1. Department of Medical Sciences; Uppsala University; Uppsala Sweden
2. Department of Health Sciences; Lund University; Lund Sweden
3. Clinical Epidemiology Unit; Department of Medicine; Karolinska Institutet; Stockholm Sweden
4. Department of Public Health Sciences; Karolinska Institutet; Stockholm Sweden
5. Centre for Epidemiology and Community Medicine; Stockholm County Council; Stockholm Sweden
6. Uppsala Clinical Research Center; Uppsala University; Uppsala Sweden