[1] St Olavs Hosp, Natl Serv Pregnancy & Rheumat Dis, Trondheim, Norway
[2] Norwegian Univ Sci & Technol, Dept Publ Hlth & Gen Practice, N-7034 Trondheim, Norway
[3] St Olavs Hosp, Trondheim, Norway
[4] St Olavs Hosp, Clin Serv, Trondheim, Norway
[5] Norwegian Univ Sci & Technol, Dept Neurosci, N-7034 Trondheim, Norway