1. University of Tampere, School of Medicine, 33014 Tampere, Finland
2. JYTA, Tunkkari Health Care Centre, Mäntöläntie 2, 69730 Veteli, Finland
3. Social and Health Services, P.O. Box 241, 65101 Vaasa, Finland
4. Centre of General Practice, Pirkanmaa Hospital District, P.O. Box 2000, 33521 Tampere, Finland