The Young Finns Study (YFS) subsample derives from longitudinal data collection from five Finnish university cities and surrounding areas (Akerblom et al. 1991; Raitakari et al. 2008). The Helsinki Birth Cohort Study (HBCS) is a birth cohort sample of individuals born at Helsinki University Central Hospital between 1934 and 1944 (Barker et al. 2005; Eriksson et al. 2006; Raikkonen et al. 2008). The Northern Finland 1966 Birth Cohort (NFBC) is a population based birth cohort comprising 12,058 individuals born in 1966 in the northernmost provinces (Rantakallio 1969).The Queensland Institute of Medical Research (QIMR) subsample includes two population based cohorts of Australian twins and their families. The first cohort was assessed in 1988 and the second in 1990. The total QIMR subsample is 5530 individuals from 2791 independent families. More details about the phenotypic and genotypic data collection at QIMR can be found elsewhere (Keller et al. 2005; Verweij et al. 2010). Note that the core analyses required unrelated individuals; discarding related individuals (using different levels of relatedness as cut-offs for different analyses) reduced the subsamples.
