The last decade has seen a dramatic improvement in our understanding of how our genes affect our height, body mass index (BMI), mental health, cancer risk, and many other traits. This has been facilitated by technological developments which allow us to measure a persons’ epigenetic data accurately and economically. Almost all epigenetic studies investigate traits collected at a single timepoint (e.g. adult height), and the epigenetic sites associated with these traits are then found using an epigenome-wide association study (EWAS). However, some traits such as BMI change over time, and the epigenetics of these repeatedly measured traits remain poorly understood. This project will apply new approaches for epigenetic analysis of longitudinal traits - in particular BMI measured repeatedly from birth to adulthood and depressive symptoms from later childhood through adolescence.