Press photo (IMAGE) Karolinska Institutet Caption Professor Per Hall at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. Credit Ulf Sirborn. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.