The population cohort included people born in Sweden between January 1, 1932, and December 31, 1997, excluding those who died or emigrated before the start of follow-up (n = 445 893). A total of 6 304 188 individuals were linked to nationwide registers via the personal identity number assigned to Swedish residents.29 We used the National Patient Register (NPR),30 the Crime Register,31 the Cause of Death Register,32 the Migration Register,33 and the Multi-Generation Register, which allows for linking individuals with their parents.34 The cohort was followed up from January 1, 1997, or the 15th birthday, whichever occurred last, until the date of outcome, first emigration, death, or December 31, 2013, whichever occurred first.
