1. From the Departments of Community Health Sciences, Lund University, Malmö, Sweden
2. Lennart Råstam MD, PhD, From the Departments of Community Health Sciences, Lund University, Malmö, Sweden, Address for offprints: Dr Lennart Råstam Dept of Communicy Health Sciences Bangatan 5 S-21426 Malmö, Sweden
3. From the Departments of Otolaryngology, Lund University, Malmö, Sweden