Pär Sparén and Jiayao Lei
![](https://mb.cision.com/Public/206/2780417/9ac4df13e27005b9_800x800ar.jpg)
Photographer: Stefan Zimmerman
Pär Sparén, professor, and Jiayao Lei, doctoral student, at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet.Photographer: Stefan Zimmerman
Pär Sparén, professor, and Jiayao Lei, doctoral student, at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet.KAROLINSKA INSTITUTET PRESS OFFICE Opening hours: Monday–Friday 09.00–17.00 CET. Karolinska Institutet – a medical university ki.se