing these cell compositions using saliva samples of 533 7-year-olds from a large pediatric cohort, the Family Life Project. The project hypothesizes that different prediction tools as well as intrinsic and extrinsic factors like oral inflammation and socio-economic status, respectively, can contribute to predicted cell compositions. This study also delves into how this cellular diversity affects results from DNAm analyses. For example, will DNAm signals significantly differ across children with very high and very lower percentage of blood cell even after accounting for cell type compositions in statistical model? By understanding these complexities, researchers hope to improve future epigenetic research involving pediatric saliva and use more appropriate epigenetic analyses to better study how genes and environment can influence children's health.