The study was conducted using data from the third cohort of the Rotterdam Study. The design of the Rotterdam Study has previously been described elsewhere [22]. Briefly, all inhabitants from the neighbourhood Ommoord in Rotterdam aged 45 years and over were invited to participate. During the centre visit, 3934 participants were examined between February 2006 and December 2008. We performed the analyses on a random subset of 747 Caucasian subjects from the centre visit. The study was approved by the medical ethics committee at Erasmus University Rotterdam, Rotterdam, the Netherlands, and all examined participants gave written informed consent.
