Sigurdur Sigurdsson has been awarded a PhD doctorate on his extensive work on the AGES-Reykjavik study (Age/Gene-Environmental Susceptibility). This population-based longitudinal study followed a community cohort of Icelandic participants collecting multiple phenotypes including sampling of genetic material, blood chemistry, cognitive test batteries and structural magnetic resonance imaging (MRI). This work from Sigurdur and many others, including Leiden radiologists that contributed to the MRI sampling methods especially, has generated some landmark studies on risk factors and protective factors of cardiovascular- and brain health. Its large dataset continues to be invaluable in better understanding bodily changes during ageing and in neurodegenerative diseases such as dementia.

The promotional ceremony took place at the Academiegebouw in Leiden on Tuesday the 21^st of February, 2023. The promotor was Prof. Dr. M. A. van Buchem, LUMC Radiology, and co-promotor Dr. L. J. Launer, Laboratory of Epidemiology and Population Sciences, NIA/NIH, Bethesda, MD, USA.