Spit for Science (S4S) is an ongoing study of college students enrolled at a large, urban university in the Mid-Atlantic region (Dick et al., 2014). Spit for Science is a cohort sequential, longitudinal study of incoming students, with the goal of understanding genetic and environmental influences on health and well-being in college students. Participants enrolled in the study in the fall of their freshman year, and follow-up assessments were completed in each subsequent spring semester. Individuals who did not participate in the first wave of data collection had the opportunity to join the study the following spring of their freshman year. Those who participated during their first year and remained enrolled at the university were eligible to complete yearly follow-up assessments each spring. Participants who completed the assessments were eligible to provide a DNA sample. Of those who completed the initial survey, 98% provided a DNA sample. A full description of genotyping, quality control, ancestry assignment, and the derivation of ancestry-specific principal components for this sample can be found in the Supplemental Information (Section 1) and in Peterson et al. (2017).
