Genome-wide association studies have largely been conducted using case-control and/or cross-sectional study designs primarily due to efficiency and ease of collection. The integration of genome-wide data into well-characterized longitudinal and prospective cohort studies that include biological relationships such as the Add Health sibling pair subsample has been much more limited. Notable exceptions include the Framingham Heart Study [NHLBI SNP-Health Association Resource (SHARe)] that follows multi-generational samples prospectively, and the Health and Retirement Study (HRS) that surveys a representative sample of individuals over the age of 50 every two years and follows them prospectively.Utilizing genetic data from longitudinal and prospective cohort studies has many potential advantages including refinement of phenotypic endpoints, phenotypic change and trajectory. Within the context of the ethnically diverse Add Health sibling pairs subsample of adolescents and young adults, there are additional advantages including family-based assessment and utilizing measured environmental and social factors collected over time.
