Paolo Angelelli from the Visualization research group of the University of Bergen, Norway visited our group in October/November 2011. His visit initiated a long-term collaboration on investigating longitudinal medical and cohort studies between the Visualization group in Bergen (Paolo Angelelli, Cagatay Turkay, and Helwig Hauser), the Department of Biomedicine (Judit Haáasz, Erlend Hodneland and Arvid Lundervold) and the Department of Biological and Medical Psychology (Astri J. Lundervold) at the University of Bergen, and our Visualization group (Steffen Oeltze-Jafra, Bernhard Preim). In the paper resulting from this long-term effort, we demonstrate the interactive visual exploration and analysis of cohort study data, helping with the generation of new hypotheses and contributing to the process of validating them. We propose a data-cube based model which handles partially overlapping data subsets during the interactive visualization. We implemented this model in an application prototype, and used it to analyze data acquired in the context of a Norwegian cohort study on cognitive aging. A pre-print of the paper is available here: http://dx.doi.org/10.1109/MCG.2014.40.