Ethnicity Breakdown
All participants were residents of Sweden.
Diagnosis & Evaluation Methods
For detailed descriptions of the structure of the Swedish Twin Registry, see Lichtenstein, et al. 2002 and Lichtenstein et al. 2006.
References
Lichtenstein P, de Faire U, Floderus B et al. The Swedish Twin Registry: a unique resource for clinical, epidemiological and genetic studies. J Intern Med 2002; 252: 184-205.
Lichtenstein P, Sullivan PF, Cnattingius S, Gatz M, Johansson S, Carlström E, Björk C, Svartengren M, Wolk A, Klareskog L, de Faire U, Schalling M, Palmgren J, Pedersen NL. The Swedish Twin Registry in the third millennium: an update. Twin Res Hum Genet. 2006 Dec;9(6):875-82.