Individuals were participants in studies conducted at the Minnesota Center for Twin and Family Research(26), which utilized a community-based ascertainment and accelerated longitudinal cohort designs. The sample included 7181individuals nested within 2299 pedigrees designed to include two parents and two offspring. Some pedigrees were incomplete because a participant failed to contribute a viable DNA sample. Offspring family members included monozygotic twins, dizygotic twins, non-twin biological offspring and siblings, or adoptive offspring and siblings. There were 1771 mothers (mean age=42, SD=5.3), 2055 fathers (45, 5.7), and 3355 offspring (47% male). The study is longitudinal, with repeated assessments on the offspring. For offspring, we maximized the size of the sample by selecting assessments as close to age 17 as possible (mean age=18.0, SD=0.8, range=[16.5, 21.0]). All research reported in this manuscript was approved by the University of Minnesota Institutional Review Board.
