We studied a subset of 4,762 individuals with phenotypic/genotypic data available from the general population-based Northern Finland 1966 Birth Cohort (NFBC 1966) (for more details see(44) and Supplement 1). Briefly, 12,068 pregnant women with expected dates of delivery in 1966 were recruited from the provinces of Oulu and Lapland. Their 12,058 live-born children, 96.3% of all eligible births, were prospectively followed until the age of 31 years. Phenotypic data were collected mainly during pregnancy/birth in 1965–67, at follow-up in 1980 (age 14), and in 1997–8 (age 31).
