The participants in this study were 117 individuals aged 71–
90 years, 54 males and 63 females, drawn from the populationbased
Age, Gene/Environment Susceptibility – AGES Reykjavik
Study [14]. Details about the characteristics of the participants
have been described previously [13]. This study was approved by
the National Bioethics Committee in Iceland (VSNb20080300114/
03-1) and all participants gave written informed consent.